STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to an endotracheal tube, and more particularly, to an endotracheal tube having an inflatable cuff that forms a tapered collection pocket when inflated for urging the collection of secretions and a rail system adapted for securely and safely guiding a suction catheter along the tube for facilitating the aspiration of secretions pooled in the cuff pocket and the area above the trachea.
2. Description of Related Art
A well known problem with endotracheal tubes is the buildup of excessive oropharyngeal and gastroesophageal secretions above the cuff of the tube in the trachea and subglottic area when a patient is intubated. Endotracheal intubation is used for mechanically ventilating a patient's lungs when the patient cannot breathe normally and/or for introducing anesthetic gases into the lungs. However, the intubated patient is almost always placed at risk by the accumulation of pooled secretions between the inflated cuff and oral pharyngeal area. The accumulation and stagnation of oral secretions breeds infectious organisms that can result in pneumonia. The accumulated secretions eventually leak into the patient's lungs or find their way into the lungs when the endotracheal cuff is deflated for removal or when a patient is turned and, or coughs. Conventional procedures for preventing pneumonia associated with tracheal intubation require confirmation that secretions are cleared from above the tube cuff before deflating the cuff and removing the tube. Some endotracheal tubes have a dorsal lumen formed in the walls of the tube above the cuff for draining accumulated secretions by suction. However, there are no known recommendations for routinely and effectively using an endotracheal tube with a dorsal lumen. This is in part due to the fact that the dorsal lumen can become easily occluded, which would require complete removal of the tube. Thus, intubated patients are always at risk of developing bronchitis, pneumonia and other life-threatening infections because of pooled secretions entering the trachea and lungs.
Up until 1936, pneumonia was the leading cause of death in the United States. Even with all the modern advances in medical technology and antibiotic therapy, pneumonia is currently the sixth leading cause of death in the U.S. (CDC, 1997). Nosocomial (hospital-acquired) pneumonia is a frequent complication in mechanically-assisted ventilator patients, according to a national, multi-million dollar, multi-center research study by the Centers for Disease Control (1997), pneumonia is the second most common nosocomial infection in the United States and is associated with substantial morbidity and mortality. The CDC further states that because intubation and mechanical ventilation alter first-line patient defenses, they greatly increase the risk for nosocomial bacterial pneumonia. The risk for pneumonia is increased by the direct access of bacteria to the lower respiratory tract, which often occurs because of leakage around the endotracheal cuff, thus enabling pooled secretions above the cuff to enter the trachea. According to Marino (1998), the aspiration of mouth secretions into the upper airways is the inciting event in most cases of pneumonia. An average of 1 billion bacteria are found in each milliliter of saliva, so aspirating only a micro-liters of saliva can introduce large numbers of bacteria into the airways.
According to Lewis et al (1997), endotracheal intubation interferes with the normal cough reflex and the mucociliary escalator mechanism. Decreased consciousness depresses the cough and epiglottal reflexes, which may allow aspiration of oropharyngeal contents into the lungs. It also bypasses the upper airways in which filtration and humidification of air normally take place (622).
Nosocomial pneumonia is a complication that not only increases mortality/morbidity rates, but also causes substantial increases in financial costs due to significant increases in length of stays (LOS) in high tech, intensive-care units. A one-two week increase in a patient's LOS in an ICU is a very significant fiscal consideration and hardship, which can cost $3,500.00 to $5,000.00 a day.
Conventional endotracheal tubes contribute to the problems associated with pooled secretions in the trachea area. The conventional endotracheal tube has an inflatable cuff that blocks the passageway and allows secretions to accumulate above the cuff. The tube has an inflation lumen that extends between a proximal end and a distal end for inflating the cuff. The inflatable cuff is joined to the tube above the distal end to prevent the passage of fluids and gases to and from the lungs when inflated. The cuff is inflated so that it engages the trachea wall thereby providing a proper seal. However, as the trachea is sealed, oral secretions tend to pool or build up above the cuff. If these secretions could be safely and conveniently aspirated the foregoing health concerns could be eliminated or greatly reduced. However, costs and practical constraints have prevented the adoption of a reliable, cost effective endotracheal and aspiration system.
In addition to the foregoing, conventional endotracheal tubes are limited in their use, difficult to monitor and provide methods of treatment but no information. As endotracheal tubes invade the body, it would be beneficial and helpful if it could provide useful information. For instance, if an endotracheal tube could be designed to also monitor a patient's temperature it would provide important medical information to a practitioner.
