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

An endotracheal or tracheostomy tube with a cuff assembly includes a cuff pressure regulator and a leak detection system. Pressure sensors monitor and measure a tracheal wall pressure and pressures in the cuff assembly. An abnormal reading from the pressure sensors may initiate a cuff-pressure adjusting process. The leak detection system detects an air leak in the seal between the cuff assembly and the tracheal wall. A scented film with a predetermined scent is positioned on an inferior portion of the cuff assembly, distally from the seal with the tracheal wall. An air leak is indicated when the predetermined scent is detected in air in the trachea proximal to the cuff assembly. An air-circulation device generates air flow into the trachea such that a new batch of air may be sampled and tested. The detection of an air leak may initiate a cuff-pressure adjusting process.

FIELD

This application relates to system and methods for a tracheostomy and/or endotracheal tube and more particularly to a pressure management and air leak detection system and method for an inflatable cuff assembly implemented on the endotracheal tube and/or tracheostomy tube.

BACKGROUND

Mechanical ventilation (MV) is a life supporting measure whereby a patient is intubated with a breathing tube and receives oxygen and air delivered by a machine through the breathing tube. A mechanically ventilated patient experiences a physiologically altered milieu: reduced ability to clear oral and nasal secretions, diminished tracheobronchial mucociliary clearance, increased accumulation of secretions in the lungs and bronchus, reduced cough reflex, and increased likelihood of gastric reflux. The combined effect of these factors is to predispose a mechanically ventilated patient to ventilator-associated pneumonia (YAP), an infection of the lungs that develops typically after 48 hours of being on mechanical ventilation.

The breathing tube in mechanical ventilation includes an endotracheal tube (ETT) or tracheostomy tube including an inflatable cuff. The inflatable cuff provides a seal between the breathing tube and the wall of the trachea to help prevent seepage of secretions into the lungs and bronchus. An accumulation of secretions above the inflatable cuff in ventilated patients is a normal physiological phenomenon. The sources of secretions are oral cavity, sinuses, and stomach (the “orogastric secretions”). It is known that under normal conditions, the oral cavity and sinuses produce up to 3 liters of secretions per day. Again, these oral cavity and sinus secretions do not include gastric refluxate, which may also be significant. While a healthy person can eliminate and/or manage such secretions, a ventilated patient cannot. Instead, in a ventilated patient, secretions may accumulate above the inflatable cuff and/or leak around the inflatable cuff into the trachea.

The concern with accumulation of secretions above the cuff is that secretions are loaded with microorganisms including bacteria and fungus. Since the secretions are heavily contaminated, they should be kept away from sterile organs of the human body. The lungs are one of those sterile organs. As such, it becomes imperative for a treating physician to do the utmost to keep the secretions out of the patient's lungs.

The inflatable cuff can be a powerful aspiration-deterrent mechanism. The inflatable cuff, located at the distal end of a breathing tube, when inflated, is supposed to contact the tracheal wall circumferentially resulting in a complete seal. The inflatable cuff, unfortunately, is known to not provide an efficient seal principally due to the formation of wrinkles or folds from the over-sized cuff as discussed below. This observation substantiates a study that showed that about 10% of patients on mechanical ventilation develop ventilator-associated pneumonia (VAP), and the mortality rate in VAP is estimated at 13%. In addition, patients with VAP face a longer hospital course and incur higher healthcare costs than similarly ill patients without VAP. Given that in the U.S., there are approximately 750,000 patients annually that require ventilation, the human and financial tolls of VAP is enormous.

Maintenance of the cuff pressure within the recommended range is recognized as a critical component of patient care, vis-a-vis reduction of tracheal injury and prevention of ventilator-associated pneumonia. The ultimate purpose of monitoring the cuff pressures is to achieve a sufficiently high pressure that maintains a good seal between the trachea and the cuff to prevent leakage of secretions, but a low enough pressure to avoid compromising tracheal blood flow.

Today, several cuff pressure management systems are on the market. The cuff pressure management systems, however, fail to show clinically significant benefits vis-a-vis the incidence of ventilator-associated pneumonia (VAP) and patient outcome measures. Thus, there is a need for improved cuff pressure management systems and methods to help reduce the incidence of VAP and improve patient outcomes.

SUMMARY

In one aspect, a medical device includes an airway tube configured for implantation within a trachea and a cuff assembly implemented on a distal portion of the airway tube, wherein the cuff assembly includes at least one inflatable cuff. At least one scented material is positioned on a distal side of the cuff assembly or on 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 scented material in air, wherein the air is sampled from the trachea on a proximal side of the cuff assembly.

In another aspect, a medical system includes an airway tube configured for implantation within a trachea and a cuff assembly on a distal portion of the airway tube. The medical system further includes at least one scented material positioned on a distal side of the cuff assembly or on a portion of the airway tube distal from the cuff assembly, wherein the at least one scented material includes at least one predetermined scent. An air intake opening is formed in an outer wall of the airway tube proximally from the cuff assembly, and a suction channel extends from the air intake opening to a proximal end of the airway tube.

In another aspect, a medical system includes an airway tube configured for implantation within a trachea and a cuff assembly on a distal portion of the airway tube, wherein the cuff assembly includes an inner cuff positioned adjacent to the airway tube and an outer bladder positioned adjacent to the inner cuff. At least one scented material is positioned on an inferior aspect of the inner cuff or on a portion of the airway tube distal from the cuff assembly, wherein the at least one scented material includes at least one predetermined scent. At least one scent detector is configured to detect the at least one predetermined scent in supracuff air from the trachea.

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

In one or more of the above aspects, a vacuum pump is fluidly coupled to the suction channel at the proximal end of the airway tube, wherein the vacuum pump suctions the air from the trachea through the air intake opening and suction channel. A filter may be used to remove fluids from the air prior to testing by the at least one scent detector.

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

In one or more of the above aspects, a pressure regulator is configured to determine the scent detector has detected a leak in the seal around the cuff assembly and generate an alert on a user interface, wherein the alert includes 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.

In one or more of the above aspects, a first inflation lumen includes a first distal end coupled to an interior of the at least one inflatable cuff. The first inflation lumen also includes a second proximal end fluidly coupled to a first air pump and a first release valve to add or remove air from the at least one inflatable cuff.

In one or more of the above aspects, a pressure sensor device measures a tracheal wall pressure exerted by the cuff assembly.

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

In one or more of the above aspects, 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 to an outer surface of the inner cuff.

In one or more of the above aspects, the pressure sensor device that is configured to measure the tracheal wall pressure is positioned between the inner cuff and the outer bladder.

In one or more of the above aspects, the inner cuff is inflated within a first pressure range and the outer bladder is configured to be inflated within a second pressure range, wherein the first pressure range is less than the second pressure range.

In one or more of the above aspects, the at least one scented material comprises a scent-embedded polymer film, wherein the scent-embedded film is not degradable, is water resistant, and does not alter an elasticity of the at least one inflatable cuff.

In one or more of the above aspects, the predetermined scent in the at least one inflatable cuff is released in detectable amounts over a period between two to three months.

In one or more of the above aspects, the at least one scent detector is configured for detection of the at least one predetermined scent in supracuff air from the trachea.

