CANNULA TO MINIMIZE DISSOLUTION OF THE DOSAGE DURING NITRIC OXIDE ADMINISTRATION

Abstract

The present invention relates generally to, among other things, systems, devices, materials, and methods that can improve the accuracy and / or precision of nitric oxide therapy, for example, by reducing the dilution of inhaled nitric oxide (NO). As described herein, NO dilution can occur due to various factors. To reduce the dilution of an intended dose of NO, several exemplary nasal cannulas, pneumatic configurations, manufacturing methods, and methods of use, etc., are described.

Description

CANNULA TO MINIMIZE DOSAGE DISSOLUTION DURING NITRIC OXIDE ADMINISTRATION αο / ηίη / ηζηζ / Β / γι TECHNICAL FIELD The present invention relates in general to improving the accuracy and / or precision of nitric oxide therapy, thereby reducing the dilution of inhaled nitric oxide, and / or ensuring mixing within the patient's nose. BACKGROUND Nitric oxide (NO) gas, when inhaled, dilates blood vessels in the lungs, improves blood oxygenation, and reduces pulmonary hypertension. Because of this, some administer nitric oxide as a therapeutic gas in inspired breathing for patients with pulmonary hypertension. Typically, inhaled nitric oxide (NO) is delivered via a gas carrier from a high-pressure source (e.g., a pressurized cylinder) to the patient at, or near, ambient pressure through a breathing tube connected to a ventilator in an intensive care unit or anesthesia patients, or via a nasal cannula for spontaneously breathing patients. Delivering an accurate and consistent dose to the patient through a nasal cannula can be particularly challenging when the flow rate is pulsatile, for example, because dose dilution can occur. Consequently, there is a need for new methods and devices for preventing dosage dilution in the supply line of a nitric oxide delivery device, as well as methods for manufacturing such devices. BRIEF DESCRIPTION Aspects of the present invention relate to improvements in nasal cannulas that minimize the backflow and / or backflow of oxygen, air, and / or other gases during nitric oxide (NO) therapy while allowing the delivery of NO to one or both nostrils. Such cannulas may reduce dilution of the delivered dose by using cannula materials and / or coatings that limit oxygen diffusion through the cannula walls and / or cannula configurations to prevent co-delivery mixing of O2 and NO and / or reduce backflow through the patient's cannula end. Aspects of the present invention also relate to methods for minimizing the dilution of the NO dose. Other aspects of the present invention relate to treatment methods using these cannulas and / or delivery methods. Further aspects of the present invention relate to methods of manufacturing multilumen cannulas and their nasal bridge cannulas. In exemplary embodiments, a nasal cannula of the present invention may be for the delivery of at least one therapeutic gas to a patient in need thereof. The nasal cannula may include a first lumen, a second lumen, and a third lumen. The nasal cannula may also include a nasal bridge cannula. The first lumen may be capable of delivering a first therapeutic gas to a patient in need thereof, the second lumen may be capable of transmitting a pressure change to a pressure change sensor and / or a respiration sensor, the third lumen may be capable of delivering a second therapeutic gas to the patient, and / or the nasal bridge cannula may include separate flow paths to the patient in the first lumen, the second lumen, and the third lumen. At least one therapeutic gas may be nitric oxide. In exemplary embodiments, a nasal cannula of the present invention can be used for the therapeutic delivery of gas to a patient. The nasal cannula may include a first lumen, a second lumen, and / or a third lumen. The first lumen may be a first therapeutic gas lumen for delivering a first therapeutic gas to a patient, the second lumen may be an activation lumen, and the third lumen may be a second therapeutic gas lumen for delivering a second therapeutic gas to the patient. Furthermore, a nasal bridge cannula may allow separate flow paths to the patient for the first therapeutic gas lumen, the activation lumen, and / or the second therapeutic gas lumen. In exemplary configurations, the nasal cannula can reduce the dilution of one or more of the first and second therapeutic gases delivered to the patient and / or can be configured to be placed in fluid communication with at least one system for delivering the first and / or second therapeutic gases to the patient. The nasal cannula can inhibit the mixing of nitric oxide and oxygen and / or the nasal cannula can reduce the delivery of nitrogen dioxide to the patient. In exemplary modalities, one or more of the first and second therapeutic gases are delivered to the patient for the treatment of pulmonary hypertension. In exemplary modalities, the nasal cannula can deliver the first and / or second therapeutic gases to the patient for the treatment of pulmonary hypertension, pulmonary hypertension secondary to chronic obstructive pulmonary disease (COPD), pulmonary hypertension such as pulmonary arterial hypertension (PAH), pulmonary hypertension secondary to idiopathic pulmonary fibrosis (IPF), and / or pulmonary hypertension secondary to sarcoidosis. The first therapeutic gas and the second therapeutic gas may be different gases or the same gas.In exemplary modalities, the first therapeutic gas may be nitric oxide and the second therapeutic gas may be oxygen, and / or the lumen of the first therapeutic gas for nitric oxide delivery may be smaller than the lumen of the second therapeutic gas for oxygen delivery and / or the activation lumen. In exemplary modalities, the first therapeutic gas lumen may be for nitric oxide delivery and / or may be approximately 1.8288 meters (six feet) to approximately 2.4384 meters (eight feet) long, with an internal diameter of approximately 0.254000 mm (0.01 inches) to approximately 2.54000 mm (0.10 inches). In exemplary forms, the triggering lumen can be from about 1.8288 meters (six feet) to about 2.4384 meters (eight feet) long, having an internal diameter of approximately 1.2700 mm (0.05 inches) to approximately 5.0800 mm (0.20 inches). In exemplary modalities, the first therapeutic gas may be nitric oxide and / or the nasal bridge cannula may include a nitric oxide flow path that may have an internal diameter smaller than the internal diameter of the first therapeutic gas lumen. In exemplary modalities, the first therapeutic gas may be nitric oxide and / or the nasal bridge cannula may include a nitric oxide flow path that has a volume less than approximately 10% of the minimum pulse volume of the nitric oxide pulse. The cannula may include a wall material that has a low oxygen transmission rate (ec}(0.0254 mm) which may be between 0.001 {24ftrsX645i6mm^(ám) ( ('pímÍi) (ee)(ü.O254 .............. (2400) and 10 (24) In exemplary embodiments, the cannula may also include a fourth lumen, which can serve as another first lumen for therapeutic gas delivery to the patient. Furthermore, the first lumen can deliver the first therapeutic gas to one of the patient's nostrils, and the fourth lumen can deliver the first therapeutic gas to another of the patient's nostrils. In exemplary embodiments, the cannula may include at least one check valve in fluid communication with the first therapeutic gas lumen, a cannula stopcock, an eliminator, and / or a flexible support bridge that cushions the patient's nasal septum. In exemplary embodiments, a nasal cannula of the present invention can be used for the delivery of therapeutic gas to a patient. The nasal cannula can include a first lumen, a second lumen, and a third lumen. The first lumen can be a first therapeutic gas lumen for delivering a first therapeutic gas to a patient, the second lumen can be an activation lumen, and / or the third lumen can be a second therapeutic gas lumen for delivering a second therapeutic gas to the patient. The first therapeutic gas lumen, the activation lumen, and the second therapeutic gas lumen can be attached to a nasal bridge cannula. The nasal bridge cannula can provide separate flow paths to the patient for the first therapeutic gas lumen, the activation lumen, and / or the second therapeutic gas lumen.The first therapeutic gas lumen may have an internal diameter that may be smaller than an internal diameter of the second therapeutic gas lumen and an internal diameter of the activation lumen and / or the first therapeutic gas lumen may have an internal diameter that may be larger than an internal diameter of the flow path for the first therapeutic gas lumen in the nasal bridge cannula. In exemplary configurations, the nasal cannula can reduce the dilution of the first and / or second therapeutic gases delivered to the patient and / or can be configured to be placed in fluid communication with at least one system for delivering the first and / or second therapeutic gases to the patient. The nasal cannula can inhibit the mixing of nitric oxide and oxygen and / or the nasal cannula can reduce the delivery of nitrogen dioxide to the patient. In exemplary modalities, one or more of the first and second therapeutic gases are delivered to the patient for the treatment of pulmonary hypertension. In exemplary modalities, the nasal cannula can deliver the first and / or second therapeutic gases to the patient for the treatment of pulmonary hypertension, pulmonary hypertension secondary to chronic obstructive pulmonary disease (COPD), pulmonary hypertension such as pulmonary arterial hypertension (PAH), pulmonary hypertension secondary to idiopathic pulmonary fibrosis (IPF), and / or pulmonary hypertension secondary to sarcoidosis. In exemplary modalities, the first therapeutic gas lumen can be for the delivery of nitric oxide and can be from approximately 1.8288 meters (six feet) to approximately 2.4384 meters (eight feet) long, with an internal diameter of approximately 0.254000 mm (0.01 in) to approximately 2.54000 mm (0.10 in). The activation lumen can be from approximately 1.8288 meters (six feet) to approximately 2.4384 meters (eight feet).4384 meters (eight feet) long that has an internal diameter of approximately 1.2700 mm (0.05 inches) to approximately 5.0800 mm (0.20 inches). In exemplary modalities, the first therapeutic gas may be nitric oxide, and the nasal bridge cannula may include a nitric oxide flow path having a volume that may be less than approximately 10% of a minimum pulse volume of the nitric oxide pulse. The cannula may include a wall material having a low oxygen transmission velocity (0.0254 mm / hr) that may be between 0.001 (0.0254 mm / hr) and 0.001 (0.0254 mm / hr). (24br«)(ioo ίη*χΛΤΜ) ) and 10 íir.'.-)(645i6 mm(x.4W ( (24M'ppee ί»<·χΑΤΜ) exemplary modalities, the cannula may include at least a check valve in fluid communication with the first lumen of therapeutic gas, a cannula key, a collection material, and / or a flexible support bridge that cushions the patient's nasal septum. In exemplary embodiments, a nasal cannula of the present invention can be used for the delivery of therapeutic gas to a patient. The nasal cannula may include a first lumen, a second lumen, and a third lumen. The first lumen may be a first therapeutic gas lumen for the delivery of nitric oxide gas to a patient, the second lumen may be an activation lumen, and the third lumen may be a second therapeutic gas lumen for the delivery of one or more oxygen and / or air gases to the patient. The first therapeutic gas lumen, the activation lumen, and / or the second therapeutic gas lumen may be attached to a nasal bridge cannula. The nasal bridge cannula may allow separate flow paths to the patient during the delivery of the first therapeutic gas lumen, the activation lumen, and / or the second therapeutic gas lumen.The flow path for the first therapeutic gas lumen for nitric oxide delivery to the patient may have a volume in the nasal bridge cannula that is less than approximately 10% of the minimum pulse volume of the nitric oxide pulse. The first therapeutic gas lumen may have an internal diameter that is smaller than the internal diameter of the second therapeutic gas lumen and the activation lumen, and / or the first therapeutic gas lumen may have an internal diameter that is larger than the internal diameter of the flow path for the first therapeutic gas lumen in the nasal bridge cannula. In exemplary modalities, a method for treating pulmonary hypertension may include the delivery of nitric oxide gas to a patient in need thereof, wherein the nitric oxide may be delivered via a nasal cannula, which may include a first lumen, a second lumen, and a third lumen. In exemplary modalities, nitric oxide is for the treatment of pulmonary hypertension. In exemplary modalities, the nasal cannula may deliver nitric oxide to the patient for the treatment of pulmonary hypertension, pulmonary hypertension secondary to chronic obstructive pulmonary disease (COPD), pulmonary hypertension such as pulmonary arterial hypertension (PAH), pulmonary hypertension secondary to idiopathic pulmonary fibrosis (IPF), and / or pulmonary hypertension secondary to sarcoidosis. In exemplary modalities, nitric oxide may be pulsed at the onset of inspiration and / or administered during the first half of inspiration. In exemplary modalities, nitric oxide may be delivered by pulsed inhalation to spontaneously breathing patients, the nitric oxide may be delivered at the beginning of inspiration, the nitric oxide dose may be approximately 0.010 mg / kg / hr, and / or the dose may be delivered at the beginning of inspiration through a pulse width of less than 260 milliseconds. In exemplary modalities, the method may further comprise the delivery of oxygen to the patient. In exemplary embodiments, a nitric oxide delivery method of the present invention can be used for the treatment of pulmonary hypertension. The method may include the delivery of nitric oxide gas to a patient, wherein the nitric oxide is delivered through a nasal cannula. The nasal cannula may include a first lumen, a second lumen, and a third lumen. The first lumen may be a first therapeutic gas lumen for the delivery of nitric oxide gas to a patient, the second lumen may be an activation lumen, and the third lumen may be a second therapeutic gas lumen for the delivery of oxygen gas to the patient. Furthermore, a nasal bridge cannula may allow separate flow paths to the patient during the first therapeutic gas lumen, the activation lumen, and / or the second therapeutic gas lumen. The second lumen may be for detecting the onset of inspiration and / or a change in pressure.In exemplary designs, the nasal cannula may reduce the dilution of one or more of the first and second therapeutic gases delivered to the patient and / or may be configured to be placed in fluid communication with at least one system for delivering the patient's first and / or second therapeutic gases. The first therapeutic gas lumen for nitric oxide delivery may be smaller than both the second therapeutic gas lumen for oxygen delivery and the activation lumen.The first therapeutic gas lumen may have an internal diameter dimension that can be selected to be substantially small, thus reducing nitric oxide dilution by decreasing NO transit time through the cannula, while also being substantially large enough not to cause significant backpressure and not substantially distort the nitric oxide pulses. The activation lumen may also have an internal diameter dimension that can be selected to be substantially small, while also being substantially large enough to reduce delay and distortion of the pressure signals. The nasal bridge cannula may include a nitric oxide flow path that may have an internal diameter smaller than the internal diameter dimension of the first therapeutic gas lumen. In exemplary modalities, the cannula may include at least a check valve in fluid communication with the first lumen of therapeutic gas, a cannula key, a pickup material, and / or a flexible support bridge that cushions the patient's nasal septum. The cannula may include a wall material that has a low oxygen transmission rate (ιχ·χο.O254 mm) t«')(mí2) which may be between 0.001 (24A«χM5A6>ηηι··9(ATM) ( ) and 10 (¿τ) (0.02 54 mm') (24Arijas56mwni) ( μ* ). In exemplary modalities, the cannula may further include a fourth lumen which may be another first lumen for therapeutic gas delivery to the patient. In addition, the first lumen may deliver the first therapeutic gas to one nostril of the patient and the fourth lumen may deliver the first therapeutic gas to another nostril of the patient. BRIEF DESCRIPTION OF THE DRAWINGS The features and advantages of various embodiments of the present invention will be more fully understood with reference to the following detailed description when taken in conjunction with the accompanying figures, where: Figure 1 shows an exemplary nasal cannula, according to the exemplary embodiments of the present invention; Figure 2A shows an exemplary flow directionality of NO gas during delivery to patients, according to exemplary modalities of the present invention; Figure 2B shows an exemplary retrograde flow path, according to exemplary embodiments of the present invention; Figures 3A and 3B show an exemplary single-lumen cannula, according to the exemplary embodiments of the present invention; Figures 4 and 5A show an exemplary double lumen cannula and / or exemplary pneumatic pathways for the NO, oxygen, and activation lumens, according to the exemplary embodiments of the present invention; Figure 5B shows an exemplary nasal bridge cannula of a double lumen cannula and / or pneumatic pathways, according to the exemplary embodiments of the present invention; αο / ηίη / ηζηζ / Β / γι Figures 6A and 6B show exemplary pneumatic trajectories for NO, oxygen, and activation lumens in a tri-lumen cannula, according to exemplary embodiments of the present invention; Figures 6C and 7 show exemplary nasal bridge cannulas of a tri-lumen cannula and / or pneumatic pathways, according to the exemplary embodiments of the present invention; Figures 8A and 8B show examples of pneumatic paths for the NO, oxygen, and activation lumens in a four-lumen cannula, according to exemplary embodiments of the present invention; Figures 8C and 8D show exemplary nasal bridge cannulas of a four-lumen cannula and / or pneumatic pathways, according to exemplary embodiments of the present invention; Figure 9A shows an exemplary duckbill check valve, according to the exemplary embodiments of the present invention; Figures 9B and 9C show exemplary umbrella and / or hinge check valves, according to exemplary embodiments of the present invention; Figure 10 shows an exemplary nasal cannula with an umbrella valve or a hinge valve for the delivery of NO, according to exemplary embodiments of the present invention; Figures 11A and 11B show examples of valves incorporated in the NO supply line, according to exemplary embodiments of the present invention; Figure 12 shows the exemplary flow from one obstructed nostril to another nostril of the patient, according to exemplary embodiments of the present invention; Figure 13 shows the injection of NO into an ambient airflow in each nostril, according to exemplary embodiments of the present invention; Figures 14A-14B show exemplary configurations of dual-channel supply systems, according to exemplary embodiments of the present invention; Figure 15 shows the components of the example device for exemplary embodiments of a dual-channel delivery system, according to exemplary embodiments of the present invention; Figure 16 shows an exemplary nasal cannula with a nasal bridge for a tri-lumen cannula, according to exemplary embodiments of the present invention; Figure 17 shows a tri-lumen nasal bridge cannula before assembly, according to exemplary embodiments of the present exemplary invention; αο / ηίη / ηζηζ / Β / γι Figure 18 shows an exemplary nasal tip of the tri-lumen mounted nasal bridge cannula, according to exemplary embodiments of the present invention; Figures 19A-19B show a perspective and two-dimensional representation of an exemplary nasal tip with a proximal NO ay lumen within an activation lumen, according to exemplary modalities of the present invention; Figure 20 shows an exemplary nasal cannula, according to exemplary embodiments of the present invention; Figure 21A shows a double-exemplary D-shaped paratube, according to exemplary embodiments of the present invention; Figures 21B and 21C show exemplary lumina having protrusions and / or geometric insertions, according to exemplary modalities of the present invention; Figures 22A-22E show views of connecting parts of an exemplary nasal cannula device, according to exemplary embodiments of the present invention; Figure 23 shows an exemplary oxygen connection piece, according to the exemplary embodiments of the present invention; Figure 24 shows an exemplary reducer and / or holder of the additional line, according to the exemplary embodiments of the present invention; Figures 25A-C show various views of an exemplary nasal bridge cannula, according to the exemplary embodiments of the present invention; Figure 25D shows a right front top perspective view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 25E shows a bottom view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 25F shows a top view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 25G shows a first side view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 25H shows a second side view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 25I shows a front