Moreover, an endotracheal tube that was able to provide a means for early detection of tissue hypoperfusion, such as structure for measuring oropharyngeal PCO2, would provide an additional benefit over conventional tubes. An eleveation in oropharyngeal PCO2 is an early warning signal for tissue hypofusion. Limiting the risk of organ damage resulting from tissue hypoxia is one of the biggest challenges in patient care. Because tissue perfusion and oxygenation help maintain organ vitality, tissue perfusion is literally a matter of life and death. A noninvasive sublingual system known in the prior art and sold under the trademark CapnoProbe measures PCO2 through fiber optic technology. Such devices comprise additional required equipment and can be expensive. An endotracheal tube having structure for continuously measuring oropharyngeal PCO2 could provide a more economical device and more convenient option that facilitates taking continuous measurements and would be well received.
Endotracheal tubes are not new in the art and several have provided structure for draining fluid from the lungs and/or insufflating the lungs with oxygen or other gases. Other known devices have addressed the problem of removing pooled secretions from the upper tracheal area, but have failed to solve the problem as contemplated by the instant invention. Many of the endotracheal tubes known have a suction lumen that is integrally formed along or through the wall of the endotracheal tube. This design increases the thickness of the tube and calls for the entire endotracheal tube to be discarded when the suction lumen becomes damaged or permanently occluded or is the wrong size for the required aspiration. Designs that have a separate but permanently attached catheter can rupture the trachea wall. These endotracheal tubes and similar designs have edges that could scrape and cause trauma to the tracheal passageway.
The prior art devices known are disclosed in the following patents. U.S. Pat. No. 5,143,062, issued to Peckham, discloses an endotracheal tube comprising a double lumen through which air may be circulated, creating an indirect gentle suction through a suction eye communicating with the distal ends of the lumens, and located at a position proximal to the inflation cuff. This design, however, does not provide adequate suction necessary for aspirating secretions and is easily occluded. The Peckham device, is not practical for convenient hospital use and appears to be unsuitably thick. U.S. Pat. No. 4,305,392, issued to Chester, discloses an inflatable cuff type endotracheal tube having a suction chamber adjacent to the upper-side of the cuff. U.S. Pat. No. 4,334,534, issued to Ozaki, discloses an emergency airway tube for use in resuscitation of non-breathing patients by inserting the tube through the mouth until it randomly lodges either in the trachea or the esophagus. U.S. Pat. No. 4,584,998, issued to McGrail, discloses an endotracheal tube including up to three lumens, in addition to the primary lumen, which serves various functions to provide versatility in the treatment of patients. One lumen is used for inflating the cuff once the tube has been placed in the trachea; another is used to deliver oxygen or other gases by constant insufflation, intermittent jet ventilation or high frequency ventilation; and the third is used for monitoring and irrigation. U.S. Pat. No. 4,607,635, issued to Heyden, discloses an endotracheal tube with an elongated passage along its length. The tube has a plurality of ports along the passage to provide for removal of secretions that accumulate outside the tube and between the tube. U.S. Pat. No. 4,632,108, issued to Geil, discloses a flexible tubular assembly having a lumen for removing smoke generated during lazer surgery. U.S. Pat. No. 4,637,389, issued to Heyden, discloses a tracheal tube providing an expansible channel along its length, which normally maintains a generally concealed attitude within the trachael tube wall and adapts by expansion for the insertion of a suction catheter. U.S. Pat. No. 4,688,568, issued to Frass, discloses a tube that has an airway for sole esophageal obturator or endotracheal and esophageal-obturator ventilation and an inflatable cuff in the area of the tip of the airway and air-outlets in the area of the pharynx. U.S. Pat. No. 4,762,125, issued to Leiman, discloses a balloon-tipped suction catheter that embodies an elongated tube with a cannula extending along the elongated tube. U.S. Pat. No. 4,840,173, issued to Porter, III, discloses an endotracheal tube having dual passages provided by the merging of a ventilation tube and a suction tube. U.S. Pat. No. 5,520,175, issued to Fry, discloses an endotracheal tube with an inflatable cuff having a convex shaped superior surface forming a collection basin to facilitate accurate suctioning while tube is in position.
The above noted patent references fail to adequately address many important issues. Conventional endotracheal and tracheal tubes lack the ability to suction both oropharyngeal and gastroesophageal secretions, even when a patient is turned according to nationally instituted decubitus prevention protocols. They fail to provide a suction catheter or lumen that is replaceable while a patient is intubated. The prior art endotracheal tube designs do not adequately accommodate chlorhexidine rinses to prevent colonization of bacteria around the trachea area above the cuff and can trigger cough reflexes, which allow secretions and fluids to flow past the cuff. Conventional designs also fail to counter torquing of the cuff balloon that can occur when a patient coughs.