In one or more of the above aspects, a user interface emits an audible or visible alert when the at least one scent detector detects the at least one predetermined scent in the supracuff air.

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

In one or more of the above aspects, a pressure sensor device measures a tracheal wall pressure exerted by the cuff assembly. The pressure regulator adjusts the pressure of the cuff assembly in response to the tracheal wall pressure.

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

DETAILED DESCRIPTION

The word “exemplary” or “embodiment” is used herein to mean “serving as an example, instance, or illustration.” Any implementation or aspect described herein as “exemplary” or as an “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.

Embodiments will now be described in detail with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the aspects described herein. It will be apparent, however, to one skilled in the art, that these and other aspects may be practiced without some or all of these specific details. In addition, well known steps in a method of a process may be omitted from flow diagrams presented herein in order not to obscure the aspects of the disclosure. Similarly, well known components in a device may be omitted from figures and descriptions thereof presented herein in order not to obscure the aspects of the disclosure.

Current pressure management systems require manually monitoring and regulating cuff pressures for an endotracheal tube or tracheostomy tube. This manual regulation is impractical and unreliable and takes valuable time away from the hospital staff. The present 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 cuffs. Such an automatic system reduces the work of the hospital staff and helps to protect the patients from tracheal injuries and ventilator-associated pneumonia.

In addition, current pressure management systems tend to fail due to their inability to detect leaks around the inflatable cuff. For, ultimately, whether a patient will experience VAP depends on the spillage of oronasal secretions into the lungs, which hinges on the existence of a gap between the cuff and the tracheal wall. The existence of a gap between the cuff and tracheal wall may be detected by measuring an air leak in the seal. The present application describes a new and innovative pressure management system and methods that can accurately determine an air leak in the seal formed by an inflatable cuff against the tracheal wall.

Another crucial reason for the failure of current pressure management systems is due to their inability to accurately determine the pressure that the cuff is exerting on the tracheal wall (the tracheal wall pressure). The current pressure management systems only measure the pressure within the cuff (intracuff pressure). But the intracuff pressure reveals little about the tracheal wall pressure. The level of safety of the cuff inflation level is proportional to the tracheal wall pressure, and not the intracuff pressure. Caring for intubated patients without knowing this vital information is less than ideal. The current practice of adjusting the cuff pressure based on an arbitrary target level (CDC recommended level of 25 cm H2O) represents a total disregard for what is essential for the patient's safety and well-being. The present application further describes a new and innovative pressure management system and methods that accurately determine the tracheal wall pressure and improve patient outcomes.

Overview

A pressure management system is described herein having an effective means to monitor a tracheal wall pressure by utilizing an intercuff pressure sensor affixed at an interface between an inner cuff and an outer bladder of a dual cuff assembly. The pressure management system performs pressure checks at predetermined intervals and adjusts a cuff volume to achieve a predetermined pressure in the cuff assembly. A leak detection system is also described herein that detects an air leak in the seal between the tracheal wall and the cuff assembly. A strip of scent-impregnated plastic film or other material is affixed to an inferior portion of the cuff assembly below the seal with the tracheal wall. In this configuration, an air leak in the seal causes the scent from the plastic film to escape and flow into the air of the trachea proximal to the cuff assembly. A scent detector is configured to sample the air proximal to the cuff assembly. When the scent detector detects the scent, an alert is generated. The pressure management system receives input from scent detector as well as the pressure sensors. The pressure management system automatically adjusts a pressure in the cuff assembly and generates alerts in response to the inputs from the pressure sensors and the scent detector.

Embodiments of an Airway Tube with a Dual Cuff Assembly

An airway tube including a tracheostomy tube or an endotracheal tube or other medical tube with an inflatable cuff assembly is now described in more detail. In one embodiment, the inflatable cuff assembly includes dual cuffs. Unlike previously known inflatable cuffs, the dual cuff assembly described herein comprises at least two separately controlled inflatable cuffs. Currently, there are two main types of cuffs, low volume, high pressure (LVHP) cuffs and high volume, low pressure (HVLP) cuffs. The first type, LVHP cuffs, are made from stiffer, relatively inelastic materials. Due to their inherent stiffness, a greater level of pressure (50 cm H2O to 100 cm H2O) is required to inflate LVHP cuffs. As a result, LVHP cuffs cause an excessively high pressure on the tracheal mucosa, even when inflated to a minimum pressure to create a seal with the tracheal wall. This high pressure causes an unacceptably high incidence of tracheal ischemia and necrosis, e.g., a 5%-20% incidence rate. Despite that, one crucial advantage of LVHP cuffs, when inflated, is the relative absence of folds or wrinkles, resulting in superior tracheal sealing. LVHP cuffs were first employed in the 1960's, but, today, have been widely replaced by HVLP cuffs.

HVLP cuffs are composed of more elastic, compliant materials that inflate at lower pressures. To compensate for the lower pressure characteristics and create a seal against the tracheal wall, the diameter of the HVLP cuffs are generally 1.5-2 times the diameter of the trachea when fully inflated. However, the increased volume of the HVLP cuffs requires a significant amount of cuff material that adds bulkiness to the HVLP cuff making it more difficult to intubate. Moreover, the excess material has a tendency to form wrinkles or folds due to “incomplete inflation.” These wrinkles or folds often create paths for orogastric secretions to pass beyond the HVLP cuff, ultimately leading to microaspiration and infection of the lungs.

In examining the effect of cuff pressure on the trachea, it is important to keep in mind that the tracheal wall mucosa capillary perfusion pressure in humans ranges from 22 to 32 mmHg, and tracheal mucosal blood flow may be compromised at applied pressures above 30 cm H2O (22 mmHg), with total occlusion of flow to certain parts at 50 cm H2O (37 mmHg). It is apparent, then, that there is only a small overlap between the safety pressure range and that of complication. The window of efficacy and safety, indeed, is very narrow, if nonexistent.

The required pressure for typical HVLP cuffs to achieve a reasonable inflation with an acceptable number of folds or wrinkles is about 32 cm H2O. The guidelines established by various medical societies and organizations recommend maintaining the HVLP cuff pressure within a range of 20 cm H2O to 30 cm H2O to avoid occlusion of tracheal mucosal blood flow. Unfortunately, studies have shown that even at pressures up to 60 cm H2O, microaspiration still occurs with HVLP cuffs, suggesting the continued presence of cuff wrinkles, allowing the passage of secretions, even at higher pressures. So, even though HVLP cuffs appear superior because they are capable of producing a seal at a lower pressure level and avoiding necrosis of the tracheal wall, they are still far from being ideal.

While the principal goals of the inflatable cuff, to provide a maximum airway seal and cause minimal damage to the airway, is simple and straightforward, successfully achieving these goals has been elusive. This failure continues despite the diverse modifications and advances that have been made vis-a-vis materials, shape, and volumetric structure. Thus, there is a need for an improved cuff system that helps to reduce microaspiration and infection of the lungs by maintaining a good seal with the tracheal wall but without unduly harming the tracheal wall.