view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 25J shows a rear view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; aa / n Ln / nznz / E / Yi Figure 25K shows a right front top perspective view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 25L shows a bottom view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 25M shows a top view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 25N shows a first side view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 250 shows a second side view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 250P shows a front view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figure 25Q shows a rear view of an exemplary nasal bridge cannula, according to exemplary embodiments of the present invention; Figures 26A-26D show cross-sectional views of various exemplary nasal bridge cannula orifices, according to exemplary embodiments of the present invention; Figure 27 shows exemplary fastening elements, according to exemplary embodiments of the present invention; Figure 28 shows an exemplary NO delivery device with a key slot and a nasal cannula with a clamping element, according to exemplary embodiments of the present invention; Figure 29 illustratively represents exemplary retrograde flows during inspiratory breathing along with the delivery of impulses, according to exemplary embodiments of the present invention; Figure 30 illustratively represents exemplary retrograde flows during both inspiratory and expiratory breathing, according to exemplary embodiments of the present invention; Figure 31 illustratively represents exemplary retrograde flows for various exemplary cannula configurations, according to exemplary embodiments of the present invention; Figures 32A-32C show exemplary cannula configurations for Tests 1-3 of Figure 31, according to exemplary embodiments of the present invention; αο / ηίη / ηζηζ / Β / γι Figure 33A shows a right front top perspective view of an exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 33B shows a front view of an exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 33C shows a rear view of an exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 33D shows a first side view of an exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 33E shows a second side view of an exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 33F shows a top view of an exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 33G shows a bottom view of an exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 34A shows a top left side perspective view of another exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 34B shows a front-right perspective view of another exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 34C shows a top view of another exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 34D shows a bottom view of another exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 34E shows a front view of another exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 34F shows a rear view of another exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention; Figure 34G shows a first side view of another exemplary therapeutic gas delivery device; according to exemplary embodiments of the present invention; and αο / ηίη / ηζηζ / Β / γι Figure 34H shows a second side view of another exemplary therapeutic gas delivery device, according to exemplary embodiments of the present invention. DETAILED DESCRIPTION The present invention relates generally to, among other things, systems, devices, materials, and methods that can improve the accuracy and / or precision of nitric oxide therapy by, for example, reducing the dilution of inhaled therapeutic gases such as nitric oxide (NO) and / or limiting the mixing of inhaled therapeutic gases before delivery to the patient's nose. As described herein, NO dilution can occur due to various factors such as, but not limited to, the mixing of NO with oxygen and / or air. To reduce the dilution of an intended NO dose, several exemplary nasal cannulas, pneumatic configurations, manufacturing methods, and methods of use, etc., are described.The present invention can reduce the mixing of NO with oxygen and / or air (for example, before being supplied to the patient's nose, etc.) thereby reducing the dilution of the intended doses of NO. Due to the unique nature of NO delivery, many factors must be considered to ensure the accurate and precise delivery of NO doses to the patient. Unlike the delivery of other gases, such as oxygen (O2), NO dosing can be particularly susceptible to dilution because, among other things, the dose volume may be less than 1 ml (e.g., a small dose that can be substantially lost even at room temperature) and / or NO may be reactive with O2 present in ambient air and / or co-administered with O2, producing nitrogen dioxide (NO2).Furthermore, the timing of NO delivery can be more critical (e.g., for efficacy) than the timing of other gases (e.g., O2 delivery). Therefore, there is a need to reduce NO dilution and ensure that the onset of a patient's breathing can be accurately determined as soon as possible and / or to ensure that the NO dose waveform is not significantly distorted during its journey through the nasal cannula from the NO delivery device to the patient. Additionally, this may need to be considered in the design of the nasal cannula, for example, because the nasal cannula may be used for extended periods for patient comfort. Various cannulas, systems, and methods of the present invention may be used, modified, and / or connected with various systems for delivering pharmaceutical gas to a patient and / or for delivering a pulse of pharmaceutical gas to a patient. For example, the various cannulas, systems, and methods of the present invention may be used, modified, and / or connected with at least the therapeutic gas delivery systems illustrated in Figures 33A-34H. The various cannulas, systems, and methods described herein may be used, modified, and / or connected with the teachings of U.S. Patent No. 7523752, entitled "System and Method for Delivering a Pharmaceutical Gas to a Patient," the contents of which are incorporated herein by reference in their entirety. Referring to Figure 1, a NO delivery system (100) can typically deliver NO to a patient via a nasal cannula (101). The nasal cannula (101) can receive NO at relatively low volumetric concentrations in a carrier gas from, for example, a therapeutic gas (e.g., NO) delivery device (103), and / or the nasal cannula (101) can receive oxygen and / or ambient air (sometimes referred to simply as oxygen, O2, etc.) from an oxygen / ambient air supply (105). A commonly used carrier gas is nitrogen because nitrogen is non-reactive with NO, but other inert carrier gases, such as helium, can be used. The delivery of the NO / N2 gas mixture (sometimes referred to simply as nitric oxide, NO, etc.) to the patient typically requires that the NO gas travel from a high-pressure NO source (e.g., a pressurised cylinder, pressurised cylinder attached to a NO delivery device (103), etc.) to the patient at, or near, ambient pressure, e.g., through a delivery tube for ventilator-connected ICU / ventilator-dependent and / or anesthesia patients and / or through a nasal cannula for spontaneously breathing patients. It is understood that various techniques and / or modalities of the invention described herein may be used for a delivery tube and / or a nasal cannula, as well as other apparatus such as nasal pads and / or nasal masks, to name a few. For ease of use, sometimes only a cannula is shown and / or described. This is merely for ease of use and is in no way intended to be a limitation. This previously described transit of NO will ideally be free of contact with other gases, such as ambient air, oxygen, carbon dioxide, etc., until the gas enters the patient's upper respiratory tract. However, in practice, this may not be easily achieved. For example, oxygen and / or ambient air may enter the delivery system (100) at a number of points, including but not limited to: αο / ηίη / ηζηζ / Β / γι • During transit time within delivery device (103) (e.g., due to oxygen diffusion through pneumatic interfaces such as elastomer O-rings in the inner tires of the delivery device, etc.); • During the passage of NO gas through the nasal cannula (101) (e.g., by diffusion through the cannula wall, nasal cannula bridge, connectors, reducer, joints, etc.); • During the inhalation / exhalation cycle when a driving pressure gradient can reverse the flow in the nasal cannula of the NO supply lumen producing a mixture inside the nasal cannula (101) with ambient air and / or exhaled gas; • During the inhalation / exhalation cycle when NO and Air / O2 mix in the patient's nostrils; • During the connection of the high-pressure source (e.g., a pressure cylinder, etc.) to the supply device (e.g., as a replacement cylinder, small amounts of gas may be trapped in the pneumatic supply system, etc.); and • During the cylinder filling operation, the high-pressure NO source may contain a substantially pure mixture of NO and carrier gas, which can be sought but is not easily achieved. Diluting nitric oxide (NO) during pulsed NO therapy can be problematic because only a substantially small volume of NO can be administered to the patient. For example, NO-containing gas can be delivered in pulses that may be less than one milliliter (mL). With substantially small pulse volumes, even small volumes of retrograde flow and / or diffuse gases can be significant, for example, because the small dose of NO can be easily diluted. Of course, larger volumes of NO can also be diluted. Minimizing CONTACT WITHOUT O2 BY O2 DIFFUSION: Minimizing transit time One or more embodiments of the present invention relate to nasal cannulas directed to the NO / O2 contact sources (e.g., one or more of the above NO / O2 contact sources) and thereby diluting (e.g., by mixing NO with O2, etc.) the intended dose of NO by minimizing the contact time of NO with O2, by minimizing the transit time through the cannula, minimizing the transit of oxygen through the cannula walls, and / or minimizing the amount of O2 that comes into contact with the NO.Referring to Figure 1, addressing at least the NO dilution of the intended dose, described below in further detail, oxygen transit can be minimized through any cannula lumen wall (101) such as, but not limited to, cannula walls associated with an activation lumen (104), the NO lumen (106), the O2 / air lumen (108), and / or any combination thereof and / or a further separation thereof, to name a few. Also, by addressing at least the dilution of the intended NO doses, oxygen transit can be minimized through any cannula lumina wall (101), such as, but not limited to, cannula walls associated with a nasal bridge cannula (102), a key member (110), the reducer (112), connecting piece (114), oxygen piece connection (116), and / or any combination thereof and / or a further separation thereof, to name a few. Lumen of NO of DI Small In one or more configurations, cannulas can be provided with a smaller internal diameter (ID) of the delivery tube / lumen for NO, for example, to reduce the dilution of the intended NO doses. This smaller ID tube can reduce the transit time of NO molecules through the cannula. This, in turn, can reduce the time available for mixing with oxygen that can diffuse through the cannula walls and the internal oxidation of NO to NO2. For example, to reduce the dilution of intended doses of NO by minimizing NO transit time through the cannula, the delivery tube diameter (DI) / lumen for NO can be approximately 0.254000 mm (0.01 in) to approximately 2.54000 mm (0.10 in) and / or approximately 0.7620000 mm (0.03 in) to approximately 2.0320 mm (0.08 in). In exemplary modalities, the delivery tube DI / lumen for NO can be selected to ensure reduced NO transit time (e.g., reduced NO dilution, etc.) while not resulting in significant backpressure and / or NO pulse shape distortion and / or NO waveform distortion (discussed in more detail later). To reduce transit time, as well as not significantly causing backpressure and / or distortion, the DI for the supply tube / lumen for the NO cannot be substantially less than around 0.7620000 mm (0.0.03 inches), for example, for a cannula that is approximately 1.8288 meters (six feet) to 2.4384 meters (eight feet) long. For shorter lengths a smaller ID can be used and / or for longer lengths a larger ID can be used as resistance and / or distortion can be a function of both the ID of the tube and the length of the tube. In exemplary modalities, the DI of short tubes / lumens for NO delivery (e.g., such as nostril cannulas, shorter nasal cannulas, etc.) may have a substantially smaller tube DI than for NO delivery / lumen tubes, which may also have a substantially smaller DI as described above, without significant backpressure and / or NO pulse shape and / or waveform distortion occurring. In exemplary modalities, the potential for NO exposure time to O2 can be minimized using other techniques such as, but not limited to, increasing the NO delivery rate through the NO lumen. The NO velocity through the NO lumen can be increased, for example, by increasing the pressure gradient within the system and / or reducing the tubing diameter. Although the NO velocity can be increased to reduce NO exposure time to O2, the velocity may be forced to be minimized so that the pulse shape is not substantially distorted, the patient does not experience discomfort, and / or by factoring in any other competing metric. It will be understood that from any of the above teachings (for example, the Small DIs for the lumen of the NO delivery tube, etc.) can be combined with any of the other pneumatic configurations, cannula configurations, and / or teachings and / or modalities described in this document. For example, the teachings above (e.g., small DIs for the NO delivery tube / lumen, etc.) can be used with the single-lumen cannulas described below, the double-lumen cannulas, triple-lumen cannulas, quad-lumen cannulas, and / or any other teachings and / or modalities described in this document. Materials to limit oxygen diffusion and / or remove O2 and / or NO2 Currently, many people use polyvinyl chloride (PVC) and / or silicone as a common material for constructing nasal cannulas; however, oxygen can diffuse through the lumen walls of these nasal cannulas. To minimize oxygen contact that occurs due to oxygen diffusion, permeation, and / or transmission through the cannula walls, the cannula wall materials can be selected to minimize the oxygen diffusion rate, permeability rate, and / or oxygen transmission rate (TTO). In exemplary designs, the cannula wall may include a material with a low oxygen diffusion coefficient, permeability number, and / or oxygen transmission rate (TTO). Specimens, the wall of the cannula may include a material that may have an oxygen transmission rate (TTO) of approximately 0.0002540cm (0.001 inches) at approximately 25.40000cm (10 inches), for example, using the following units:. (cc) (0.0254 mm) (24 hrs)(6^ where: cc refers to the cubic centimeters (mi) of oxygen passing through a square of material; Mil refers to 1 mil 0.0002540cm (0.001 inch) thick) of the square of material, which is equal to 0.0254mm; ATM refers to the number of atmospheres of ambient pressure; hrs refers to the permitted duration for the oxygen flow; and 64516mm2(645.1600cm2) (100in2) refers to the surface area of ​​the square of material. Occasionally, when describing oxygen diffusion, permeability, and / or transmission through cannula walls and / or cannula materials, only one of the diffusion rates, diffusion coefficients, permeability rates, permeability ratings, and / or TTR may be referenced. It is understood that any reference to the above terms may be used interchangeably with, or substituted for, any of the terms listed above, and similar terms. For ease of use, sometimes only one or some of the above terms are described. This is purely for convenience and is in no way intended as a limitation. In exemplary modalities, (for example, the material for the cannula tube, the nasal bridge cannula, etc.) cannula materials can be adjusted and / or varied to cope with O2 permeation along with patient comfort. In exemplary embodiments, the cannulas can be constructed using polyurethane and / or similar soft material. In exemplary embodiments, the polyurethane and / or similar soft material may include an additive to improve resistance to oxygen diffusion and / or a coaxially positioned tube over at least part of the cannula filled with NO or a gas that provides resistance to oxygen diffusion. The cannulas can be constructed coaxially and by coating a tube and / or co-extruding two or more materials (e.g., to form the tube, etc.). Of course, other methods and / or techniques of construction are within the scope of this description. Examples of at least some of the materials that can be used for cannula construction and / or that have desired oxygen permeability properties include, but are not limited to, polymers such as polyvinylidene chloride (PVDC), ethylene vinyl alcohol (EVOH), polyamide (PA), polyvinylidene difluoride (PVDF), fluorinated polyurethane, Nylon 6, Nylon 12, and / or similar materials, to name a few. In addition, PVC can be used as the cannula material with one or more materials and / or additives, such as oxygen-resistant polymers, which are incorporated to reduce oxygen permeation, diffusion coefficient, and similar properties. Oxygen-resistant polymers can be incorporated with polyurethane, PVC, and / or other cannula materials, for example, through co-extrusion. As an example, such extrusion can be achieved with co-extrusion dies and / or the use of other known techniques. Tube / lumen barriers to oxygen entry can take one of a number of potential forms, such as, but not limited to: • extrusions of homogeneous and / or individual material that can use at least one material with low oxygen permeability characteristics; • Co-extrusion of two or more polymers, one or more of the polymers having low oxygen permeability characteristics; • Surface coatings / surface treatment on materials / pipes with such coatings may have characteristics of low oxygen permeability; • Mixtures; and • Eliminators / Acquirers / Purifiers. Extrusions of homogeneous and / or individual materials with low oxygen permeability: In exemplary embodiments, materials such as polyvinylidene chloride (PVDC, trade name Saran®), ethylene vinyl alcohol (EVOH), Nylon 6, Nylon 12, and / or any extrusions of homogeneous and / or individual materials with low oxygen permeability may be used for the cannula material. Other materials with these properties are foreseen, and the use of compatible low oxygen permeability extrusion material substitutes is within the scope of this invention. Co-extrusions of two or more polymers: In exemplary embodiments, tube-in-tube and / or multi-layered configurations can be constructed using co-extrusions of two or more polymers. For example, two or more polymers, at least one with low oxygen permeation properties, can be co-extruded (e.g., using common co-extrusion methods known in the art) to construct a tube-in-tube or multi-layered configuration. The low oxygen permeability layer may include the polymers described herein (e.g., such as those listed in the preceding section) and / or other polymers with similar characteristics. Since these polymers may or may not co-extrude well with other polymers, it may be necessary to extrude an intermediate polymer, or so-called bonding layer.Exemplary coextruded polymers may include, but are not limited to, PVC / EVOH / PVDC, PVC / EVOH / PFDF, fluorinated polyurethane / EVOH / PVDC and fluorinated polyurethane / EVOH / PVDF, PVC / PVDC, polyurethane / PVDC, PVC / Nylon 6, PVC / Nylon 12, PVC / PVDC / Nylon 6, PVC / PVDC / Nylon 12, polyurethane / PVDC / Nylon 6, polyurethane / PVDC / Nylon 12, bonding layer polymers, any combination and / or separation thereof, and / or any other material that may be used with co-extrusions of two or more polymers. In exemplary configurations, co-extrusions can be layered in a specific order, for example, to reduce oxygen penetration and / or diffusion and / or for construction purposes. For instance, if an adhesive used (e.g., in bonding cannula components, etc.) bonds PVC to PVC, then the outer layer of a co-extrusion exposed to that adhesive can be made of PVC. Furthermore, additional polymers (e.g., those that may have reduced properties when in contact with water vapor), such as, but not limited to, EVOH, can be sandwiched between inner and / or outer water-resistant and / or hydrophobic extrusion layers to minimize contact of the inner compound with water vapor. Surface Treatment / Surface Coatings on the Pipe: In exemplary embodiments, surface coatings (e.g., surface treatments, surface coatings, etc.) for low oxygen permeability can be applied to the nasal cannula construction. Such coatings may include, but are not limited to, vacuum-deposited silicon dioxide (silica) and / or aluminum (e.g., aluminum oxides, etc.) coatings heated above their sublimation temperature that can be deposited in thin layers (a few micrometers or less) thick. For example, silica coatings can be approximately 0.001 micrometers to approximately 10 micrometers and / or approximately 0.01 micrometers to approximately 1 micrometer, and / or approximately 0.04 micrometers. In exemplary embodiments, silica coatings can be deposited onto plastic in layers that can be substantially thin enough so that the flexibility of the