System and method for pressure management and air leak detection of an inflatable cuff of a medical device

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 No. 18 / 103,641, filed on January 31, 2023, entitled "Pressure Management and Air Leak Detection of an Inflatable Cuff in a Medical Device", which claims priority as a continuation - in - part under 35 U.S.C. § 120 to Application No. 17 / 902,691, filed on September 2, 2022, the entire disclosure of which is incorporated herein by reference. This U.S. Application 17 / 902,691 claims priority as a continuation - in - part under 35 U.S.C. § 120 to Application No. 17 / 848,273, filed on June 23, 2022, and now issued as U.S. Patent 11,602,605, the entire disclosure of which is incorporated herein by reference.

[0002] This application relates to systems and methods for tracheotomy tubes and / or endotracheal tubes, and more particularly, to pressure management and air leak detection systems and methods for an inflatable cuff assembly implemented in an endotracheal tube and / or a tracheotomy tube.

Background Art

[0003] Mechanical ventilation (MV) is a life - support means that intubates a patient with a breathing tube and delivers oxygen and air from a machine through the breathing tube. Patients undergoing mechanical ventilation experience a physiologically changed environment, such as a reduced ability to remove oral and nasal secretions, a reduced tracheobronchial mucociliary clearance, an increased accumulation of secretions in the lungs and bronchi, a reduced cough reflex, and an increased likelihood of gastric juice reflux. The combined action of these factors makes patients using a mechanical ventilator more susceptible to ventilator - associated pneumonia (VAP). VAP is a lung infection that usually develops 48 hours after the use of a mechanical ventilator.

[0004] In mechanical ventilation, breathing tubes include endotracheal tubes (ETT) or tracheostomy tubes with inflatable cuffs. The inflatable cuff seals the space between the breathing tube and the tracheal wall, preventing secretions from leaking into the lungs or bronchi. In patients receiving mechanical ventilation, it is a normal physiological phenomenon for secretions to accumulate on top of the inflatable cuff. The sources of secretions are the oral cavity, paranasal sinuses, and stomach ("oropharyngeal secretions"). In a normal state, it is known that up to 3 liters of secretions are produced from the oral cavity and paranasal sinuses per day. Again, these oral and paranasal sinus secretions do not include gastric reflux, which can also be a significant problem. Healthy people can remove or manage secretions, but patients wearing a ventilator cannot. Instead, in ventilated patients, secretions may accumulate on top of the inflatable cuff or leak from around the inflatable cuff into the trachea.

[0005] Concerns regarding the accumulation of secretions above the cuff are that the secretions contain microorganisms including bacteria and fungi. Since the secretions are highly contaminated, it is necessary to keep them away from the sterile organs of the human body. The lungs are one of those sterile organs. Therefore, it is essential for the treating physician to make maximum efforts to prevent the secretions from entering the patient's lungs.

[0006] The inflatable cuff serves as a strong anti-aspiration mechanism. The inflatable cuff located at the distal end of the breathing tube contacts the tracheal wall circumferentially when inflated, providing a complete seal. Unfortunately, this inflatable cuff is known to be unable to provide an efficient seal mainly due to the formation of wrinkles and folds caused by an oversized cuff, as will be described later. This observation is supported by studies indicating that approximately 10% of patients undergoing mechanical ventilation develop ventilator-associated pneumonia (VAP), and the mortality rate due to VAP is estimated to be 13%. Furthermore, patients with VAP have a longer hospital stay and higher medical costs compared to patients with similar illnesses without VAP. Considering that approximately 750,000 patients in the United States require mechanical ventilation annually, the human and financial damage caused by VAP is enormous.

[0007] Maintaining the cuff pressure within the recommended range is recognized as an important element of patient care, such as reducing tracheal injury and preventing ventilator-associated pneumonia. The ultimate goal of monitoring cuff pressure is to achieve a pressure low enough not to impair tracheal blood flow while maintaining the seal between the trachea and the cuff and maintaining a pressure high enough to prevent leakage of secretions.

[0008] Currently, several cuff pressure management systems are commercially available. However, these cuff pressure management systems have not shown clinically significant advantages in terms of the incidence of ventilator-associated pneumonia (VAP) and patient outcome metrics. Therefore, there is a need for improvement in cuff pressure management systems and methods to reduce the incidence of VAP and improve patient outcomes.

Summary of the Invention

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

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

[0011] In another aspect, a medical system includes an airway tube configured to be placed within a trachea and a cuff assembly at a distal portion of the airway tube. The cuff assembly includes 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 a lower surface of the inner cuff or a portion of the airway tube distal from the cuff assembly, and the at least one fragrance material has at least one predetermined scent. At least one scent detector is configured to detect the at least one predetermined scent in the air above the cuff from the trachea.

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

[0013] In one or more of the above aspects, a vacuum pump is fluidly coupled to the suction channel at a 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 inspection by the at least one scent detector.

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

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

[0016] In one or more of the above aspects, the first inflation lumen includes a first distal end coupled inside at least one inflatable cuff. 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 aspects, a pressure sensor device measures the tracheal wall pressure applied by the cuff assembly.

[0018] In one or more of the above aspects, a 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 aspects, the at least one inflatable cuff is an inner cuff disposed adjacent to the airway tube, and the cuff assembly further includes an inflatable outer bladder disposed adjacent to the outer surface of the inner cuff.

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

[0021] In one or more of the above aspects, 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 smaller than the second pressure range.

[0022] In one or more of the above aspects, the at least one fragrance material includes a fragrance-embedded polymer film, the fragrance-embedded film is non-degradable, water-resistant, and does not change the elasticity of the at least one inflatable cuff.

[0023] In one or more of the above aspects, a predetermined fragrance within the at least one inflatable cuff is released in a detectable amount over a period of two to three months.

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

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

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

[0027] In one or more of the above aspects, a pressure sensor device measures the tracheal wall pressure applied by the cuff assembly. The pressure regulator adjusts the pressure of the cuff assembly according to the tracheal wall pressure.

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

Brief Description of the Drawings

[0029]

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[0030] As used herein, the words "exemplary" or "embodiment" mean "an example, instance, or illustration". Embodiments or aspects described herein as "exemplary" or "embodiments" should not necessarily be construed as preferred or advantageous over other aspects of the present disclosure. Similarly, the term "aspects" does not require that all aspects of the present disclosure include the discussed features, advantages, or modes of operation.

[0031] Embodiments will be described in detail below with reference to the drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the aspects described herein. However, it will be apparent to those skilled in the art that some or all of these specific details may not be required to practice these and other aspects. Further, well-known steps in a process method may be omitted from the flow diagrams presented herein in order not to obscure the aspects of the present disclosure. Similarly, well-known components within an apparatus may be omitted from the figures and their description presented herein in order not to obscure the aspects of the present disclosure.

