Systems and methods for pressure management and leak detection in inflatable cuffs of medical devices

Abstract

An endotracheal tube or tracheostomy tube with a cuff assembly comprises a cuff pressure regulator and a leak detection system. A pressure sensor monitors and measures the tracheal wall pressure and the pressure within the cuff assembly. When the measured value of the pressure sensor is abnormal, the cuff pressure adjustment process is initiated. The leak detection system detects air leakage from the seal between the cuff assembly and the tracheal wall. A scented film with a predetermined scent is placed on the lower portion of the cuff assembly distal to the seal with the tracheal wall. If a predetermined scent is detected in the air within the trachea proximal to the cuff assembly, it indicates an air leak. An air circulation device can generate an air flow within the trachea and sample and inspect a new batch of air. When an air leak is detected, the cuff pressure adjustment process is initiated.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. patent application Ser. No. 18 / 103,641, entitled "Pressure Management and Air Leak Detection of an Inflatable Cuff in a Medical Device," filed on January 31, 2023, which claims priority as a continuation-in-part under 35 U.S.C. § 120 of application Ser. No. 17 / 902,691, filed on September 2, 2022, which is incorporated herein by reference in its entirety. U.S. application Ser. No. 17 / 902,691 claims priority as a continuation-in-part under 35 U.S.C. § 120 of application Ser. No. 17 / 848,273, filed on June 23, 2022, now issued as U.S. Patent No. 11,602,605, which is incorporated herein by reference in its entirety.

[0002] This application relates to systems and methods for tracheostomy and / or endotracheal tubes, and more particularly to systems and methods for pressure management and air leak detection for inflatable cuff assemblies implemented on endotracheal and / or tracheostomy tubes. [Background technology]

[0003] Mechanical ventilation (MV) is a life-support technique in which a patient is intubated with a breathing tube and receives oxygen and air from a machine through the tube. Patients receiving mechanical ventilation experience an altered physiological environment, including a decreased ability to remove oral and nasal secretions, decreased bronchial mucociliary clearance, increased accumulation of secretions in the lungs and bronchi, a decreased cough reflex, and an increased likelihood of gastric reflux. The combined effects of these factors predispose patients on mechanical ventilation to ventilator-associated pneumonia (VAP). VAP is a lung infection that typically develops 48 hours after mechanical ventilation.

[0004] Breathing tubes used in mechanical ventilation include endotracheal tubes (ETTs) or tracheostomy tubes with inflatable cuffs. The inflatable cuff creates a seal between the breathing tube and the tracheal wall, preventing secretions from leaking into the lungs or bronchi. In mechanically ventilated patients, secretions accumulate above the inflatable cuff. These secretions originate from the oral cavity, sinuses, and stomach ("orogastric secretions"). Under normal conditions, up to 3 liters of secretions are known to be produced per day from the oral cavity and sinuses. Again, these oral and sinus secretions do not include gastric reflux, which can be a significant problem. While healthy individuals are able to clear or manage secretions, mechanically ventilated patients are unable to do so. Instead, in mechanically ventilated patients, secretions may accumulate above the inflatable cuff or leak around the inflatable cuff into the trachea.

[0005] The concern with secretions accumulating above the cuff is that they contain microorganisms, including bacteria and fungi. Because secretions are highly contaminated, they must be directed away from sterile organs in the body, including the lungs. Therefore, it is essential that treating physicians make every effort to prevent secretions from entering the patient's lungs.

[0006] Inflatable cuffs provide a powerful aspiration deterrent. When inflated, the cuff, located at the distal end of the breathing tube, contacts the tracheal wall circumferentially, creating a complete seal. Unfortunately, these cuffs are known to fail to provide an efficient seal, primarily due to wrinkles and creases caused by oversized cuffs, as discussed below. This observation supports previous studies showing that approximately 10% of mechanically ventilated patients develop ventilator-associated pneumonia (VAP), with an estimated mortality rate of 13%. Furthermore, patients with VAP experience longer hospital stays and higher medical costs than similarly ill patients without VAP. Considering that approximately 750,000 patients require mechanical ventilation annually in the United States, the human and financial toll of VAP is significant.

[0007] Maintaining cuff pressure within recommended ranges is recognized as an important component of patient care, including reducing tracheal injury and preventing ventilator-associated pneumonia. The ultimate goal of monitoring cuff pressure is to achieve a pressure high enough to maintain a seal between the trachea and the cuff and prevent secretion leakage, yet low enough so as not to impair tracheal blood flow.

[0008] Currently, several cuff pressure management systems are commercially available. However, these systems have not demonstrated clinically significant benefits on the incidence of ventilator-associated pneumonia (VAP) or patient outcome measures. Therefore, improved cuff pressure management systems and methods are needed to reduce the incidence of VAP and improve patient outcomes. Summary of the Invention

[0009] In one aspect, the medical device includes an airway tube configured for placement within the trachea and a cuff assembly mounted on a distal portion of the airway tube, the cuff assembly including at least one inflatable cuff. At least one fragrance substance is disposed distal to the cuff assembly or in a portion of the airway tube distal from the cuff assembly. At least one scent detector is configured to detect a predetermined scent from the fragrance substance in air, and air is sampled from the trachea proximal to the cuff assembly.

[0010] In another aspect, a medical system includes an airway tube configured for placement within the trachea and a cuff assembly at a distal portion of the airway tube. The medical system further includes at least one flavoring substance disposed distal to the cuff assembly or on a portion of the airway tube distal from the cuff assembly, the at least one flavoring substance having at least one predetermined scent. An insufflation opening is formed in an outer wall of the airway tube proximal to the cuff assembly, and a suction channel extends from the insufflation opening to the proximal end of the airway tube.

[0011] In another aspect, a medical system includes an airway tube configured for placement within the trachea and a cuff assembly at a distal portion of the airway tube, the cuff assembly including an inner cuff disposed adjacent to the airway tube and an outer bladder disposed adjacent to the inner cuff. At least one fragrance material is disposed on an underside of the inner cuff or on a portion of the airway tube distal to the cuff assembly, the at least one fragrance material having at least one predetermined fragrance. At least one fragrance detector is configured to detect the at least one predetermined fragrance in air above the cuff from the trachea.

[0012] In one or more of the above embodiments, the airway tube includes an insufflation opening formed in the outer wall of the airway tube proximal from the cuff assembly, and a suction channel extending from the insufflation opening to the proximal end of the airway tube.

[0013] In one or more embodiments above, a vacuum pump is fluidly coupled to the suction channel at the proximal end of the airway tube, and the vacuum pump draws air from the trachea through the intake opening and the suction channel. A filter may be used to remove liquid from the air before testing with the at least one scent detector.

[0014] In one or more of the above embodiments, the pressure regulator system is configured to adjust the pressure in the at least one inflatable cuff of the cuff assembly in response to the scent detector.

[0015] In one or more embodiments above, the pressure regulator is configured to determine that the scent detector has detected a leak in the seal around the cuff assembly and to generate an alert on a user interface, the alert including one or more of an audible alert or a visual alert. The pressure regulator is also configured to adjust the pressure in the at least one inflatable cuff of the cuff assembly in response to the detected leak.

[0016] In one or more embodiments above, the first inflation lumen includes a first distal end coupled to the interior of the at least one inflatable cuff, and the first inflation lumen also has a second proximal end fluidly coupled to a first air pump and a first release valve for adding or removing air from the at least one inflatable cuff.

[0017] In one or more of the above embodiments, a pressure sensor device measures the tracheal wall pressure applied by the cuff assembly.

[0018] In one or more of the above embodiments, the pressure regulator adjusts the pressure of at least one inflatable cuff of the cuff assembly in response to the detected leak and tracheal wall pressure.

[0019] In one or more of the above embodiments, the at least one inflatable cuff is an inner cuff positioned adjacent to the airway tube, and the cuff assembly further includes an inflatable outer bladder positioned adjacent an outer surface of the inner cuff.

[0020] In one or more of the above embodiments, a pressure sensor device configured to measure tracheal wall pressure is positioned between the inner cuff and the outer bladder.

[0021] In one or more embodiments above, the inner cuff is configured to be inflated within a first pressure range and the outer bladder is configured to be inflated within a second pressure range, where the first pressure range is less than the second pressure range.

[0022] In one or more embodiments above, the at least one perfume material comprises a perfume-embedded polymeric film, wherein the perfume-embedded film is non-degradable, water-resistant, and does not alter the elasticity of the at least one inflatable cuff.

[0023] In one or more embodiments above, the predetermined scent in the at least one inflatable cuff is released in detectable amounts over a period of 2 to 3 months.

[0024] In one or more embodiments above, the at least one scent detector is configured to detect at least one predetermined scent in above-cuff air from the trachea.

[0025] In one or more of the above embodiments, the user interface issues an audible or visual alert when the at least one scent detector detects the at least one predetermined scent in the air above the cuff.