plastic is not materially affected. It is understood that any reasonable technique may be used for the deposition of such materials. For example, low-cost deposition can be achieved using chemical vapor deposition treatment. Of course, other methods of deposition of these coatings may also be used, such as, but not limited to, electron beam and thermal evaporation, CD sputtering, plasma-assisted reactive sputtering, any combination thereof and / or further separation thereof, and / or any technique capable of deposition. In exemplary applications, other coatings such as, but not limited to, thermoset epoxy-amine coatings, epoxy-amine coatings, etc., may be used. The coatings may be applied and / or provided using techniques described herein and / or known techniques. Blends: In exemplary embodiments, materials can be blended together to obtain the beneficial properties of one or more of the other materials and / or used as the cannula material. In exemplary embodiments, nylon 6 and EVOH, which can bond together in co-extrusions without the need for a bonding layer, can be used as a blended cannula material. Other blends may include, but are not limited to, nylon 6 with amorphous nylon and nylon 6 with HDPE. Of course, other blends may be used. In exemplary configurations, a subsequent material can be coated onto a prior material. For instance, when two materials are incompatible with coextrusion due to different melting temperatures, one polymer can be extruded first, and the second polymer can be heated and coated onto the first in a secondary operation. Scavengers / Acquirers: In exemplary embodiments, scavengers may be coated inside the lumen (e.g., by cooking the liquid into a liquid slurry of the scavenger inside the lumen, by condensation of the scavenger inside the lumen through evaporation processes, by absorption / adsorption to the inner surface of the lumen using a liquid or gaseous scavenger source, by chemical bonding of the scavenger to the inner surface of the cannula, etc.) and / or the scavenger may be packed inside the connector device and / or nasal bridge, e.g., as a plug (e.g., a plug with at least one orifice to allow gas flow through it, etc.) to eliminate oxygen and / or nitrogen dioxide. These scavengers may include, but are not limited to, compounds such as activated alumina, ascorbic acid, and / or any other scavenger compound.Potential drawbacks of this approach include the finite lifespan of the removal material. This drawback can be overcome by factoring the cannula's usage time into the design. At least one additional potential drawback is that any plug configuration for gas passage through an eliminator can distort the gas waveform. Considering these described plugs... QQ / nLn / nznz / B / Yi design to minimize such waveform distortion. Any method can be used to coat the inside of the lumen. For example, a liquid that is concentrated with a scavenger (e.g., ascorbic acid) can be passed through the tube and then dried on it so that it can later be deposited on the inner wall of the tube. In exemplary applications, activated alumina can be used in the cannula, for example, as a coating inside the lumen, as a plug fitting, and / or in any other way, for example, to trap nitrogen dioxide. With a thin layer of alumina coated inside the lumen, the effect can be not only a reduction in the oxygen permeation rate but also successful trapping of nitrogen dioxide. Activated alumina and / or other scavengers can also be made in the form of a plug fitted into the tubing, for example, in close proximity to the patient's nostrils. The plug can be designed to minimize pressure drop and / or to maintain the nitric oxide pulse waveform. The high surface area of ​​activated alumina can effectively wash nitrogen dioxide out of the gas mixture.Furthermore, the eliminator can also be located on the device, for example, at the device connector. In this way, the eliminator can be part of the cannula and / or removable (for example, so that it can be removed when the cannula is changed) and / or the design life of the eliminator can be matched to an anticipated and / or actual usage duration of the cannula. It is understood that the invention is not limited to activated alumina and includes any material with a high surface area, substantial nitrogen dioxide washing capacity, suitable pore sizes, sufficient physical strength to maintain its shape, and / or that does not generate dust and / or other materials that may be ejected or detached from the cannula and impair the washing capacity of the material. It is further understood that the internal filtration may be used to contain spilled compounds to prevent aspiration into the respiratory system. Examples of washing materials include, but are not limited to, zeolites, silica-alumina, activated carbon / carbon, and adsorbents that may have solid base sites on their surface. For the sake of simplicity, activated alumina is sometimes described as a washing material. This is merely for convenience and is in no way intended as a limitation. In exemplary applications, a reducing agent can be applied to the surface of the washing material, for example, to enhance its ability to trap and / or reduce nitrogen dioxide to nitric oxide. Such reducing agents include, but are not limited to, ascorbic acid. αο / ηίη / ηζηζ / Β / γι In exemplary embodiments, additives can be added to the polymer to change its permeation / barrier properties, such as, but not limited to, oxidizable plastic (e.g., PET or polyamide), nanoclays, any combination thereof and / or a further separation thereof, and / or any other additive. The additives can work to remove oxygen and / or provide a permeation barrier within the polymer matrix, either of which can result in a reduction of the oxygen that penetrates the material. Oxidizable plastics (e.g., PET or polyamide) can react with the oxygen that may permeate through the polymer matrix. Oxygen that may permeate through the membrane can react with the oxidizable plastic before passing through the cannula and / or react with NO.Nanoclays (which, for example, can tend to have a plate-like morphology) can provide a permeation barrier, for example, when properly dispersed within the polymer matrix. When dispersed, diffusion around the plates may be necessary, which can result in a tortuous path through the polymer, effectively reducing gas permeability. It is understood that any of the above teachings (e.g., materials, etc.) can be combined with any of the other pneumatic configurations, cannula configurations, and / or teachings and / or modalities described herein. For example, the above teachings (e.g., materials, etc.) can be used with the single-lumen cannulas described below, double-lumen cannulas, three-lumen cannulas, four-lumen cannulas, and / or any other teachings and / or modalities described herein. CONFIGURATIONS Retrograde flow With reference to Figures 2A-2B, it was surprisingly found that another source of dilution can be caused by a phenomenon (e.g., backflow, crossflow, etc.) in which ambient air and / or exhaled gas flows into the nasal cannula (e.g., in and / or near the nasal bridge cannula (200)). This gas flow into the nasal cannula can occur between two nasal cannulas (e.g., nasal cannulas (202) / (203)), displacing the resident nitric oxide gas and / or pushing the nitric oxide gas out of the cannula. Consequently, the displaced and / or pushed nitric oxide cannot be delivered to the patient and / or may mix with the gas flow and / or other gases, thus diluting the NO in the intended dose. Furthermore, backflow can depend on factors such as, but not limited to, QQjnLn / nznz / E / Yi limited to, the pressure difference between the nostrils during inhalation and exhalation. The pressure difference between the nostrils can vary depending on factors such as, but not limited to, the person's breathing pattern, occlusions and / or partial occlusions in the person's nostrils (e.g., as shown in Fig. 12), the placement of the nostrils, and the degree of imbalance between nasal flow during breathing, to name a few. Accordingly, one or more embodiments of the present invention relate to nasal cannulas that can minimize retrograde flow and / or the resulting dilution of retrograde flow in the nasal cannula. As shown in Figure 2A, during normal pulse delivery, NO flows out of both nostrils (202) / (203) of the cannula mouthpiece (200). However, during at least the static phase between pulses, backflow can occur. For example, during the static phase, ambient and exhaled air may flow in a circular and / or reverse flow pattern through one nostril port (202) and out the other nostril port (203), as shown in Figure 2B. This backflow can result in dilution and / or washing of NO in the nostrils and / or flow pathway, which may cause a delay and / or reduction in the delivered dose. In addition, this retrograde flow can result in oxygen in the air and / or the exhaled gas stream mixing with NO to a greater degree and / or reacting with nitric oxide in the nasal cannula, which can cause the formation of NO2 that dilutes the concentration of NO.Therefore, to reduce backflow (e.g., which can result in the formation of NO2 that dilutes NO doses and can act as a known respiratory irritant, etc.), the volume of potential nitric oxide mixed with either exhaled gas and / or ambient gas can be minimized. Taking the above into account, the amount of dilution resulting from retrograde flow may depend on the volume of the lumen associated with the NO delivery (e.g., the NO lumen; the combined and activation NO lumen; the combined, activation, and O2 / air NO lumen; etc.) in the nasal bridge cannula (e.g., flow path), where retrograde flow can occur. The segment where retrograde flow can occur can be any shape. For ease of reference, this segment where retrograde flow occurs is sometimes described as U-shaped, and so on. This is merely for ease of reference and is in no way intended as a limitation. In exemplary modalities, the optimized DI dimensions (e.g., DI size, DI shape, etc.) of the lumen associated with NO delivery (e.g., NO lumen; combined and activation NO lumen; combined, activation, and O2 / air NO lumen; etc.) in the nasal bridge cannula (e.g., flow path) may be selected to reduce the volume of the U-shaped region, thereby minimizing the potential volumetric exchange associated with flow and / or retrograde dilution resulting from backflow. Furthermore, in exemplary modalities, such optimal DI dimensions may vary depending on the volume of NO gas delivered. For example, a nitric oxide delivery device may deliver pulses of NO-containing gas with a minimum dose volume of 0.35 mL.In order to ensure volumetric dosing accuracy, it may be preferable that no more than a small percentage (e.g., 10%, 5%, 20%, etc.) of the dose is lost due to backflow. One or more embodiments of the present invention limit the internal volume of this U-shape to no more than a small percentage (e.g., 10%, 5%, 20%, etc.) of the minimum dose volume (e.g., 0.035 ml for a 0.35 ml pulse of therapeutic gas) to ensure that if NO loss occurs, it is an acceptable amount of NO loss due to retrograde flow (e.g., loss to the environment during the exhalation phase). Following the above example, for a minimum 10% dose volume of 0.035 ml, the lumen ID within the U-segment may be no more than 0.11684 cm (0.046 in) given a tooth length of 0.800100 cm (0.315 in) and a tip separation of 1.60020 cm (0.63 in). Therefore, for a lumen DI significantly greater than 0.11684 cm (0.046 inches) it may not be advantageous to maintain dose volume accuracy for minimum dose volumes of 0.35 ml. It is understood that the mathematics of this construction may be modified by variations in systems such as, but not limited to, systems with larger volumes or appropriately lower minimum doses, systems with different tooth lengths, and / or tooth spacing systems, to name a few. A person skilled in the art can perform the necessary calculations to determine the required DI to provide a desired volume in the U-shaped segment such that it does not exceed 10% of the dose volume. Furthermore, depending on the required dosing accuracy, the internal volume in the U or other volume available for crossflow may be, but is not limited to, less than 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 4%, 3%, 2%, or 1% of the dose volume, to name a few. For example, if the U-shape consists of two nostrils and a posterior plane, the maximum dimensions such that the volume of the U does not exceed 20% of the minimum dose volume can be calculated using the following formula, in which baseplate refers to the length of the lumens within the nasal bridge cannula and / or forming the base of the U-shape: αο / ηίη / ηζηζ / Β / γι Minimum dose Volume> 5 [2π (Tooth diameter / 2)2* (Tooth length) + π (Base plate diameter / 2)2* (Base plate length)] Therefore, if the minimum dose is known, the dimensions of the U-shaped section of the cannula can be calculated. For dosing accuracies other than 20%, the volume ratio factor of 5 can be changed accordingly to a volume ratio factor equal to [100 / (100% dose accuracy)]. In exemplary modalities, during exhalation and / or prior to inhalation (e.g., sensed and / or detected by the delivery device, etc.), the U-shaped volume in the nasal bridge cannula can be purged with a pulse of NO substantially equal to the U-shaped volume. This can cause the U-shaped volume to become substantially filled with NO (e.g., after exhalation). Furthermore, this NO filling in the U-shaped volume can be delivered to the patient during the next inhalation, for example, ensuring early NO delivery to the patient to provide optimal clinical efficacy (e.g., as discussed below). In exemplary configurations, retrograde flow can be reduced by at least reducing the diameter (DI) of the NO supply lumen at the nasal tip (e.g., NO flow path) so that the resistance to flow through the NO lumen at the nasal tip can be increased. Under this configuration, and at the same pressure differential, the flow within the NO lumen of the nasal tips can be reduced compared to teeth with larger lumens. This can result in a reduction of transverse flow under at least these conditions, for example, because the smaller DI of the NO lumen can produce resistance to gas flow that can be inversely proportional to the fourth power of the lumen radius, according to Poiseuille's law. In exemplary models, backflow can be reduced by the use of valves and / or check valves, for example, as discussed in more detail below. Sometimes, the NO lumen described herein may be described as being optimized for a minimum pulse volume of 0.35 mL and / or a 10% allowable error resulting in an allowable U-shaped volume in the NO lumen (e.g., 0.035 mL dosage). In exemplary modalities, changes in this minimum pulse volume and / or the optimum pulse volume range may affect at least the size of the NO lumen. For example, if the minimum pulse volume is smaller due to, for instance, the use of higher nitric oxide concentrations, the internal diameter of the NO lumen and / or U-shaped volume may be decreased to ensure the 10% error target. For example, the NO lumen and / or U-shaped volume may be decreased considering various optimization metrics such as, but not limited to, pulse shape.Furthermore, for example, if the minimum pulse volume needs to be increased due to, for instance, the use of a lower nitric oxide concentration, then the internal diameter of the NO lumen and / or U volume may need to be increased. For example, the NO lumen and / or U volume may need to be increased considering various optimization metrics such as, but not limited to, pulse shape. It is understood that if the NO lumen and / or U volume is too large (e.g., approximately 0.1 mi to approximately 0.5 mi), then small-volume pulses may not be able to be delivered accurately, delivery may be delayed, dilution may occur, and / or other problems may arise due to the unique nature of NO delivery. MINIMIZE DELAY AND / OR DISTORTION For nitric oxide delivery systems (e.g., those that can deliver nitric oxide gas to patients) to achieve optimal clinical efficacy, it may be necessary to deliver a nitric oxide pulse or flow to the patient as early as possible in the inspiratory phase and / or with a desired flow waveform (e.g., pulse shape). Given this, delays may be pneumatic and / or should be minimized because, for example, patient pressure signals can be used as an indication of the patient's inspiratory effort and / or the onset of inspiration. Furthermore, distortion of pulse or flow waveforms can be and / or should be minimized, as, for example, the waveform shape and / or timing may be linked to clinical efficacy.Accordingly, one or more embodiments of the present invention relate to nasal cannula configurations that minimize the delay and / or distortion of pressure signals, for example, when they are in transit through the patient's cannula back to the device and / or that minimize the distortion of flow waveforms. In exemplary configurations, the lumen of the cannula connected to the activation (e.g., activation lumen; combined activation and NO lumen; combined activation, NO, and O2 / air lumen, etc.) can be configured to minimize the delay and / or distortion of pressure signals as they travel through the cannula. To minimize the delay and / or distortion of pressure signals as they travel through the cannula, the cross-sectional area of ​​the lumen connected to the activation can be selected to reduce the delay and / or distortion, and / or the size of the cross-section can be increased. QQ / nLn / nznz / B / Yi maximize to reduce delays and / or distortions. In exemplary configurations, the lumen of the cannula connected to the NO supply (e.g., NO lumen; combined NO and activation lumen; combined NO, activation, and O2 / air lumen; etc.) can be configured to minimize waveform distortion. To minimize waveform distortion, the cross-sectional area of ​​the lumen connected to the supply can be increased or maximized, and / or the shape of the cross-section can be selected to reduce delay and / or distortion. Furthermore, in exemplary configurations, to minimize waveform distortion in the lumen connected to the NO supply, the supply can be made with reduced compliance, i.e., with increased rigidity. For example, to minimize waveform distortion, the lumen connected to the NO supply can be made of a substantially rigid material.The stiffness of the material can be selected to reduce compliance while still factoring in at least the patient's comfort. COMPETITION METRICS In at least some configurations, the cannula can be configured so that at least one lumen can be used for both NO delivery and activation (e.g., single-lumen cannulas, double-lumen cannulas, etc.). These configurations may require optimization of the lumen for both NO delivery and activation to minimize NO dose dilution and to allow the activation signal to propagate to the device without substantial attenuation in the spectral band of human respiration (e.g., 0–4 Hz). This can be quite challenging, as these metrics may be competing for optimization.For example, in order to deliver an early NO pulse and / or flow in the inspiratory phase, reduce pneumatic delays, reduce flow waveform distortion, reduce delay and / or distortion of pressure signals, reduce NO mixing volume and / or NO oxidation to the nasal cavity, and / or address any other desired property (e.g., for a combined total NO / lumen activation), various lumen DI competence metrics can be optimized, such as, but not limited to: a. Reduce NO2 formation -> Reduce lumen DI; b. Maintain the volumetric accuracy of NO dosing -> Reduce DI αο / ηίη / ηζηζ / Β / γι of lumen; c. Reduce NO flow distortion -> Increase lumen DI; and d. Minimize the attenuation of the activation signal or the delay -> Increase the Lumen DI. In exemplary embodiments, the cannulas of the present invention having combined NO / activation lumen configurations may require the optimal geometry (e.g., shape, size, etc.) of the NO / activation lumen to be involved for, for example, delivering pulses and / or NO flows in the early inspiratory phase, reducing pneumatic delays, reducing distortion of flow waveforms, reducing delay and / or distortion of pressure signals, reducing the volume of NO mixed in the mouthpiece, and / or oxidation of NO in the nasal cannula. Such involvement may be necessary for cannulas of the present invention that have been combined with NO / activation lumens (e.g., single-lumen cannulas, double-lumen cannulas, etc.). However, cannulas of configurations of the present invention that have at least three lumens (e.g., three-lumen cannula, four-lumen cannula, etc.) do not require this.As discussed below, these cannulas can allow dedicated lumens for NO delivery and the activation signal, and may, at least in some cases, allow a dedicated lumen for O2 / air delivery. Therefore, for the cannulas of the present invention with dedicated lumens for NO delivery and activation (e.g., three-lumen cannulas, four-lumen cannulas, etc.), the optimized NO lumen may be smaller than the optimized activation lumen, since it may be beneficial to have a larger activation lumen to ensure at least minimal signal attenuation, while it may be beneficial to have a smaller NO lumen to at least reduce NO dilution. Therefore, the cannulas of the present invention that have combinations of NO / activation lumens (e.g., single-lumen, double-lumen cannulas, etc.) may also be considered.) and the cannulas of the present invention having NO lumens dedicated to supply and dedicated to activation