In an embodiment described herein, a high-pressure outer bladder is attached to the outer surface of an inner cuff. The inner cuff couples to a distal end of an endotracheal tube or tracheostomy tube. The inner cuff is a low-pressure inflatable cuff and is configured to function at a low pressure range of 10 cm H2O to 20 cm H2O. In contrast, the outer inflating bladder is configured to inflate to a high pressure range of 50 cm H2O to 150 cm H2O. The inner cuff thus operates in a pressure range that is less than the pressure range of the outer bladder.

FIGS.1-3illustrate one embodiment of a tracheostomy tube100with leak detection.FIG.1illustrates a perspective view of the tracheostomy tube100andFIGS.2-3illustrate different cross-sectional views of the tracheostomy tube100shown inFIG.1. Though a tracheostomy tube100is illustrated in this example, the leak detection system and method described herein may be implemented with an endotracheal tube or other medical device with an inflatable cuff or other type of airtight seal. The tracheostomy tube100in this example includes an outer cannula102and an inner cannula150, wherein the inner cannula150is positioned internally to the outer cannula102. The outer cannula102and the inner cannula150may comprise a soft polyvinyl chloride (PVC) material.

The outer cannula102includes a proximal segment112, a curved middle segment114, and a distal segment116. The proximal segment112of the outer cannula102includes a flange108or plate that circumferentially extends outward and includes two slits118a,118bon opposing sides. A cotton bandage or strap is secured in the slits118a,118bof the flange108to hold the tracheostomy tube100against a neck of a patient. The proximal segment112further includes a hub110extending upward proximally from the flange108. The inner cannula150is inserted through a proximal opening in the hub110. The proximal opening152of the inner cannula150is configured for connection to a ventilator through a tube or hosing.

The outer cannula102of the tracheostomy tube100includes a curved middle segment114and a distal segment116configured and sized for implantation within a trachea of a patient. The middle segment114is curved such that the proximal segment112is between an approximately 80 degree to an approximately 90 degree angle to the distal segment116. The distal segment116includes a cuff assembly120, a distal end126, and a main distal opening138.

The tracheostomy tube100includes the novel dual cuff assembly120disposed at the distal segment116. The cuff assembly120comprises at least two separately controlled inflatable cuffs, a first inner cuff and a second outer bladder122. The first inner cuff124is positioned around and adjacent to the outer cannula102and is configured to inflate radially outwards from the tracheostomy tube100. The second outer bladder122is positioned around and adjacent to an outer surface of the inner cuff124such that at least a portion of the inner cuff124lays between the outer bladder122and the tracheostomy tube100. The outer bladder122is configured to inflate radially outward from the inner cuff124such that when implanted in a trachea of a patient, an outer surface of the outer bladder122contacts the tracheal wall and forms a seal.

The inner cuff124and the outer bladder122may be a cylindrical or toroidal shape. For example, as seen inFIG.1, the outer bladder122is a torus shaped ring with a circular cross section when inflated. The inner cuff124has a cylindrical shape with an arched outer surface that forms a ring around the tracheostomy tube100. In this example, the length of the inner cuff is in the range of 10 mm to 20 mm, and the length of the outer cuff is in the range of 5 mm to 9 mm. The outer bladder122is bonded to the inner cuff124and not tethered to the outer cannula102of the tracheostomy tube100. The inner cuff124is attached to the outer cannula102by an adhesive and/or a band. These specifications are exemplary and the inner cuff124and/or the outer bladder122may have alternate shapes, dimensions and attachment means.

The inner cuff124and the outer bladder122are configured for differing operating pressures, and so the tracheostomy tube100includes a means to inflate the inner cuff124and the outer bladder122to different pressures. In one example, a first inflation line106ais positioned in a first channel200shown inFIG.2. The first channel200is formed between an inner wall and an outer wall of the outer cannula102. The first channel200extends from a proximal side of the flange108, such as at the hub110, to at least the cuff assembly120on an anterior side of the outer cannula102. A distal end206of the inflation line106aextends through an opening204in the outer wall of the outer cannula102and into the inner cuff124. The inflation line106aforms an airtight, fluid connection for inflation and deflation of the inner cuff124.

A second inflation line106bis positioned in a second channel300shown inFIG.3. The second channel300is formed between an inner wall302band an outer wall302aon an anterior side of the outer cannula102. The second channel300extends from a proximal side of the flange108at the hub110of the outer cannula102to at least the cuff assembly120. The second inflation line106bis positioned inside the second channel300. A distal end of the inflation line106bextends through a sealed opening304in the outer wall302aof the outer cannula102into the outer bladder122. The inflation line106bthus forms an airtight, fluid connection for inflation and deflation of the outer bladder122.

In this embodiment, there are two channels200,300formed in the anterior wall of the outer cannula102for holding the inflation lines106a,106b. In another embodiment, the two channels200,300may be formed in a lateral wall of the outer cannula102. In yet another embodiment, a single channel may hold both inflation lines106a,106b. In yet another embodiment, the channels200,300may be formed between the inner cannula150and outer cannula102, e.g. on the anterior side of the tracheostomy tube100. Other implementations may also be possible for positioning the inflation lines106a,106bfrom a proximal side of the flange108to the cuff assembly120of the tracheostomy tube100.

Due to the separate means for inflation, such as inflation lines106a-b, the outer bladder122and inner cuff124may be inflated to and maintained at different pressures. In an embodiment, the inner cuff124is a low-pressure inflatable cuff and is configured to function at a low pressure range of 10 cm H2O to 20 cm H2O. In contrast, the outer inflating bladder122is configured to inflate to a higher pressure range of 50 cm H2O to 150 cm H2O. The inner cuff124thus operates in a pressure range that is less than the pressure range of the outer bladder122.

In addition, the inner cuff124comprises a relatively elastic material while the outer bladder122comprises a relatively inelastic material, e.g., the material of the outer bladder122is less elastic than the material of the inner cuff124. For example, the relatively elastic material of the inner cuff124may include one or more of: rubber, silicone, latex, polyvinyl chloride (PVC), neoprene, polyisoprene, or polyurethane (PU). The relatively inelastic material of the outer bladder122may include one or more of: polyethylene teraphthalate (PETP), low-density polyethylene (LDPE), polyvinyl chloride (PVC), silicone, neoprene, polyisoprene, or polyurethane (PU).

In use, e.g., when positioned into a trachea of a patient and pressurized to an inflated state, the first, inner cuff124behaves as a HVLP type cuff while the second, outer bladder122behaves as a LVHP type cuff. The more compliant inner cuff124is able to temper the pressure applied on the tracheal wall (the “tracheal pressure”) by the higher pressurized outer bladder122. In other words, the lower pressure, more elastic inner cuff124is configured to absorb excessive pressure that may otherwise be exerted on the tracheal wall by the outer bladder122. For example, since the inner cuff124is more compliant and elastic, the cuff assembly120applies a lower total pressure/force against the tracheal wall, e.g., lower than the outer bladder pressure. The force of the inner cuff124acts radially on the outer bladder122and thus represents the force ultimately exerted on the trachea as the tracheal pressure. So, the radial force produced by the inner cuff124and acted upon the outer bladder122, then, is the tracheal pressure. For example, when the outer bladder pressure is greater than that of the inner cuff pressure, and the outer bladder122is inflated so that the outer surface touches the trachea, the intercuff pressure is the same as the tracheal wall pressure.