[0032] In current pressure management systems, it is necessary to manually monitor and adjust the cuff pressure of an endotracheal tube or a tracheostomy tube. This manual regulation is unrealistic and unreliable, and it takes valuable time from hospital staff. This application describes a newly innovative pressure management system that continuously receives and processes input from relevant sources and seamlessly and automatically adjusts the pressure within an inflatable cuff. Such an automated system helps to reduce the workload of hospital staff and protect patients from tracheal injury and ventilator-associated pneumonia.

[0033] Furthermore, current pressure management systems tend to fail because they cannot detect leaks around the inflatable cuff. Ultimately, whether a patient develops VAP depends on whether oropharyngeal and nasal secretions leak into the lungs, which in turn depends on whether there is a gap between the cuff and the tracheal wall. Whether there is a gap between the cuff and the tracheal wall can be detected by measuring air leakage in the seal. This application describes a newly innovative pressure management system and method that can accurately determine the air leakage in the seal formed by an inflatable cuff against the tracheal wall.

[0034] Another significant reason for the failure of current pressure management systems is the inability to accurately measure the pressure exerted by the cuff on the tracheal wall (tracheal wall pressure). Current pressure management systems only measure the pressure inside the cuff (intracuff pressure). However, little can be inferred about the tracheal wall pressure from the intracuff pressure. The safety of the cuff inflation level is proportional to the tracheal wall pressure, not the intracuff pressure. It is not ideal to care for intubated patients without this important information. The current method of adjusting the cuff pressure based on any target value (25 cmH2O recommended by the CDC) completely ignores what is essential for the safety and health of the patient. This application further describes a new and innovative pressure management system and method that accurately determines the tracheal wall pressure and improves patient outcomes.

[0035] Summary This specification describes a pressure management system having an effective means for monitoring tracheal wall pressure by utilizing an intercuff pressure sensor attached to the interface between the inner cuff and the outer bladder of a dual cuff assembly. The pressure management system performs pressure checks at predetermined intervals and adjusts the cuff volume so that the pressure within the cuff assembly reaches a predetermined pressure. This specification also describes a leak detection system for detecting air leakage in the seal between the tracheal wall and the cuff assembly. A strip, such as a plastic film impregnated with fragrance, is attached to the underside of the cuff assembly under the seal with the tracheal wall. In this configuration, if there is air leakage in the seal, the fragrance leaks from the plastic film and flows into the air within the trachea proximal to the cuff assembly. A fragrance detector is configured to sample air proximal to the cuff assembly. When the fragrance detector detects the fragrance, a warning is generated. The pressure management system receives inputs from the pressure sensor along with the fragrance detector. The pressure management system automatically adjusts the pressure within the cuff assembly and generates warnings in response to inputs from the pressure sensor and the fragrance detector.

[0036] Example of an airway tube having a dual cuff assembly The airway tube including a medical tube having an inflatable cuff assembly, such as a tracheotomy tube or an endotracheal tube, will be described in more detail. In one embodiment, the inflatable cuff assembly includes a dual cuff. Different from the conventionally known inflatable cuff, the dual cuff assembly described herein comprises at least two individually controlled inflatable cuffs. Currently, there are mainly two types of cuffs: low-volume high-pressure (LVHP) cuffs and high-volume low-pressure (HVLP) cuffs. The former type, LVHP cuffs, are made of a harder and relatively inelastic material. Since LVHP cuffs are essentially hard, a higher pressure (50 cmH2O to 100 cmH2O) is required to inflate the LVHP cuffs. As a result, even when the LVHP cuffs are inflated to the minimum pressure to create a seal with the tracheal wall, excessive high pressure is applied to the tracheal mucosa. This high pressure causes an unacceptable high incidence rate of tracheal ischemia and necrosis, with the incidence rate ranging from 5% to 20%. Nevertheless, when the LVHP cuffs are inflated, there are relatively few folds and wrinkles, so there is an important advantage of excellent tracheal sealing. LVHP cuffs were first adopted in the 1960s, but today they have been widely replaced by HVLP cuffs.

[0037] HVLP cuffs are composed of a more stretchable and flexible material that inflates at a low pressure. To compensate for the low pressure characteristics and create a seal against the tracheal wall, the diameter of HVLP cuffs is usually 1.5 to 2 times the diameter of the trachea when fully inflated. However, when the volume of the HVLP cuffs increases, a large amount of cuff material is required, and the HVLP cuffs become bulky, making intubation difficult. Furthermore, the extra material tends to form wrinkles and folds due to "incomplete inflation". These wrinkles and folds create a path for gastric secretions to pass over the HVLP cuffs, ultimately leading to microaspiration and lung infections.

[0038] When examining the effects of cuff pressure on the trachea, it is important to note that the capillary perfusion pressure of the tracheal wall mucosa in humans is 22 - 32 mmHg. Applying a pressure of 30 cmH2O (22 mmHg) or more can impair tracheal mucosal blood flow, and at 50 cmH2O (37 mmHg), blood flow to certain parts may be completely blocked. That is, it is clear that there is only a small overlap between the safe pressure range and the range of complications. The frame of effectiveness and safety is very narrow, if not non - existent.

[0039] For a general HVLP cuff, the pressure required to achieve appropriate inflation with wrinkles and folds within the acceptable range is approximately 32 cmH2O. Guidelines established by various medical associations and groups recommend maintaining the HVLP cuff pressure between 20 cmH2O and 30 cmH2O to avoid occlusion of tracheal mucosal blood flow. Unfortunately, studies have shown that even at a maximum pressure of 60 cmH2O, micro - aspiration occurs with HVLP cuffs, and it is suggested that even at high pressures, wrinkles in the cuff remain and secretions may pass through. Although HVLP cuffs seem to be excellent in that they can seal at lower pressure levels and avoid tracheal wall necrosis, they are still hardly ideal.

[0040] The main goal of the inflatable cuff is to provide maximum airway sealing and minimize damage to the airway. This is simple and straightforward, but it has been difficult to achieve this goal well. Despite various improvements and advancements regarding materials, shape, and volume structure, this failure has continued. Thus, there is a need for an improved cuff system that can help reduce pulmonary micro - aspiration and infection without overly damaging the tracheal wall while maintaining a good seal with the tracheal wall.

[0041] In the embodiments described herein, a high-pressure outer bladder is attached to the outer surface of the inner cuff. The inner cuff is coupled to the distal end of an endotracheal tube or a 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 inflatable bladder is configured to inflate up to a high-pressure range of 50 cmH2O to 150 cmH2O. Thus, the inner cuff operates at a pressure range lower than that of the outer bladder.