The patent references found fail to provide an endotracheal tube that adequately addresses the foregoing issues or that has a suction catheter or lumen that is replaceable while a patient is intubated, adapts to the contours of the tube and contains secretions even when a patient is turned. As the background devices fail to disclose an endotracheal tube and suction catheter system having these structural characteristics, the need for such a device is apparent. The instant invention addresses this by providing an endotracheal tube and suction catheter system comprising a replaceable suction/aspiration catheter, guide rail system and collection pocket that is designed to hold secretions even when a patient is turned.
BRIEF SUMMARY OF THE INVENTION
In light of the foregoing, it is an object of the present invention to provide an endotracheal tube that facilitates the convenient, safe removal of pooled secretions in the tracheal area above the cuff.
It is another object of the instant invention to provide an endotracheal tube having an aspiration or suction catheter that is replaceable, smooth and adapted for traversing an endotracheal tube for routine use of the suction catheter.
It is an additional object of the instant invention to provide an endotracheal tube system having a suction catheter that can be replaced while a patient is intubated with the endotracheal tube allowing for routine suction catheter changes.
It is a further object of the instant invention to provide an endotracheal tube and suction catheter system that facilitates the introduction of anti-microbial solutions into the tracheal area to kill bacterial colonizations.
It is also an object of the instant invention to provide an endotracheal tube and suction catheter system that can decrease the occurrence of aspiration/nosocomial pneumonia.
It is another object of the instant invention to provide an endotracheal tube and suction catheter system that can decrease the requirement for antibiotics.
It is still another object of the instant invention to provide an endotracheal tube and suction catheter system that can suction both oropharyngeal and gastroesophageal secretions, even when a patient is turned.
It is still an additional object of the instant invention to provide an endotracheal tube and suction catheter system that facilitates the use of chlorhexidine rinses to prevent colonization of bacteria around the trachea and cuff mating surfaces in a manner that alleviates aspiration secondary to the suction of fluids at the trachea cuff and avoids the triggering of the cough reflex as fluids migrate to the tracheal cuff.
It is still another object of the instant invention to provide an endotracheal tube and suction catheter system having a geometric design that counters the torque forces on the cuff when a patient coughs to keep the walls of the cuff against the trachea wall to prevent subglottic secretions from slipping past the cuff.
It is still a further object of the instant invention to provide an endotracheal tube and suction catheter system having a cuff with elongated sides to provide a greater surface area and less pressure per unit area on sensitive, delegate tracheal tissue to decrease the incidence of injuries associated with cuff pressure on the trachea.
It is yet another object of the instant invention to provide an endotracheal tube that is cost effective and adapted for existing manufacturing techniques.
In light of these and other objects, the instant invention comprises an endotracheal tube and suction catheter system having an inflatable cuff with a unique shape, collection pocket formed by the inflatable cuff and a unique railing system for controllably guiding a suction catheter along the tube and into or proximal to the pocket. The cuff and pocket facilitate the collection of pooled secretions that accumulate in the trachea area. Pooled secretions are collected in the cuff pocket and the cuff may be pitched toward the pocket or have a concave hemispherical design at the posterior pocket end and, or a convex hemispherical design at the anterior end to further urge pooled secretions into the pocket. The cuff preferably has an elongated parallelogram-like shape to counter the rocking phenomenon caused by a patient coughing or turning. The parallelogram-like shape causes the cuff to maintain its contact with the trachea walls so secretions and fluid do not leak past the cuff balloon. The suction catheter, which is guided along the tube toward the pocket, is used to aspirate the collected secretions in the pocket and above the cuff. The railing system allows the suction catheter to be replaced without having to remove the endotracheal tube. Although the instant invention is primarily described with reference to flexible endotracheal tubes, it may also be adapted for tracheal tubes, which are typically shorter and more rigid. The instant invention may also comprise a system having a suction catheter with a temperature probe and, or oropharyngeal system probe.