In addition, due to its operation at a high pressure, the outer bladder122in an inflated state forms a relatively smooth surface with fewer folds or wrinkles, e.g. than a LVHP cuff. This reduction in wrinkles reduces the risk for leakage and creates a more uniform tracheal seal.

In this way, the cuff assembly120utilizes an innovative system to titrate the tracheal pressure thereby reducing tracheal complications. By incorporating the characteristics of HVLP and LVHP cuffs into the cuff assembly120, the cuff assembly120exploits the advantages found in both types of cuffs: superior tracheal seal and greater safety to the trachea. The cuff system120features the advantages of superior seal against the tracheal wall with reduced tracheal damage. The cuff assembly120thus helps protect the lungs from being contaminated with orogastric contents or blood without undue harm to the tracheal wall.

The cross-section of the airway tube100inFIG.2further shows the suction channel136and tubing134coupled thereto. The air intake opening130is shown on a posterior side of the airway tube but may be positioned anteriorly or otherwise on a proximal side of the cuff assembly120. In this example, a stopper210is positioned in the suction channel136distally from the air intake opening130. The stopper210is sized to block and provide a seal to the suction channel136to prevent air or fluids from flowing to the distal end126of the airway tube100.

Embodiment of the Leak Detection System

In an embodiment, the tracheostomy tube100also includes a leak detection system that detects an air leak in the seal between the tracheal wall and the cuff assembly120. The leak detection system includes a scent-impregnated plastic film128or other material, as shown inFIGS.1-3, positioned on a distal end126of the tracheostomy tube100, e.g., distally to the seal with the tracheal wall. In this example, the scented film128includes a strip affixed circumferentially around an anterior portion of the inner cuff124.

The scented film128may include one or more types of scents—woody scents, fresh scents, herbaceous scents, floral scents, fruity scents, etc. The predetermined scent is preferably long-lasting, well-tolerated, pleasing, and safe for humans. The predetermined scent, furthermore, is configured to interact chemically with a chemical sensor of a scent detector.

The one or more predetermined scents are impregnated into one or more plastic polymers and manufactured into thin films. The one or more plastic polymers may include polyethylene, polypropylene, polystyrene, cellulose derivatives, and acrylonitrilbutadiene-styrene. The one or more plastic polymers are formulated such that the impregnated scents are released slowly in detectable amounts over a long period, such as 2 to 3 months after opening. The thin films preferably have a long shelf-life, e.g. such as with a sealed, airtight packaging, that preserves the one or more predetermined scents impregnated in the one or more plastic polymers until opening. The scented film128is preferably thin and flexible, such as equal to or less than 1 mm, so that it does not significantly alter the elastic properties of the inner cuff124. The scented film128is preferably harmless to the human body and resistant to degradation and fluids. The scented film128may be affixed with an adhesive and/or with heat or by other means. Though a scent embedded plastic polymer film is described herein, any other type of scented material may be implemented that includes a slowly evaporating scent detectable by a scent detector.

The scented film128may be affixed to an anterior portion of the inner cuff124as shown, or may alternatively be positioned on an anterior portion of the outer bladder122, providing the scented film128is below the seal created between the cuff assembly120and the tracheal wall. In another example, the scented film128may be positioned on a distal end126of the tracheostomy tube100, preferably near or adjacent to the cuff assembly120. The scented film128is preferably not positioned near the distal opening138of the airway tube100where it may be unnecessarily exposed to inhaling and exhaling air, thereby possibly evaporating the scent from the film128too quickly. By placing the scented film128further from the air flow, such as on the posterior side of the cuff assembly120, or adjacent to the cuff assembly120or just distal to the cuff assembly120, the scent on the scented film128may persist for a longer period.

To detect an air leak, an air intake opening130is formed in the outer wall of the airway tube100on a proximal side of the cuff assembly120, e.g., above the seal with the tracheal wall. The air intake opening130fluidly connects supracuff air in the trachea to a suction channel136(seen inFIGS.2and3). A stopper140is positioned in the suction channel136distally from the opening310to prevent air from flowing into the suction channel136from a distal side of the cuff assembly120. In another embodiment, the suction channel136ends at the air intake opening130. A proximal end of the suction channel136attaches to air tubing134at the hub110. An air pump fluidly attaches to an opposing end of the air tubing134such that the air pump is fluidly coupled to the air intake opening130. The air tubing134or air pump further includes a valve that fluidly couples a scent detector to supracuff air flowing through the air tubing134.

When the tracheostomy tube100is positioned in a patient and the cuff assembly120is inflated, an airtight seal should be formed between the cuff assembly120and the tracheal wall to prevent fluids and/or secretions from leaking into the trachea. When an airtight seal is not formed, air flow occurs from the scented film128, through the seal, and into the air intake opening130. The scented air then flows through the suction channel136to the air tubing134and to the scent detector. The scent detector may thus detect the scent and generate an alert that the seal is compromised, as described in more detail herein.

FIG.4Aillustrates a schematic block diagram of an embodiment of a scent detector system400. The system400includes one or more scent detectors410and a vacuum pump420. In one embodiment, the scent detector410is an electronic device that includes at least one receptor and at least one transducer. The receptor includes a compound designed to react with the chemicals in a predetermined scent in the scented film128. The transducer then measures the chemical reaction to the predetermined scent. The chemical reaction may increase or decrease an impedance of the receptor. For example, when a polymer in the transducer contacts the predetermined scent, it expands, thereby changing its resistance. This change in resistance of the polymer is measured, and from that measurement, the presence of the predetermined scent is ascertained.

The vacuum pump420in the scent detector system acts as a low pressure vacuum to suction the supracuff air from the trachea. The vacuum pump420or air tubing134includes a valve and port to provide a sample of the supracuff area to the scent detector. Prior to the next test, the supracuff air in the trachea needs to be circulated and replaced to determine whether the scented air is still leaking from the tracheal wall seal. Otherwise, after the seal is improved and becomes airtight, the air pump may provide scented air remaining in the trachea from the previous test to the scent detector410. The scent detector410would then detect the scent and generate an alert even though the seal is now airtight. To prevent this repeated sampling of the same air, the vacuum pump420suctions air from the trachea for a predetermined period of time. This period of suctioning removes the previously sampled air from the trachea and helps to draw a new batch of air into the trachea. After the predetermined period of suction, the air vacuum420provides a sample of air to the scent detector410where it is tested for the presence of the predetermined scent. When the scent detector410detects the predetermined scent, it then generates an alert. For example, the alert may include an audible alarm and/or a visible alert on a display, etc.

A filter430may also be implemented to filter the air sample from the suction channel136and/or tubing134. The air sample may include secretions and other fluids that accumulate in the supracuff region, especially on the proximal side of the cuff assembly120. So the air sample in the suction channel136and tubing134may also include such fluid. The filter430is configured to remove secretions or other fluids in the air sample with little to no removal of any predetermined scent in the air sample. In an embodiment, the suction of air and secretions from the supracuff region and filtering may occur at periodic intervals even when scent detection testing is not being performed. This periodic suction of the fluids in the supracuff region helps to prevent the accumulation of secretions that may cause leakage into the lungs.