[0042] Figures 1-3 illustrate one embodiment of a tracheostomy tube 100 with a leak detection function. Figure 1 is a perspective view of the tracheostomy tube 100, and Figures 2-3 are different cross-sectional views of the tracheostomy tube 100 shown in Figure 1. Although the tracheostomy tube 100 is illustrated in this example, the leak detection systems and methods described herein can be implemented in an endotracheal tube, or other medical devices having an inflatable cuff or other type of airtight seal. The tracheostomy tube 100 of this example includes an outer cannula 102 and an inner cannula 150, and the inner cannula 150 is disposed inside the outer cannula 102. The outer cannula 102 and the inner cannula 150 can be made of a soft polyvinyl chloride (PVC) material.

[0043] The outer cannula 102 includes a proximal segment 112, a curved intermediate segment 114, and a distal segment 116. The proximal segment 112 of the outer cannula 102 extends radially outward and has a flange 108 or plate with two slits 118a, 118b on opposite sides. A cotton bandage or strap is fixed to the slits 118a, 118b of the flange 108 to hold the tracheostomy tube 100 around the patient's neck. The proximal segment 112 further includes a hub 110 that extends upward in the proximal direction from the flange 108. The inner cannula 150 is inserted through the proximal opening of the hub 110. The proximal side opening 152 of the inner cannula 150 is configured to be connected 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 to be placed within the patient's trachea. The intermediate segment 114 is curved such that the proximal segment 112 is at an angle of about 80 degrees to about 90 degrees with respect 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 separately controlled inflatable cuffs, which include a first inner cuff and a second outer bladder 122. The first inner cuff 124 is disposed adjacent to the periphery of the outer cannula 102 and is configured to bulge radially outward from the tracheostomy tube 100. The second outer bladder 122 is disposed adjacent to and around the outer surface of the inner cuff 124 such that at least a portion of the inner cuff 124 is positioned between the outer bladder 122 and the tracheostomy tube 100. The outer bladder 122 is configured to bulge radially outward from the inner cuff 124 such that when placed in the 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 the outer bladder 122 can be cylindrical or toroidal in shape. For example, as seen in FIG. 1, the outer bladder 122 is a toroidal ring having 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 length of the inner cuff is 10 mm to 20 mm and the length of the outer cuff is 5 mm to 9 mm. The outer bladder 122 is adhered to the inner cuff 124 and is not fixed to the cannula 102 outside the tracheostomy tube 100. The inner cuff 124 is attached to the outer cannula 102 by an adhesive and / or a band. These specifications are exemplary, and the inner cuff 124 and / or the outer bladder 122 may have different shapes, dimensions, and attachment means.

[0047] The inner cuff 124 and the outer bladder 122 are configured for different operating pressures, and thus 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 wall and the outer wall of the outer cannula 102. The first channel 200 extends from the proximal side of the flange 108 such as the hub 110 to at least the front cuff assembly 120 of the outer cannula 102. The distal end 206 of the inflation line 106a extends into the inner cuff 124 through an opening 204 in the outer wall of the outer cannula 102. The inflation line 106a forms a hermetic fluid connection for inflation and deflation of the inner cuff 124.

[0048] A second inflation line 106b is disposed within a second channel 300 shown in FIG. 3. The second channel 300 is formed between the front inner wall 302b and the outer wall 302a of the outer cannula 102. The second channel 300 extends from the proximal side of 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 inside the second channel 300. The distal end of the inflation line 106b extends into the outer bladder 122 through a sealed opening 304 in the outer wall 302a of the outer cannula 102. The inflation line 106b forms a hermetic 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, the 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 of the inflation lines 106a, 106b. In still 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 tracheotomy tube 100. Other implementations are possible for arranging the inflation lines 106a, 106b from the proximal side of the flange 108 to the cuff assembly 120 of the tracheotomy tube 100.

[0050] By separate means for inflation such as the inflation lines 106a-b, the outer bladder 122 and the inner cuff 124 can be inflated at different pressures and maintained at different pressures. In one embodiment, the inner cuff 124 is a low-pressure inflatable cuff and is configured to function in a low-pressure range of 10 cmH2O to 20 cmH2O. In contrast, the outer inflation bladder 122 is configured to inflate up to a high pressure range of 50 cmH2O to 150 cmH2O. Thus, the inner cuff 124 operates in 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 non-elastic material. For example, the material of the outer bladder 122 has lower elasticity 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 non-elastic 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] When 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 cuff, and the second outer bladder 122 operates as an LVHP cuff. The more flexible inner cuff 124 can mitigate the pressure ("intratracheal pressure") applied to the tracheal wall by the more pressurized outer bladder 122. In other words, the lower-pressure and elastic inner cuff 124 is configured to absorb the excessive pressure that may be applied to the tracheal wall by the outer bladder 122. For example, since the inner cuff 124 is more flexible and elastic, the cuff assembly 120 applies a lower total pressure / force to the tracheal wall, for example, a pressure lower than the outer bladder pressure. The force of the inner cuff 124 acts radially on the outer bladder 122, and ultimately the force applied to the trachea is represented as the intratracheal pressure. That is, the radial force generated by the inner cuff 124 and acting on the outer bladder 122 becomes the intratracheal pressure. For example, when the outer bladder pressure is greater than the inner cuff pressure and the outer bladder 122 expands and its outer surface contacts the trachea, the pressure between the cuffs becomes the same as the tracheal wall pressure.

[0053] Furthermore, because it operates at a high pressure, the inflated outer bladder 122 has fewer wrinkles and folds than, for example, an LVHP cuff, forming a relatively smooth surface. The reduction in wrinkles reduces the risk of leakage and forms a more uniform tracheal seal.

[0054] In this way, the cuff assembly 120 reduces tracheal complications by utilizing an innovative system for titrating the intratracheal pressure. By incorporating the characteristics of the HVLP cuff and the LVHP cuff into the cuff assembly 120, the cuff assembly 120 utilizes the advantages seen in both types of cuffs, namely excellent tracheal sealing and higher safety for the trachea. The cuff system 120 is characterized by excellent sealing performance against the tracheal wall and less damage to the trachea. Therefore, the cuff assembly 120 helps protect the lungs from contamination by gastric contents and blood without excessively damaging the tracheal wall.

[0055] In the cross-section of the airway tube 100 of FIG. 2, a suction channel 136 and a tube 134 coupled thereto are further shown. The intake opening 130 is shown on the rear side of the airway tube, but may be arranged on the front side or proximal side of the cuff assembly 120. In this example, the stopper 210 is arranged in the suction channel 136 distal to the intake opening 130. The stopper 210 is sized to seal the suction channel 136 and prevent air or liquid from flowing to the distal end 126 of the airway tube 100.

