Perilaryngeal oral airway with temperature sensor

An oral airway (510) includes an elongate tubular member (512) having a distal (510) and a proximal end (514), the oral airway being configured to place the distal end in a supraglottic position and prevent insertion of the distal end into the patient's larynx when operatively placed within the hypopharynx of a patient. A temperature sensor (554) is operatively associated with the elongate tubular member to detect a core temperature of a patient with the distal end of the oral airway operatively placed in a supraglottic position within the hypopharynx of the patient.

TECHNICAL FIELD

The present invention relates generally to a class of medical devices commonly referred to as oral airways and supraglottic airways which are inserted through a patient's mouth and into the patient's pharynx while the patient is undergoing general anesthesia or is undergoing respiratory treatment such as is carried out with cardiopulmonary resuscitation. More specifically, the present invention is directed to a perilaryngeal oral airway and perilaryngeal supraglottic airway which is capable of monitoring a patient's core body temperature.

BACKGROUND ART

Oral airways were introduced into the practice of anesthesia and cardiopulmonary resuscitation several decades ago for two basic purposes. First, they prevent the patient's biting down on and occlusion of a previously placed oral endotracheal tube. Second, and most important, oral airways help to provide a patent airway that allows positive pressure ventilation to be carried out by the practitioner. More recently, some oral airways have been developed to facilitate blind (not visually directed) placement of an endotracheal tube.

For most patients, mask ventilation is carried out successfully by insertion of an oral airway and by a variety of physical adjustments, such as extension of the patient's neck and elevation of the patient's jaw. However, in some patients, no matter what physical adjustments are made or the particular oral airway which is inserted, mask ventilation cannot be successfully achieved. Such cases are literally life-threatening as hypoxemia and death can quickly ensue if the patient's blood is deprived of oxygen due to a lack of ventilation.

When mask ventilation (even with the use of an oral airway) cannot be carried out, there are multiple mechanisms responsible. Most significantly, soft tissue structures in the hypopharynx (the area between where conventional oral airways end and the glottis opens into the trachea) collapse inwardly and obstruct airflow. This collapse occurs from both an antero-posterior direction, as well as from the sides of the hypopharynx. Unfortunately, all oral airways which have been introduced into practice to date end bluntly well above the epiglottis (the cartilaginous structure just above the glottis or laryngeal opening) and glottis and thus place patients at risk for significant airway obstruction. Another mechanism of airway obstruction which occurs while using oral airways is the patient having large lips covering the outside opening of the oral airway with subsequent inadequate airflow through the nasal passages (due to the solid posterior wall of the airway limiting passage of air into the airway at the level of the nasopharynx).

Additionally, most known oral airways are comprised of a hard plastic material throughout their length with no variation in softness between one end of the oral airway and the opposite end. As a result, the distal end (i.e., the end which first enters the mouth and passes down into the pharynx of the patient) often bruises or otherwise damages soft mucosal surfaces of the patient during insertion or once the oral airway has been seated in place.

Representative prior art airways include Baildon, U.S. Pat. No. 4,919,126, which discloses an oral airway formed of plastic which includes an air passageway extending longitudinally through the airway. The distal end has a projecting solid anterior portion which serves as an “epiglottis elevator.” As such, the oral airway is blunt-shaped in configuration and ends well above the glottis. For this reason, the Baildon oral airway suffers from the problems discussed above in that it fails to provide any structure to prevent the collapse of soft tissue structures in the hypopharynx.

Berman, U.S. Pat. Nos. 4,054,135 and 4,067,331, relate to an intubating pharyngeal airway having a side access for passage of an endotracheal tube. The airway includes a blunt end on the anteriorly extending wall which is designed to fit into the vallecula (area between the epiglottis and tongue). Accordingly, the devices disclosed in both of Berman's patents are similar to the device of Baildon in that they can detrimentally allow soft tissue structures to invaginate inward and thereby occlude the passage of air.

Moses, U.S. Pat. No. 3,908,665, discloses an oro-pharyngeal airway wherein the outer diameter of the body portion progressively increases from the end closest to the mouth to the opposite end thereof so as to relieve any obstruction to the flow of air by the base of the tongue falling back on the posterior pharyngeal wall. However, the airway of Moses likewise suffers from the problems discussed in detail above in that the blunt-shaped end terminates well above the glottis, thereby allowing possible soft tissue obstruction to occur.