FIG.4Billustrates a perspective view of an embodiment of the filter430and vacuum pump420. In this example, the filter430is a liquid collection canister coupled to the suction channel136through the tubing134. The supracuff air with secretions or other fluid enter the collection canister and liquids fall to a bottom of the canister due to their heavier weight. The air and any scent remain on the top of the canister. The suction vacuum siphons the air sample from the top of the canister and exposes the air sample to the scent detector. The collection canister may be equipped with overflow cut-off valves to prevent spillage.

Though a liquid collection canister is described herein, other types of air filters may be implemented. For example, coalescing filters may be implemented that use a filter media to remove droplets and other particulates from the air. In other examples, a mist eliminator or vapor removal filter provide alternatives to a coalescing filter.

In an embodiment, a syringe or vacuum may also attach to the tubing134to remove the secretions or other fluids that accumulate on the proximal side of the cuff assembly120when air testing is not being performed. The suction of secretions may occur at periodic intervals and may be competed manually or automatically.

Though a tracheostomy tube100is described herein, the cuff assembly120may be implemented in conjunction 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.

Embodiments of the Pressure Regulation System

FIG.5illustrates a schematic block diagram of an embodiment of pressure sensors for an airway tube100(e.g., a tracheostomy tube, endotracheal tube, or other airway tube) including the cuff assembly120. In an embodiment, the cuff assembly120includes at least one intracuff pressure sensor510aassociated with the inner cuff124and at least one intracuff pressure sensor510bassociated with the outer bladder122. The intracuff pressure sensor510ais positioned within the inner cuff124and is configured to measure an air pressure in the inner cuff124. Additionally or alternatively, a pressure sensor (not shown) may be positioned at the proximal end of the inflation line106a, e.g. as part of a pilot balloon, to measure the air pressure inside the inner cuff124. The intracuff pressure sensor510bis positioned inside the outer bladder122and is configured to measure an air pressure in the outer bladder122. Additionally or alternatively, a pressure sensor (not shown) may be positioned at the proximal end of the inflation line106b, e.g. at a pilot balloon, to measure the air pressure inside the outer bladder122.

In an embodiment, one or more pressure sensors530a-bmay be positioned on an outer surface of the outer bladder122to measure a pressure or force that the cuff assembly120applies to the tracheal wall (the “tracheal pressure”). However, these sensor530a-bmay cause harm to the tracheal wall when pressed against it. So alternatively, or in addition to, one or more intercuff pressure sensors520a-bmay be positioned between the outer bladder122and the inner cuff124to measure the tracheal pressure. Since the force of the inner cuff124acts radially on the outer bladder122, the intercuff pressure sensors520a-bultimately measure the force exerted by the cuff assembly120against the tracheal wall. As such, the intercuff pressure sensors520a-bmeasure the tracheal pressure, e.g. the pressure exerted by the cuff assembly120against the tracheal wall. In one example, the tracheal wall pressure sensors520a-band530a-bmay include thin film pressure sensors with force sensitive resistors that change resistance based on an applied force. The pressure sensors510a-bmay include resistive or capacitive air pressure transducers. Additional pressure sensor devices may be positioned within the pilot balloons of the inflation lines106a-bto measure the intracuff pressures or within the airway tube100or at the tip of the airway tube100, to measure a pressure of the oxygenated air delivered to a patient.

The pressure sensors may each include a wireless transmitter to communicate pressure measurements to a pressure regulation system. For example, the wireless transmitter may include a wireless transmitter, such as a near field or radio frequency identification (RFID) transmitter or Internet of Things (IoT) cellular type transmitter. The pressure sensors may alternatively include wired transmitters to communicate pressure measurements.

The benefit and risks of the cuff assembly120, more than the airway tube100itself, depends on maintaining a predetermined pressure range in the cuff assembly120. For example, overinflation of the cuff assembly120may result in tracheal mucosal injury by causing ischemic damage and vocal cord nerve injury. The damage is due to the constant pressure exerted by the cuff that prevents blood flow to the mucosa of the trachea. This loss of blood flow may lead tissue necrosis. In addition, damage may also arise due to the repeated abrasion from the cuff moving against the tracheal wall. When the cuff is underinflated and the tracheal seal is inadequate, the patient may not receive sufficient oxygen. Further, the patient is subjected to increased possibility of pneumonia from the aspiration of orogastric content. Thus, maintenance of the pressure of the cuff assembly120for an airway tube100is a critical component of patient care, vis-a-vis reduction of tracheal injury and prevention of ventilator-associated pneumonia (VAP).

Currently, several types of automated cuff pressure regulators are available. These current devices monitor an intracuff pressure within a single cuff. However, a close examination reveals a major flaw in this approach. The intracuff pressure does not reflect the precise 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 benefits of the cuff. Thus, there is a need for an improved system and method to monitor and regulate the cuff pressure.

FIG.6illustrates a schematic block diagram of an exemplary embodiment of a pressure regulator and control system (“regulator system”)600for the cuff assembly120. The regulator system600fluidly communicates with and inflates and adjusts the pressure within the cuff assembly120, e.g. when the airway tube100is implanted into the patient's trachea, using a measurement of the tracheal wall pressure and leak detection. The regulator system600includes a pressure controller606and pneumatic system620. The pressure controller606includes a processor device608and a memory device610. The memory device610includes one or more non-transitory processor readable memories that store instructions which when executed by the processor device608or other components of the regulator system600, causes the regulator system600to perform one or more functions described herein. The processor device608includes at least one processing circuit, such as a microprocessor, micro-controller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, analog circuitry, digital circuitry, and/or any device that manipulates signals (analog and/or digital) based on hard coding of the circuitry and/or operational instructions. The memory device610includes a non-transitory memory device and may be an internal memory or an external memory, and may be a single memory device or a plurality of memory devices. The memory device610may be a 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.

The pressure controller606may be co-located with the pneumatic system620in a same physical device or located separately in a different device or encasement. The pressure controller606further includes a user interface612. The user interface612generates user input and output (I/O) and includes one or more of a display, keyboard, touch screen, mouse, touchpad, gauge, switch, or other I/O device.

In use, pressure settings are determined for the cuff assembly120. The pressure controller606may use default pressure settings or pressure settings received from a user. Different pressure settings are used for the inner cuff124and the outer bladder122. For example, the pressure setting for the inner cuff may be a pressure (plus or minus 2 cm H2O) within the range of 10 cm H2O to 20 cm H2O. In contrast, the pressure setting for the outer inflating bladder may be a pressure (plus or minus 2 cm H2O) within the range of 50 cm H2O to 150 cm H2O. The inner cuff124thus operates in a pressure range that is less than the operational pressure range of the outer bladder122. The pressure controller606further determines a frequency of measuring and adjusting the pressure of the cuff assembly120, e.g. either through a user input or default setting.

The pneumatic system620has a first pneumatic pathway for the outer bladder122that includes, e.g., a first air pump622aand release valve624athat fluidly couples with the outer bladder122through inflation line106b. The pneumatic system620further includes a different, second pneumatic pathway for the inner cuff124that includes a second air pump622band release valve624bthat fluidly couples with the inner cuff124through, e.g., inflation line106a. Though two air pumps622a,622bare described herein, a single air pump may supply the pressurized air to the inner cuff124and the outer bladder122, e.g. using a valve or switch between the two fluid pathways. The pneumatic system620thus includes separate pneumatic pathways to fluidly increase or decrease the pressure in the inner cuff124and the outer bladder122independently and separately.