lumens (e.g., three-lumen cannulas, four-lumen cannulas, etc.) can have different geometries when optimized. As an example, in addition to ensuring volumetric dosing accuracy (e.g., as described above regarding minimizing dilution resulting from backflow), the internal diameter (ID) of the NO / activation lumen combination can be designed to reduce and / or eliminate gas flow distortion and / or undue signal propagation delay, for example, from the patient to the device (e.g., as described above regarding minimizing delay and / or distortion of pressure signals). Such distortion and / or delay can occur because pneumatic tubing can act as first-order low-pass filters, attenuating higher frequency components of the signal. Modifying the internal diameters can change the bandpass characteristics of the filtering effect.However, as noted above, the internal diameter (e.g., in the U) can be set to a certain maximum DI based on the delivery accuracy of the required dose of the system. In view of at least the foregoing, in exemplary embodiments, to minimize the effects of the potentially frequency-attenuated pressure signal: (1) the ascending diameter (near the device) of the combined NO / lumen activation of the cannulas of the present invention can be adjusted to broaden (e.g., optimize) the bandwidth of the cannula features and / or (2) activation of the initiation of the NO pulse delivery (e.g., by means of the delivery device) can have the typical threshold pressure activation strategy (e.g., the pressure signal can be attenuated and / or delayed by the pneumatic filtering effect of the cannula construction) and it may therefore be advantageous to supplement / replace this threshold pressure activation with a pressure slope based on strategic activation based on an inclined pressure pattern indicative of patient exertion.Such a pressure slope based on an activation strategy in the presence of significant signal attenuation may be more sensitive (e.g., faster) to patient effort. It is understood that to minimize the effects of potentially attenuated / delayed pressure, the combined NO / activation lumen descending diameter of the cannulas of the present invention may be adjusted to amplify (e.g., optimize) the bandwidth of the combined cannula features; however, this may produce an undesirable side effect of increasing the size of the cannula's nasal bridge, which in turn may make the cannula less comfortable for the patient. In exemplary modalities, the ascending diameter of the combined NO / activation lumen can be adjusted to expand the bandpass characteristics of the cannula to ensure that unnecessary compressible volume is not available above the nasal cavity restriction (e.g., 0.1168400 cm (0.046 in) ID restriction, etc.). This can reduce the compressible volume in the cannula and / or effectively increase the bandpass characteristics of the cannula. In exemplary modalities, dose delivery activation (e.g., by the delivery device) may be based on a pressure slope pattern indicative of patient exertion, and / or the slope may be reduced in magnitude by the tubing's filtration characteristics. However, the slope may still be present for algorithmic activation decisions (e.g., by the delivery device). In exemplary modalities, activation methodologies may not be based on pressure thresholds. Instead, triggering methodologies may be based on pressure slope trends, which can also be employed to improve the overall timely delivery of the dose to the patient. It is understood that implementing such activation may be optional. SINGLE-LUMEN CANNULA With reference to Figure 3A, in exemplary embodiments, the nasal cannula may have at least one lumen (i.e., a single-lumen cannula (300)) that can deliver nitric oxide in the same lumen as is used for oxygen delivery and / or activation of a delivery device (303). Using the single-lumen cannula (300), oxygen and / or ambient airflow (305) can be delivered to a patient in a single lumen with intermittently pulsed doses of NO (307). This same lumen can also be used for activation. Using this technique, backflow can be substantially reduced, for example, because the O2 and / or air can effectively clear the nasal bridge of the cannula after each NO pulse, or because the single lumen can be a closed system within the device after the valve is closed, thus preventing backflow into the cannula lumen.However, using this technique, oxygen and / or air (305) may come into contact with NO (307) within the lumen of the cannula (300) and react (e.g., forming NO2) thereby diluting the NO from the intended dose. In exemplary modalities, a gas carrier can be used as a buffer (e.g., to isolate) the NO from the O2 and / or a gas carrier can be used to increase the effective volume of the delivered dose, for example, to reduce the transit time of the NO in the cannula. This gas buffer can be diffused into the NO dose and / or surround the NO dose (e.g., spatially before and after). With reference to Figure 3B, in exemplary configurations, to reduce the dilution of NO (307) with oxygen and / or air (305) within the NO / O2 lumen, a buffer agent (309) can be supplied between the NO (307) and the oxygen (305). For example, oxygen can first be supplied through the NO / O2 lumen, then a buffer agent (e.g., an inert gas, nitrogen gas, etc.) can be supplied, then NO can be supplied, then another buffer agent can be supplied, and finally oxygen can be supplied. The buffer agent can reduce the interaction between NO and oxygen, thereby reducing the dilution of NO, for example, caused by the formation of NO2. In exemplary embodiments, by using a buffer gas to carry the NO within the cannula, the amount of contact between the NO and the O2 and the contact time can be minimized without substantially distorting the shape of the NO pulse dose. In exemplary embodiments, the buffer gas may be substantially devoid of O2 so that it can act as a buffer for any trapped O2 and / or the volume of gas delivered may be increased, thereby decreasing the time the NO dose is in the cannula. In exemplary embodiments, the buffer gas may include oxygen; however, the diameter of the cannula lumen may be small enough so that the cross-section of the NO dose exposed to O2 can be minimized and / or the diameter may be large enough to ensure that the pulse shape of the dose cannot be substantially distorted. In exemplary modalities, a buffer gas can be provided by using the spent O2 gas mixture left over after an oxygen concentrator system has removed the O2 from the air. It is understood that the disclosed buffer can be used with any multi-lumen cannula (e.g., double-lumen cannula, three-lumen cannula, four-lumen cannula, etc.) where NO and O2 can be delivered in the same lumen. For example, a double-lumen cannula may have an activation lumen and a combined NO / O2 lumen where NO can be intermittently pulsed into O2 with a buffer separating the NO and O2. In exemplary configurations, the internal diameter of the single-lumen (e.g., combined NO / O2 lumen, combined NO / O2 / activation lumen, etc.) can be configured to be substantially small, for example, to reduce the residual gas in the mixture. As discussed earlier, lumens that must include different functions (e.g., NO delivery, activation, O2 delivery, etc.) may have competing metrics for optimization. For optimization, the dimensions of the single-lumen cross-section may require consideration of at least some of these competing metrics. For example, because the single-lumen has a combined NO / activation lumen and / or a combined NO / O2 / activation lumen, the optimal geometry (e.g., shape, size, etc.) may be a factor.The single-lumen design may require the involvement of at least some competing metrics for, for example, delivering NO pulses and / or flows in the early expiratory phase, reducing pneumatic delays, reducing distortion of flow waveforms, reducing delay and / or distortion of pressure signals, reducing the volume of NO mixed into the nasal bridge cannula, and / or oxidation of NO into the nasal bridge cannula. Considering at least the competing metrics for optimization, in at least some modalities, the internal diameter of the single-lumen device (for example, combined NO / O2 lumen, combined NO / O2 / triggered lumen, etc.) may be less than approximately (0.1778000 cm) 0.07 inches. DOUBLE LUMEN CANNULA With reference to Figure 4, in exemplary embodiments, the nasal cannula may have at least two lumens (i.e., a double-lumen cannula (400)) that can deliver nitric oxide in a separate lumen (e.g., NO lumen (404)), at least one lumen (406) that can deliver oxygen (e.g., from the oxygen / air supply (405)) and / or that can trigger the delivery device (e.g., delivery device (403)). The NO lumen may carry therapeutic NO gas from a NO delivery device (403) to the patient (e.g., in the trigger cannula (402)). The two lumens may be combined in a single nasal bridge cannula (e.g., trigger cannula (402)) that may have separate flow paths for each lumen. In exemplary modalities, the lumen (e.g., of the double-lumen cannula) that carries the nitric oxide-containing gas may have a substantially small internal diameter that may be smaller than the other lumen (e.g., the activation lumen, oxygen lumen, etc.).In at least these modalities, having a substantially small internal diameter for the lumen carrying NO to the cannula can reduce dilution by at least the following mechanisms: (i) minimizing the mixing of oxygen and NO due to a reduction in retrograde flow in the small NO-carrying lumen IO due to a smaller IO; (ii) minimizing the volume of the gas mixture mass because the NO gas volume per unit length can be reduced by having a small NO lumen IO; and / or (iii) a small NO-carrying lumen IO can produce a narrow jet of gas flow that can effectively minimize O2 / NO mixing during NO delivery and / or can minimize O2 / NO mixing during NO delivery well into the nasal cavity.Similar mechanisms for dilution reduction can be achieved by reducing the DI of the NO delivery lumen used in other multi-lumen cannulas described in this document (e.g., three-lumen cannulas, four-lumen cannulas, etc.). In exemplary modalities, the diameter of the small lumens can be minimized so that it can be as small as reasonably possible without producing confusing upstream effects on the flow delivery mechanics of the device. For example, in one or more modalities, the NO lumen may have an ID in the range of approximately 0.02540000cm (0.01 in) to approximately 0.2540000cm (0.10 in) and / or from approximately 0.07620000cm (0.03 in) to approximately 0.2032000cm (0.08 in). In addition, in one or more modes, the oxygen lumen and / or activation lumen (e.g., the dedicated activation lumen, etc.) may have a DI in the range of approximately 0.1270000cm (0.05 inches) to approximately 0.5080000cm (0.20 inches) and / or approximately 0.2032000cm (0.08 inches). With reference to Figures 5A-5B, in exemplary configurations, a double-lumen cannula may have a first lumen (502) for oxygen delivery and a second lumen (504) for NO delivery and transmission of the pressure signal to the delivery device activation sensor (505). In this configuration, the first lumen (502) may deliver oxygen from an oxygen storage / concentrator (507) to the cannula mouthpiece (506). The second lumen (504) may deliver NO from the nitric oxide delivery device to the patient and / or may provide the activation signal based on patient pressure to activate the nitric oxide delivery device sensor. Both lumens may be constructed to connect (e.g., via a tee) to both nostrils (508) / (510) and thus be in unobstructed, seamless communication with both nostrils (508) / (510). The first lumen may carry oxygen and is constructed with an internal lumen diameter geometry consistent with industry standards. For example, nasal cannulas with a nominal oxygen delivery capacity of 6 LPM may have an oxygen and NO lumen with an internal diameter of approximately 0.2032000 cm (0.08 in) at, or near, the mouthpiece. Consequently, in one or more configurations, the oxygen lumen may have an internal diameter in the range of approximately 0.1270000 cm (0.05 in) to approximately 0.5080000 cm (0.20 in) and / or approximately 0.2032000 cm (0.08 in). The second lumen for NO delivery and activation can be constructed based on the involvement of competing metrics (e.g., as mentioned previously). For example, because the second lumen combines NO delivery and activation, the optimal geometry (e.g., shape, size, etc.) of the second lumen may require the involvement of at least some competing metrics to, for example, deliver NO pulses and / or flows in the early inspiratory phase, reduce pneumatic delays, reduce flow waveform distortion, reduce delay and / or distortion of pressure signals, reduce the volume of NO mixed into the nasal bridge cannula, and / or reduce NO oxidation in the nasal bridge cannula.Taking into account at least the competition metrics for optimization, in at least some modalities, the geometry of the combined NO / activation lumen of the double lumen cannula may be in the range of approximately 0.2032000cm (0.08 inches). In exemplary modalities, the internal diameter of the second lumen may be dictated by volumetric dosing accuracy considerations; the second lumen may have an ID in the range of approximately 0.02540000cm (0.01 inches) to approximately 0.2540000cm (0.10 inches), and / or the second lumens may have an ID in the range of approximately 0.02540000cm (0.01 inches) to approximately 0.1524000cm (0.06 inches) with riser piping that can be adjusted to optimize (e.g., widen, etc.) the bandpass performance of the system. In exemplary configurations, a dual-lumen cannula may have a first lumen for NO delivery and a second lumen for O2 delivery, transmitting the pressure signal to the delivery device's activation sensor. In this configuration, the NO lumen may be substantially small (e.g., having dimensions similar to those of the NO lumen described below in a three-lumen cannula) and / or O2 combined, resulting in a lumen with an internal diameter in the range of approximately 0.1778000 cm (0.07 in) to approximately 0.3556000 cm (0.14 in) and / or approximately 0.07620000 cm (0.03 in) to approximately 0.2032000 cm (0.08 in) in the nasal bridge cannula. In exemplary forms, a double lumen cannula may have a first lumen for supplying NO and O2 and a second lumen for transmitting the pressure signal to the activation sensor of the supply device.In this configuration, the first lumen for NO and O2 delivery can use similar techniques for NO and O2 delivery in the same lumen, for example, as described herein with reference to a single-lumen cannula. THREE-LUMEN CANNULA With reference to Figures 6A-7, in exemplary embodiments, the nasal cannula may have at least three lumens (i.e., a three-lumen cannula (600)): one lumen that can supply nitric oxide to one lumen (e.g., NO lumen (604)), e.g., from a delivery device (e.g., delivery device (603)); another lumen that can be for the activation of (e.g., activation lumen (606)), e.g., the delivery device (e.g., delivery device (603)); and another lumen that can supply O2 to one lumen (e.g., O2 lumen (608)), e.g., from an O2 / air source (e.g., preservative and / or concentrator (605)). The three lumens can be added to a single nasal bridge cannula (e.g., nasal cannula (602)) which can have separate flow paths for each lumen and / or at least one lumen. The NO lumen may be a dedicated lumen capable of delivering therapeutic gas comprising NO from a NO delivery device (603) to the patient (e.g., through the nostrils (610) / (612) to the nasal bridge cannula (602)). The oxygen lumen may be a dedicated lumen capable of delivering oxygen-enriched gas (e.g., such as oxygen-enriched air, substantially pure oxygen, etc.) from an oxygen source to the patient (e.g., through the nostrils (610) / (612) to the nasal bridge cannula (602)). The oxygen source may be an oxygen pulse device (e.g., such as an oxygen conservator) and a constant flow / oxygen device (e.g., such as an oxygen concentrator) and / or may be a port on the NO delivery device that provides the oxygen-enriched gas.The activation lumen can be a dedicated lumen that allows the propagation of activation signals from the patient to the NO delivery device (603). In exemplary configurations, the nasal cannula can connect the oxygen lumen to an oxygen source (e.g., an oxygen pulse device, an oxygen conserver, a constant flow oxygen device, an oxygen concentrator, etc.) and / or the NO nasal cannula can connect the oxygen lumen to an oxygen source (e.g., for patients not receiving supplemental oxygen). For patients not receiving supplemental oxygen, the oxygen lumen can be removed and / or partially removed. For example, the oxygen lumen can be partially retained to support the oxygen side of the cannula that goes around the patient's head, while the portion of the lumen that provides the connection to an oxygen source (e.g., a flexible oxygen connection cable outside the regulator) can be removed.The removal and / or partial removal of the oxygen lumen can be done similarly for other multi-lumen cannulas described in this document (e.g., double lumen cannulas, four lumen cannulas, etc.). With reference to Figures 6C and 7, an exemplary cannula may include three lumens in the nasal bridge cannula (e.g., appropriate nasal bridge fitting, etc.) and / or the pneumatic pathways and / or lumens may be separated by partitions and / or diaphragms that may be located within the nasal bridge and / or nostril of the cannula. The NO supply may pass through the bridge via a lower gas resistance source to higher resistance orifices that may be included in the nostril cannulas. In exemplary modalities, each lumen may be separated by a diaphragm septum within the nasal bridge cannula and / or within the nostril cannulas. QQjnLn / nznz / E / Yi avoid mixing of fluid streams in separate lumens. The three lumens can be extruded through a single die producing a multi-lumen tube, can be extruded in a single multi-cavity extrusion, can be extruded separately and fixed together in a para-tube arrangement as described herein, and / or using any other reasonable technique. Similar techniques may be used for other multi-lumen cannulas described in this document (e.g., double-lumen cannulas, quad-lumen cannulas, etc.). With reference to Figure 7, in exemplary embodiments, the NO delivery lumen / tube (604) may decrease in internal diameter (ID) at least once when it is about to, and / or just after, entering the nasal cannula (602). Consequently, in one or more embodiments, the pneumatic resistance may be greater in the nostrils of the nasal cannula than in the tube that carries the NO from the NO delivery device to the nasal bridge cannula. In exemplary embodiments, the smaller ID of the dedicated NO delivery lumen may allow advantages such as, but not limited to: • short gas transit times; • retrograde inspiratory / expiratory phase reduction flow of ambient air into the lumen (e.g., reduced according to Knudsen diffusion which states that the diffusion rate is proportional to the mean free path length of the gas molecule which can be reduced with a smaller DI); • Increased gas resistance to gas flow (e.g., smaller DI tubes produce resistance to gas flow that can be inversely proportional to the fourth power of the tube radius by Poiseuille's law); and • Reduction of the volume in the NO supply lumen tee circuit. The above can reduce the potential for backflow, reduce the backflow volume, and / or reduce the contact and / or duration of contact between NO and other gases, including oxygen, in the cannula, to name a few. This, in turn, can reduce NO dilution and / or thus increase the accuracy of the delivered NO dose. Consequently, in exemplary modalities, the NO lumen DI can be approximately 0.02540000 cm³ (0.01 in) to approximately 0.2540000 cm³ (0.10 in) and / or approximately 0.1778000 cm³ (0.07 in). The DI of the NO lumen can be decreased from a maximum DI to a minimum DI, for example, to at least reduce crossflow and / or increase patient comfort. In exemplary modalities, the ratio of the minimum DI to the maximum DI of the NO lumen can be, but is not limited to, 1:1, 1:1.2, 1:1.3, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6. QQjnLn / nznz / E / Yi 1:7, 1:8, 1:9, and / or 1:10, to name a few. Similar minimum DI to maximum DI ratios of NO lumens can be used for other multi-lumen cannulas (e.g., double-lumen, three-lumen, four-lumen cannulas, etc.) described herein that may have dedicated delivery lumens for NO and / or combined NO delivery and activation lumens. The activation lumen diameter (DI) can be comparatively much larger than the NO lumen DI. The activation lumen DI can be substantially larger so that the activation pressure drop upon inhalation can be transmitted through this cannula lumen with minimal loss of signal magnitude and / or phase delay to the NO delivery device, which in turn can use this pressure signal to deliver the NO pulse. Consequently, in exemplary modalities, the activation lumen DI can range from approximately 0.1270000 cm² (0.05 in) to approximately 0.5080000 cm² (0.20 in) and / or approximately 0.2032000 cm² (0.08 in). In exemplary modalities, the ratio of the NO lumen DI to the activation lumen DI can be, but is not limited to, 1:1, 1:1.2, 1:1.3, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:12, 1:15, 1:20, 1:25, and / or 1:30, to name a few. The oxygen lumen can also be larger than the NO lumen, for example, to minimize resistance to oxygen flow and / or to reduce the gas flow velocity in the nasal passages, which can