Augustine, U.S. Pat. No. 5,203,320, discloses a tracheal intubation guide which similarly seats above the glottis. Moreover, the device of Augustine functions as a guide for placing an endotracheal tube in a “blind” manner and is neither designed for nor could it possibly function to allow mask ventilation to be carried out.

In addition, for some patients it is important to use an airway device which provides a seal within the patient's airway (trachea, oro- or hypopharynx) in order to better allow positive pressure ventilation to be accomplished. These airways are referred to herein as superglottic airways. Traditionally, this has been achieved by using an endotracheal tube passed between a patient's vocal cords. In an effort to avoid the deleterious effects of tracheal intubation (e.g., bronchospasm, dental injury and cardiovascular stimulation), the laryngeal mask airway (“LMA”) has been introduced into clinical practice. The LMA is illustrated and described in Brain, U.S. Pat. No. 4,509,514. While providing a seal with which to administer positive pressure ventilation, there are several potential problems when using an LMA. First, the device is easily malpositioned so that ventilation is not possible, for example, by virtue of the epiglottis bending back over the glottis and thereby obstructing air flow. Second, by directly covering the glottic aperture, trauma to the glottic structures (arrhytenoid cartilages, vocal cords) can occur. In addition, the cost of this product (over $200) becomes a factor when limitations to reuse occur due to physical damage of the device or accidental loss. Third, as a reusable product, the hazard of cross-contamination from one patient to another cannot be completely eliminated.

Because of the above-limitations of the LMA, a cuffed oro-pharyngeal airway has been introduced into clinical practice. Greenberg, U.S. Pat. No. 5,443,063, describes such a device as an oro-pharyngeal cuff placed over a conventional oral airway. However, this device has several significant limitations which prevent it from functioning adequately. First, the airway suffers from the problems of those previously discussed in that it ends well above the glottis, thereby allowing soft tissue obstruction to impair the flow of oxygen to the lungs. Second, with the cuff placed so far proximally in the oro-pharynx, the device tends to push itself out of the patient's mouth, thereby requiring that the device be secured in place by means of a strap placed around the patient's head. Finally, the cuff is positioned so far proximally in the patient's airway that it often allows leakage of oxygen and anesthetic gases around the cuff, thereby preventing the formation of an air-tight seal. This, of course, makes positive pressure ventilation impossible in those patients.

Several oral airways, including those described in the patents to Berman and Augustine, have been introduced into clinical practice in an effort to provide a means to accomplish blind intubation of a patient's trachea with an endotracheal tube (or to facilitate fiberoptic intubation). These devices end well above the glottic opening and thus function poorly in terms of reliably directing the end of an endotracheal tube into the glottis with blind passage. As a result, the hard distal end of the endotracheal tube may be directed against the structures which surround the glottic opening (arytenoid, cuneiform and corniculate cartilages, epiglottis, aryepiglottic folds) and cause damage to these structures or their soft tissue surfaces. Further, that damage may result in hemorrhage which obscures vision if subsequent placement of the endotracheal tube by means of a fiberoptic device is attempted. Other prior art has attempted to better direct an endotracheal tube into the glottis by having walls which surround and thus engage the arytenoid cartilages or which have projections which physically enter in between those cartilages. Representative are Patil, U.S. Pat. No. 5,720,275; Krüger, U.S. Pat. No. 4,612,927; and Williams, U.S. Pat. No. 4,338,930. However, these structures have hard advancing surfaces which can likewise cause trauma.

Recently, a version of the LMA which is meant to facilitate blind intubation with an endotracheal tube has been introduced into clinical use which attempts to surmount the problems of a misguided endotracheal tube causing trauma to perilaryngeal and glottic structures. This LMA is described in Brain, U.S. Pat. No. 5,896,858. However, in addition to sharing the above discussed problems common to all LMA's, this device relies on precise positioning so that a movable flap raises an obstructing epiglottis out of the way of an advancing endotracheal tube. Because the attached flap resides within the body of the LMA it does not physically contact the epiglottis upon insertion, but rather the advancing endotracheal tube pushes the flap up against the epiglottis to move it out of the way and thus open the glottic aperture for the endotracheal tube to enter. Perfect alignment of the recessed flap with the epiglottis is thus necessary to reliably accomplish blind placement of the endotracheal tube. However, LMA's occupy a somewhat variable and inconsistent position within the hypopharynx in relation to the precise anatomic location of the glottis (due to anatomic variability among patients as well as the distensible nature of the proximal epiglottis and hypopharynx where it resides). As a result, blind intubation with an endotracheal tube with this device can also result in tissue trauma by virtue of its advancing end being misdirected.

