59 results about "End tidal" patented technology

Disclosed is an apparatus and method for the delivery of inspired gas, e.g., supplemental O2, to a person combined with gas sampling, including for the purpose of monitoring of the ventilation of the person. In the invention, the delivery of inspired gas and gas sampling are accomplished without the use of a sealed face mask. The apparatus of one embodiment of the present invention comprises an oxygen delivery device, nasal airway pressure sampling devices, optionally an oral airway pressure sampling device and at least one pressure analyzer connected to the sampling devices which determine the phase of the person's respiration cycle and the person's primary airway. The oxygen delivery device is connected to a controller such that it delivers a higher flow of oxygen to the person during the inhalation phase of the person's respiratory cycle. The invention thus increases end tidal oxygen concentrations. The invention further comprises carbon dioxide sampling tubes that continuously sample gas from two nasal sites and the mouth. The nasal sampling tubes are connected to a switching valve that is in turn connected to a capnometer which determines carbon dioxide concentration during exhalation. The oral gas sampling site is connected to a second capnometer.

Disclosed is an apparatus and method for the delivery of supplemental oxygen gas to a person combined with the monitoring of the ventilation of the person with both being accomplished without the use of a sealed face mask. Preferred embodiments of the present invention combine an oxygen delivery device, a nasal airway pressure sampling device, an oral airway pressure sampling device, and a pressure analyzer connected to the sampling devices to determine the phase of the person's respiration cycle and the person's primary airway. The oxygen delivery device is connected to a controller such that it delivers a higher flow of oxygen to the person during the inhalation phase of the person's respiratory cycle. The invention thus increases end tidal oxygen concentrations with improved efficiency comparative to known open airway devices. Embodiments of the invention can include carbon dioxide sampling tubes that continuously sample air from the nose and mouth to determine carbon dioxide concentration during exhalation.

Techniques are provided for detecting the circadian state of a patient using an implantable medical device based on selected blood carbon dioxide (CO2) parameters. In one example, the implantable device tracks changes in end tidal CO2 (etCO2) levels and changes in maximum variations of pCO2 levels per breathing cycle (ΔcycleCO2) over the course of the day and determines the circadian state based thereon. It has been found that average etCO2 levels are generally highest and average ΔcycleCO2 levels are generally lowest while a patient is asleep and opposite while a patient is awake. Hence, by tracking changes in average etCO2 and ΔcycleCO2 levels over the course of the day, circadian states can be detected. Minute ventilation and activity levels are used to assist in the determination of the circadian state. Additional techniques are directed to detecting the stage of sleep.

A noninvasive apparatus and method for measuring a subject's end tidal carbon monoxide concentration is disclosed, featuring the ability to (i) determine carbon monoxide concentration on a breath-by-breath basis, (ii) determine mean carbon monoxide concentration by averaging local carbon monoxide values, (iii) avoid the premature determination that an end tidal phase is over, and (iv) determine when breath variability or system variability will likely preclude accurate testing. The disclosed device and method allow for more robust determination of end tidal carbon monoxide concentration in subjects with turbulent or irregular breath patterns.

Methods and apparatus for enhancing reliability of, and monitoring, the operation of airway valves to enhance patient safety. Pneumatic control line pressure (positive or negative) for actuation of the airway valve may be specified at a given magnitude or within a selected range and monitored continuously. Reduced or excessive pressure may be compensated by actuation of a pressure source or a bleed valve, and monitoring may be effected so as to warn the user of any deviation from the range, or deviations of selected magnitudes or frequencies or a combination thereof. The inspired volume of CO2 may be monitored using air flow and CO2 sensing, with detection of excessive CO2 volume triggering a warning. Similarly, measured end-tidal or end-inspired CO2 or other appropriate measures of CO2 concentration may be employed as a warning trigger. Other driving energy sources for airway valves, and monitoring thereof, are also disclosed.