interfere with the trigger pressure signal due to gas flow effects (e.g., as from Bernoulli's principle), and / or to reduce high-frequency (e.g., auditory range) resonance with high-velocity oxygen transit, thus reducing noise associated with oxygen delivery. Consequently, in exemplary modalities, the oxygen lumen diameter (DI) can range from approximately 0.1270000 cm² (0.05 in) to approximately 0.5080000 cm² (0.20 in) and / or approximately 0.2032000 cm² (0.08 in). In exemplary modalities, the ratio of the DI of the NO lumen to the DI of the oxygen lumen can be, but is not limited to, 1:1, 1:1.2, 1:1.3, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:12, 1:15, 1:20, 1:25, and / or 1:30, to name a few. FOUR-LUMEN CANNULA With reference to Figures 8A-8D, in the exemplary embodiments, the nasal cannula may have at least four lumens (i.e., a four-lumen cannula (800)): two lumens that can deliver nitric oxide in one lumen (e.g., NO lumen (804A) and (804B)), e.g., from a delivery device (e.g., delivery device (803)); another lumen that can be for activation (e.g., activation lumen (806)), QQ / nLn / nznz / B / Yi, for example, the delivery device (for example, delivery device (803)); and another lumen that can deliver O2 in one lumen (for example, O2 lumen (808)), for example, from an O2 / air source (for example, conservator and / or concentrator (805)). The four lumens can be aggregated into a single nasal bridge cannula (for example, nasal bridge cannula (802)) which can have separate flow paths for each lumen and / or at least one lumen. In exemplary configurations, such as the pneumatic settings discussed above, this configuration can separate the pneumatic pathways for NO, oxygen, and activation. Furthermore, in exemplary configurations, the NO flow delivery pathways to each nostril can be kept separate and distinct and / or have their own pneumatic supply source within the NO delivery device. With reference to Figure 8D, an exemplary four-lumen cannula having the above configuration can be constructed in the nasal bridge cannula, where the four-lumen cannula can merge its cannula lumen into a single umbilical channel between the nasal bridge cannula and the device, for example, as can be done similarly with the three-lumen cannula. Similar to the three-lumen cannula (for example, as described with reference to at least Figure 7), the NO delivery lumen / tube (804A) and (804B) can decrease in internal diameter (ID) at least once when they are about to, and / or just after, the tube enters the nasal cannula (802). Consequently, in one or more modalities, the pneumatic resistance may be greater in the nostril holes of the nasal cannula than in the tube that carries the NO from the NO delivery device to the nasal bridge cannula. In exemplary modalities, the dimensions of the activation lumen (806), oxygen lumen (808), NO lumens (804A) and (804B) may be similar to the respective lumens in the three-lumen cannula and / or the geometry of these lumens may provide similar benefits to those described above with respect to the three-lumen cannula. In addition to the benefits mentioned above, the four-lumen cannula configuration can, among other things, prevent gas movement through the connected supply loop (e.g., tee) of the NO supply line during exhalation. This can reduce NO / oxygen contact and / or substantially reduce or eliminate crossflow. In at least some cases, the use of a four-lumen cannula may require a dedicated pneumatic circuit for each NO lumen. In exemplary embodiments, the four-lumen cannula configuration αο / ηίη / ηζηζ / Β / γι may include two activation lumens (e.g., one for each nostril), as well as one NO delivery lumen and one O2 delivery lumen. Of course, other configurations are within the scope of the invention. CHECK VALVES AND VALVES In one or more configurations, a nasal cannula (e.g., single-lumen cannula, multi-lumen cannula, any of the nasal cannulas described herein, etc.) may include one or more check valves that can be located in, and / or in fluid communication with, the nitric oxide delivery line. Furthermore, in the exemplary configurations, one or more check valves located in, and / or in fluid communication with, the nitric oxide delivery line may be combined with any of the multi-lumen configurations described. The check valves can be used, among other things, to prevent backflow of gas in the NO delivery lumen during inhalation / exhalation. The check valves may be any low-crack pressure check valve that can be placed at any point in, and / or in fluid communication with, the NO delivery line.These check valves may include, among others, duckbill valves, agglomerating valves and / or any other valve. With reference to Figure 9A, an example of a duckbill valve (902), and / or with reference to Figures 9B to 9C of the agglomerator valves (904), it is illustrated that these valves can be used in accordance with the nasal cannulas of the present invention. These check valves can be miniature check valves, for example, so that they can be sized to fit in the NO delivery lumen and / or be in fluid communication with the NO delivery lumen and / or can be constructed outside the lumen itself by molding and / or appropriate slitting of the lumen outlet during the molding and / or manufacturing process. With reference to Figure 10, in one or more embodiments, the NO delivery cannula and / or lumen may have a small flapper check valve and / or binder (1000) located in the cannula mouthpiece (1002) that may allow the delivery of NO pulses to the general nose / mouth area during NO pulse device operation. This configuration may allow NO to flow into one and / or both nostrils opened by inhalation and / or may restrict backflow into the NO lumen (e.g., during exhalation). The O2 and / or trigger lumen may be combined with or kept separate from the NO lumen, for example, to reduce any adverse signal-to-noise ratio impact on the trigger lumen's performance due to oxygen flow.This configuration with the flap valve can prevent backflow of oxygen in the NO delivery path, thus reducing the potential for dose dilution. A diaphragm and / or other barrier can separate the NO delivery line from the O2 / trigger line in the nasal bridge cannula, for example, to prevent mixing. In one or more configurations, the nasal cannula may incorporate an impermeable and / or semipermeable membrane that may be movable or fixed and / or may be actively or passively moved as needed. Furthermore, the membrane may separate the NO-containing gas or material from the O2-containing gas or material, for example, until the NO needs to be delivered to the patient. This membrane may reduce the contact time, surface area, and / or diffusion rate between the NO-containing gases and O2. This may reduce the formation of NO2, which could dilute the intended NO delivery concentration. With reference to Figure 11A, in one or more embodiments of the invention, a normally closed valve (1100) (e.g., a duckbill valve, check valve, pressure valve, etc.) substantially in and / or near the end of the cannula containing the NO, the NO lumen, and / or nasal cavity may prevent air from coming into contact with the NO-containing gas within the cannula, e.g., until the valve opening can be activated (e.g., by a pressure drop caused by the patient's inhalation or by positive pressure caused by the delivery device when attempting to administer the NO-containing gas to the patient). When the valve opening is activated, the NO can be delivered to the patient. In one or more modalities, a system may be used and / or provided to expel NO-containing gas or other material that comes into contact with O2-containing gas or material, which might otherwise have formed NO2 in this mixture. The system may subsequently allow the patient to be delivered another portion of the NO-containing gas or material that has minimal or no NO2. With reference to Figure 11B, in one or more embodiments of the invention, the system and / or nasal cannulas may include and / or be in fluid communication with an electromechanical valve system (1104) that can, for example, pump a fixed or adjustable quantity of gas mixture that may contain NO through a separate orifice in the cannula that opens to the patient. The system can then be actuated to pump the NO-containing gas or material to the patient. It is understood that any of the above teachings (e.g., check valves, check valve configurations, diaphragms, valves, electromechanical valve systems, etc.) can be combined with any of the other pneumatic configurations, cannula configurations, and / or teachings and / or modalities described in this document. For example, the above teachings (e.g., check valve configurations, etc.) can be used with the single-lumen or multi-lumen cannulas described herein and / or any other teachings and / or modalities described in this document. MINIMIZE CONTACT WITH NO / O2 DURING CONNECTION TO THE SOURCE One or more embodiments of the present invention relate to nasal cannulas and / or systems that reduce contact NO / O2 during connection of the high-pressure source (e.g., a pressurized cylinder, etc.) to the delivery device (e.g., one or more of the above contact oxygen / NO sources) and thereby dilute the intended dose of NO using a three-way valve. For example, the nasal cannulas and / or systems of the present invention may include a three-way valve with an ambient port that can be configured so that the three-way valve opens to ambient temperature after connection of the bottle to expel (e.g., blow out) the oxygen. PROPORTIONAL SUPPLY OF NASAL ORIFICES With reference to Figures 12-13, one or more embodiments of the present invention relate to nasal cannulas and / or systems that address the problem of drug loss (e.g., to the environment) when a gaseous drug (e.g., in the form of pulsed nitric oxide, etc.) is delivered through a nasal cannula due to at least one partially occluded nasal passage (e.g., as shown in Figure 12). By way of examples of such a problem, if one side of the nose (e.g., nostril (1201)) is occluded (e.g., occlusion (1203)) and the drug is being delivered to both sides of the nose through a cannula / delivery system (1200) that does not discriminate which part of the drug goes to which nostril (e.g., nostril (1205)), then there can be drug loss due to the occluded nostril.In addition, there may be other unwanted consequences such as the reaction of the unused therapy gas with other materials and / or compounds that may come into contact with the gas. Inadequate dosing can be a particular problem when drug therapy is delivered in limited quantities, such as when the drug is pulsed (for example, when administered synchronously with a patient's breathing pattern and rhythm) through a single lumen from the delivery device, which may then split at some point downstream before reaching the patient. Furthermore, this can be particularly problematic because when the drug dose through a single lumen is split, the dose may be equally or substantially equally divided into two streams without regard for nasal obstruction downstream of the split. Thus, a significant portion (for example, up to half) of the dose may not be delivered to the patient and / or may remain in the vicinity of blocked or obstructed nostrils. One or more embodiments of the present invention relate to nasal cannulas and / or systems that solve or minimize the aforementioned problem by, for example, providing an approximately proportional delivery of therapy to each nostril, with the delivery proportional to the air and gas flow in the nostrils and / or inversely proportional to the resistance in the nostrils. This can be achieved by utilizing the driving force of the patient's respiration, which can generally be approximately proportional to the air / gas flow rate in each nostril, to divide and / or draw the therapy gas from the patient's nose proportionally and subsequently into the patient's lungs.This system can deliver the dose to a patient in such a way as to ensure that the assigned or appropriately adjusted dose can be administered proportionally to the airflow in each nostril (or inversely proportional to the resistance of each nostril) such that partial or complete blockage (whether permanent or temporary) of one or both nostrils does not affect the amount of drug administered to the patient. For example, the cannula / lumen may be designed to deliver a desired amount of the therapeutic gas such that the administered dose can be injected and / or delivered in a flowing stream of inspiratory air, driven by the patient's breathing, with such a division of the flow, downstream of the drug delivery point, proportional to the amount of air entering each nostril or simply delivered to one nostril if the flow from the other nostril is below a predetermined threshold such that the delivered drug may also be divided proportionally and / or approximately proportionally or directed to one or the other nostril in an all-or-none configuration based on the upper nostril flowing to said gas flow.Airflow in a stream to the patient can be achieved by having a flow path from ambient air (e.g., through a simple hole in the nasal cannula) to each nostril in such a way that this flow path crosses the drug delivery point / area / volume before passing to the split point leading to each nostril. In exemplary modalities, exemplary cannula / lumen configurations may allow the delivery of NO to each nostril by injecting NO into an ambient airflow into each nostril (e.g., as shown in Figure 13) and / or the configurations may allow a beneficial crossflow between the two nostrils to be designed and / or used to help guide the NO to the unobstructed nostril (e.g., as shown in Figure 12). The delivery cannula / lumen shall be designed to ensure that the therapeutic gas cannot be drawn or transmitted out of the airflow path in the patient.The delivery cannula / lumen and the inspiratory airflow path to the patient may be designed to ensure that drug delivery in the ambient airstream cannot be impeded or accelerated by the creation of backpressure, lower partial pressure, or other detrimental flow patterns at the drug injection site. The delivery cannula / lumen, the inspiratory airflow path, the airflow splitting in the nostrils, and the nasal bridges may be designed to ensure that there is adequate airflow relative to other air or oxygen sources to the patient, such that the drug can be drawn into and carried in the nostrils in proportion or substantially proportional to the airflow in the nostrils. INDEPENDENT SUPPLY OF THE NASAL HOLES One or more embodiments of the present invention relate to nasal cannulas and / or systems that address the problem of underdosing due to a partially or completely blocked nostril, for example, by detecting and / or determining the amount of driving force in each nostril and adjusting the amount of drug delivered to each nostril. This can be achieved by using valves, baffles, flaps, and / or any other device to ensure proportional and / or substantially proportional dosing in each nostril. The routing of at least the above dual-channel systems (e.g., those that can work with multi-lumen cannulas, such as four-lumen cannulas) can utilize at least two independent flow channels: one for each nostril. In exemplary modalities, these independent flow channels can have drug flows tailored to the inspiration of each nostril, for example, by configuring the flow channels to deliver flow proportional to the attraction of each nostril, with total flow to both nostrils added to the appropriate dose, and / or by configuring the flow channels to deliver to a single working nostril (e.g., high-flow nostril) if the flow from the occluded nostril falls below a preset threshold. With reference to Figures 14A-14B, in order to implement such a dual-channel system, it may be necessary to have two independent flow distribution channels coupled by a single (global) controller module (e.g., a control module associated with a delivery device, etc.). Each of these distribution channels may require a pressure and / or flow signal from the particular nostril of interest, as well as the ability to deliver gas to the nostril. For example, as illustrated in Figure 14A, the cannula (1400) may have separate sensing lumens (1402) and delivery lumens (1404) in each nostril (e.g., a dual-lumen cannula, a three-lumen cannula, a four-lumen cannula, etc.).As another example, as illustrated in Figure 14B, the cannula (1410) can be combined for the detection and delivery of lumens (1412) for each nostril where the activation or breathing detection signal can be determined and / or the drug can be detected and delivered through the same lumen of the cannula (e.g., a single-lumen cannula, a double-lumen cannula, etc.) as illustrated in Figure 14B. With reference to Figure 15, in the exemplary embodiments, pneumatic systems (1500) (e.g., the supply device) may be required for the cannula to be implemented in order to support the above lumen configurations (e.g., as described above) and / or may require configurations that have (1) a pressure sensor (1502) and / or an integral flow sensor (1504) that can control each channel independently or in pneumatic isolation and / or (2) a flow supply mechanism that could have software-controlled solenoid valves (on / off type) and / or software-controlled proportional solenoid valves (1506).Configurations using a pressure and / or flow sensor may include a dedicated pressure and / or flow sensor for each supply channel and / or a pressure switching valve and / or flow sensor that can alternate between distribution channels and / or determine and / or detect pressure and / or flow readings for each channel in isolation. Pressure and / or flow can be measured (e.g., using the pressure sensor (1502), integral flow sensor (1504), etc.) independently and / or differentially using one or more sensors. Furthermore, one or more valves can be actuated (e.g., independently, in tandem, proportionally, etc.) to deliver the appropriate quantity of therapeutic gas. αο / ηίη / ηζηζ / Β / γι In typical configurations, pneumatic channels can be controlled by a controller and / or an integrated (global) controller module capable of independent control of the two channels, for example, to ensure proper dosing overall. This controller can receive input from a pressure or flow sensor (e.g., two separate pressure sensors, a single pressure sensor capable of obtaining two isolated pressure measurements, etc.) and can control both solenoid valves to achieve the appropriate dosing. MANUFACTURING OF MULTI-LUMEN NASAL CANNULAS As described above, the individual lumen of a multi-lumen cannula can be manufactured separately and then fitted together (e.g., tube arrangement, etc.) and / or multiple lumens can be extruded through a single die producing a multi-lumen tube. According to one or more of the multi-lumen nasal bridge cannulas described herein, they can be manufactured using molding techniques. For example, the cannula can be manufactured to have a three-lumen nasal bridge cannula for separating oxygen, nitric oxide, and activation light. With reference to Figure 16, in one or more modalities, the nasal bridge cannula (1602) for a three-lumen cannula may include three lumens, two lumens with inner diameters of approximately 0.2032000cm (0.08 inches) (e.g., for oxygen lumen (1608) and activation lumen (1066)) and one lumen with a smaller inner diameter of approximately 0.1143000cm (0.045 inches) (e.g., for nitric oxide lumen (1604)). This configuration cannot be easily molded by typical injection molding techniques, for example, such as small lumens that may require an injector holder (with an outside diameter of approximately 0.1143000cm (0.045 inches)) which may be too small to be robust (e.g., able to support a substantially large number of parts without bending) in a molding tool designed for many uses. With reference to Figure 17, to manufacture the multi-lumen nasal bridge cannula from a single mold, at least two halves (e.g., (1701) and (1702)) can be used in urethane, PVC, silicone, and / or other low-hardness elastomer with the inner portion of the large lumen (1704) and (1705) (e.g., oxygen lumen, activation lumen, etc.) being defined by the larger injector / core fasteners (outer diameter of approximately 0.2032000 cm (0.08 in)) and with small mid-lumen fissures (by QQjnLn / nznz / E / Yi example, (1706) and (1708)) which define the small lumen (e.g., the NO lumen). These two halves can then be folded and joined together, preferably with a residue-free joining technique such as RF welding and / or solvent bonding, to form a nose bridge cannula. In exemplary embodiments, to circumvent the limitation of the injector holder with the small DI lumens being defined by slits in the halves, the two halves can be molded flat in a single run, for example, with a band (for example, bands (1709)) that holds the halves together and provides rough alignment during the folding and joining process. The molded halves may, in some cases, include integral cylindrical holes and mating tabs or other complementary members (for example, tab (1710) and accompanying tab (1712)) so that the halves can be correctly aligned when folded together. The band may also be optional, for example, if appropriate complementary indexing members on the two halves ensure that the two parts forming the outer wall of the NO lumen can be correctly aligned.The assembled nasal bridge cannula can accommodate three lumen inlets and can be connected (e.g., via a tee) to each inlet lumen within the internal portion of the appropriate nasal bridge