[0026] In one or more of the above embodiments, the pressure regulator is configured to adjust the pressure of the cuff assembly when the at least one scent detector detects the at least one predetermined scent in the air above the cuff.

[0027] In one or more of the above embodiments, the pressure sensor device measures the tracheal wall pressure applied by the cuff assembly, and the pressure regulator adjusts the pressure in the cuff assembly in response to the tracheal wall pressure.

[0028] In one or more embodiments above, the pressure regulator adjusts the pressure in the inner cuff and / or the outer bladder in response to the scent detector detecting at least one predetermined scent. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a perspective view of one embodiment of a leak detection airway tube. [Figure 2] FIG. 2 is a cross-sectional view of one embodiment of a leak detecting airway tube. [Figure 3] FIG. 3 is another cross-sectional view of an exemplary embodiment of a leak detecting airway tube. [Figure 4] 4A and 4B are a schematic block diagram and a perspective view of an embodiment of a scent detection system, respectively, and a filter and vacuum pump of the scent detection system, respectively. [Figure 5] FIG. 5 is a schematic block diagram of one embodiment of a pressure sensor for a dual cuff assembly in an airway tube. [Figure 6] FIG. 6 is a schematic block diagram of an exemplary embodiment of a pressure regulator and control system for a cuff assembly. [Figure 7] FIG. 7 is a flow diagram of an embodiment of one or more methods for monitoring and controlling the pressure in the cuff assembly by a regulator system. [Figure 8] 8A and 8B are a flow diagram of one embodiment of a method for determining the operating pressure of a cuff assembly. [Figure 9] FIG. 9 is a schematic block diagram of one embodiment of a user interface for the pressure regulator system. [Figure 10] FIG. 10 is a schematic block diagram of one embodiment of a pressure regulator system. [Figure 11] FIG. 11 is a schematic block diagram of one embodiment of a leak detection and pressure regulation system for a single cuff assembly. [Figure 12] FIG. 12 is a schematic flow diagram of one embodiment of a method for detecting leaks in a tracheal seal formed by a cuff assembly in an airway tube. DETAILED DESCRIPTION OF THE INVENTION

[0030] The words "exemplary" or "embodiment" are used herein to mean "serving as an example, instance, or illustration." Any embodiment or aspect described herein as "exemplary" or "embodiment" is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term "aspects" does not require that all aspects of the disclosure include the discussed feature, advantage, or mode of operation.

[0031] The following embodiments will be described in detail with reference to the drawings. In the following description, numerous specific details are set forth in order to thoroughly understand the aspects described herein. However, it will be apparent to one skilled in the art that these and other aspects may be practiced without some or all of these specific details. Furthermore, well-known steps in process methods may be omitted from the flow diagrams presented herein so as not to obscure aspects of the present disclosure. Similarly, well-known components in devices may be omitted from the figures and descriptions thereof presented herein so as not to obscure aspects of the present disclosure.

[0032] Current pressure management systems require manual monitoring and adjustment of cuff pressure on endotracheal or tracheostomy tubes. This manual regulation is impractical, unreliable, and takes up valuable hospital staff time. This application describes a new and innovative pressure management system that continuously receives and processes input from relevant sources and seamlessly and automatically adjusts the pressure in the inflatable cuff. Such an automated system could reduce the workload for hospital staff and help protect patients from tracheal injury and ventilator-associated pneumonia.

[0033] Furthermore, current pressure management systems are prone to failure because they cannot detect leaks around the inflatable cuff. Ultimately, whether a patient suffers from VAP depends on whether oral and nasal secretions leak into the lungs, which in turn depends on whether there is a gap between the cuff and the tracheal wall. The presence of a gap between the cuff and the tracheal wall can be detected by measuring air leakage through the seal. This application describes a new and innovative pressure management system and method that can accurately determine air leakage through the seal formed by the inflatable cuff against the tracheal wall.

[0034] Another significant reason current pressure management systems fail is their inability to accurately measure the pressure the cuff is exerting on the tracheal wall (tracheal wall pressure). Current pressure management systems only measure the pressure inside the cuff (intracuff pressure). However, intracuff pressure provides little insight into tracheal wall pressure. Safe cuff inflation levels are proportional to tracheal wall pressure, not intracuff pressure. Caring for intubated patients without knowing this critical information is less than ideal. Current methods of adjusting cuff pressure based on an arbitrary target value (such as the CDC-recommended 25 cmH2O) completely ignore something essential to patient safety and well-being. This application further describes new and innovative pressure management systems and methods that accurately determine tracheal wall pressure and improve patient outcomes.

[0035] overview Described herein is a pressure management system that has an effective means of monitoring tracheal wall pressure by utilizing an inter-cuff pressure sensor attached to the interface between the inner cuff and outer bladder of a dual-cuff assembly. The pressure management system performs pressure checks at predetermined intervals and adjusts the cuff volume to maintain a predetermined pressure within the cuff assembly. Also described herein is a leak detection system that detects air leaks in the seal between the tracheal wall and the cuff assembly. A strip, such as a scent-impregnated plastic film, is applied to the underside of the cuff assembly below the seal with the tracheal wall. In this configuration, if there is an air leak in the seal, the scent leaks through the plastic film and enters the air in the trachea proximal to the cuff assembly. A scent detector is configured to sample the air proximal to the cuff assembly. If the scent detector detects a scent, an alert is generated. The pressure management system receives input from the pressure sensor along with the scent detector. The pressure management system automatically adjusts the pressure within the cuff assembly and generates an alert depending on the input from the pressure sensor and the scent detector.

[0036] Embodiments of an Airway Tube Having a Dual Cuff Assembly This paper further describes airway tubes, including medical tubes with inflatable cuff assemblies, such as tracheostomy tubes and endotracheal tubes. In one embodiment, the inflatable cuff assembly includes a dual cuff. Unlike previously known inflatable cuffs, the dual cuff assembly described herein includes at least two independently controlled inflatable cuffs. Currently, there are two main types of cuffs: low-volume, high-pressure (LVHP) cuffs and high-volume, low-pressure (HVLP) cuffs. LVHP cuffs are made of stiffer, relatively inelastic materials. Because of their inherent stiffness, LVHP cuffs require higher pressures (50 cmH2O to 100 cmH2O) to inflate them. As a result, LVHP cuffs exert excessive pressure on the tracheal mucosa, even when inflated to the minimum pressure required to create a seal with the tracheal wall. This high pressure results in an unacceptably high incidence of tracheal ischemia and necrosis, ranging from 5% to 20%. Nevertheless, when inflated, LVHP cuffs have the important advantage of providing a better tracheal seal due to the relatively few folds and wrinkles.LVHP cuffs were first adopted in the 1960s, but today they have been widely replaced by HVLP cuffs.

[0037] HVLP cuffs are constructed of a more stretchy, flexible material that inflates at lower pressures. To compensate for the low-pressure characteristics and create a seal against the tracheal wall, the diameter of the HVLP cuff is typically 1.5 to 2 times the diameter of the trachea when fully inflated. However, the increased volume of the HVLP cuff requires a larger amount of cuff material, making the HVLP cuff bulky and difficult to intubate. Furthermore, the excess material tends to form wrinkles and folds due to "incomplete inflation." These wrinkles and folds can create a pathway for gastric secretions to pass past the HVLP cuff, ultimately leading to microaspiration and pulmonary infection.

[0038] When examining the effects of cuff pressure on the trachea, it is important to remember that the human tracheal wall mucosal capillary perfusion pressure is 22–32 mmHg, and that pressures above 30 cmH2O (22 mmHg) impair tracheal mucosal blood flow, and 50 cmH2O (37 mmHg) may completely block blood flow to some areas. Thus, it is clear that there is little overlap between the safe pressure range and the range of complications. The window of efficacy and safety is very narrow, if nonexistent.

[0039] The pressure required to achieve proper inflation with acceptable levels of wrinkles and folds in a typical HVLP cuff is approximately 32 cmH2O. Guidelines established by various medical societies and organizations recommend maintaining HVLP cuff pressures between 20 and 30 cmH2O to avoid obstruction of tracheal mucosal blood flow. Unfortunately, studies have shown that even at pressures up to 60 cmH2O, microaspiration occurs with HVLP cuffs, suggesting that even higher pressures can leave cuff wrinkles, potentially allowing secretions to pass through. While HVLP cuffs appear superior because they can seal at lower pressure levels and avoid tracheal wall necrosis, they are still not ideal.

[0040] The primary goal of an inflatable cuff is to provide a maximal airway seal and minimize airway trauma, a straightforward goal that has been difficult to achieve successfully. Despite numerous refinements and advancements in materials, shapes, and volumetric configurations, this failure continues. Thus, there is a need for improved cuff systems that maintain a good seal with the tracheal wall, without excessive trauma to the tracheal wall, and that help reduce pulmonary microaspiration and infection.