In a first aspect, the invention relates to an apparatus for inducing or maintaining a target end tidal concentration of a gas in a subject comprising a breathing circuit, a source of gas flow into the circuit, means for controlling the rate of the source of gas flow into the circuit and means for controlling the concentration of gases in the source gas flow independently from each other. In another aspect, the invention relates to a method of preparing an apparatus for inducing or maintaining a target end tidal concentration of a gas X in a subject comprising selecting a rate of a source gas flow into a breathing circuit, selecting the concentration of at least one constituent gas of a component gas making up the source gas to a level corresponding to the end tidal concentration of the gas X, whereby the apparatus is adapted to administer a source gas having a first gas composition

An oropharyngeal device for insertion into the mouth of a patient. The device includes a body having a distal end and a proximal end with a flange formed at the proximal end. The distal end is inserted into the mouth until the flange is disposed outside and adjacent to the patient's mouth. The flange keeps the proximal device from entering the mouth. The body is sized such that the distal end of the body is disposed within the pharynx above the epiglottis. The device includes a channel that forms an airway between the ends. The device also includes at least three separate conduits integrated into the body for administering oxygen, suctioning, and for assessing ventilation thorough end-tidal carbon dioxide monitoring. The conduits for oxygenation and suctioning extend through the body between its proximal and distal ends. The conduit for end-tidal carbon dioxide monitoring terminates within the channel.

A method and apparatus for determining the presence or absence of a pulmonary embolism (PE) in a patient. The breathing gas CO2 partial pressure (PCO2) during the expiration of breathing gases by the patient, the end tidal (EtCO2), CO2 partial pressure, and the CO2 partial pressure (PaCO2) of the blood are measured. The volume (V) of breathing gases expired during the expiration of breathing gases by the patient is also measured and a relationship between changes in breathing gas CO2 partial pressure (PCO2) and changes in breathing gas volume (V) in an alveolar expiration phase of patient expiration is determined. The difference between the blood CO2 partial pressure (PaCO2) and the end expiration CO2 partial pressure is divided by the relationship between PCO2 and V produce a quantity which is compared to a threshold value. If the quantity is below the threshold value, the absence of a pulmonary embolism is indicated.

Apparatus and methods for non-invasively determining cardiac output using partial re-breathing techniques are disclosed in which the apparatus is constructed with an instantaneously adjustable deadspace for accommodating differences in breathing capacities of various patients. The apparatus is constructed of inexpensive elements, including a single two-way valve which renders the apparatus very simple to use and inexpensive so that the unit may be readily disposable. The method of the invention provides a novel means of estimating cardiac output based on alveolar CO2 values rather than end-tidal CO2 values as previously practiced. A program for calculating cardiac output is also disclosed.

An oropharyngeal device for insertion into the mouth of a patient. The device includes a body having a distal end and a proximal end with a flange formed at the proximal end. The distal end of the body is inserted into the mouth of the patient until the flange at the proximal end is disposed outside and adjacent to the patient's mouth. The flange keeps the proximal device from entering the mouth. The body is sized such that the distal end of the body is disposed within the pharynx above the epiglottis. The device includes a channel through the body that forms an airway between its proximal and distal ends. The device also includes at least three separate conduits integrated into the body for administering oxygen, suctioning, and for assessing ventilation through end-tidal carbon dioxide monitoring. The conduits for oxygenation and suctioning extend through the body between its proximal and distal ends. The conduit for end-tidal carbon dioxide monitoring extends along and is attached to a side wall of the channel and terminates within the channel.

A method and apparatus for determining a user's Respiratory Quotient (RQ) using just measured O2 and CO2 concentrations without use of a flow meter. The RQ is determined by measuring the user's real-time inspired O2 concentration (INS O2) and end tidal O2 concentration (ETO2) and measuring the user's real-time inspired CO2 concentration (INS CO2) and end tidal CO2 concentration (ETCO2), and then determining the user's RQ from the measured INS O2, ETO2, INS CO2, and ETCO2 values in accordance with the following equation: RQ=(ETCO2−INS CO2) / (INS O2−ETO2). In order to avoid error introduced by the flow rate, the measurement steps are preferably performed while the user is in a resting condition. Also, ETCO2 is preferably measured as the maximum CO2 value in a breath cycle of the user, while INS CO2 is preferably measured as the minimum CO2 value in a breath cycle of the user. Similarly, ETO2 is preferably measured as the minimum O2 value within a breath cycle of the user, while INS O2 is measured as the maximum O2 value within a breath cycle of the user. On the other hand, the values of INS CO2 and ETCO2 also may be determined in accordance with the invention by analysis of a CO2 waveform of a breath cycle of the user and the values of INS O2 and ETO2 determined by synchronizing timing of the O2 waveform of a breath cycle of the user with the CO2 waveform and sampling INS O2 and ETO2 values simultaneously with sampling of complementary CO2 values determined by analysis of the CO2 wavefomm. The RQ measuring device may include the oxygen and CO2 sensors in a mainstream or sidestream configuration.