cannula. Of course, the nasal bridge cannula can be constructed using any reasonable technique. For example, a nasal bridge cannula with a substantially small NO lumen can also be constructed using liquid silicone rubber injection molding (e.g., a low-pressure molding technique that allows for a more robust mold tool) and / or a low-pressure molding technique. Furthermore, a nasal bridge with a substantially small NO lumen can be constructed using micromolding techniques known in the art, which can be used for the high-resolution production of small parts, including parts with small mold fasteners.Examples of a nasal bridge cannula with a substantially small NO lumen can be constructed using micro-molding techniques known in the art. With reference to Figure 18, a perspective view of the nasal receptacle (e.g., nasal receptacle (1716)) of the multi-lumen nasal bridge cannula of Figure 17 is represented illustratively after the two halves have been assembled. The lumen DI can be adjusted as described above. For example, the oxygen lumen DI can range from approximately 0.1270000cm (0.05 inches) to approximately 0.5080000cm (0.20 inches), and the activation lumen DI can vary. QQ / nLn / nznz / B / Yi from approximately 0.1270000cm (0.05 inches) to approximately 0.5080000cm (0.20 inches), and the NO lumen DI can vary from approximately 0.02540000cm (0.01 inches) to approximately 0.2540000cm (0.10 inches). In one or more modalities, the oxygen lumen Dls and the activation lumen may both be in the range of approximately 0.1778000cm (0.07 inches) to approximately 0.2286000cm (0.09 inches) and / or approximately 0.2032000cm (0.08 inches) and the NO lumen DI may be in the range of approximately 0.08890000cm (0.035 inches) to approximately 0.1397000cm (0.055 inches) and / or approximately 0.1143000cm (0.045 inches). With reference to Figure 19A-19B, within and / or before the nasal receptacle (1900), the small NO lumens (1902) may be proximal to and / or within the larger activation lumen (1904), for example, so that any tip blockage of the larger activation lumen (for which there may not be a purge capacity) can be blown out / expelled by the NO pulse function. The geometry may be designed to ensure that all, and / or substantially all, of the NO in the larger activation lumen can reach the respiratory system during inspiration and / or not remain behind so that it can be swept out during exhalation. SAMPLE NASAL CANNULA Referring to Figure 20, according to the exemplary modalities, a nasal cannula (2001) is shown, which includes three separate lumens for oxygen delivery, NO delivery, and respiratory activation. The nasal cannula may include a nasal bridge cannula (2002) for interface with the patient's nose. The NO lumen (2003) and the activation lumen (2004) deliver NO to the patient and transmit the pressure signal, respectively. The NO lumen (2003) and the activation lumen (2004) may both be tubes (e.g., D-shaped tubes), such that their combined tubes appear as a single "paratube" (2003) / (2004). The paratube (2003) / (2004) may be connected to the NO delivery device via a nasal cannula connector (2014). The nasal cannula (2001) may also include the key member (2010), reducer (2012), and / or oxygen connection nasal bridge (2016) which is described in more detail below. With reference to Figure 21A, the "paratube" can be formed from two tubes (e.g., two D-shaped tubes). For example, the D-shaped tubes can be extruded separately and / or joined in a subsequent operation, for example, by adhesion (e.g., adhesive, glue, etc.) and / or bonding (e.g., heating, melting, etc.) to form a single paratube that may appear as one tube. Furthermore, the flat interface between the tube halves can be altered to have a tab-and-groove configuration, allowing for easy alignment of the tubes with each other for a subsequent joining operation. As another example, the D-shaped tubes can be extruded in a single operation and later split at the ends (e.g., using a splicer). Additionally, the D-shaped tube extrusions can be made of the same or different materials.For example, the D-shaped NO tube can be constructed of oxygen-resistant materials, and / or the other D-shaped tube can be constructed of PVC and / or other materials commonly used for tube construction. The paratube (2003) / (2004) can be connected to the NO delivery device via the nasal cannula connector (2014). With reference to Figures 21B and 21C, in exemplary configurations, the internal diameter of the tubes (e.g., NO lumen (2003), activation lumen (2004), oxygen lumen (2008), combined lumens, etc.) and / or paratube may include geometric protrusions (e.g., cores, ribs, etc.) and / or inserts (e.g., tabs, etc.) to prevent complete occlusion of the tube, for example, due to tube flange formation and / or tube compression. These geometric protrusions may be radially spaced so that they can be symmetrically and / or asymmetrically positioned within the tube and / or paratube. With reference to Figures 20 and 22A-22E, nasal bridge cannulas (2014) can be constructed to ensure smooth communication between the patient and the device. The connecting piece can be attached to the device and / or designed to require a one-way connection (e.g., so that it cannot be inserted backward). Furthermore, the connecting piece can include additional features, such as, but not limited to, a colored pattern and / or a differentially reflective area that can be used with an IR sensor to confirm insertion, and / or the connecting piece can include a strain-relief component (2202) (e.g., as shown in Figures 22C-22E), which can be integral to the connecting piece to prevent twisting of the tubing, for example, as the tubing exits the connector.Of course, other techniques can be used to ensure intersection detection / sensing. The nasal cannula connector (2014) may include ribs and / or substantially smooth exteriors to aid in at least the handling and removal of elements; releasing tension, for example, which may be to prevent twisting. The nasal cannula connector (2014) may be constructed to ensure that the connector seats in its cavity can be detected or seen by the user; to name a few. With reference to Figures 20 and 23, in the exemplary embodiments, the oxygen connection piece (2016) may allow connection to external oxygen delivery devices such as, but not limited to, oxygen storage tanks and / or concentrators. The oxygen connection piece (2016) may be designed with industry-standard dimensions, for example, to ensure ease of use and / or connection to oxygen delivery devices. Furthermore, the oxygen lumen (2008) may be connected to an oxygen storage tank or other oxygen delivery device via the oxygen connection piece (2016). With reference to Figures 20 and 24, the NO lumen (2003), activation lumen (2004), and oxygen lumen (2008) may each have a smaller internal and / or external diameter due to the nasal bridge cannula (2002) than the corresponding connecting pieces (2014) and (2016). Accordingly, a reducer (2012) with different dimensions and / or cross-sectional profiles may be used. Furthermore, the reducer (2012) may also be used to terminate the oxygen lumen, for example, when no oxygen braid is provided, when ambient air is received within the cannula, and / or when the nasal cannula is not connected to an oxygen source, among other situations. In exemplary embodiments, the tubes (e.g., NO lumen (2003), activation lumen (2004), oxygen lumen (2008), combined lumens, etc.) can be attached to the nasal bridge cannula (2002) and / or device connector (e.g., connecting pieces (2014) and (2016)) using any technique such as, but not limited to, bonding, adhesives (e.g., epoxy, cyanoacrylate, etc.), solvent bonding, insert molding, and / or by any other technique. With reference to Figure 24, the reducer (2012) can allow a transition between, and / or connection between, tubes of different dimensions (e.g., different outer diameters, different inner diameters, etc.) so that the tubes, for example, the one closest to the patient, can be optimized for patient comfort (e.g., increased flexibility, reduction of outer diameter dimensions, etc.) and / or so that the pneumatic performance of each lumen of the cannula can optimize the use of multiple diameters, for example, to optimize patient comfort by minimizing the diameters of the tubes located proximal to the patient's head. NASAL BRIDGE With reference to figures 25A-25Q, various views of different cannulas of The nasal bridge specimens (2002) are represented for illustrative purposes. Figure 25A shows the cannula side of the nasal bridge (2002) where the oxygen lumen (2008) connects to the cannula (2002). Figure 25B shows the two D-shaped openings for the NO lumen (2003) and the activation lumen (2004). Figure 25C shows each end of the nasal cannula connecting piece, which has a central lumen for NO and two outer lumens for oxygen and activation. In exemplary embodiments, the nasal bridge cannula and / or at least some of the nasal bridge cannula and / or cannula may have material properties (e.g., durometer, etc.) selected to provide guaranteed comfort while maintaining structural and pneumatic integrity. For example, to provide comfort while ensuring structural and pneumatic integrity, the nasal bridge cannula and / or at least some of the nasal bridge cannula and / or cannula may have a durometer of approximately 30 to 70 and / or around 50 durometers (Side A). In exemplary designs, the nasal bridge cannula (2002) may include three lumens in a “tornado” design (2515) that can provide sufficient rigidity for the nostrils, yet allows the nostrils to be partially compressible, for example, because the dividing lines for the oxygen lumen (2008) and activation lumen (2004) can be offset (e.g., not aligned across the center of the NO delivery lumen (2003)). This compressibility may allow the nasal tip to be more flexible and comfortable than other three-lumen cannula tip designs. In exemplary modalities, the tornado can also encapsulate the smaller NO lumen (2004). The nostrils can be designed to ensure an optimal and / or desired insertion distance and / or to increase the comfort of the nasal cannula, which can be tapered from base to tip and / or arched (e.g., inward, toward the nasal openings). In exemplary modalities, this optimal and / or desired insertion distance can range from approximately 0.2540000 cm (0.1 in) to approximately 1.524000 cm (0.6 in) and / or approximately 1.016000 cm (0.40 in). In exemplary designs, the delineated geometry of the oxygen lumen (e.g., in the nasal bridge cannula) can be designed to reduce audible frequency noise (e.g., approximately 20 Hz to 15 kHz) by, for example, narrowing the oxygen lumen outlet. Furthermore, noise reduction can also be achieved by modifying the durometer of the oxygen delivery lumen to prevent oscillation in the audible range and noise due to oxygen flow, and / or by selecting an oxygen lumen geometry that does not generate noise (e.g., vibration, resonance, etc.). With reference to Figures 26A-26C, the cross-sectional views show several exemplary configurations for nasal cannulas. For example, Figure 26A illustrates a “tornado” pattern. Figures 26B-26D illustrate additional configurations that may include at least some of the benefits described for the “tornado” configuration. For example, other configurations may allow sufficient rigidity for the nostrils and may allow the nostrils to be partially compressible, and / or other configurations may provide at least some of the aforementioned benefits that are within the scope of this invention. In exemplary designs, the outer diameter of the nasal bridge cannula's nostrils can be minimized to increase patient comfort. Considering this outer dimension, the dimensions of the various lumens (e.g., activation lumen, NO lumen, O2 lumen, etc.) can be selected not only to be optimized (e.g., as discussed herein) but also limited in size to consider patient comfort. For example, while optimizing the nostrils with a larger outer diameter may be beneficial (e.g., an outer diameter of approximately 0.635 cm (0.25 in. or more)), the cannula's nostrils may have an outer diameter of less than, or approximately 0.508 cm (0.2 in.) for patient comfort. By way of example, taking into account patient comfort, as well as at least some and / or all of the optimization parameters described in this document, a three-lumen cannula (e.g., with a length of approximately 2.133600m (7 feet)) may have tubing with a NO lumen having an ID of about 0.001752600m (0.069 inches), an activation lumen having an ID of about 0.002260600m (0.089 inches), and an O2 lumen having an ID of about 0.002260600m (0.089 inches) with at least some of the lumens decreasing in the nasal bridge cannula (e.g., having a baseplate length of about 0.01498600m (0.59 inches)) and / or decreasing (e.g., decreasing again) in the nostrils. (for example, having a length of approximately 0.01193800m (0.47 inches) of the nasal bridge cannula. For example, the nasal bridge cannula of the NO lumen can be reduced to an ID of around 0.001244600m (0.049 inches), the activation lumen αο / ηίη / ηζηζ / Β / γι may have a DI of around 0.002260600m (0.089 inches), and / or the lumens of 02 may have a DI of around 0.002260600m (0.089 inches). Still following the previous example, the NO lumen nostrils of the cannula can be reduced to an ID of about 0.0009652000m (0.038 inches), the activation lumen can be reduced to an ID of about 0.002006600m (0.079 inches), and / or the O2 lumens can be reduced to an ID of about 0.002006600m (0.079 inches). In addition, before the reducer and / or connecting piece, the NO lumen may have a DI of about 0.001752600m (0.069 inches), the trigger lumen may have a DI of about 0.002260600m (0.089 inches), and the O2 lumens may have a DI of about 0.003352800m (0.132 inches). By way of example, taking into account patient comfort, as well as at least some and / or all of the optimization parameters described in this document, a three-lumen cannula (e.g., with a length of about 0.9144000m (3 ft)) may have tubing with a NO lumen having an ID of about 0.001625600m (0.064 in), an activation lumen having an ID of about 0.002133600m (0.084 in), and an O2 lumen having an ID of about 0.002133600m (0.084 in) with at least some of the lumens decreasing in the nasal bridge cannula (e.g., having a baseplate length of about 0.01498600m (0.59 in)) and / or decreasing (e.g., decreasing again) in the nostrils. (for example, having a length of approximately 0.01193800m (0.47 inches) of the nasal bridge cannula. For example, in the nasal bridge cannula, the NO lumen can be reduced to an ID of around 0.001117600m (0.0.044 inches), the activation lumen may have an ID of around 0.002133600m (0.084 inches), and / or the O2 lumens may have an ID of around 0.002133600m (0.084 inches). Still following the previous example, in the nostrils of the cannula, the NO lumen may be reduced to an ID of around 0.0009144000m (0.036 inches), the activation lumen may be reduced to an ID of around 0.001879600m (0.074 inches), and / or the O2 lumens may be reduced to an ID of around 0.001879600m (0.074 inches). Additionally, before the reducer and / or connecting piece, the NO lumen may have a DI of about 0.001625600m (0.064 inches), the trigger lumen may have a DI of about 0.002133600m (0.084 inches), and the O2 lumens may have a DI of about 0.003225800m (0.127 inches). By way of example, taking into account patient comfort, as well as at least some and / or all of the optimization parameters described in this document, a three-lumen cannula (for example, with a length of approximately 4.572000m (15 feet)) may have tubes with a lumen of NO that have an ID of around αο / ηίη / ηζηζ / Β / γι 0.001879600m (0.074 in), an activation lumen having an ID of about 0.002387600m (0.094 in), and an O2 lumen having an ID of about 0.002387600m (0.094 in), with at least some of the lumens decreasing in the nasal bridge cannula (e.g., having a baseplate length of about 0.01498600m (0.59 in)) and / or decreasing (e.g., decreasing again) in the nostrils (e.g., having a length of about 0.01193800m (0.47 in) of the nasal bridge cannula). For example, in the nasal bridge cannula, the NO lumen can be reduced to an ID of about 0.001371600m (0.054 in). inches), the activation lumen may have an ID of around 0.002387600m (0.094 inches), and / or the O2 lumens may have an ID of around 0.002387600m (0.094 inches). Still following the previous example, in the nostrils of the cannula, the NO lumen may be reduced to an ID of about 0.001016000m (0.04 inches), the activation lumen can be reduced to a DI of about 0.002133600m (0.084 inches), and / or the O2 lumens can be reduced to a DI of about 0.002133600m (0.084 inches). In addition, before the reducer and / or connecting piece, the NO lumen can have a DI of about 0.001879600m (0.074 inches), the activation lumen can have a DI of about 0.002387600m (0.094 inches), and the O2 lumens can have a DI of about 0.003479800m (0.137 inches). By way of example, taking into account patient comfort, as well as at least some and / or all of the optimization parameters described in this document, a four-lumen cannula (e.g., with a length of approximately 2.133600m (7 ft)) may have tubing with at least one NO lumen having an ID of about 0.001752600m (0.069 in), at least one trigger lumen having an ID of about 0.002260600m (0.089 in), and one O2 lumen having an ID of about 0.002260600m (0.089 in) with at least some of the lumens decreasing in the nasal bridge cannula (e.g., having a baseplate length of about 0.01498600m (0.59 in)) and / or decreasing (e.g., reducing again) in the nostrils nasal (for example, having a length of approximately 0.01193800m (0.47 inches) of the nasal bridge cannula.For example, in the nasal bridge cannula, the NO lumen can be reduced to an ID of approximately 0.001244600 m (0.049 in), the activation lumen can have an ID of approximately 0.002260600 m (0.089 in), and / or the O2 lumens can have an ID of approximately 0.002260600 m (0.089 in). Still following the previous example, in the nostrils of the nasal bridge cannula, the NO lumen can be reduced to an ID of approximately 0.0009652000 m (0.038 in), the lumen of. QQ / nLn / nznz / B / Yi activation can be reduced to a DI of approximately 0.002006600m (0.079 inches), and / or the O2 lumen can be reduced to a DI of approximately 0.002006600m (0.079 inches). In addition, before the reducer and / or connecting piece, the NO lumen can have a DI of approximately 0.001752600m (0.069 inches), the activation lumen can have a DI of approximately 0.002260600m (0.089 inches), and the O2 lumens can have a DI of approximately 0.003352800m (0.132 inches). By way of example, taking into account patient comfort, as well as at least some and / or all of the optimization parameters described in this document, a four-lumen cannula (e.g., with a length of about 0.9144000m (3 ft)) may have tubing with at least one NO lumen having an ID of about 0.001625600m (0.064 in), at least one trigger lumen having an ID of about 0.002133600m (0.084 in), and one O2 lumen having an ID of about 0.002133600m (0.084 in) with at least some of the lumens decreasing in the nasal bridge cannula (e.g., having a baseplate length of about 0.01498600m (0.59 in)) and / or decreasing (e.g., decreasing again) in the nostrils (for example, having a length of approximately 0.01193800m (0.47 inches) of the nasal bridge cannula.For example, in the nasal bridge cannula, the NO lumen can be reduced to an ID of about 0.001117600m (0.044 inches), the trigger lumen can have an ID of about 0.002133600m (0.084 inches), and / or the O2 lumens can have an ID of approximately 0.002133600m (0.084 inches). Still following the previous example, in nasal bridge cannula nostrils, the NO lumen can be reduced to an ID of about 0.0009144000m (0.036 inches), the activation lumen can be reduced to an ID of about 0.001879600m (0.074 inches), and / or the O2 lumen can be reduced to an ID of about 0.001879600m (0.074 inches). In addition, before the reducer and / or connecting piece, the NO lumen may have a DI of about 0.001625600m (0.064 inches), the trigger lumen may have a DI of about 0.002133600m (0.084 inches), and the O2 lumens may have a DI of about 0.003225800m (0.127 inches). By way of example, taking into account patient comfort, as well as at least some and / or all of the optimization parameters described in this document, a four-lumen cannula (e.g., with a length of approximately 4.572000m (15 ft)) may have tubing with at least one NO lumen having an ID of about 0.001879600m (0.074 in), at least one trigger lumen having an ID of about 0.002387600m (0.094 in), and one O2 lumen having an ID of about 0.002387600m (0.094 in) with at least some of the lumens tapering at the nasal bridge cannula (e.g., having a baseplate length of about 0.01498600m (0.59 inches) and / or decreasing (e.g., decreasing again) in the nostrils (e.g., having a length of approximately 0.01193800m (0.47 inches) from the nasal bridge cannula.For example, in the nasal bridge cannula, the NO lumen can be reduced to an ID of about 0.001371600m (0.054 inches), the trigger lumen can have an ID of about 0.002387600m (0.094 inches), and / or the O2 lumens can have an ID of approximately 0.002387600m (0.094 inches). Still following the previous example, in the nostrils of the nasal bridge cannula, the NO lumen can be reduced to an ID of about 0.001016000m (0.04 inches), the activation lumen can be reduced to an ID of about 0.002133600m (0.084 inches), and / or the O2 lumen can be reduced to an ID of about 0.002133600m (0.084 inches). In