[0041] In the embodiments described herein, a high-pressure outer bladder is attached to the outer surface of an inner cuff. The inner cuff is coupled to the distal end of an endotracheal or tracheostomy tube. The inner cuff is a low-pressure inflatable cuff configured to function in a low-pressure range of 10 cmH2O to 20 cmH2O. In contrast, the outer inflation bladder is configured to inflate to a high-pressure range of 50 cmH2O to 150 cmH2O. Thus, the inner cuff operates in a lower pressure range than the outer bladder.

[0042] 1-3 illustrate one embodiment of a leak detection tracheostomy tube 100. FIG. 1 is a perspective view of the tracheostomy tube 100, and FIGS. 2-3 are different cross-sectional views of the tracheostomy tube 100 shown in FIG. 1. While a tracheostomy tube 100 is illustrated in this example, the leak detection systems and methods described herein may be implemented in an endotracheal tube or other medical device that includes an inflatable cuff or other type of airtight seal. The tracheostomy tube 100 in this example includes an outer cannula 102 and an inner cannula 150, with the inner cannula 150 positioned inside the outer cannula 102. The outer cannula 102 and inner cannula 150 may be constructed of a soft polyvinyl chloride (PVC) material.

[0043] The outer cannula 102 includes a proximal segment 112, a curved middle segment 114, and a distal segment 116. The proximal segment 112 of the outer cannula 102 includes a flange 108 or plate extending radially outward and having two slits 118a, 118b on opposite sides. A cotton bandage or strap can be secured to the slits 118a, 118b in the flange 108 to hold the tracheostomy tube 100 around the patient's neck. The proximal segment 112 further includes a hub 110 extending proximally upward from the flange 108. The inner cannula 150 is inserted through a proximal opening in the hub 110. A proximal opening 152 of the inner cannula 150 is configured to connect to a ventilator through a tube or hose.

[0044] The outer cannula 102 of the tracheostomy tube 100 includes a curved intermediate segment 114 and a distal segment 116 that are configured and sized for placement within a patient's trachea. The intermediate segment 114 is curved such that the proximal segment 112 is at an angle of about 80 to about 90 degrees relative to the distal segment 116. The distal segment 116 includes a cuff assembly 120, a distal end 126, and a main distal opening 138.

[0045] The tracheostomy tube 100 includes a novel dual-cuff assembly 120 disposed on the distal segment 116. The cuff assembly 120 comprises at least two independently controlled inflatable cuffs, including a first inner cuff and a second outer bladder 122. The first inner cuff 124 is disposed adjacent to the circumference of the outer cannula 102 and is configured to inflate radially outward from the tracheostomy tube 100. The second outer bladder 122 is disposed adjacent to the outer surface of the inner cuff 124, such that at least a portion of the inner cuff 124 is located between the outer bladder 122 and the tracheostomy tube 100. The outer bladder 122 is configured to inflate radially outward from the inner cuff 124 such that, when placed in a patient's trachea, the outer surface of the outer bladder 122 contacts the tracheal wall to form a seal.

[0046] The inner cuff 124 and outer bladder 122 may be cylindrical or toroidal. For example, as seen in FIG. 1, the outer bladder 122 is a torus-shaped ring with a circular cross section when inflated. The inner cuff 124 is cylindrical with an arched outer surface that forms a ring around the tracheostomy tube 100. In this example, the inner cuff is 10 mm to 20 mm long, and the outer cuff is 5 mm to 9 mm long. The outer bladder 122 is glued to the inner cuff 124 and is not fixed to the outer cannula 102 of the tracheostomy tube 100. The inner cuff 124 is attached to the outer cannula 102 by adhesive and / or bands. These specifications are exemplary, and the inner cuff 124 and / or outer bladder 122 may have other shapes, dimensions, and attachment means.

[0047] The inner cuff 124 and the outer bladder 122 are configured for different operating pressures, and therefore, the tracheostomy tube 100 includes means for inflating the inner cuff 124 and the outer bladder 122 to different pressures. In one example, a first inflation line 106a is disposed within a first channel 200, shown in FIG. 2 . The first channel 200 is formed between the inner and outer walls of the outer cannula 102. The first channel 200 extends from a flange 108, such as the hub 110, proximal to at least the cuff assembly 120 on the front side of the outer cannula 102. A distal end 206 of the inflation line 106a extends through an opening 204 in the outer wall of the outer cannula 102 into the inner cuff 124. The inflation line 106a forms an airtight fluid connection for inflation and deflation of the inner cuff 124.

[0048] A second inflation line 106b is disposed within the second channel 300 shown in FIG. 3 . The second channel 300 is formed between the inner wall 302b and the outer wall 302a of the front of the outer cannula 102. The second channel 300 extends from proximal to the flange 108 of the hub 110 of the outer cannula 102 to at least the cuff assembly 120. The second inflation line 106b is disposed within the second channel 300. The distal end of the inflation line 106b extends through a sealed opening 304 in the outer wall 302a of the outer cannula 102 into the outer bladder 122. The inflation line 106b forms an airtight fluid connection for inflating and deflating the outer bladder 122.

[0049] In this embodiment, two channels 200, 300 are formed in the front wall of the outer cannula 102 to hold the inflation lines 106a, 106b. In another embodiment, two channels 200, 300 may be formed in the side wall of the outer cannula 102. In yet another embodiment, a single channel may hold both inflation lines 106a, 106b. In yet another embodiment, the channels 200, 300 may be formed between the inner cannula 150 and the outer cannula 102, for example, on the front side of the tracheostomy tube 100. Other implementations for disposing the inflation lines 106a, 106b from the proximal side of the flange 108 to the cuff assembly 120 of the tracheostomy tube 100 are also possible.

[0050] Separate means for inflation, such as inflation lines 106a-b, allow the outer bladder 122 and the inner cuff 124 to be inflated and maintained at different pressures. In one embodiment, the inner cuff 124 is a low-pressure inflatable cuff configured to function at a low pressure range of 10 cmH2O to 20 cmH2O. In contrast, the outer inflation bladder 122 is configured to inflate to a high pressure range of 50 cmH2O to 150 cmH2O. Thus, the inner cuff 124 operates at a lower pressure range than the pressure range of the outer bladder 122.

[0051] Furthermore, the inner cuff 124 is made of a relatively elastic material while the outer bladder 122 is made of a relatively inelastic material, e.g., the material of the outer bladder 122 is less elastic than the material of the inner cuff 124. For example, the relatively elastic material of the inner cuff 124 may include one or more of rubber, silicone, latex, polyvinyl chloride (PVC), neoprene, polyisoprene, or polyurethane (PU). The relatively inelastic material of the outer bladder 122 may include one or more of polyethylene terephthalate (PETP), low-density polyethylene (LDPE), polyvinyl chloride (PVC), silicone, neoprene, polyisoprene, or polyurethane (PU).

[0052] In use, for example, when placed in a patient's trachea and pressurized to an inflated state, the first inner cuff 124 operates as an HVLP-type cuff, and the second outer bladder 122 operates as an LVHP-type cuff. The more flexible inner cuff 124 can cushion the pressure exerted on the tracheal wall by the more pressurized outer bladder 122 ("intratracheal pressure"). In other words, the lower-pressure, more elastic inner cuff 124 is configured to absorb excess pressure that may be exerted on the tracheal wall by the outer bladder 122. For example, because the inner cuff 124 is more flexible and elastic, the cuff assembly 120 exerts a lower total pressure / force on the tracheal wall, e.g., a pressure lower than the outer bladder pressure. The force of the inner cuff 124 acts radially on the outer bladder 122, ultimately resulting in a force on the trachea that is referred to as intratracheal pressure. In other words, the radial force generated by the inner cuff 124 and acting on the outer bladder 122 is the intratracheal pressure. For example, when the outer bladder pressure is greater than the inner cuff pressure and the outer bladder 122 is inflated so that its outer surface contacts the trachea, the pressure between the cuffs becomes equal to the tracheal wall pressure.

[0053] Additionally, because it operates at high pressure, the inflated outer bladder 122 presents a relatively smooth surface with fewer wrinkles and creases than, for example, an LVHP cuff. The reduced wrinkles reduce the risk of leaks and create a more uniform tracheal seal.

[0054] Thus, the cuff assembly 120 reduces tracheal complications by utilizing an innovative system for titrating intratracheal pressure. By incorporating the characteristics of HVLP and LVHP cuffs into the cuff assembly 120, the cuff assembly 120 utilizes the advantages of both types of cuffs: excellent tracheal sealing and increased tracheal safety. The cuff system 120 provides an excellent seal against the tracheal wall and is less damaging to the trachea. Therefore, the cuff assembly 120 helps protect the lungs from contamination by stomach contents and blood without excessively damaging the tracheal wall.