[0056] Example of leak detection system In one embodiment, the tracheostomy tube 100 also includes a leak detection system that detects air leakage in the seal between the tracheal wall and the cuff assembly 120. The leak detection system includes a plastic film 128 impregnated with fragrance or other material, which is arranged on the distal end 126 of the tracheostomy tube 100, for example, on the distal side of the seal with the tracheal wall, as shown in FIGS. 1-3. In this example, the scented film 128 includes a strip circumferentially attached around the front portion of the inner cuff 124.

[0057] The scented film 128 may include one or more scents such as the scent of wood, a refreshing scent, the scent of grass, the scent of flowers, a fruity scent, etc. The predetermined scent preferably has a long-lasting, resistant, pleasant and safe nature for humans. Further, the predetermined scent is configured to chemically interact with the chemical sensor of the scent detector.

[0058] Impregnate one or more plastic polymers with a predetermined fragrance of 1 or more, and manufacture it into a thin film. Examples of the plastic polymer may include polyethylene, polypropylene, polystyrene, cellulose derivatives, acrylonitrile butadiene styrene, etc. The one or more plastic polymers are formulated such that the impregnated fragrance is slowly released in a detectable amount over a long period such as 2 to 3 months after opening. The thin film preferably has a long storage period, and stores one or more predetermined fragrances impregnated in 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 change the elastic properties of the inner cuff 124. The scented film 128 is preferably harmless to the human body and resistant to deterioration and liquids. The scented film 128 can be attached by an adhesive and / or heat or other means. In this specification, a plastic polymer film impregnated with a fragrance is described, but other types of fragrance materials containing a slowly evaporating fragrance detectable by a fragrance detector may also be used.

[0059] The scented film 128 may be attached to the front portion of the inner cuff 124 as shown in the figure, or may be arranged in the front portion of the outer bladder 122 as long as the scented film 128 is below the seal formed between the cuff assembly 120 and the tracheal wall. In another example, the scented film 128 may be arranged at the distal end 126 of the tracheostomy tube 100, preferably in the vicinity or adjacent to the cuff assembly 120. The scented film 128 is preferably not arranged in the vicinity of the distal opening 138 of the airway tube 100. In that case, it may be unnecessarily exposed to the intake and exhalation air, and the fragrance may rapidly evaporate from the film 128. By arranging the scented film 128 in a place away from the air flow, such as behind the cuff assembly 120, adjacent to the cuff assembly 120, or immediately distal to the cuff assembly 120, the fragrance of the scented film 128 can be made to last longer.

[0060] To detect air leakage, an intake opening 130 is formed in the outer wall of the airway tube 100 proximal to the cuff assembly 120, for example, above the seal with the tracheal wall. The intake opening 130 fluidly connects the air above the cuff in the trachea to the suction channel 136 (see FIGS. 2 and 3). To prevent air from flowing into the suction channel 136 from the distal side of the cuff assembly 120, a stopper 140 is disposed in the suction channel 136 on the distal side from the opening 310. In another embodiment, the suction channel 136 ends at the intake 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 intake opening 130. The air tube 134 or the air pump further includes a valve that fluidly connects a scent detector to the air above the cuff flowing through the air tube 134.

[0061] When the tracheostomy tube 100 is attached to a patient and the cuff assembly 120 is inflated, an airtight seal needs to be formed between the cuff assembly 120 and the tracheal wall to prevent liquid and / or secretions from leaking into the trachea. If the airtight seal is not formed, an air flow occurs 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 sent to the scent detector. In this way, the scent detector can detect the scent and generate a warning that there is a defect in the seal, as described in more detail herein.

[0062] FIG. 4A is a schematic block diagram of an 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 including at least one receptacle and at least one transducer. The receptor contains a compound designed to react with the chemicals contained in a predetermined scent of the scented film 128. Then, the transducer measures the chemical reaction to the predetermined scent. Due to the chemical reaction, the impedance of the receptor can increase or decrease. For example, when the polymer in the transducer touches a predetermined scent, it expands and the resistance value changes. The change in the resistance value of this polymer is measured, and the presence of the predetermined scent is confirmed from the measurement value.

[0063] The vacuum pump 420 of the scent detection system functions as a low-pressure vacuum and sucks the air above the cuff from the trachea. The vacuum pump 420 or the air tube 134 includes valves and ports that supply a sample of the area above the cuff to the scent detector. In order to check whether there is still leakage of scented air from the seal of the trachea wall, it is necessary to circulate and replace the air above the cuff in the trachea before the next inspection. Otherwise, after enhancing the seal to be airtight, the air pump will supply the scented air remaining in the trachea from the previous test to the scent detector 410. Then the scent detector 410 detects the scent and issues an alarm even though the seal has become airtight. To prevent repeated sampling of the same air in this way, the vacuum pump 420 sucks air from the trachea for a predetermined time. During this suction period, the previously collected air is removed from the trachea and new air is sucked into the trachea. After a predetermined suction period, the air aspirator 420 supplies the air sample to the scent detector 410 to inspect for the presence of a predetermined scent. When the scent detector 410 detects a predetermined scent, it issues an alarm. For example, the alarm may include an audible alarm and / or a visual alarm on the display.

[0064] A filter 430 may be implemented to filter the air sample from the suction channel 136 and / or the tube 134. The air sample may include secretions and other liquids accumulated in the supra-cuff region, particularly proximal to the cuff assembly 120. The air samples in the suction channel 136 and the tube 134 may contain such fluids. The filter 430 is configured to remove secretions and other liquids in the air sample without substantially removing a predetermined scent in the air sample. In one embodiment, the suction and filtration of air and secretions from the supra-cuff region may be performed at regular intervals even when the scent detection test is not being carried out. By periodically sucking the fluid in the supra-cuff region in this way, the accumulation of secretions that can cause leakage into the lungs can be prevented.

[0065] Figure 4B is a perspective view of one embodiment of the filter 430 and the vacuum pump 420. In this example, the filter 430 is a liquid recovery canister coupled to the suction channel 136 through the tube 134. When the supra-cuff air containing secretions and other liquids enters the canister, the liquid falls to the bottom of the canister due to its weight. The air and scent remain at the top of the canister. The air sample is sucked up from the top of the canister by the suction vacuum and sent to the scent detector. This recovery canister can be equipped with an overflow shut-off valve to prevent outflow.

[0066] Although a liquid recovery canister has been described here, other types of air filters may be implemented. For example, a coalescing filter using a filter medium to remove droplets and other fine particles from the air may be implemented. In other examples, a mist eliminator or a vapor removal filter may be an alternative to the coalescing filter.

[0067] In one embodiment, a syringe or a vacuum can be attached to the tube 134 to remove secretions or other liquids accumulated proximal to the cuff assembly 120 when the air test is not being carried out. The suction of secretions is performed periodically and can be manual or automatic.