The endotracheal tube generally comprises a main lumen, cuff lumen, inflatable cuff with a tapered pocket and rail system designed for guiding a suction catheter along the main lumen. The rail system is found on the main lumen and suction catheter such that the catheter engages and slides along the main lumen to allow for the removal of pooled secretions. The rail system comprises a monorail that traverses the exterior surface of the main lumen and terminates at a predetermined distance above the cuff and pocket, and a corresponding bi-rail traversing the suction catheter. The suction catheter bi-rail slidably interlocks with the monorail and terminates at a stop defined by the distal end of the monorail. The monorail stop prevents the catheter from extending too far into the trachea and cuff pocket to protect the patient from trauma and the cuff from being punctured and to facilitate optimum placement of the suction catheter. The monorail stop is smooth and curved and tapers downward to the tube to prevent trauma to the patient's trachea during intubation. The bi-rail comprises two substantially parallel rails having a hooked contour along its interior surface that forms a channel for sliding over the monorail. The monorail comprises an elongated tongue having a cross-sectional shape, such as a mushroom-like shape or similar shape, that corresponds to the cross-sectional shape of the bi-rail groove. The bi-rail and tube provide walls of adherence for hardened, ossified secretions that inevitably develop during long term intubation. When removing the suction catheter the hardened secretions along the endotracheal tube, bi-rail, and in some instances the monorail, are removed. The bi-rail channel accommodates the application of a water-based lubricant, such as those sold under the trademark Surgilube, for decreasing friction as the catheter bi-rail is urged over the monorail. The bi-rail also provides increased stability for inserting the suction catheter. In an alternative embodiment, the cuff pocket and/or catheter section may comprise a radio opaque material or plastic that is detectable and viewable when inserted.
The cuff balloon comprises a cuff pocket for collecting pooled secretions. The cuff preferably has two interior pocket walls that form a tapered pocket when the cuff is inflated. The pocket walls may have a higher tensile strength to prevent the pocket from collapsing and to achieve the desired pocket shape. The superior anterior portion of the cuff may also extend outward at or near the top end in a manner that pitches toward the pocket or provides a hemispherical convex contour that facilitates migration of secretions into the tapered pocket. The cuff's posterior pocket end may also be pitched toward the pocket or have a concave, hemispherical design to further urge secretions into the pocket. The pocket preferably expands ninety to one-hundred and eighty degrees over the tube at its widest section and tapers into a point at the back of the pocket and a point at the top of the pocket. The point at the top of the pocket is preferably secured to the interior wall of the cuff and the point at the back of the pocket is secured to the tube proximal the bottom of the cuff. The pocket walls share common edges between the two points and each have a lower edge that is secured to main lumen. The lower edges are preferably ninety to one hundred and eighty degrees apart near the top of the pocket to achieve the proper width of the pocket. This retains collected secretions in the pocket and continues to facilitate the collection of secretions when the patient is turned. The pocket walls and cuff define an airtight interior volume that is inflated through the cuff lumen. The cuff lumen extends through the wall of the main tube and communicates with the inflatable cuff for selectively inflating and deflating the cuff with an external source of air, as is known in the art. When the cuff lumen is inflated it raises the top point and pocket walls until fully erect. When the cuff is deflated, the pocket collapses with the cuff. The design of the cuff and collection pocket urges the migration of secretions into the pocket, which retains the secretions even when a patient is turned. The cuff balloon may also be impregnated or coated with an anti-microbial solution that prevents the colonization of bacteria
The main lumen comprises the main body of the invention. The main lumen is inserted into a patient's trachea for ventilation and/or anesthetic treatment of the patient's lungs. The cuff inflation lumen fluidly communicates with the cuff balloon for inflating and deflating the cuff.
To use the instant invention, a patient is intubated with the endotacheal tube. The tube may be fitted with the suction catheter at the time of intubation or thereafter. To mount the suction catheter on the tube, the bi-rail is aligned with and slidably inserted over the monorail so that the bi-rail wraps around the monorail. The suction catheter is urged down the tube until the bi-rail engages the monorail stop. When fully inserted, the suction catheter extends beyond the stop and into the cuff pocket. The same procedure is followed to insert a suction catheter while the patient is intubated. The suction catheter may be replaced without removing the endotracheal tube by sliding the suction catheter off the monorail and out of the patient's mouth and inserting a new catheter over the monorail as discussed. Once installed, an external vacuum source is used to aspirate secretions through the suction catheter.
In an alternative embodiment, the instant invention may comprise a tracheostomy tube instead of an endotracheal tube. The tracheostomy tube is merely a shorter, rigid version of the endotracheal tube of the instant invention and is inserted through the neck instead of through the mouth. Accordingly, the tracheostomy tube of the instant invention comprises all the elements of the endotracheal tube.
In accordance with these and other objects, which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.