[0055] The cross section of airway tube 100 in Figure 2 also shows suction channel 136 and associated tubing 134. Inspiratory opening 130 is shown at the rear of the airway tube, but may be located at the front or proximal side of cuff assembly 120. In this example, stopper 210 is located in suction channel 136 distal to inspiratory opening 130. Stopper 210 is sized to occlude and seal suction channel 136 and prevent air or liquid from flowing into the distal end 126 of airway tube 100.

[0056] Example of a leak detection system In one embodiment, the tracheostomy tube 100 also includes a leak detection system that detects air leaks in the seal between the tracheal wall and the cuff assembly 120. The leak detection system includes a scent-impregnated plastic film 128 or other material that is positioned at the distal end 126 of the tracheostomy tube 100, e.g., distal to the seal with the tracheal wall, as shown in Figures 1-3. In this example, the scented film 128 includes a strip circumferentially applied around the anterior portion of the inner cuff 124.

[0057] The scented film 128 may include one or more scents, such as woody, refreshing, grassy, ​​floral, fruity, etc. The predetermined scent is preferably long-lasting, tolerable, pleasant, and safe for humans. Furthermore, the predetermined scent is configured to chemically interact with the chemical sensor of the scent detector.

[0058] One or more predetermined scents are impregnated into one or more plastic polymers and fabricated into a thin film. The plastic polymers may include polyethylene, polypropylene, polystyrene, cellulose derivatives, acrylonitrile butadiene styrene, etc. The one or more plastic polymers are formulated to slowly release detectable amounts of the impregnated scent over an extended period of time, such as two to three months, after opening. The thin film preferably has a long shelf life, preserving the one or more predetermined scents impregnated into the one or more plastic polymers until opened, such as in a sealed, airtight package. The scented film 128 is preferably thin and flexible, such as 1 mm or less, so as not to significantly alter the elastic properties of the inner cuff 124. The scented film 128 is preferably non-toxic to the human body and resistant to degradation and liquids. The scented film 128 can be applied with adhesive and / or heat or other means. While a scent-embedded plastic polymer film is described herein, other types of scented materials may be used, including slowly evaporating scents detectable by a scent detector.

[0059] The scented film 128 may be applied to the anterior portion of the inner cuff 124 as shown, or may be positioned on the anterior portion of the outer bladder 122, so long as the scented film 128 is below the seal formed between the cuff assembly 120 and the tracheal wall. Alternatively, the scented film 128 may be positioned near or adjacent to the distal end 126 of the tracheostomy tube 100, preferably near or adjacent to the cuff assembly 120. The scented film 128 is preferably not positioned near the distal opening 138 of the airway tube 100, as this may result in unnecessary exposure to inhaled and exhaled air, which could cause the scent to evaporate quickly from the film 128. Positioning the scented film 128 away from the airflow, such as behind, adjacent to, or just distal to the cuff assembly 120, may allow the scent of the scented film 128 to last longer.

[0060] To detect air leaks, an inlet opening 130 is formed in the outer wall of the airway tube 100 proximal to the cuff assembly 120, e.g., above the seal with the tracheal wall. The inlet opening 130 fluidly connects the above-cuff air in the trachea to a suction channel 136 (see FIGS. 2 and 3 ). A stopper 140 is disposed in the suction channel 136 distal to the opening 310 to prevent air from entering the suction channel 136 from the distal side of the cuff assembly 120. In another embodiment, the suction channel 136 terminates at the inlet opening 130. The proximal end of the suction channel 136 is attached to the air tube 134 at the hub 110. An air pump is fluidly connected to the opposite end of the air tube 134, and the air pump is fluidly connected to the inlet opening 130. The air tube 134 or the air pump further includes a valve that fluidly connects the scent detector to the above-cuff air flowing through the air tube 134.

[0061] When the tracheostomy tube 100 is placed on a patient and the cuff assembly 120 is inflated, an airtight seal must be formed between the cuff assembly 120 and the tracheal wall to prevent leakage of fluids and / or secretions into the trachea. If an airtight seal is not formed, air will flow from the scented film 128, through the seal, and into the intake opening 130. The scented air flows through the suction channel 136 into the air tube 134 and is delivered to the scent detector. In this manner, the scent detector can detect the scent and generate an alert that the seal is faulty, as described in more detail herein.

[0062] FIG. 4A is a schematic block diagram of one embodiment of a scent detection system 400. The system 400 includes one or more scent detectors 410 and a vacuum pump 420. In one embodiment, the scent detector 410 is an electronic device that includes at least one receptor and at least one transducer. The receptor contains a compound designed to react with chemicals contained in a predetermined scent of the scented film 128. The transducer then measures the chemical response to the predetermined scent. The chemical response can increase or decrease the impedance of the receptor. For example, a polymer in the transducer expands when exposed to a predetermined scent, causing a change in resistance. The change in the polymer's resistance is measured, and the measurement identifies the presence of the predetermined scent.

[0063] The scent detection system's vacuum pump 420 acts as a low-pressure vacuum, aspirating above-cuff air from the trachea. The vacuum pump 420 or air tube 134 includes a valve and port for supplying above-cuff air samples to the scent detector. Before the next test, the air above the cuff in the trachea must be circulated and replaced to determine whether scented air is still leaking through the seal on the tracheal wall. Otherwise, after the seal is strengthened and airtight, the air pump will supply scented air remaining in the trachea from the previous test to the scent detector 410. The scent detector 410 will then detect the scent and trigger an alarm, even though the seal is now airtight. To prevent this repeated sampling of the same air, the vacuum pump 420 aspirates air from the trachea for a predetermined period of time. This suction period removes previously collected air from the trachea and draws new air into the trachea. After the predetermined suction period, the air aspirator 420 supplies the air sample to the scent detector 410 to test for the presence of the desired scent. When the scent detector 410 detects a predetermined scent, it issues an alarm, which may include, for example, an audible alarm and / or a visual alarm on a display.

[0064] A filter 430 may be implemented to filter the air sample from the suction channel 136 and / or tubing 134. The air sample may contain secretions and other liquids that have accumulated in the supracuff region, particularly proximal to the cuff assembly 120. The air sample in the suction channel 136 and tubing 134 may contain such fluids. The filter 430 is configured to remove secretions and other liquids from the air sample without substantially removing predetermined scents in the air sample. In one embodiment, suction and filtering of air and secretions from the supracuff region may be performed at regular intervals, even when a scent detection test is not being performed. Periodic suction of fluid from the supracuff region in this manner can prevent the accumulation of secretions that could lead to leakage into the lungs.

[0065] 4B is a perspective view of one embodiment of filter 430 and vacuum pump 420. In this example, filter 430 is a liquid collection canister coupled to suction channel 136 through tubing 134. When supracuff air containing secretions and other liquids enters the canister, the liquid falls to the bottom of the canister due to its own weight. The air and aroma remain at the top of the canister. An aspiration vacuum draws an air sample from the top of the canister and sends it to the aroma detector. This collection canister can be equipped with an overflow shut-off valve to prevent spillage.

[0066] While a liquid collection canister is described herein, other types of air filters may be implemented. For example, a coalescing filter may be implemented, which uses a filter media to remove liquid droplets and other particulates from the air. In other examples, a mist eliminator or vapor removal filter is an alternative to a coalescing filter.

[0067] In one embodiment, a syringe or vacuum can be attached to tube 134 to remove secretions or other fluids that accumulate proximal to cuff assembly 120 when air testing is not being performed. Aspiration of secretions occurs periodically and can be manual or automatic.

[0068] Although a tracheostomy tube 100 is described herein, the cuff assembly 120 may be implemented in combination with any suitable medical device, including, but not limited to, an endotracheal tube or other airway tube, a catheter, a stent, and / or a feeding tube.

[0069] Example of a pressure regulation system 5 is a schematic block diagram of one embodiment of a pressure sensor for airway tube 100 (e.g., a tracheostomy tube, an endotracheal tube, or other airway tube) including cuff assembly 120. In one embodiment, cuff assembly 120 includes at least one intra-cuff pressure sensor 510a associated with inner cuff 124 and at least one intra-cuff pressure sensor 510b associated with outer bladder 122. Intra-cuff pressure sensor 510a is disposed within inner cuff 124 and configured to measure the air pressure within inner cuff 124. Additionally or alternatively, a pressure sensor (not shown) may be disposed at the proximal end of inflation line 106a, for example as part of a pilot balloon, to measure the air pressure within inner cuff 124. Intra-cuff pressure sensor 510b is disposed within outer bladder 122 and configured to measure the air pressure within outer bladder 122. Additionally or alternatively, a pressure sensor (not shown) may be located at the proximal end of inflation line 106b, for example, at the pilot balloon, to measure the air pressure within outer bladder 122.