In operation, the pressure controller606receives pressure measurements from one or more pressure sensor devices to regulate the pressure of the cuff assembly120. For example, the one or more pressure sensor devices may include one or more intracuff pressure sensor devices510a-blocated within the inflated inner cuff124and outer bladder122and/or in the pilot balloons of the inflation lines106a-bto the cuff assembly120. For example, the intracuff pressure sensor devices510a-bmeasure the internal air pressures of the inner cuff124and the outer bladder122and communicate the measurements to the pressure controller606. In addition, one or more intercuff pressure sensor devices520a-bmeasure a tracheal wall pressure. One or more outer cuff assembly pressure sensor devices530a-bmay be positioned on an outer surface of the outer bladder106to further measure the tracheal wall pressure. The pressure controller606may also receive input from the one or more scent detectors410. Additional pressure sensor devices may also be implemented. The pressure sensor devices generate and communicate pressure measurements to the pressure controller606, e.g. either through a wired lead and/or a wireless transmitter614.

The regulator system600includes a pressure feedback loop wherein the pressure controller606controls the pneumatic system620to adjust the pressures for both the inner cuff124and the outer bladder122responsive to the pressure measurements and/or the scent detectors. The pressures of the inner cuff124and the outer bladder122are monitored and controlled separately. The pressure controller606signals the pneumatic system620to add or release air to the outer bladder122and/or the inner cuff124. For example, to adjust the pressure in the outer bladder122, the pressure controller606may signal the air pump622ato add air to the outer bladder122or signal the release valve624ato release air from the outer bladder122. In another example, to adjust the pressure in the inner cuff124, the pressure controller606may signal the air pump622bto add air to the inner cuff124or signal the release valve624bto release air from the inner cuff124.

The regulator system600monitors the pressure measurements from the pressure sensors and alerts from the scent detectors and adjusts the pressures in the cuff assembly120automatically in response thereto. The pressure controller606may monitor and adjust the pressure of the cuff assembly120continuously or may monitor and adjust the pressure at predetermined intervals. The regulator system600may further include visible and/or audible alarms in the event of unsafe pressure measurements.

FIG.7illustrates a flow chart of an embodiment of one or more methods700for monitoring and controlling the pressure of the cuff assembly120, e.g. by the regulator system600. At step702, one or more pressure measurements relating to the tracheal wall pressure are obtained by the regulator system600from one or more pressure sensor devices. Using these pressure measurements, the regulator system600determines whether the tracheal pressure, e.g. the pressure exerted by the cuff assembly120on the tracheal wall, is within a predetermined pressure range at step704. The pressure measurements may be from the one or more intercuff pressure sensor devices520a-bbetween the inner cuff124and the outer bladder122and/or from one or more pressure sensors530a-blocated on an outer surface of the outer bladder122. When the tracheal pressure exceeds a predetermined pressure range, the regulator system600decreases at least the pressure in the inner cuff124at Step706. For example, the regulator system600may control the release valve624bto release air from the inner cuff124. Since the tracheal mucosal blood flow may be compromised at applied pressures above 30 cm H2O (22 mm Hg), when the measured tracheal pressure exceeds 30 cm H2O (22 mmHg), then the regulator system600may decrease at least the pressure of the inner cuff124.

When the tracheal pressure is less than a predetermined pressure range, the regulator system600increases at least the pressure in the inner cuff124at step706. For example, the regulator system600may control the air pump622bto pump air into the inner cuff124. In addition, the pressure of the outer bladder122may also be adjusted. These steps may be performed at preset intervals or continuously.

At step708, one or more pressure measurements relating to the outer bladder pressure are obtained by the regulator system600from one or more pressure sensor devices. Using these pressure measurements, the regulator system600determines whether the pressure of the outer bladder122is within a predetermined pressure range at step710. For example, the pressure measurements may be from one or more pressure sensor devices510blocated within the outer bladder122or a pilot balloon for the outer bladder122or the inflation line106bfor the outer bladder122. When the outer bladder122pressure is less than or more than the predetermined pressure range, the regulator system600increases or decreases the pressure in the outer bladder122at Step712. For example, the regulator system600may control the air pump622ato pump air into the outer bladder122when its pressure is below the predetermined pressure range or control the release valve624ato release air from the outer bladder122when its pressure is above the predetermined pressure range. The outer bladder122may have a predetermined pressure range of 50 cm H2O to 150 cm H2O.

At step714, one or more pressure measurements relating to the pressure of the inner cuff124are obtained by the regulator system600from one or more pressure sensor devices. Using these pressure measurements, the regulator system600determines whether the pressure of the inner cuff124is within a predetermined pressure range at step716. For example, the pressure measurements may be from one or more pressure sensor devices510alocated within the inner cuff124or at a pilot balloon for the inner cuff124or the inflation line106afor the inner cuff124. When the inner cuff pressure is less than or more than the predetermined pressure range, the regulator system600may increases or decrease the pressure in the inner cuff124at Step718. For example, the regulator system600may control the air pump622bto pump air into the inner cuff124when its pressure is below the predetermined pressure range or control the release valve624bto release air from the inner cuff124when its pressure is above the predetermined pressure range. In one example, the predetermined pressure range may be 10 cm H2O to 20 cm H2O.

The pressure of the inner cuff124and the outer cuff bladder122of the cuff assembly120are thus controlled separately using separate pneumatic pathways, e.g., separate air pumps622and/or release valves624and separate inflation lines106a-b. The pressure of the more inelastic outer bladder122is maintained at a higher pressure than the pressure of the more elastic inner cuff124. The pressure controller602may thus independently adjust a pressure of the inner cuff124or the outer bladder122to adjust the tracheal pressure.

FIGS.8A-Billustrate a schematic block diagram of an embodiment of a method800for determining an operating pressure for the cuff assembly120. After implantation, a cuff-bladder pressure adjusting process may be performed to determine an operating pressure. The process800may also be performed, in whole or in part, after inflation in response to a leak detection, an out-of-range pressure measurement from either the inner cuff124, the outer bladder122, or the tracheal wall pressure (e.g., from the intercuff sensors520a-bor outer cuff assembly sensors530a-b), or in response to a manual request.

The process800begins with the pressure regulator system600inflating or deflating the inner cuff124and the outer bladder122to respective initial pressure levels at802. For example, the initial pressure level for the inner cuff124may include a pressure range of 8-12 cm H2O, or approximately 10 cm H2O. The initial pressure level for the outer bladder122may include a pressure range of 35-45 cm H2O, or approximately 40 cm H2O. The initial pressure levels may be set by default or may be input by an operator through a user interface612.

After the inner cuff124and outer bladder122are at their respective initial pressure levels, the tracheal wall pressure is obtained at804. The pressure regulator600may determine the tracheal wall pressure from an average, mean or maximum of the measurements from the intercuff pressure sensors520a-band/or pressure sensor devices530a-bon the outer surface of the cuff assembly120. When the tracheal wall pressure is greater than a predetermined maximum tracheal pressure at806, an alert is generated at808. The alert may indicate that the maximum tracheal pressure is exceeded and/or may indicate to replace the current airway tube (such as an endotracheal or tracheotomy tube), e.g., with an airway tube having a greater outer diameter. When the airway tube is replaced, the process800begins again at802.