The present invention provides for a unique modification of the intravenous catheter, attached to the terminal line of the mass spectrometer and the use of a disposable nasal oxygen cannula provide an effective and efficient port to monitor end tidal carbon dioxide (PETCO2) in unintubated, conscious, spontaneously breathing patients who are receiving administration of local and regional anesthesia or during recovery from residual general anesthesia.

The invention resides in a respiratory sonification monitoring method and system for monitoring respiration in a subject including the use of capnometric means for measuring carbon dioxide concentrations, flowmeter means for measuring gas flow and volume of gas; means adapted to process into digital information, signal output from the capnometric means and the flowmeter means, sound synthesizer means adapted to convert the digital information into synthesised audio output, wherein, changes in respiratory flow during inhalation and exhalation, and changes in end tidal carbon dioxide concentrations (ETC02) and cumulative tidal volume (cumVt) of the subject can be represented as changes in synthesised sound heard through a loudspeaker, headphone or ear piece.

Apparatuses are described to accurately determine a gas concentration of a sample of a patient's breath. The apparatuses may include a sample compartment, a breath speed analyzer, a gas analyzer, and a processor. The sample compartment includes an inlet that receives the breath. The breath speed analyzer determines the speed of a portion of the breath. The gas analyzer determines a gas concentration. The processor includes an algorithm that determines a degree of non-homogeneity of the sample based on the speed, and a corrected gas concentration based on the degree of non-homogeneity. In some variations, the gas correction is determined independently of patient cooperation. Apparatuses may be tuned based on the intended population's expected breathing pattern ranges such that the sample compartment is filled with a homogenous end-tidal gas sample regardless of an individual's breathing pattern. These apparatuses are useful, for example, for end-tidal CO analysis. Methods are also described.

An oral airway providing a patent airway to a patient, supplies oxygen to the patient and monitors expelled gases during endoscopic or intubating procedures. The oral airway includes a central lumen and two lateral breathing channels. A bracket at the proximal end of the oral airway functions to guide an oxygen supply line and an end tidal carbon dioxide monitoring line into the lateral breathing channels and to act as a barrier beyond which the airway cannot be inserted into the mouth of the patient. The airway has a straight main central lumen which serves as a guide and conduit to facilitate endoscope, bronchoscope, or fiber optic bronchoscope placement and manipulation.

A sensor adaptor (20) couples a face mask (22) to a gas sampling tube (24) connected to a device detecting end-tidal carbon dioxide. The sensor adaptor (20) includes a shaft (30) and connector (54). The shaft (30) includes a channel (40) providing a pathway for the carbon dioxide to travel toward the gas sampling tube (24). One end of the shaft (30) includes an adaptor tip (26) which extends through an exit port (28) of the face mask (22). A connector (54) is attached to the other end of the shaft (30) and couples the sensor adaptor (20) to the gas sampling line. A gripper (42) may surround the shaft (30) and prevent improper advancement of the shaft (30) into the face mask (22). The sensor adaptor (20) can be designed for use with any gas sampling tube and any face mask including exit ports.

A system for controlling an amount of at least one gas X in a subject's lung to target at least one end tidal partial pressure of at least one gas X (PetXT) uses a control system for controlling the gas delivery device, wherein the control system implements a sequential gas delivery system and a feedback algorithm which compares a PetXT for a respective breath of variable size and preferably a respective current PetX value measured by a measurement system, to obtain an error signal, the feedback algorithm adapted for generating a control signal based on the error signal, the control signal determining the amount of gas X to be inspired by the subject in at least a first portion of a respective ensuing respective inspiratory cycle to target PetXT for the respective interval.

A method of setting expiratory time in controlled mechanical ventilation varies a subject's expiratory times; determines end tidal gas concentrations associated with the expiratory times; establishes a stable condition of the gas concentrations; and determines an optimal expiratory time based on a deviation from the stable condition. A device for use in controlled mechanical ventilation comprises means for the same.

A method for non-invasively determining functional cardiac output (FCO) and / or venous blood CO2 partial pressure (PvCO2). The amount of CO2 (VCO2N) released from the blood and end capillary blood CO2 content (CcCO2N) are determined from measurements from exhaled breathing gases. The CO2 content of the breathing gases inhaled by the subject is increased and values for VCO2R and CcCO2R are obtained. A regression analysis is performed using the obtained VCO2N, VO2R, CcCO2N, and CcCO2R values. The regression line is extrapolated to obtain a value for CcCO2 when (VCO2) is zero so that CvCO2 becomes known. The CvCO2 thus determined can be inserted in a non-differential form in the Fick equation, along with VCO2 and CcCO2 values from normal breathing, to determine FCO. To determine PvCO2, CvCO2 is altered in accordance with the amount of oxygen in the venous blood, to correctly indicate PvCO2. The continuing validity of the FCO measurement can be examined on a breath-by-breath basis by noting changes in an indicator variable, such as VCO2 or end tidal CO2 amounts.