[0070] In one embodiment, one or more pressure sensors 530a-b may be positioned on the outer surface of the outer bladder 122 to measure the pressure or force ("tracheal pressure") that the cuff assembly 120 exerts on the tracheal wall. However, if these sensors 530a-b are pressed against the tracheal wall, they may cause damage to the tracheal wall. Therefore, additionally or alternatively, one or more inter-cuff pressure sensors 520a-b may be positioned between the outer bladder 122 and the inner cuff 124 to measure intra-tracheal pressure. Because the force of the inner cuff 124 acts radially on the outer bladder 122, the inter-cuff pressure sensors 520a-b ultimately measure the force that the cuff assembly 120 exerts against the tracheal wall. In this manner, the inter-cuff pressure sensors 520a-b measure the tracheal pressure, e.g., the pressure that the cuff assembly 120 exerts against the tracheal wall. In one example, tracheal wall pressure sensors 520a-b and 530a-b may comprise thin-film pressure sensors including force-sensing resistors whose resistance changes based on applied force. Pressure sensors 510a-b may include resistive or capacitive air pressure transducers. Additional pressure sensor devices may be located within the pilot balloons of inflation lines 106a-b to measure intra-cuff pressure, or within or at the distal end of airway tube 100 to measure the pressure of oxygenated air being delivered to the patient.

[0071] Each pressure sensor may include a wireless transmitter for communicating pressure measurements to the pressure regulation system. For example, the wireless transmitter may include a short-range wireless transmitter, a radio frequency identification (RFID) transmitter, an Internet of Things (IoT) cellular transmitter, etc. The pressure sensors may alternatively include a wired transmitter for communicating pressure measurements.

[0072] The benefits and risks of the cuff assembly 120 lie more in maintaining a predetermined pressure range within the cuff assembly 120 than in the airway tube 100 itself. For example, overinflation of the cuff assembly 120 can cause ischemic injury and vocal cord nerve damage, leading to tracheal mucosal damage. This damage occurs when the constant pressure exerted by the cuff restricts blood flow to the tracheal mucosa. This lack of blood flow can lead to tissue necrosis. Furthermore, repeated friction of the cuff against the tracheal wall can cause injury. If the cuff is underinflated and the tracheal seal is inadequate, the patient may not receive enough oxygen. Furthermore, the patient may be at increased risk of pneumonia due to aspiration of gastric contents. Therefore, maintaining pressure within the cuff assembly 120 of the airway tube 100 is a critical component of patient care in terms of reducing tracheal injury and preventing ventilator-associated pneumonia (VAP).

[0073] Several types of automatic cuff pressure regulators are currently available. These current devices monitor intracuff pressure within a single cuff. However, closer examination reveals significant flaws in this approach. The intracuff pressure does not reflect the exact pressure exerted on the tracheal wall, but only the air pressure within the inflated cuff. Ultimately, it is the tracheal wall pressure that determines both the risks and benefits of the cuff. Therefore, improved systems and methods for monitoring and adjusting cuff pressure are needed.

[0074] 6 is a schematic block diagram of an exemplary embodiment of a pressure regulator and control system (“regulator system”) 600 for cuff assembly 120. Regulator system 600 is in fluid communication with cuff assembly 120, for example, when airway tube 100 is placed in a patient's trachea, and uses tracheal wall pressure measurement and leak detection to inflate and regulate the pressure in cuff assembly 120. Regulator system 600 includes a pressure controller 606 and a pneumatic system 620. Pressure controller 606 includes a processor device 608 and a memory device 610. Memory device 610 includes one or more non-transitory processor-readable memories that store instructions that, when executed by processor device 608 or other components of regulator system 600, cause regulator system 600 to perform one or more functions described herein. The processor device 608 includes at least one processing circuit, such as a microprocessor, microcontroller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuit, analog circuit, digital circuit, and / or any device that manipulates signals (analog and / or digital) based on hard-coding of circuit and / or operational instructions. The memory device 610 includes non-transitory memory devices and may be internal or external memory, and may be a single memory device or multiple memory devices. The memory device 610 may be read-only memory, random-access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, and / or any non-transitory memory device that stores digital information.

[0075] The pressure controller 606 may be located with the pneumatic system 620 in the same physical device or may be located separately in a separate device or case. The pressure controller 606 further includes a user interface 612. The user interface 612 generates user input / output (I / O) and includes one or more of a display, keyboard, touch screen, mouse, touch pad, gauges, switches, or other I / O devices.

[0076] In use, a pressure setting for the cuff assembly 120 is determined. The pressure controller 606 can use a default pressure setting or a pressure setting received from the user. Different pressure settings are used for the inner cuff 124 and the outer bladder 122. For example, the pressure setting for the inner cuff can be a pressure within the range of 10 cmH2O to 20 cmH2O (plus or minus 2 cmH2O). In contrast, the pressure setting for the outer inflation bladder can be a pressure between 50 cmH2O and 150 cmH2O (plus or minus 2 cmH2O). Thus, the inner cuff 124 operates at a lower pressure range than the operating pressure range of the outer bladder 122. The pressure controller 606 also determines the frequency at which to measure and adjust the pressure in the cuff assembly 120, for example, either by user input or a default setting.

[0077] The pneumatic system 620 has a first air pressure path for the outer bladder 122, which includes, for example, a first air pump 622a and a release valve 624a fluidly coupled to the outer bladder 122 via inflation line 106b. The pneumatic system 620 also has a separate, second air pressure path for the inner cuff 124, which includes, for example, a second air pump 622b and a release valve 624b fluidly connected to the inner cuff 124 via inflation line 106a. While two air pumps 622a, 622b are described herein, a single air pump may supply pressurized air to the inner cuff 124 and the outer bladder 122, for example, using a valve or switch between the two fluid paths. In this manner, the pneumatic system 620 includes separate air pressure paths that fluidly increase and decrease the pressure in the inner cuff 124 and the outer bladder 122 independently and separately.

[0078] In operation, the pressure controller 606 receives pressure measurements from one or more pressure sensor devices and regulates the pressure in the cuff assembly 120. For example, the one or more pressure sensor devices may include one or more intra-cuff pressure sensor devices 510a-b disposed within the inflated inner cuff 124 and outer bladder 122 and / or within pilot balloons of the inflation lines 106a-b to the cuff assembly 120. For example, the intra-cuff pressure sensor devices 510a-b measure the internal pressure of the inner cuff 124 and outer bladder 122 and communicate the measurements to the pressure controller 606. Additionally, one or more inter-cuff pressure sensor devices 520a-b measure tracheal wall pressure. One or more outer cuff assembly pressure sensor devices 530a-b may be disposed on the exterior of the outer bladder 106 to further measure tracheal wall pressure. The pressure controller 606 may also receive input from one or more scent detectors 410. Additional pressure sensor devices may also be implemented. The pressure sensor device generates and communicates pressure measurements to the pressure controller 606, for example, via wired leads and / or a wireless transmitter.

[0079] The regulator system 600 includes a pressure feedback loop in which a pressure controller 606 controls an air pressure system 620 to adjust the pressure in both the inner cuff 124 and the outer bladder 122 in response to pressure measurements and / or a scent detector. The pressure in the inner cuff 124 and the outer bladder 122 are monitored and controlled separately. The pressure controller 606 signals the air pressure system 620 to add or release air to the outer bladder 122 and / or the inner cuff 124. For example, to adjust the pressure in the outer bladder 122, the pressure controller 606 can signal an air pump 622a to add air to the outer bladder 122 or a release valve 624a to release air from the outer bladder 122. In another example, to adjust the pressure in the inner cuff 124, the pressure controller 606 can signal an air pump 622b to add air to the inner cuff 124 or a release valve 624b to release air from the inner cuff 124.

[0080] Regulator system 600 monitors pressure readings from the pressure sensor and alerts from the scent detector and automatically adjusts the pressure in cuff assembly 120 accordingly. Pressure controller 606 may continuously monitor and adjust the pressure in cuff assembly 120 or may monitor and adjust the pressure at predetermined intervals. Regulator system 600 may further include a visual and / or audible alarm if the pressure reading is unsafe.

[0081] FIG. 7 is a flowchart of one or more embodiments of a method 700 for monitoring and controlling pressure in the cuff assembly 120, for example, by the regulator system 600. At step 702, the regulator system 600 obtains one or more pressure measurements related to the tracheal wall pressure from one or more pressure sensor devices. Using these pressure measurements, the regulator system 600 determines, at step 704, whether the intratracheal pressure, e.g., the pressure exerted by the cuff assembly 120 on the tracheal wall, is within a predetermined pressure range. The pressure measurements may be obtained from one or more inter-cuff pressure sensor devices 520a-b between the inner cuff 124 and the outer bladder 122 and / or from one or more pressure sensors 530a-b disposed on the outer surface of the outer bladder 122. If the intratracheal pressure exceeds the predetermined pressure range, the regulator system 600 reduces the pressure in at least the inner cuff 124 at step 706. For example, the regulator system 600 may control the release valve 624b to release air from the inner cuff 124. Because blood flow to the tracheal mucosa can be impaired at pressures above 30 cmH2O (22 mmHg), the regulator system 600 may reduce the pressure in at least the inner cuff 124 when the measured intratracheal pressure exceeds 30 cmH2O (22 mmHg).