When the tracheal wall pressure is under the predetermined maximum tracheal pressure at806, an air leak test is performed at810. The air leak test includes obtaining an air sample from a supracuff area of the trachea. The air-evacuating system (such as the opening130, suction channel136, and airway tubing134) of the airway100is connected to a low-pressure vacuum pump420to provide good circulation in the supracuff area. The supracuff air is sampled for the presence of the one or more predetermined scents. When no air leak is detected at812, it indicates that the cuff assembly120has a good seal with the tracheal wall. The pressures of the cuff assembly120are then maintained and monitored at814. The air-leak testing may be repeated periodically or upon command to ensure the cuff assembly120maintains a good seal with the tracheal wall.

When an air leak is detected at812, this indicates that the cuff assembly120does not have a good seal against the tracheal wall. To obtain a better seal, the pressure in the inner cuff124is adjusted at816. For example, the pressure in the inner cuff124may be increased in increments of 1-2 cm H2O. After an increment increase in pressure of the inner cuff124, it is determined at818whether the pressure in the inner cuff is greater than 25 H2O, e.g. the maximum inner cuff pressure. When it is not, it is determined whether the tracheal wall pressure is more than the maximum tracheal wall pressure at820. When the tracheal wall pressure exceeds the maximum tracheal wall pressure at820, then an alert is generated at822. The alert may indicate that the maximum tracheal pressure is exceeded and/or may indicate to replace the current airway tube (such as an endotracheal or tracheotomy tube), e.g., with an airway tube having a greater outer diameter. When the airway tube100is replaced, the process800begins again at802.

When the tracheal wall pressure is below the maximum tracheal wall pressure at820, another air leak test is performed at824. These steps of incrementing the pressure in the inner cuff124and performing an air leak test may be repeated until the pressure in the inner cuff124is greater than the maximum inner cuff pressure (e.g., 25 cm H2O) or the tracheal wall pressure exceeds the maximum tracheal pressure (e.g., 25 cm H2O). When no leak is detected at824, then the pressure of the cuff assembly120is maintained and monitored at826. The air-leak testing may be repeated periodically or upon command to ensure the cuff assembly120maintains a good seal with the tracheal wall.

When a leak is still detected at824and the incremented pressure of the inner cuff124exceeds the maximum inner cuff pressure at818, then the process proceeds to step830ofFIG.8B, as shown by the arrow A. At step830, the pressure in the outer bladder122is adjusted. For example, the pressure in the outer bladder may be increased in increments of 2-3 cm H2O. After an increment increase in pressure of the outer bladder122, it is determined at832whether the pressure in the outer bladder122is greater than a maximum outer bladder pressure, e.g. 60 cm H2O. When the outer bladder122is greater than a maximum outer bladder pressure at832, then an alert is generated at834. The alert may indicate that the maximum outer bladder pressure is exceeded with a leak detection and/or may indicate to replace the current airway tube (such as an endotracheal or tracheotomy tube), e.g., with an airway tube having a greater outer diameter. When the airway tube100is replaced, the process800begins again at802.

When the pressure in the outer bladder122is not greater than a maximum outer bladder pressure at832, the inner cuff pressure is adjusted to a lower pressure, such as the initial pressure of 10 cm H2O at836. At838, it is determined whether the tracheal wall pressure is more than the maximum tracheal wall pressure. When it is greater than the maximum tracheal wall pressure, then an alert is generated at840. The alert may indicate that the maximum tracheal pressure is exceeded and/or may indicate to replace the current airway tube (such as an endotracheal or tracheotomy tube), e.g., with an airway tube having a greater outer diameter. When the airway tube100is replaced, the process800begins again at802.

When the tracheal wall pressure is below the maximum pressure at838, an air leak test is performed at842. The air leak test determines whether a good seal has been formed at the new incremented pressure of the outer bladder122and the initial pressure of the inner cuff124. When no leak is detected at844, the pressures of the cuff assembly120are maintained and monitored at846. The process continues to step810inFIG.8Aas shown by arrow C. Periodic air leak testing is performed to ensure the cuff assembly120maintains a good seal with the tracheal wall.

When a leak is detected at844at the new incremented pressure of the outer bladder122and the initial pressure of the inner cuff124, then the process continues to step816inFIG.8Aas shown by arrow B. The initial pressure of the inner cuff124is then incremented until no leak is detected at824or a maximum inner cuff pressure is reached at818. When the maximum inner cuff pressure is reached at818, then the process again continues to830and the pressure in the outer bladder122is incremented to a higher pressure. The process800is completed when no air leak is detected at824or844, the pressures of the inner cuff and the outer bladders are less than their respective maximums, and the tracheal wall pressure is less than a maximum.

In this process800, the pressure in the inner cuff124is incremented first 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 its initial pressure and incremented through its operating range until a leak is not detected. Throughout the process800, the tracheal wall pressure is not to exceed a maximum pressure, e.g. within a range of 20-25 cm H2O. Should the tracheal wall pressure exceed the maximum pressure to achieve an air-tight cuff-bladder inflation, the size of the airway tube is adjusted, e.g., up-sized to a next size larger. When another airway tube is implanted in the patient, the entire process800is repeated to adjust the pressures in the cuff assembly120. The cuff assembly120and the regulator system600thus provide for a process to determine and maintain an optimized operating pressure without leaks for the cuff assembly120. This process helps to reduce micro-aspiration and infection of the lungs by obtaining and maintaining a good seal with the tracheal wall without unduly harming the tracheal wall.

FIG.9illustrates a schematic block diagram of an embodiment of a user interface900for the pressure regulator system600. The user interface900receives settings and commands from a user. In one example, the user interface900includes a display902that may be an interactive touch screen. The display902includes one or more icons or data displays, such as a display of a current tracheal wall pressure904and alarms/alerts906. The display902further includes a display of the cuff pressure908, such as the set or target pressure910and current pressure912of the inner cuff124and outer bladder122. The display902may also include a display of the leak detection914, such as a time of the last test916and result of the last test918. Additional and/or alternate data may also be presented in the display902.

The user interface900further includes one or more user input devices, such as knob controllers, push buttons, touch pads, switches, etc. to receive one or more commands from a user. Alternatively, the display900may include an interactive touch screen that displays one or more icons to receive the user commands. For example, the user interface900includes a power button/icon930to initiate power up of the pressure regulator600. A deflate button/icon940initiates deflation of the cuff assembly120, e.g. such as for removal of the airway tube100from a patient.

An auto mode button/icon942may be activated to initiate auto mode. In the auto mode, the pressure regulator600automatically inflates the cuff assembly to default settings and performs one or more processes described inFIGS.8A-Bto determine an operating pressure without detected leaks for the cuff assembly120. After inflation, in an auto mode, the pressure regulator600performs automatic cuff pressure measurements and pressure adjustments of the cuff assembly120in addition to leak detection tests at predetermined intervals. The predetermined interval may have a default of 30 minutes with a manual setting between 5 minutes to 4 hours.