addition, before the reducer and / or connecting piece, the NO lumen may have a DI of about 0.001879600m (0.074 inches), the trigger lumen may have a DI of about 0.002387600m (0.094 inches), and the O2 lumens may have a DI of about 0.003479800m (0.137 inches). By way of example, taking into account patient comfort, as well as at least some and / or all of the optimization parameters described in this document, a double-lumen cannula (e.g., with a length of approximately 2.133600m (7 ft)) may have tubing with a combined NO / activation lumen having an ID of about 0.001778000m (0.07 in) and an O2 lumen having an ID of about 0.002260600m (0.089 in) with at least some of the lumens decreasing in the nasal bridge cannula (e.g., having a baseplate length of about 0.01498600m (0.59 in)) and / or decreasing (e.g., decreasing again) in the nostrils (e.g., having a bridge cannula length of approximately 0.01193800m (0.47 in)). nasal. For example, in the nasal bridge cannula the combined NO / activation lumens can be reduced to an ID of approximately 0.001270000m (0.0.05 inches) and / or the O2 lumens may have a DI of around 0.002260600m (0.089 inches). Still following the previous example, in the nostrils of the cannula, the combined NO / trigger lumens may be reduced to a DI of about 0.001016000m (0.04 inches) and / or the O2 lumens may be reduced to a DI of about 0.002006600m (0.079 inches). Each of these dimensions for the combined NO / trigger lumens may be increased slightly (for example, by a few thousand), for example, to reduce attenuation of the trigger signal. In addition, before the reducer and / or connection piece, the combined NO / activation lumens may have a DI of approximately 0.001778000m (0.07 inches), and the O2 lumens may have a DI of around 0.003352800m (0.132 inches). By way of example, taking into account patient comfort, as well as at least some and / or all of the optimization parameters described in this document, a double-lumen cannula (e.g., with a length of about 0.9144000m (3 ft)) may have tubing with combined NO / activation lumens having an ID of about 0.001625600m (0.064 in) and an O2 lumen having an ID of about 0.002133600m (0.084 in) with at least some of the lumens decreasing in the nasal bridge cannula (e.g., having a baseplate length of about 0.01498600m (0.59 in)) and / or decreasing (e.g., decreasing again) in the nostrils (e.g., having a length of about 0.01193800m (0.47 in)). the nasal bridge cannula. For example, in the nasal bridge cannula the combined NO / activation lumens can be reduced to an ID of around 0.001117600m (0.0.044 inches) and / or the O2 lumens may have a DI of approximately 0.002133600m (0.084 inches). Still following the previous example, in the nostrils of the cannula, the combined NO / trigger lumens may be reduced to a DI of about 0.0009144000m (0.036 inches) and / or the O2 lumens may be reduced to a DI of about 0.001879600m (0.074 inches). Each of these dimensions for the combined NO / trigger lumens may be increased slightly (for example, by a few thousand), for example, to reduce attenuation of the trigger signal. Additionally, before the reducer and / or connecting piece, the combined NO / activation lumens may have a DI of about 0.001625600m (0.064 inches), and the O2 lumens may have a DI of about 0.003225800m (0.127 inches). By way of example, taking into account patient comfort, as well as at least some and / or all of the optimization parameters described in this document, a double-lumen cannula (e.g., with a length of approximately 4.572000m (15 ft)) may have tubing with combined NO / activation lumens having an ID of about 0.001879600m (0.074 in) and an O2 lumen having an ID of about 0.002387600m (0.094 in) with at least some of the lumens decreasing in the nasal bridge cannula (e.g., having a baseplate length of about 0.01498600m (0.59 in)) and / or decreasing (e.g., decreasing again) in the nostrils (e.g., having a length of approximately 0.01193800m (0.47 in)). the nasal bridge cannula. For example, in the nasal bridge cannula the combined NO / activation lumens aa / n Ln / nznz / E / Yi can be reduced to an ID of around 0.001371600m (0.0.054 inches) and / or the O2 lumens may have a DI of around 0.002387600m (0.094 inches). Still following the previous example, in the nostrils of the cannula, the combined NO / trigger lumens may be reduced to a DI of about 0.001016000m (0.040 inches) and / or the O2 lumens may be reduced to a DI of about 0.002133600m (0.084 inches). Each of these dimensions for the combined NO / trigger lumens may be increased slightly (for example, by a few thousandths of an inch), for example, to reduce attenuation of the trigger signal. Additionally, before the reducer and / or connecting piece, the combined NO / activation lumens may have a DI of around 0.001879600m (0.074 inches), and the O2 lumens may have a DI of around 0.003479800m (0.137 inches). TRAMPOLINE In exemplary models, the nasal bridge cannula (2002) may include a flexible support bridge or “trampoline” (2517) that can cushion the nasal septum. The flexible support bridge (2517) can offer greater patient comfort, for example, by increasing the contact surface area between the cannula and the nasal septum, and / or patient comfort can be increased because the tip bridge can be designed to deflect away from the nasal septum. In exemplary embodiments, the flexible support bridge (2517) may be an element (e.g., a free-floating element) that can be supported at both ends by the tips of the nasal cannula. Instead of the patient's nose (e.g., nasal septum) resting on a central bridge member (2518) as commonly found in nasal cannulas (e.g., separating the nostrils of a nasal cannula; a hard plastic, sometimes curved, connection between the nostrils of a nasal cannula; etc.), a flexible support bridge (2517) may be an element (e.g., in addition to the central bridge (2518), passing through the central bridge (2518), passing from one nostril to the other nostril, etc.) that contacts the patient's septum, thereby providing at least greater comfort for the patient.In exemplary modalities, the flexible support bridge (2517) can bend and / or flex toward the central bridge element (2518) when the cannula is in use. The bending and / or flexing of the flexible support bridge (2517) can lessen transient forces on the nasal septum due to patient movement or cannula movement. The bending and / or flexing can also increase the surface area in contact with the nasal septum, which in turn can reduce the force on it. QQjnLn / nznz / E / Yi the nasal septum at any point, thus improving comfort (for example, since comfort can be negatively affected by increased load at the nasal septum point). In exemplary embodiments, the flexible support bridge (2517) can restrict the insertion depth of the nostrils, for example, as mentioned above, to an optimal and / or desired distance of approximately 0.002540000 m (0.1 in.) from insertion to approximately 0.01524000 m (0.6 in.) and / or about 0.01016000 m (0.40 in.). By way of example, this distance may be shorter than the length of the nostrils extending from the central bridge (2518). In exemplary embodiments, the nasal bridge cannula may include a tab (2519) between the nostrils (e.g., extending from the central bridge (2518)) that allows the nasal cannula's connecting piece to seat correctly against the upper lip. The tab (2519) may provide an additional measure of patient comfort by, for example, orienting the nostrils so that they point inward, toward the nasal passages, and / or distributing the force on the upper lip over a larger surface area, thereby improving patient comfort. With reference to Figures 20 and 27, in exemplary modalities, the nasal cannula may include a key member (2010) that is described in more detail below. In exemplary modalities, the key member (2010) may be a bolus and / or part of a bolus that can be included and used to adjust the length of the cannula section proximal to the nasal bridge, for example, to increase patient comfort by ensuring that the cannula fits snugly around the user's head. In exemplary embodiments, the nasal cannula may also include ear pads that can, for example, slide over and / or be incorporated into the cannula tube at the point where the cannula tube wraps around the ears to improve comfort and / or the ear pads may be foam tube extrusions that may have axial grooves so that they can slide over the cannula tube. Although this exemplary nasal cannula may be described as having certain components, any and all of these components may be optional, may be omitted, and / or may be combined and / or further separated. In addition, the nasal cannula may have any of the other components or materials described herein in a different manner. αο / ηίη / ηζηζ / Β / γι CANNULA KEY During the purging and / or flushing procedure, which can be used to clear the nasal cannula of air and other gases before administering nitric oxide (NO), the air / gases can be purged by flowing NO-containing gas through the nasal cannula. However, due to the reaction of NO and oxygen in the air, this flushing procedure can produce nitrous oxide (NO2). Therefore, it may be important that the patient not be using the nasal cannula during the purging and / or flushing procedure, so that NO2 is not delivered to the patient. With reference again to Figure 20, one or more embodiments of the present invention may provide a key element (2010) in the nasal cannula. Such a key element may be fixed near the nostrils of the nasal cannula, such as within 0.1270000 m - 0.6350000 m (5-25 inches) of the cannula orifices. One or more exemplary embodiments may be seen by reference to the element (2010) as shown in Figure 20. The key element may be provided as a bolus that can be stopped on the chest and / or neck of a patient when the cannula is used by the patient. With reference to Figure 28, the key element (2010) may need to be connected to the NO delivery device (2803) with a key slot or lock (2804), and / or this may need to be done during the lavage procedure. Due to the proximity of the modulating device and the nostrils, the nasal cannula's nozzles cannot be in the patient's nostrils when the key element is connected to the NO delivery device. In one or more exemplary implementations of a NO delivery device with a lock slot and a nasal cannula with a key element, the NO delivery device can perform the following functions: a. The NO delivery device may require the patient to remove the cannula and insert the key element contained in the cannula into the lock slot on the NO delivery device. b. The lock slot can detect the presence of the key in the lock slot. Exemplary methods for detecting the presence of the key include, but are not limited to, electronic detection (e.g., lumen beam detector, actuated switch, IR detection, magnetic detection, etc.) or mechanical detection (e.g., microswitch). c. The NO supply device can ensure that the key is in the lock before performing the washing procedure and can be programmed not to QQ / nLn / nznz / B / Yi perform the maneuver if the key is not in the lock slot. d. The NO supply device can then perform the washing procedure and inform the user of the completion of the procedure. e. The NO delivery device may allow the user to remove the key from the lock to start NO therapy. In exemplary modalities, the key element and / or key slot can be used to ensure that the patient is not using the nasal cannula during the flushing and / or irrigation procedure. In exemplary modalities, the locking element and / or key slot can be used to verify the authenticity and expiration date of at least one cannula. For example, the key element and / or key slot can be used to limit the number of uses of the cannula and / or prevent patients from reusing it. As another example, if it is necessary to ensure that patients do not use the cannula, the key element and / or key slot can be used to prevent users from using a defective cannula. It is understood that any of the above teachings (e.g., spring, flange, paratube, connecting piece, oxygen connecting piece, reducer, wrench member, wrench, bolus, cannula constructions, nose bridge constructions, etc.) may be combined with any of the other pneumatic configurations, cannula configurations, and / or teachings and / or modalities described herein. For example, the above teachings (e.g., spring, flange, paratube, connecting piece, oxygen connecting piece, reducer, wrench member, wrench, bolus, cannula constructions, nose bridge constructions, etc.) may be used with single-lumen cannulas, double-lumen cannulas, three-lumen cannulas, four-lumen cannulas, and / or any other teachings and / or modalities described herein. EXAMPLES With reference to figures 29-30, an example of retrograde flow during inspiratory breathing along with pulse delivery is shown in figure 29, and an example of retrograde flow during both inspiratory and expiratory breathing is shown in figure 30. With reference to Figures 31 and 32A, 32B, and 32C, retrograde flow was tested for various nasal cannula configurations. Typical nasal cannulas inserted into both nostrils result in significant retrograde flow, as shown in Test 1 in Figure 31. The nasal cannula configuration for Test 1 is shown in Figure 32A. For Test 2, the interconnection between the two nostrils was occluded to increase the distance between them to approximately 5.791200 m (19 inches) in the hope of eliminating retrograde flow. The nasal cannula configuration for Test 2 is shown in Figure 32B. As shown in Test 2 of Figure 31, while the total volume of retrograde flow could be reduced, it was not eliminated. Furthermore, the occluded pathway was located at a distance of 2.133,600 m (7 ft) between the nostrils, as shown in Figure 32C, had a minimal impact, as shown in Test 3 in Figure 31. Surprisingly, the only proven method found to completely eliminate backflow was when separate circuits were used for NO delivery to each nostril (i.e., a dual-channel delivery system). The document attached to U.S. Provisional Application No. 61 / 856,367, filed July 19, 2013, as Appendix 1, entitled “Exploratory Evaluation of Nitrogen Dioxide Formation in Candidate Nitric Oxide Delivery Lumens,” examined the concentration of NO2 expected to be present in the NO delivery lumen through cannulas of three lumens made of different materials. Appendix 1 attached to Provisional Application No. 61 / 856,367, filed July 19, 2013, is incorporated herein by reference in its entirety, to the extent that it is not inconsistent with the present invention. The experimental technique consisted of flowing 2440 ppm of nitric oxide (nitrogen balance) gas through multiple tubes (of three types of materials) arranged in parallel so that proximal (based on the circuit without the tubes) and distal readings of the effluent NO2 content could be taken with a NO2 CAPs plate.Parallel tubes were used to improve the signal-to-noise ratio (i.e., to amplify the NO2 signal strength) of the data, and a final mathematical calculation of the individual tube's NO2 change was obtained. The nitric oxide flow through the parallel tube banks was set to equate a residence time of 7.57 min / tube (e.g., based on a 50 kg patient with a dosage set at 0.003 mg / kg*hr using a NO2 delivery tube 2.133600 m (84 in) long and 0.001930400 m (0.076 in) in internal diameter). The expected per-tube NO2 rise for the three types of materials tested is shown below. αο / ηίη / ηζηζ / Β / γι NO2 Levels Supplied per Tube Tube Material NO2 Level per Tube Polyvinyl Chloride 12.7 ppm Silicone 10.9 ppm Polyurethane 6.8 ppm QQ 7Π ίΠ / Π7ηZ / E / YΙΛ TREATMENT METHODS The invention herein may reduce retrograde flow, ensure accurate dose delivery, and / or minimize NO2 formation and be used in conjunction with a delivery device that may be used for the treatment and / or prevention of pulmonary hypertension secondary to COPD and / or pulmonary hypertension as PAH and / or pulmonary hypertension secondary to IPF and / or pulmonary hypertension secondary to sarcoidosis. For safe and effective use, the described cannula may be used with the described delivery device, and similar devices, and / or nitric oxide. A person skilled in the art will appreciate that using a cannula other than the disclosed cannula with the described delivery device, and similar devices, and / or nitric oxide, may increase safety risks and / or reduce or eliminate effective use. Accordingly, the cannula of the present invention may be necessary for the delivery of nitric oxide for PAH, IPF, and / or COPD.Any of the nasal cannulas described in this document can be used in nitric oxide therapy to treat appropriate diseases. For example, the cannulas can be used for pulsed NO therapy to treat chronic obstructive pulmonary disease (COPD) or pulmonary arterial hypertension (PAH). For these diseases, delivering the appropriate dose amounts and dosing schedule can be very important. For COPD, it may be necessary to pulse the NO during early inspiration, such as the first half of inspiration. If the NO, for example, is not delivered in the correct amount or at the right time, reversal of hypoxic vasoconstriction can occur, which could worsen the patient's condition. Furthermore, the dose amount can be very important for PAH because abrupt discontinuation of treatment can lead to serious events such as rebound hypertension.Therefore, significant dilution of the NO dose should be minimized for these diseases. Any of the cannula materials, configurations, or methods described here can be used to minimize NO dose dilution during NO therapy. In exemplary embodiments, the lumens (e.g., tubing) of the cannula may be brought back toward the patient and / or may be fixed together to produce a substantially single umbilical element between the nasal bridge cannula and the device, which may provide a cross-section. It shall be understood that when a plurality of lumens is described (e.g., two lumens, three lumens, four lumens, etc.), all the lumens may be included in a single cannula. In exemplary embodiments, the cannula components may be manufactured using any of the techniques described herein and / or using techniques known in the art. For example, the cannula lumens (e.g., tubing), the actuator, the key member, the connectors, reducers, any combination and / or further separation thereof, and / or any cannula component described herein may be manufactured using extrusion techniques, molding techniques, and / or any other manufacturing technique. It is understood that each lumen of the nasal cannula and / or cross-section of the collective nasal cannula lumen may be of any shape, such as, but not limited to, circular, parabolic, ellipsoidal, square, rectangular, triangular, and / or any other regular or irregular cross-sectional shape to minimize dose dilution. For ease of use, the geometry and / or cross-section is sometimes described as circular, parabolic, and / or ellipsoidal, and / or the cross-section is described as a diameter, internal diameter, or similar. This is merely for ease of use and is in no way intended as a limitation. When one or more cross-sectional areas are not circular, then the ratio of internal diameters may be the square root of the ratio of the surface areas of the two lumen sections. It is understood that any of the above may be used for the pulsed and / or non-pulsed delivery of a therapeutic gas (e.g., NO). For example, any of the above modalities that refer to the pulsed delivery of a therapeutic gas, where applicable, may be used with the non-pulsed delivery of a therapeutic gas, and vice versa. For ease of use, pulsed or non-pulsed delivery may sometimes be referred to. This is purely for convenience and is in no way intended as a limitation. Throughout this description, reference to an embodiment, certain embodiments, one or more embodiments, exemplary embodiment, exemplary embodiments, and / or embodiment means that a particular feature, structure, material, or function described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, occurrences of phrases such as "in one or more embodiments," "in certain embodiments," "in an embodiment," "exemplary embodiment," "exemplary embodiments," and / or "in an embodiment" in various places throughout this description do not necessarily refer to the same embodiment of the invention. Furthermore, the particular features, structures, materials, or functions may be combined in any suitable manner in one or more embodiments. It is understood that any of the steps described may be rearranged, separated, and / or combined without departing from the scope of the invention. For ease of understanding, the steps are sometimes presented sequentially. This is merely for convenience and is in no way intended as a limitation. Furthermore, it is understood that any of the elements and / or embodiments of the invention described herein may be rearranged, separated, and / or combined without departing from the scope of the invention. For ease of understanding, various elements are sometimes described separately. This is merely for convenience and is in no way intended as a limitation. Although the present description has been given with reference to particular embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It will be evident to those skilled in the art that various modifications and variations can be made to the method and apparatus of the present invention without departing from the spirit and scope of the invention. Therefore, the present invention is intended to include modifications and variations that are within the scope of the appended claims and their equivalents.