[0082] If the intratracheal pressure is below the predetermined pressure range, regulator system 600 increases the pressure in at least inner cuff 124 in step 706. For example, regulator system 600 may control air pump 622b to pump air into inner cuff 124. Additionally, regulator system 600 may adjust the pressure in outer bladder 122. These steps may be performed at preset intervals or continuously.

[0083] In step 708, regulator system 600 obtains one or more pressure measurements related to the outer bladder pressure from one or more pressure sensor devices. Using these pressure measurements, regulator system 600 determines whether the pressure in outer bladder 122 is within a predetermined pressure range in step 710. For example, the pressure measurements may be from one or more pressure sensor devices 510b located in outer bladder 122, a pilot balloon for outer bladder 122, or inflation line 106b for outer bladder 122. If the outer bladder pressure is below or above the predetermined pressure range, regulator system 600 increases or decreases the pressure in outer bladder 122 in step 712. For example, regulator system 600 may control air pump 622a to pump air into outer bladder 122 when the pressure is below the predetermined pressure range and control release valve 624a to release air from outer bladder 122 when the pressure is above the predetermined pressure range. The outer bladder 122 may have a predetermined pressure range of 50 cmH2O to 150 cmH2O.

[0084] At step 714, the regulator system 600 obtains one or more pressure measurements of the pressure in the inner cuff 124 from one or more pressure sensor devices. Using these pressure measurements, the regulator system 600 determines at step 716 whether the pressure in the inner cuff 124 is within a predetermined pressure range. For example, the pressure measurements may be from one or more pressure sensor devices 510a located within the inner cuff 124, a pilot balloon for the inner cuff 124, or an inflation line 106a for the inner cuff 124. If the inner cuff pressure is below or above the predetermined pressure range, the regulator system 600 may increase or decrease the pressure in the inner cuff 124 at step 718. For example, the regulator system 600 may control the air pump 622b to pump air into the inner cuff 124 when the pressure is below the predetermined pressure range and may control the release valve 624b to release air from the inner cuff 124 when the pressure is above the predetermined pressure range. In one example, the predetermined pressure range may be between 10 cmH2O and 20 cmH2O.

[0085] In this manner, the pressure in the inner cuff 124 and the outer bladder 122 of the cuff assembly 120 are independently controlled using separate air pressure paths, e.g., separate air pumps 622 and / or release valves 624, and separate inflation lines 106a-b. The pressure in the less elastic outer bladder 122 is maintained at a higher pressure than the pressure in the more elastic inner cuff 124. Thus, the pressure controller 602 can independently adjust the pressure in the inner cuff 124 or the outer bladder 122 to regulate intratracheal pressure.

[0086] 8A-B are schematic block diagrams of one embodiment of a method 800 for determining the operating pressure of the cuff assembly 120. After implantation, a cuff-bladder pressure adjustment process can be performed to determine the operating pressure. Process 800 may also be performed, in whole or in part, after inflation, in response to leak detection, an out-of-range pressure measurement from either the inner cuff 124, outer bladder 122, or tracheal wall pressure (e.g., from inner cuff sensors 520a-b or outer cuff assembly sensors 530a-b), or in response to a manual request.

[0087] Process 800 begins with pressure regulator system 600 inflating or deflating inner cuff 124 and outer bladder 122 to their respective initial pressure levels at 802. For example, the initial pressure level for inner cuff 124 may include a pressure range of 8-12 cmH2O, or approximately 10 cmH2O. The initial pressure level for outer bladder 122 may include a pressure range of 35-45 cmH2O, or approximately 40 cmH2O. The initial pressure levels may be set by default or may be entered by an operator via user interface 612.

[0088] After the inner cuff 124 and outer bladder 122 are at their respective initial pressure levels, the tracheal wall pressure is obtained at 804. The pressure regulator 600 may determine the tracheal wall pressure from the mean, median, or maximum of measurements from the inter-cuff pressure sensors 520a-b and / or the pressure sensor devices 530a-b on the outer surface of the cuff assembly 120. If the tracheal wall pressure is greater than a predetermined maximum tracheal wall pressure at 806, an alert is generated at 808. The alert may indicate that the maximum intratracheal pressure has been exceeded and / or may indicate that the current airway tube (e.g., endotracheal tube or tracheostomy tube) should be replaced, for example, with an airway tube having a larger outer diameter. Once the airway tube is replaced, the process 800 begins again at 802.

[0089] Once the tracheal wall pressure is below a predetermined maximum tracheal wall pressure at 806, a leak test is performed at 810. The air leak test involves taking an air sample from the supracuff region of the trachea. The air evacuation system of the airway 100 (e.g., opening 130, suction channel 136, airway tube 134, etc.) is connected to a low-pressure vacuum pump 420 to improve circulation in the supracuff region. The aspirated air is sampled for the presence of one or more predetermined scents. No air leak is detected at 812, indicating that the cuff assembly 120 has formed a good seal with the tracheal wall. The pressure in the cuff assembly 120 is maintained and monitored at 814. The air leak test may be repeated periodically or on command to ensure that the cuff assembly 120 maintains a good seal with the tracheal wall.

[0090] If an air leak is detected at 812, this indicates that the cuff assembly 120 is not sealing well against the tracheal wall. To achieve a better seal, the pressure in the inner cuff 124 is adjusted at 816. For example, the pressure in the inner cuff 124 can be increased by 1-2 cmH2O. After the increase in the pressure in the inner cuff 124, it is determined at 818 whether the pressure in the inner cuff is greater than, for example, a maximum inner cuff pressure of 25 cmH2O. If not, it is determined at 820 whether the tracheal wall pressure is greater than or equal to the maximum tracheal wall pressure. If the tracheal wall pressure exceeds the maximum tracheal wall pressure at 820, an alert is generated at 822. The alert may indicate that the maximum tracheal pressure has been exceeded and / or may advise replacing the current airway tube (e.g., endotracheal tube or tracheostomy tube) with, for example, an airway tube with a larger outer diameter. Once the airway tube 100 is replaced, the process 800 begins again at 802.

[0091] If the tracheal wall pressure falls below the maximum tracheal wall pressure at 820, another air leak test is performed at 824. These steps of increasing the pressure in the inner cuff 124 and performing the air leak test may be repeated until the pressure in the inner cuff 124 exceeds the maximum inner cuff pressure (e.g., 25 cmH2O) or the tracheal wall pressure exceeds the maximum tracheal pressure (e.g., 25 cmH2O). If no leak is detected at 824, the pressure in the cuff assembly 120 is maintained and monitored at 826. The air leak test may be repeated periodically or on command to ensure that the cuff assembly 120 maintains a good seal with the tracheal wall.

[0092] If a leak is still detected at 824 and the increase in pressure in the inner cuff 124 exceeds the maximum inner cuff pressure at 818, the process proceeds to step 830 of FIG. 8B, as indicated by arrow A. At step 830, the pressure in the outer bladder 122 is adjusted. For example, the outer bladder pressure may be increased in increments of 2-3 cmH2O. After increasing the pressure in the outer bladder 122, a determination is made at 832 as to whether the pressure in the outer bladder 122 is greater than the maximum outer bladder pressure, e.g., 60 cmH2O. If the outer bladder 122 is greater than the maximum outer bladder pressure at 832, an alert is generated at 834. The alert may indicate that the maximum outer bladder pressure has been exceeded in leak detection and / or may indicate that the current airway tube (e.g., endotracheal tube or tracheostomy tube) should be replaced, for example, with an airway tube having a larger outer diameter. Once the airway tube 100 is replaced, process 800 begins again at 802.

[0093] If the pressure in the outer bladder 122 is not greater than the maximum outer bladder pressure at 832, then the inner cuff pressure is adjusted at 836 to a lower pressure, such as an initial pressure of 10 cmH2O. At 838, it is determined whether the tracheal wall pressure exceeds the maximum tracheal wall pressure. If the maximum tracheal wall pressure is exceeded, then an alert is generated at 840. The alert may indicate that the maximum intratracheal pressure has been exceeded and / or may advise replacing the current airway tube (e.g., endotracheal tube or tracheostomy tube) with, for example, an airway tube having a larger outer diameter. Once the airway tube 100 is replaced, process 800 begins again at 802.