[0068] Although this specification describes the tracheostomy tube 100, the cuff assembly 120 can be implemented in combination with any suitable medical device, including but not limited to endotracheal tubes or other airway tubes, catheters, stents, and / or feeding tubes.

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

[0070] In one embodiment, one or more pressure sensors 530a - b are disposed on the outer surface of the outer bladder 122 to measure the pressure or force ( "tracheal pressure") applied by the cuff assembly 120 to the tracheal wall. However, when these sensors 530a - b are pressed against the tracheal wall, there is a possibility of damaging the tracheal wall. Therefore, additionally or alternatively, one or more inter - cuff pressure sensors 520a - b may be disposed between the outer bladder 122 and the inner cuff 124 to measure the intratracheal pressure. Since 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 exerted by the cuff assembly 120 on the tracheal wall. Thus, the inter - cuff pressure sensors 520a - b measure the tracheal pressure, for example, the pressure exerted by the cuff assembly 120 on the tracheal wall. In one example, the tracheal wall pressure sensors 520a - b and 530a - b may comprise thin - film pressure sensors including force - sensing resistors whose resistance values change based on the applied force. The pressure sensors 510a - b may include resistive or capacitive pneumatic transducers. An additional pressure sensor device may be disposed within the pilot balloon of the inflation lines 106a - b to measure the cuff internal pressure, or may be disposed within the airway tube 100 or at the tip of the airway tube 100 to measure the pressure of the oxygen - containing air delivered to the patient.

[0071] Each pressure sensor may include a wireless transmitter for communicating the pressure measurement value to a pressure adjustment system. For example, the wireless transmitter may include wireless transmitters such as short - range wireless transmitters, radio - frequency identification (RFID) transmitters, Internet of Things (IoT) cellular - type transmitters, etc. The pressure sensor may alternatively include a wired transmitter for communicating the pressure measurement value.

[0072] The advantages and risks of the cuff assembly 120 lie in maintaining a predetermined pressure range within the cuff assembly 120 rather than in the airway tube 100 itself. For example, over-inflation of the cuff assembly 120 can cause ischemic injury and vocal cord nerve injury, potentially leading to tracheal mucosal injury. This injury occurs when a certain pressure is applied by the cuff, preventing blood flow to the tracheal mucosa. This lack of blood flow can potentially lead to tissue necrosis. Additionally, the cuff may repeatedly rub against the tracheal wall, causing damage. If the cuff is under-inflated and the tracheal seal is insufficient, the patient may not receive adequate oxygen supply. Furthermore, the patient is also at a higher risk of pneumonia due to aspiration of gastric contents. Therefore, maintaining the pressure of the cuff assembly 120 of the airway tube 100 is an important element of patient care from the perspective of reducing tracheal injury and preventing ventilator-associated pneumonia (VAP).

[0073] Currently, several types of automatic cuff pressure regulators are available. These current devices monitor the pressure within a single cuff. However, upon closer examination, it can be seen that this approach has significant drawbacks. The pressure within the cuff does not reflect the exact pressure applied to 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 advantages of the cuff. Therefore, an improved system and method for monitoring and adjusting cuff pressure are needed.

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

[0075] The pressure controller 606 may be disposed with the pneumatic system 620 within the same physical device, or may be separately disposed within a different 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, gauge, switch, or other I / O device.

[0076] During use, the pressure setting of 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 of 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 of the outer inflation bladder can be a pressure of 50 cmH2O to 150 cmH2O (plus or minus 2 cmH2O). Thus, the inner cuff 124 operates within a lower pressure range than the operating pressure range of the outer bladder 122. The pressure controller 606 further determines the frequency of measuring and adjusting the pressure of the cuff assembly 120, for example, according to either user input or a default setting.

[0077] The pneumatic system 620 has a first pneumatic path for the outer bladder 122, which includes, for example, a first air pump 622a and a discharge valve 624a that are fluidly coupled to the outer bladder 122 via an inflation line 106b. The pneumatic system 620 further has a separate second pneumatic path for the inner cuff 124, which includes, for example, a second air pump 622b and a discharge valve 624b that are in fluid communication with the inner cuff 124 via an inflation line 106a. Although two air pumps 622a, 622b are described herein, for example, a valve or switch may be used between the two fluid paths to supply pressurized air to the inner cuff 124 and the outer bladder 122 with a single air pump. Thus, the pneumatic system 620 includes separate pneumatic paths that independently and separately fluidly increase and decrease the pressures of the inner cuff 124 and the outer bladder 122.

[0078] During operation, the pressure controller 606 receives pressure measurements from one or more pressure sensor devices and adjusts the pressure of the cuff assembly 120. For example, the one or more pressure sensor devices may comprise one or more intracuff pressure sensor devices 510a-b disposed within the inflated inner cuff 124 and outer bladder 122 and / or within the pilot balloons of inflation lines 106a-b to the cuff assembly 120. For example, the intracuff pressure sensor devices 510a-b measure the internal pressure of the inner cuff 124 and outer bladder 122 and transmit the measurements to the pressure controller 606. Additionally, one or more intercuff pressure sensor devices 520a-b measure the tracheal wall pressure. To further measure the tracheal wall pressure, one or more outer cuff assembly pressure sensor devices 530a-b may be disposed on the outer surface of the outer bladder 106. The pressure controller 606 may also receive input from one or more scent detectors 410. Additionally, additional pressure sensor devices may be implemented. The pressure sensor devices generate pressure measurements and communicate with the pressure controller 606, for example, via wired leads and / or wireless transmitters.

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

[0080] The regulator system 600 monitors the pressure measurement values from the pressure sensor and the warnings from the aroma detector, and automatically adjusts the pressure within the cuff assembly 120 accordingly. The pressure controller 606 may continuously monitor and adjust the pressure of the cuff assembly 120, or may monitor and adjust the pressure at predetermined intervals. The regulator system 600 may further include visual and / or audible alarms if the pressure measurement values are not safe.

[0081] Figure 7 is a flowchart of an embodiment of one or more methods 700 for monitoring and controlling the pressure of the cuff assembly 120 by, for example, the regulator system 600. At step 702, one or more pressure measurement values regarding the tracheal wall pressure are obtained from one or more pressure sensor devices by the regulator system 600. Using these pressure measurement values, the regulator system 600 determines, at step 704, whether the intratracheal pressure, for example, the pressure exerted by the cuff assembly 120 on the tracheal wall, is within a predetermined pressure range. The pressure measurement can be performed 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. When the intratracheal pressure exceeds the predetermined pressure range, the regulator system 600 reduces, at step 706, at least the pressure within the inner cuff 124. For example, the regulator system 600 can control the discharge valve 624b to discharge air from the inner cuff 124. Since the blood flow of the tracheal mucosa may be impaired at pressures exceeding 30 cmH2O (22 mmHg), if the measured intratracheal pressure exceeds 30 cmH2O (22 mmHg), the regulator system 600 may reduce at least the pressure of the inner cuff 124.