A processor obtains input of a logistically attainable end tidal partial pressure of gas X (PetX[i]T) for one or more respective breaths [i] and input of a prospective computation of an amount of gas X required to be inspired by the subject in an inspired gas to target the PetX[i]T for a respective breath [i] using inputs required to utilize a mass balance relationship, wherein one or more values required to control the amount of gas X in a volume of gas delivered to the subject is output from an expression of the mass balance relationship. The mass balance relationship is expressed in a form which takes into account (prospectively), for a respective breath [i], the amount of gas X in the capillaries surrounding the alveoli and the amount of gas X in the alveoli, optionally based on a model of the lung which accounts for those sub-volumes of gas in the lung which substantially affect the alveolar gas X concentration affecting mass transfer.

An air mixing chamber is herein provided. More particularly, the air mixing chamber mixes the end-tidal and dead space air of exhaled breath for purposes of analysis using baffles with holes that direct the flow of the exhaled breath. The baffles are enclosed inside an enclosure that includes an inlet tube, an outlet tube and a sensor.

In a first aspect, the invention relates to an apparatus for inducing or maintaining a target end tidal concentration of a gas in a subject comprising a breathing circuit, a source of gas flow into the circuit, means for controlling the rate of the source of gas flow into the circuit and means for controlling the concentration of gases in the source gas flow independently from each other. In another aspect, the invention relates to a method of preparing an apparatus for inducing or maintaining a target end tidal concentration of a gas X in a subject comprising selecting a rate of a source gas flow into a breathing circuit, selecting the concentration of at least one constituent gas of a component gas making up the source gas to a level corresponding to the end tidal concentration of the gas X, whereby the apparatus is adapted to administer a source gas having a first gas composition.

A biological signal measuring apparatus includes: a pressure sensor which measures a pressure in a living body; a respiratory sensor which measures respiratory information; and an outputting unit which detects an end-tidal based on the respiratory information measured by the respiratory sensor and which outputs a pressure value based on the pressure measured by the pressure sensor when detecting the end-tidal.

An apparatus and method for controlling the end tidal partial pressure of a gas X in a subject's lung, and to the use of such an apparatus and method for research, diagnostic and therapeutic purposes, wherein the method consists of: obtaining input of a series of logistically attainable PetX values for a series of respective breaths: determining an amount of gas X required to be inspired by the subject in an inspired gas to target the PetX for each of said respective breaths: and controlling a gas delivery device to deliver the amount of gas in a volume of gas delivered to the subject in each of said respective breaths to target the respective PetX for that breath.

A method and apparatus for the non-evasive determination of the cardiac output of a subject by causing the subject to inhale and exhale air via a respiratory tube in a plurality of breathing cycles including normal breathing cycles in which the inhaled air does not receive any significant amount of exhaled air from the preceding cycle, and rebreathing cycles in which the inhaled air receives an end tidal portion of the exhaled air from the preceding cycle, propagating ultrasonic pulses through the air passing through the respiratory tube and computing the flow volume through the tube from the measured transit times of the pulses and determining the carbon dioxide content in the exhaled air during both the normal breathing cycles and the rebreathing cycles to determine the cardiac output of the subject.

The invention discloses a monitoring method and a device for partial pressure of carbon dioxide. The monitoring method for partial pressure of carbon dioxide comprises the steps: acquiring arterial carbon dioxide pressure PaCO2 and end-tidal carbon dioxide pressure EtCO2; and determining the estimated value of arterial carbon dioxide pressure PaCO2' at the measurement time according to the arterial carbon dioxide pressure PaCO2 and end-tidal carbon dioxide pressure EtCO2. According to the invention, the number of invasive measurement to a human body is reduced, the pain of a person to be measured is alleviated, the monitoring of partial pressure of carbon dioxide is more safe, the estimated value of corresponding arterial carbon dioxide pressure can be quickly obtained by the end-tidal carbon dioxide pressure EtCO2, the blood and vigor status of the human body is dynamically reflected in real time, and the monitoring of the arterial carbon dioxide pressure is quicker and more visual.