[0094] Once the tracheal wall pressure drops below the maximum pressure at 838, an air leak test is performed at 842. The air leak test determines whether a good seal is formed with the new incremental pressure in the outer bladder 122 and the initial pressure in the inner cuff 124. If no leak is detected at 844, the pressure in the cuff assembly 120 is maintained and monitored at 846. This process continues to step 810 in FIG. 8A and is indicated by arrow C. Periodic air leak tests are performed to ensure that the cuff assembly 120 maintains a good seal with the tracheal wall.

[0095] If a leak is detected at 844 with the new incremental pressure in the outer bladder 122 and the initial pressure in the inner cuff 124, the process proceeds to step 816 in Figure 8A, as indicated by arrow B. The initial pressure in the inner cuff 124 is then increased until either no leak is detected at 824 or the intracuff pressure reaches a maximum value at 818. Once the intracuff pressure reaches a maximum value at 818, the process again proceeds to 830, where the pressure in the outer bladder 122 is increased to a higher pressure. If no air leak is detected at 824 or 844, the inner cuff and outer bladder pressures are below their respective maximum values, and the tracheal wall pressure is below a maximum value, the process 800 is complete.

[0096] In this process 800, the pressure of the inner cuff 124 is first increased through its operating range while maintaining the initial pressure of the outer bladder. If a leak is still detected, the outer bladder pressure is incremented to a higher pressure, and the inner cuff is reset to the initial pressure and incremented within its operating range until no leak is detected. Throughout process 800, the tracheal wall pressure is prevented from exceeding a maximum pressure, for example, within a range of 20-25 cmH2O. If the tracheal wall pressure exceeds the maximum pressure required to achieve airtight inflation of the cuff bladder, the airway tube size is adjusted, for example, by increasing the size to the next larger size. When another airway tube is placed in the patient, the entire process 800 is repeated to adjust the pressure of the cuff assembly 120. In this way, the cuff assembly 120 and regulator system 600 provide a process for determining and maintaining an optimized leak-free operating pressure for the cuff assembly 120. This process helps reduce pulmonary microaspiration and infection by establishing and maintaining a good seal with the tracheal wall without excessive trauma to the tracheal wall.

[0097] 9 is a schematic block diagram of an embodiment of a user interface 900 of the pressure regulator system 600. The user interface 900 receives settings and commands from a user. In one example, the user interface 900 includes a display 902, which may be an interactive touchscreen. The display 902 includes one or more icons or data displays, such as a display of the current tracheal wall pressure 904 and an alarm / warning 906. The display 902 further includes a display of the cuff pressure 908, such as a set or target pressure 910 and a current pressure 912 for the inner cuff 124 and outer bladder 122. The display 902 may also include a display of leak detection 914, such as a last test time 916 and a last test result 918. Additional and / or alternative data may be displayed on the display 902.

[0098] The user interface 900 further includes one or more user input devices, such as a knob controller, push button, touch pad, switch, or the like, for receiving one or more commands from a user. Alternatively, the display 900 may include an interactive touch screen that displays one or more icons for receiving user commands. For example, the user interface 900 includes a power button / icon 930 for initiating power-up of the pressure regulator 600. A deflate button / icon 940 initiates deflation of the cuff assembly 120, such as when disconnecting the airway tube 100 from the patient.

[0099] Activating the automatic mode button / icon 942 initiates automatic mode. In automatic mode, the pressure regulator 600 automatically inflates the cuff assembly to a default setting and performs one or more of the processes described in Figures 8A-B to determine an operating pressure at which no leaks in the cuff assembly 120 are detected. After inflation, in automatic mode, the pressure regulator 600 performs automatic cuff pressure measurements and pressure adjustments of the cuff assembly 120, in addition to leak detection tests, at predetermined intervals. This predetermined interval is 30 minutes by default, but can be manually set between 5 minutes and 4 hours.

[0100] The user interface 900 further includes a manual mode button / icon 944 for initiating manual mode. In manual mode, default settings can be entered, such as a default pressure setting for the cuff assembly 120, a maximum pressure setting for the cuff assembly and / or tracheal wall pressure, a leak detection test interval, and a pressure measurement interval. In manual mode, the "Initial Pressure Settings" button / icon can be manually activated to inflate the cuff assembly 120 to the default settings and perform one or more of the processes described in FIGS. 8A-B to determine the optimal leak-free operating pressure for the cuff assembly 120. After inflation, a cuff pressure measurement check can be manually activated, such as manually adjusting the pressure using the arrow keys 946. A leak detection test can be manually initiated by activating the corresponding icon / button 948. The user interface 900 can also include other commands and / or data for operating the pressure regulator 600.

[0101] 10 is a schematic block diagram of one embodiment of pressure regulator system 600. In one example, user interface 900 is included in a control module 1000, which may also include pressure controller 606. Pneumatic system 620 may be in a separate housing as shown, or may be included in control module 1000. If in a separate housing, pneumatic system 620 and pressure controller 606 may communicate using wired or wireless transmitters.

[0102] The pneumatic system 620 includes a first output port 626a connected to an extension tube 1002a for inflating the outer bladder 122 of the cuff assembly 120. The extension tube 1002a includes an air filter 1004a for filtering contaminants and may be attached to the inflation line 106a of the airway tube 100. The inflation line 106a may include a pilot balloon 1010a for indicating the air pressure within the outer bladder 122. The pneumatic system 620 includes a second output port 626b connected to an extension tube 1002b for inflating the inner cuff 124 of the cuff assembly 120. The extension tube 1002b includes an air filter 1004b for filtering contaminants and may be attached to the inflation line 106b of the airway tube 100. The inflation line 106b may include a pilot balloon 1010b for indicating the air pressure within the inner cuff 124. In addition to inflation lines 106a-b, additional manual inflation lines may be connected to cuff assembly 120 for manually inflating inner cuff 124 and outer bladder 122 using, for example, a parenteral syringe.

[0103] Although the cuff assembly 120 is described as including an inner cuff 124 and an outer bladder 122, the pressure regulation system 600 and methods described herein can also be implemented using a single inflatable cuff. FIG. 11 is a schematic block diagram of one embodiment of a leak detection and pressure regulation system for a single cuff assembly. In this example, the cuff assembly includes a single inflated cuff 1100 surrounding the airway tube 100. One or more intra-cuff sensors 1102 are positioned to measure air pressure within the cuff 1100, for example, within the cuff 1100 and / or within a pilot balloon connected to the inflation line of the cuff 1100. One or more pressure sensors 1104 may be attached to the exterior of the cuff 1100 to measure the force exerted on the tracheal wall. Tracheal wall pressure may be measured using one or more pressure sensors 1106 positioned between the cuff 1100 and the airway tube 100. Pressure measurements from the pressure sensors 1102 , 1104 , 1106 may be periodically transmitted to the pressure controller 606 using a wired or wireless transmitter 614 .

[0104] The airway tube 100 and cuff 1100 may include a leak detection system 1120. The leak detection system 1120 includes one or more scented films 128 disposed distally of the cuff 1100. One or more scented films 128a may be circumferentially disposed around the distal side of the cuff 1100. Additionally or alternatively, one or more scented films 128b may be circumferentially disposed around the airway tube 100. The scented films 128a-b have embedded therein a scent that is detectable by one or more scent detectors 410.

[0105] The airway tube 100 further includes an intake opening 130 formed in its outer wall and in fluid communication with a suction channel 136. The suction channel 136 and opening 130 are preferably proximal to the cuff assembly 120. An air tube 134 is attached to the proximal end of the suction channel 136, and a vacuum pump 420 is attached to the air tube 134. The vacuum pump 420 draws air from the trachea through the opening 130. The vacuum pump 420 obtains air samples for one or more scent detectors 410. The scent detectors 410 communicate measurements to the pressure controller 606.

[0106] The pressure controller 606 may control the vacuum pump 420 and the scent detector 410, and / or a separate processor device 1122 with a memory device 1124 may control the leak detection system 1120. The memory device 1124 includes one or more non-transitory, processor-readable memories that store instructions that, when executed by the processor device 1122 or other components of the leak detection system 1120, cause the leak detection system 1120 to perform one or more functions described herein. The leak detection system 1120 may further include a user interface 1126 and a transmitter 1128.

[0107] 12 is a schematic flow diagram of one embodiment of a method 1200 for detecting leaks in the tracheal seal formed by the cuff assembly 120 in the airway tube 100. The cuff assembly 120 may include a single inflation cuff 1100 or dual cuffs 122, 124. The method 1200 may be performed by a separate leak detection system 1120 or by the pressure controller 606 controlling the cuff assembly 120. At 1202, a command to initiate a leak detection test is obtained. The command may be generated automatically at preset intervals or may be entered manually.