[0082] When the intratracheal pressure is below a predetermined pressure range, the regulator system 600 increases at least the pressure inside the inner cuff 124 in step 706. For example, the regulator system 600 can control the air pump 622b to send air into the inner cuff 124. Further, the pressure of the outer bladder 122 can also be adjusted. These steps may be executed at preset intervals or continuously.

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

[0084] In step 714, the regulator system 600 obtains one or more pressure measurement values regarding the pressure of the inner cuff 124 from one or more pressure sensor devices. Using these pressure measurement values, in step 716, the regulator system 600 determines whether the pressure of the inner cuff 124 is within a predetermined pressure range. For example, the pressure measurement can be from one or more pressure sensor devices 510a disposed within the inner cuff 124, in a pilot balloon for the inner cuff 124, or in the inflation line 106a for the inner cuff 124. If the inner cuff pressure is less than or greater than the predetermined pressure range, the regulator system 600 can increase or decrease the pressure within the inner cuff 124 in step 718. For example, the regulator system 600 can control the air pump 622b to send air into the inner cuff 124 when the pressure is lower than the predetermined pressure range, and control the discharge valve 624b to release air from the inner cuff 124 when the pressure is higher than the predetermined pressure range. In one example, the predetermined pressure range can be 10 cmH2O to 20 cmH2O.

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

[0086] Figures 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. The process 800 can also be performed, in whole or in part, in response to leak detection, out - of - range pressure measurements from either the inner cuff 124, the outer bladder 122, or the tracheal wall pressure (e.g., from the inner cuff sensors 520a - b or the outer cuff assembly sensors 530a - b) after inflation, or in response to a manual request.

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

[0088] After the inner cuff 124 and the outer bladder 122 reach their respective initial pressure levels, the tracheal wall pressure is acquired at 804. The pressure regulator 600 can determine the tracheal wall pressure from the average, median, or maximum value 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, a warning is generated at 808. This warning indicates that the maximum tracheal pressure has been exceeded and / or can instruct to replace the current airway tube (such as an endotracheal tube or a tracheostomy tube) with, for example, an airway tube with a larger outer diameter. When the airway tube is replaced, process 800 starts again from 802.

[0089] When the tracheal wall pressure becomes less than or equal to a predetermined maximum tracheal wall pressure at 806, a leak test is performed at 810. The air leak test includes collecting an air sample from the region above the cuff of the trachea. The air exhaust system of the airway 100 (such as the opening 130, the suction channel 136, the airway tube 134, etc.) is connected to a low-pressure vacuum pump 420 to improve the circulation in the region above the cuff. The aspirated air is sampled to check for the presence of one or more predetermined scents. If no air leak is detected at 812, it indicates that the cuff assembly 120 is sealing well against the tracheal wall. The pressure of the cuff assembly 120 is maintained and monitored at 814. The air leak test can be repeated periodically or in response to an order to confirm 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 obtain a better seal, the pressure of the inner cuff 124 is adjusted at 816. For example, the pressure of the inner cuff 124 can be increased by 1 - 2 cmH2O each time. After the increase in the pressure of the inner cuff 124, it is determined at 818 whether the pressure inside the inner cuff is greater than, for example, 25H2O of the maximum inner cuff pressure. 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, a warning is generated at 822. This warning indicates that the maximum tracheal pressure has been exceeded and / or may instruct to replace the current airway tube (such as an endotracheal tube or a tracheostomy tube) with, for example, an airway tube with a larger outer diameter. When the airway tube 100 is replaced, the process 800 starts again from 802.

[0091] When 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 can 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 of the cuff assembly 120 is maintained and monitored at 826. The air leak test can be repeated periodically or upon command to confirm 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 the pressure of the inner cuff 124 exceeds the maximum inner cuff pressure of 818, the process proceeds to step 830 in Figure 8B as indicated by arrow A. At step 830, the pressure of the outer bladder 122 is adjusted. For example, the pressure of the outer bladder can be increased in increments of 2 - 3 cmH2O. After increasing the pressure of the outer bladder 122, it is determined at 832 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, a warning is generated at 834. This warning indicates that the maximum outer bladder pressure has been exceeded in leak detection and / or may instruct to replace the current airway tube (such as an endotracheal tube or a tracheostomy tube) with, for example, an airway tube with a larger outer diameter. When the airway tube 100 is replaced, the process 800 starts again from 802.

[0093] If at 832 the pressure inside the outer bladder 122 is not greater than the maximum outer bladder pressure, at 836 the inner cuff pressure is adjusted to a low 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 it exceeds the maximum tracheal wall pressure, a warning is generated at 840. This warning indicates that the maximum tracheal pressure has been exceeded and / or may instruct to replace the current airway tube (such as an endotracheal tube or a tracheostomy tube) with, for example, an airway tube with a larger outer diameter. When the airway tube 100 is replaced, the process 800 starts again from 802.

[0094] If at 838 the tracheal wall pressure is below the maximum pressure, an air leak test is performed at 842. The air leak test determines whether a good seal is formed with the new incremental pressure of the outer bladder 122 and the initial pressure of the inner cuff 124. If no leak is detected at 844, the pressure of the cuff assembly 120 is maintained and monitored at 846. This process continues to step 810 of FIG. 8A, as indicated by arrow C. Periodic air leak tests are performed to confirm 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 of the outer bladder 122 and the initial pressure of the inner cuff 124, the process proceeds to step 816 of FIG. 8A as indicated by arrow B. Next, the initial pressure of the inner cuff 124 is increased until no leak is detected at 824 or until the cuff internal pressure reaches the maximum value at 818. When the cuff internal pressure reaches the maximum at 818, the process proceeds back to 830 and the pressure of the outer bladder 122 is increased to a higher pressure. If no air leak is detected at 824 or 844, the pressure of the inner cuff and the outer bladder is less than their respective maximum values, and the tracheal wall pressure is less than the maximum value, the process 800 is completed.

[0096] In this process 800, while maintaining the initial pressure of the outer bladder, the pressure of the inner cuff 124 is first increased through its operating range. If leakage is still detected, the outer bladder pressure is incremented to a higher pressure, the inner cuff is reset to the initial pressure, and incremented within the operating range until no leakage is detected. Throughout process 800, the tracheal wall pressure is kept from exceeding a maximum pressure, for example, in the range of 20 - 25 cmH2O. If the tracheal wall pressure exceeds the maximum pressure for achieving an airtight inflation of the cuff - bladder, adjustments are made, such as upsizing the airway tube to the next 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. Thus, the cuff assembly 120 and the regulator system 600 provide a process for determining and maintaining an optimized operating pressure of the cuff assembly 120 without leakage. This process helps reduce pulmonary micro - aspiration and infection by establishing and maintaining a good seal with the tracheal wall without overly damaging the tracheal wall.