Claims

1. A nitric oxide delivery system, wherein the nitric oxide delivery system delivers a pulse of a gas comprising nitric oxide to a patient in need thereof, wherein the pulse is delivered via a nasal cannula comprising a cannula nozzle comprising a nitric oxide flow path a volume that is less than approximately 20% of the pulse volume of the gas comprising nitric oxide.

2. The nitric oxide delivery system of claim 1, wherein the nasal cannula comprises a first lumen for delivering the gas comprising nitric oxide to the patient and a second lumen, wherein the first lumen has a smaller internal diameter than the internal diameter of the second lumen.

3. The nitric oxide delivery system of claim 1 or 2, wherein the nasal cannula comprises: a first lumen, a second lumen, and a third lumen; the first lumen being a first therapeutic gas lumen for delivering the gas comprising nitric oxide to the patient, the second lumen being a trigger lumen, and the third lumen being a second therapeutic gas lumen for delivering a gas comprising oxygen to the patient; and wherein the nozzle of the cannula has separate flow paths to the patient for each of (i) the first therapeutic gas lumen, (ii) the trigger lumen, and (iii) the second therapeutic gas lumen.

4. The nitric oxide delivery system of any of claims 1 to 3, wherein the nitric oxide flow path comprises a first tip, a second tip, and a tip spacing.

5. The nitric oxide delivery system of any of claims 1 to 4, wherein the gas pulse comprising nitric oxide has a volume of less than approximately 1 ml.

6. The nitric oxide delivery system of any of claims 1 to 5, wherein the nitric oxide flow path is less than approximately 10% of the pulse volume of the gas comprising nitric oxide.

7. The nitric oxide delivery system of any of claims 1 to 6, wherein the nitric oxide flow path has a volume less than or equal to approximately 0.035 mL 8. The nitric oxide delivery system of any of claims 1 to 7, wherein the nitric oxide delivery system delivers a plurality of pulses of the gas comprising nitric oxide and the nitric oxide flow path has a volume that is less than approximately 20% of the volume of each pulse of the gas comprising nitric oxide.

9. The nitric oxide delivery system of any of claims 1 to 8, wherein each pulse of the gas comprising nitric oxide has a volume of less than approximately 1 mL 10. The nitric oxide delivery system of any of claims 1 to 9, wherein the nitric oxide flow path is less than approximately 10% of the volume of each pulse of the gas comprising nitric oxide.

11. The nitric oxide delivery system of any of claims 1 to 10, for use in the treatment of pulmonary hypertension.

12. The nitric oxide delivery system of any one of claims 1 to 11, for use in the treatment of at least one of the cases of pulmonary hypertension secondary to chronic obstructive pulmonary disease (COPD), pulmonary hypertension as pulmonary arterial hypertension (PAH), pulmonary hypertension secondary to idiopathic pulmonary fibrosis (IPF), and pulmonary hypertension secondary to sarcoidosis.

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