[0108] The vacuum pump 420 is activated for a predetermined period of time at 1204 to obtain an air sample from the trachea proximal to the cuff assembly at 1206. This predetermined period is set to allow the air above the cuff in the trachea to circulate and refresh between tests. The scent detector 410 is exposed to the air sample and determines whether a scent is detected at 1208. If no scent is detected at 1208, the leak detection system 1120 returns to step 1202 and awaits a command to perform another test. If a scent is detected at 1208, an alert is generated at 1210. This alert may be an audible alarm and / or a visual display. The pressure in the cuff assembly 120 may then be adjusted, and the leak detection process may be repeated.

[0109] The cuff assembly 120, pressure adjustment system 600, and leak detection system 1120 improve the protection and safety of intubated patients. The cuff assembly 120 and pressure adjustment system 600 maintain an improved seal with the tracheal wall without excessive trauma to the tracheal wall, reducing secretion leakage and lung infection. Additionally, automated pressure measurement and adjustment saves caregivers time. The leak detection system 1120 provides early warning of a potential problem with the seal the cuff assembly 120 forms with the tracheal wall, allowing for earlier intervention to prevent secretions from leaking into the lungs. Additional or alternative advantages and modifications are possible in one or more of the embodiments described and / or claimed herein.

[0110] As used herein, the terms "operable to" or "configurable to" indicate that an element includes one or more circuits, instructions, modules, data, inputs, outputs, etc., to perform one or more of the described or required corresponding functions, and may further include inferential coupling to one or more other items to perform the described or required corresponding functions. As used herein, the terms "coupled," "coupled," "connected," and / or "connect" or "interconnect" include direct connections or links between nodes / devices and / or indirect connections between nodes / devices through intermediaries. Furthermore, as used herein, an inferred connection (i.e., when one element is connected to another element by inference) includes direct and indirect connections between two items, similar to "connected." As used herein, the terms "substantially" and "about" provide an industry-recognized tolerance for relativity between corresponding terms and / or items.

[0111] It is noted that aspects of the present disclosure may be described herein as a process that is depicted as a schematic, flowchart, flow diagram, structure diagram, or block diagram. While a flowchart describes operations as sequential, many operations may be performed in parallel or concurrently. Additionally, the order of operations may be rearranged. A process terminates when the operation is completed. A process corresponds to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination corresponds to a return of the function to the calling function or the main function.

[0112] Various features of the present disclosure described herein can be implemented in different systems or devices without departing from the present disclosure. It should be noted that the above-described aspects of the present disclosure are merely exemplary and should not be construed as limiting the present disclosure. The description of the aspects of the present disclosure is intended to be illustrative, not limiting, of the claims. Thus, the present teachings can be readily applied to other types of devices, and many alternatives, modifications, and variations will be apparent to those skilled in the art.

[0113] In the foregoing specification, certain representative embodiments have been described with reference to illustrative examples. However, various modifications and changes can be made without departing from the scope of the invention as set forth in the claims. The specification and drawings are illustrative rather than restrictive, and variations are intended to be included within the scope of the invention. Accordingly, the scope of the invention should be determined by the claims and their legal equivalents, rather than merely by the examples described. For example, the components and / or elements recited in any device claim may be assembled or otherwise operatively configured in various permutations and therefore are not limited to the specific configurations recited in the claims.

[0114] Furthermore, although certain advantages, other benefits, and solutions to problems have been described above with respect to particular embodiments, any advantage, effect, solution to a problem, or any element that may cause or make more pronounced any particular advantage, effect, or solution, should not be construed as a critical, essential, or required feature or component of any or all claims.

[0115] As used herein, the terms "comprise," "comprises," "comprising," "having," "including," "includes," or variations thereof are intended to refer to a non-exclusive inclusion, and a process, method, article, composition, or apparatus that includes a list of elements does not include only the listed elements, but may include other elements not expressly listed or elements inherent in such process, method, article, composition, or apparatus. Other combinations and / or variations of the above-described structure, arrangement, application, proportions, elements, materials, or components used in the practice of the invention, in addition to those not specifically described, may be modified or otherwise specifically adapted to particular environments, manufacturing specifications, design parameters, or other operating requirements without departing from its general principles.

[0116] Furthermore, reference to an element in the singular does not mean "one and only one" unless otherwise specified, but rather "one or more." The term "some" refers to one or more unless otherwise specified. All structural and functional equivalents to the elements of the various embodiments described throughout this disclosure that are known or later become known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is expressly recited in the claims. Claim elements are not to be construed as "means-plus-function" type elements under 35 U.S.C. § 112(f) unless the element is expressly recited with the phrase "means for," or, in the case of a method claim, unless the element is recited with the phrase "step for."

Claims

1. A medical device, an airway tube configured for placement in the trachea; a cuff assembly mounted on a distal portion of the airway tube, the cuff assembly including at least one inflatable cuff; at least one flavoring material disposed on a lower portion of the cuff assembly or on an airway tube distal to the cuff assembly; and at least one scent detector configured to detect a predetermined scent from a fragrance substance in the air in response to a leak, wherein the air is sampled from the trachea proximal to the cuff assembly.

2. The airway tube further comprises: an inhalation opening formed in an outer wall of the airway tube proximal to the cuff assembly; 10. The medical device of claim 1, further comprising a suction channel extending from the inlet opening to the proximal end of the airway tube.

3. The at least one scent detector is fluidly coupled to the suction channel at the proximal end of the airway tube; The medical device further comprises: a vacuum pump fluidly coupled to the suction channel at a proximal end of the airway tube, the vacuum pump configured to draw air from the trachea through the inlet opening and the suction channel and deliver the air to the at least one aroma detector; 3. The medical device of claim 2, further comprising: a filter fluidly coupled to the suction channel at the proximal end of the airway tube, the filter configured to remove liquid from the air prior to testing by the at least one scent detector.

4. moreover, 10. The medical device of claim 1, comprising a pressure regulator system configured to adjust the pressure of at least one inflatable cuff of the cuff assembly in response to the at least one scent detector.

5. The pressure regulator system further comprises: determining that the at least one scent detector has detected a leak around the cuff assembly, wherein the at least one scent detector is a chemical and / or electronic sensor configured to detect the predetermined scent; generating an alert in a user interface, the alert comprising one or more of an audible alert or a visual alert; The medical device of claim 4 , configured to adjust the pressure of at least one inflatable cuff of the cuff assembly in response to detecting a leak.

6. moreover, 6. The medical device of claim 5, comprising a first inflation lumen having a first distal end coupled to an interior of the at least one inflatable cuff and a second proximal end fluidly coupled to a first air pump and a first release valve for adding or removing air from the at least one inflatable cuff.

7. moreover, 7. The medical device of claim 6, comprising a pressure sensor device configured to measure tracheal wall pressure exerted by the cuff assembly.

8. The pressure regulator system further comprises:

8. The medical device of claim 7, configured to adjust the pressure of at least one inflatable cuff of the cuff assembly in response to detection of a leak and tracheal wall pressure.

9. 10. The medical device of claim 1, wherein the at least one fragrance material comprises a fragrance-embedded polymer film, the fragrance-embedded polymer film being non-degradable, water-resistant, and not altering the elasticity of the at least one inflatable cuff.

10. 10. The medical device of claim 9, wherein the predetermined scent is released in detectable amounts over a period of 2 to 3 months.

11. 1. A health care system comprising: an airway tube configured for placement in the trachea; a cuff assembly on a distal portion of the airway tube; at least one flavoring material disposed distal to the cuff assembly or on a portion of the airway tube distal to the cuff assembly, the at least one flavoring material having at least one predetermined scent; an inhalation opening formed in an outer wall of the airway tube proximal to the cuff assembly; a suction channel extending from the inspiratory opening to the proximal end of the airway tube, the suction channel and the inspiratory opening being used to sample air from the trachea proximal to the cuff assembly; and at least one scent detector configured to test the sampled air to detect the at least one predetermined scent.

12. The medical system further comprises:

12. The medical system of claim 11, further comprising a user interface that issues an audible or visual alert when the at least one scent detector detects the at least one predetermined scent in the sampled air.

13. The medical system further comprises:

13. The medical system of claim 12, further comprising a pressure regulator configured to adjust the pressure of the cuff assembly when the at least one scent detector detects the at least one predetermined scent in the sampled air.

14. The medical system further comprises: a pressure sensor device configured to measure tracheal wall pressure applied by the cuff assembly; 14. The medical system of claim 13, wherein the pressure regulator is further configured to adjust the pressure of the cuff assembly in response to tracheal wall pressure.

15. 1. A health care system comprising: an airway tube configured for placement in the trachea; a cuff assembly at a distal portion of the airway tube, the cuff assembly including an inner cuff positioned adjacent the airway tube and an outer bladder positioned adjacent the inner cuff; at least one fragrance material disposed on a lower portion of the inner cuff or on a portion of the airway tube distal to the cuff assembly, the at least one fragrance material having at least one predetermined fragrance; and at least one scent detector configured to detect the at least one predetermined scent in air sampled from the trachea proximal to the cuff assembly.

Images