[0097] Figure 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 the user. In one example, the user interface 900 includes a display 902, which can be an interactive touch screen. The display 902 includes one or more icons or data displays, such as the display of the current tracheal wall pressure 904 and alarms / warnings 906. The display 902 further includes the display of cuff pressures 908, such as the set or target pressure 910 and the current pressure 912 of the inner cuff 124 and the outer bladder 122. The display 902 may also include the display of leakage detection 914, such as the final inspection time 916 and the final inspection 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 buttons, touch pads, switches, etc. for receiving one or more commands from the 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-on of the pressure regulator 600. The shrink button / icon 940 initiates shrinkage of the cuff assembly 120, such as when removing the airway tube 100 from the patient.

[0099] Activating the automatic mode button / icon 942 starts the automatic mode. In the automatic mode, the pressure regulator 600 automatically inflates the cuff assembly to the default setting and executes one or more of the processes described in FIGS. 8A - B to determine the operating pressure at which no leakage of the cuff assembly 120 is detected. After inflation, in the automatic mode, the pressure regulator 600 performs automatic cuff pressure measurement and pressure adjustment of the cuff assembly 120, in addition to leakage detection inspections at predetermined intervals. This predetermined interval is 30 minutes by default and can be set manually between 5 minutes and 4 hours.

[0100] The user interface 900 further includes a manual mode button / icon 944 for starting the manual mode. In the manual mode, default settings such as the default pressure setting of the cuff assembly 120, the maximum pressure setting of the cuff assembly and / or the tracheal wall pressure, the leak detection inspection interval, and the pressure measurement interval can be input. In the manual mode, the "initial pressure setting" button / icon can be manually actuated to inflate the cuff assembly 120 to the default setting and perform one or more of the processes described in FIGS. 8A - B to determine the optimal operating pressure without leakage of the cuff assembly 120. After inflation, the cuff pressure measurement check may be manually actuated, such as manually adjusting the pressure using the arrow keys 946. The leak detection inspection may be manually started by actuating the corresponding icon / button 948. The user interface 900 may also include other commands and / or data for operating the pressure regulator 600.

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

[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 can be attached to the inflation line 106a of the airway tube 100. The inflation line 106a can include a pilot balloon 1010a indicating the pneumatic 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 can be attached to the inflation line 106b of the airway tube 100. The inflation line 106b can include a pilot balloon 1010b indicating the pneumatic pressure within the inner cuff 124. In addition to the inflation lines 106a - b, an additional manual inflation line for manually inflating the inner cuff 124 and the outer bladder 122, for example using a syringe, may be connected to the cuff assembly 120.

[0103] The cuff assembly 120 has been described as including an inner cuff 124 and an outer bladder 122, but the pressure regulation system 600 and method 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 adjustment system for a single cuff assembly. In this example, the cuff assembly comprises a single inflated cuff 1100 surrounding the airway tube 100. One or more cuff internal sensors 1102 are arranged to measure the pneumatic pressure within the cuff 1100 and are located, 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 outside the cuff 1100 to measure the force applied to the tracheal wall. The tracheal wall pressure may be measured using one or more pressure sensors 1106 arranged between the cuff 1100 and the airway tube 100. The pressure measurements from the pressure sensors 1102, 1104, 1106 can be periodically transmitted to the pressure controller 606 using a wired or wireless transmitter 614.

[0104] The airway tube 100 and the 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 scents embedded therein that are detectable by one or more scent detectors 410.

[0105] The airway tube 100 further includes an intake opening 130 formed in the outer wall and in fluid communication with a suction channel 136. The suction channel 136 and the 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 sucks air from the trachea through the opening 130. The vacuum pump 420 obtains an air sample for one or more scent detectors 410. The scent detector 410 transmits a measurement to a pressure controller 606.

[0106] The pressure controller 606 may control the vacuum pump 420 and the scent detector 410, and / or another processor device 1122 having 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 of the functions described herein. The leak detection system 1120 may further include a user interface 1126 and a transmitter 1128.

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

[0108] The vacuum pump 420 is operated for a predetermined period at 1204 and an air sample is taken from the trachea proximal to the cuff assembly at 1206. This predetermined period is set so that the air above the cuff within the trachea circulates and is refreshed between tests. The scent detector 410 is exposed to the air sample and it is determined at 1208 whether a scent is detected. If no scent is detected at 1208, the leak detection system 1120 returns to step 1202 and waits for a command to perform another test. If a scent is detected at 1208, a warning is generated at 1210. This warning may be an audible alarm and / or a visual display. Thereafter, the pressure within the cuff assembly 120 may be adjusted and the leak detection process repeated.

[0109] The protection and safety of the intubated patient is improved by the cuff assembly 120, the pressure adjustment system 600, and the leak detection system 1120. The cuff assembly 120 and the pressure adjustment system 600 maintain an improved seal with the tracheal wall without unduly damaging the tracheal wall and reduce leakage of secretions and lung infections. Also, since the measurement and adjustment of pressure is automated, caregiver time can be saved. The leak detection system 1120 warns early of the possibility of a problem with the seal formed by the cuff assembly 120 against the tracheal wall. Then, intervention can be performed at an earlier stage to prevent secretions from leaking into the lungs. Additional or alternative advantages and improvements are possible in one or more of the embodiments described herein and / or in the claims.

[0110] As used herein, the terms "operable to" or "configurable to" mean that an element includes one or more of circuits, instructions, modules, data, inputs, outputs, etc. to perform one or more of the described or required corresponding functions, and may further include inferential couplings to one or more other items to perform the described or required corresponding functions. As used herein, the terms "coupled", "coupled to", "connected", and / or "connecting" or "interconnecting" include direct connections or links between nodes / devices and / or indirect connections between nodes / devices through intervening articles. Further, as used herein, inferred connections (i.e., where one element is connected to another element by inference) include direct and indirect connections between two articles, as well as "connected to". The terms "substantially" and "about" as used herein provide for industry-recognized tolerances with respect to the relativity between the corresponding terms and / or items.

[0111] Note that aspects of the present disclosure may be described herein as a process depicted as a schematic diagram, flowchart, flow diagram, structural diagram, or block diagram. Although operations are described as sequential processes in flowcharts, many operations can be performed in parallel or concurrently. Further, the order of the operations can be rearranged. A process ends when its operations are completed. A process corresponds to a method, function, procedure, subroutine, subprogram, etc. When a process corresponds to a function, its end corresponds to a return of the function to the calling function or main function.