The user interface900further includes a manual mode button/icon944to initiate a manual mode. In the manual mode, default settings may be input such as default pressure settings for the cuff assembly120, maximum pressure settings for the cuff assembly and/or the tracheal wall pressure, interval between leak detection tests, interval between pressure measurements, etc. In the manual mode, an “initial pressure set” button/icon may be manually activated to inflate the cuff assembly120to default settings and perform one or more processes described inFIGS.8A-Bto determine an optimized operating pressure without leaks for the cuff assembly120. After inflation, a cuff pressure measurement check may be manually activated including a manual pressure adjustment using the arrow key946. A leak detection test may be initiated manually by activating the corresponding icon/button948. The user interface900may include other commands and/or data for operation of the pressure regulator600.

FIG.10illustrates a schematic block diagram of an embodiment of the pressure regulator system600. In one example, the user interface900is included in a control module1000that may also include the pressure controller606. The pneumatic system620may be in a separate encasement as shown or included with the control module1000. When in separate encasements, the pneumatic system620and the pressure controller606may communicate using wired or wireless transmitters.

The pneumatic system620includes the first output port626acoupled to extension tubing1002afor inflating the outer bladder122of the cuff assembly120. The extension tubing1002amay include an air filter1004ato filter any contaminants and attaches to the inflation line106aof the airway tube100. The inflation line106amay include a pilot balloon1010athat serves as an indication of the air pressure in the outer bladder122. The pneumatic system620includes the second output port626bcoupled to extension tubing1002bfor inflating the inner cuff124of the cuff assembly120. The extension tubing1002bmay include an air filter1004bto filter any contaminants and attaches to the inflation line106bof the airway tube100. The inflation line106bmay also include a pilot balloon1010bthat serves as an indication of the air pressure is in the inner cuff124. In addition to the inflation lines106a-b, additional manual inflation lines may be connected to the cuff assembly120for manually inflating the inner cuff124and outer bladder122, e.g., using a parenteral syringe.

Though the cuff assembly120is described as including an inner cuff124and outer bladder122, the pressure regulation system600and methods described herein may also be implemented with a single inflatable cuff.FIG.11illustrates a schematic block diagram of an embodiment of the leak detection and pressure regulation system for a single cuff assembly. In this example, the cuff assembly includes a single inflated cuff1100encircling the airway tube100. One or more intracuff sensors1102are positioned to measure an air pressure within the cuff1100, e.g. positioned within the cuff1100and/or in a pilot balloon connected to an inflation line for the cuff1100. One or more pressure sensors1104may be coupled externally to the cuff1100to measure a force applied to the tracheal wall. The tracheal wall pressure may also be measured using one or more pressure sensors1106positioned between the cuff1100and the airway tube100. The pressure measurements may be transmitted periodically to the pressure controller606using wired or wireless transmitters in the pressure sensors1102,1104,1106.

The airway tube100and cuff1100may also include the leak detection system1120. The leak detection system1120includes one or more scented films128located on a distal side of the cuff1100. The one or more scented films128amay be located circumferentially around a distal side of the cuff1100. Additionally or alternatively, one or more scented films128bmay be located circumferentially around the airway tube100. The scented films128a-binclude an embedded scent detectable by the one or more scent detectors410.

The airway tube100further includes an air intake opening130formed in the outer wall that fluidly connects to a suction channel136. The suction channel136and opening130are preferably on a proximal side of the cuff assembly120. Air tubing134attaches to a proximal end of the suction channel136and a vacuum pump420attaches to the air tubing134. The vacuum pump420suctions air from the trachea through the opening130. The vacuum pump420obtains an air sample for the one or more scent detectors410. The scent detectors410communicate measurements to the pressure controller606.

The pressure controller606may control the vacuum pump420and scent detectors410and/or a separate processor device1122with a memory device1124may control the leak detection system1120. The memory device1124includes one or more non-transitory processor readable memories that store instructions which when executed by the processor device1122or other components of the leak detection system1120, causes the leak detection system1120to perform one or more functions described herein. The leak detection system1120also includes a user interface1126and transmitter1128.

FIG.12illustrates a schematic flow diagram of an embodiment of a method1200for leak detection of a tracheal seal formed by a cuff assembly120in an airway tube100. The cuff assembly120may include a single inflated cuff1100or dual cuffs122,124. The method1200may be performed by a separate leak detection system1120or by a pressure controller606that controls the cuff assembly120. At1202, a command is obtained to initiate a leak detection test. The command may be automatically generated at preset intervals or manually input.

The vacuum pump420is activated for a predetermined period at1204to obtain an air sample from the trachea proximal to the cuff assembly at1206. The predetermined period is set such that the supracuff air in the trachea is circulated and refreshed between tests. The scent detectors410are exposed to the air sample and determine whether a scent is detected at1208. When a scent is not detected at1208, the leak detection system1120returns to step1202to wait for a command to perform another test. When a scent is detected at1208, an alert is generated at1210. The alert may be an audible alarm and/or a visual display. The pressure in the cuff assembly120may then be adjusted, and the leak detection process repeated.

The cuff assembly120, pressure regulator system600, and the leak detection system1120improve the protection and safety of intubated patients. The cuff assembly120and the pressure regulator system600maintain an improved seal with the tracheal wall that reduces leakage of secretions and infection of the lungs without unduly harming the tracheal wall. The automated pressure measurements and adjustments also helps save caregiver time. The leak detection system1120provides an early warning of a possible problem with the seal formed by the cuff assembly120against the tracheal wall. Intervention may then be provided earlier to help prevent leakage of secretions into the lungs. Additional or alternative advantages and improvements are possible in one or more of the embodiments described in the specification and/or the claims.

As may be used herein, the term “operable to” or “configurable to” indicates that an element includes one or more of circuits, instructions, modules, data, input(s), output(s), etc., to perform one or more of the described or necessary corresponding functions and may further include inferred coupling to one or more other items to perform the described or necessary corresponding functions. As may also be used herein, the term(s) “coupled,” “coupled to,” “connected to” and/or “connecting” or “interconnecting” includes direct connection or link between nodes/devices and/or indirect connection between nodes/devices via an intervening item. As may further be used herein, inferred connections (i.e., where one element is connected to another element by inference) includes direct and indirect connection between two items in the same manner as “connected to.” As may be used herein, the terms “substantially” and “approximately” provides an industry-accepted tolerance for its corresponding term and/or relativity between items.

In the foregoing specification, certain representative aspects have been described with reference to specific examples. Various modifications and changes may be made, however, without departing from the scope of the present invention as set forth in the claims. The specification and figures are illustrative, rather than restrictive, and modifications are intended to be included within the scope of the present invention. Accordingly, the scope of the invention should be determined by the claims and their legal equivalents rather than by merely the examples described. For example, the components and/or elements recited in any apparatus claims may be assembled or otherwise operationally configured in a variety of permutations and are accordingly not limited to the specific configuration recited in the claims.

Furthermore, certain benefits, other advantages and solutions to problems have been described above with regard to particular embodiments; however, any benefit, advantage, solution to a problem, or any element that may cause any particular benefit, advantage, or solution to occur or to become more pronounced are not to be construed as critical, required, or essential features or components of any or all the claims.