[0112] The various features of the present disclosure described herein can be implemented in different systems and devices without departing from the present disclosure. It should be noted that the above-described aspects of the present disclosure are merely illustrative and should not be construed as limiting the present disclosure. The description of the aspects of the present disclosure is intended to be illustrative and not to limit the scope of the claims. Accordingly, 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, specific representative aspects have been described with reference to specific examples. However, various modifications and changes can be made without departing from the scope of the invention as set forth in the claims. This specification and the 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 not by the merely described embodiments, but by the claims and their legal equivalents. For example, the components and / or elements recited in any apparatus claim may be assembled in various permutations or otherwise operably configured and thus are not limited to the specific configurations recited in the claims.

[0114] Furthermore, specific advantages, other advantages, and solutions to problems have been described with respect to specific embodiments, but any advantage, effect, solution to a problem, or any element that may cause or make more prominent any specific advantage, effect, or solution should not be construed as an important, essential, or critical feature or component of any or all of the claims.

[0115] As used herein, the terms "comprise," "comprises," "comprising," "having," "including," "includes," or variations thereof are intended to refer to non-exclusive inclusion, such that a process, method, article, composition, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or elements inherent to such process, method, article, composition, or apparatus. The above-described structures, arrangements, uses, ratios, elements, materials, or other combinations and / or modifications of components used in the practice of the present invention, in addition to those not specifically described, may be varied or otherwise particularly adapted in accordance with specific environments, manufacturing specifications, design parameters, or other operational requirements without departing from its general principles.

[0116] Furthermore, references to elements in the singular are not intended to mean "sole" unless specifically stated otherwise, but rather "one or more." Unless specifically stated otherwise, the term "some" refers to one or more. All structural and functional equivalents to the various aspects of the elements described throughout this disclosure that are known or later become known to those of ordinary skill in the art are hereby expressly incorporated by reference herein and are intended to be included within the claims. Additionally, what is disclosed herein is not intended to be dedicated to the public whether or not such disclosure is expressly recited in the claims. A claim element should not be construed as a "means-plus-function" type element under 35 U.S.C. § 112(f) unless the element is expressly recited using the phrase "means for" or, in the case of a method claim, the element is expressly recited using the phrase "step for."

Claims

1. A medical device, an airway tube configured to be placed in the trachea, a cuff assembly mounted on the distal portion of the airway tube, the cuff assembly including at least one inflatable cuff, at least one fragrance material disposed on the lower portion of the cuff assembly or on the airway tube distal to the cuff assembly, and at least one fragrance detector configured to detect a predetermined fragrance from the fragrance substance in the air in response to leakage, the air being sampled from the trachea proximal to the cuff assembly. The medical device is characterized by comprising at least one fragrance detector.

2. The airway tube further includes an intake opening formed on the outer wall of the airway tube proximal to the cuff assembly, and a suction channel extending from the intake opening to the proximal end of the airway tube. The medical device according to claim 1.

3. Furthermore, a vacuum pump fluidly coupled to the suction channel at the proximal end of the airway tube, the vacuum pump sucking air from the trachea through the intake opening and the suction channel, and a filter configured to remove liquid from the air before inspection by the at least one fragrance detector. The medical device according to claim 2.

4. Furthermore, a pressure regulator configured to adjust the pressure of at least one inflatable cuff of the cuff assembly in response to the fragrance detector. The medical device according to claim 1.

5. The pressure regulator further determines that the fragrance detector has detected leakage around the cuff assembly, generates an alert on the user interface, the alert including one or more of an audible alert or a visual alert, and is configured to adjust the pressure of at least one inflatable cuff of the cuff assembly in response to the detection of leakage. The medical device according to claim 4.

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

7. Furthermore, a pressure sensor device configured to measure the tracheal wall pressure applied by the cuff assembly. The medical device according to claim 4.

8. The pressure regulator further is configured to adjust the pressure of at least one inflatable cuff of the cuff assembly in response to the leakage detected by the fragrance detector and the tracheal wall pressure, the medical device according to claim 7.

9. The at least one inflatable cuff is an inner cuff disposed adjacent to the airway tube, the cuff assembly further comprising an inflatable outer bladder disposed adjacent to the outer surface of the inner cuff, the medical device according to claim 8.

10. The pressure sensor device is configured to measure the tracheal wall pressure and is disposed between the inner cuff and the outer bladder, the medical device according to claim 9.

11. The inner cuff is configured to expand within a first pressure range, the outer bladder is configured to expand within a second pressure range, and the first pressure range is smaller than the second pressure range, the medical device according to claim 9.

12. The at least one fragrance material includes a fragrance-embedded polymer film, the fragrance-embedded polymer film is not degradable and is water-resistant, and does not change the elasticity of the at least one inflatable cuff, the medical device according to claim 1.

13. The predetermined fragrance within the at least one inflatable cuff is released in a detectable amount over a period of 2 to 3 months, the medical device according to claim 12.

14. A medical system, comprising: an airway tube configured to be placed in the trachea, a cuff assembly at the distal portion of the airway tube, at least one fragrance material disposed on the distal side of the cuff assembly or a part of the airway tube distal from the cuff assembly, the at least one fragrance material having at least one predetermined fragrance, an intake opening formed on the outer wall of the airway tube proximal to the cuff assembly, a suction channel extending from the intake opening to the proximal end of the airway tube, and at least one fragrance detector configured to detect the at least one predetermined fragrance.

15. The at least one fragrance detector is configured to detect the at least one predetermined fragrance in the air above the cuff from the trachea, the medical system according to claim 14.

16. The medical system further The medical system according to claim 15, comprising a user interface that issues an audible or visual warning when the at least one scent detector detects the at least one predetermined scent in the air above the cuff.

17. The medical system further comprises 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 air above the cuff, the medical system according to claim 15.

18. The medical system further comprises a pressure sensor device configured to measure the tracheal wall pressure applied by the cuff assembly, wherein the pressure regulator is configured to adjust the pressure of the cuff assembly according to the tracheal wall pressure, the medical system according to claim 17.

19. A medical system, comprising an airway tube configured to be placed in the trachea, 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 disposed in a lower portion of the inner cuff or a part of the airway tube distal from the cuff assembly, the at least one fragrance material having at least one predetermined scent, and at least one scent detector configured to detect the at least one predetermined scent in the air above the cuff from the trachea.

20. Furthermore, the medical system according to claim 19, comprising a pressure regulator configured to adjust the pressure of the inner cuff and / or the outer bladder in response to the scent detector detecting the at least one predetermined scent.

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