The importance of monitoring and maintaining core body temperature when patients undergo general anesthesia is now being more clearly recognized. Significant reductions in body temperature (which are the common and usual course following induction of general anesthesia) in patients undergoing surgery are associated with an increased incidence of cardiac morbidity, increased rates of wound infection, impaired wound healing and alterations in blood coagulation status. In addition, although rare, a patient undergoing general anesthesia may have a sudden and dramatic rise in body temperature due to an abnormal acceleration of metabolic rate in a condition termed malignant hyperthermia. This is a life-threatening syndrome which requires prompt recognition and treatment if a patient is to survive, and the rise in body temperature is one of the hallmarks used to diagnose its occurrence. Further, in order to reliably measure body temperature, a “core” temperature must be used. As such, a thermistor or thermal couple temperature probe must be in contact with a deep visceral cavity (e.g., urinary bladder, esophagus), blood, or an internal mucosal surface (e.g., hypopharynx, nasopharynx) which reflects inner body temperature as opposed to surface temperature of the patient. No supraglottic airway or oral airway which is currently in use provides measurement of core temperature by a temperature sensor incorporated into that device.

The present invention is intended to overcome one or more of the problems discussed above.

SUMMARY OF THE INVENTION

A first aspect of the present invention is an oral airway consisting of an elongate tubular member having a distal end and a proximal end. The elongate tubular member is configured to place the distal end in a supraglottic position and to prevent advancement of the distal end into a patient's larynx when operative placed within a patient. A temperature sensor is operatively associated with the elongate tubular member and is positioned on the elongate tubular member to detect a supraglottic core temperature of a patient with the distal end of the oral airway operatively placed in a supraglottic position within a patient. Preferably the temperature sensor is positioned on the elongate tubular member to contact an internal mucosal surface of the hypopharynx. The temperature sensor is preferably coupled to an external display. The elongate tubular member may include an enlarged housing at the distal end with the temperature sensor positioned on the enlarged housing. The enlarged housing may be wedge-shaped and include anterior and posterior walls forming an enlarged proximal portion tapering to a small distal portion and sidewalls extending between the anterior and posterior walls. The wedge-shaped housing is configured so that the sidewalls abut the aryepiglottic folds with the wedge-shaped housing operatively placed within they hypopharynx of a patient.

A second aspect of the present invention is a method of delivering air to a patient which includes providing an oral airway having a distal end and a proximal end with an air delivery opening near the distal end and a temperature sensor attached to the oral airway near the distal end. The oral airway is configured to prevent insertion of the distal end into a patient's larynx when operatively placed within a patient. The distal end of the oral airway is inserted into the mouth of a patient and is seated in a supraglottic operative position within the patient with the opening adjacent the glottis and the temperature sensor contacting a mucosal surface within the patient's hypopharynx.

The oral airway including a temperature sensor of the present invention allows for the accurate determination of a patient's core temperature while the patient's breathing is being assisted by the oral airway without requiring additional invasive instrumentation. The ease of use will promote the monitoring of body temperature of a patient undergoing general anesthesia and reduce the risk of the patient undergoing significant body temperature changes which can severely threaten the patient's well being.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention will now be described with reference to the drawings; however, the position of a conventional oral airway is first briefly discussed.

FIG. 1shows a simplified anatomical illustration of a patient's head, including the oral airway defined by the mouth1, the oral cavity2, the tongue3, and the epiglottis4, the trachea5, the esophagus6and the hypopharynx7. A conventional oral airway10is positioned within the patient's oral airway, with the distal end11ending well above the glottis so that no structure is provided to prevent the collapse of soft tissue structures T in the hypopharynx.

FIGS. 2,3,4A and4B relate to one embodiment of the perilaryngeal oral airway according to the present invention. Note that inFIG. 2, like elements are denoted with like reference numerals with reference to the patient's oral airway.

Referring toFIGS. 4A and 4B, the perilaryngeal oral airway100includes a curved hollow, tubular longitudinally extending body member110. The curvature of the body member preferably, but not necessarily, is between 100° and 140°. The body member110includes a flanged proximal end portion120for location at the mouth of the patient (seeFIG. 2). The body member110further includes a distal end portion130for insertion into the mouth and pharynx of the patient. In the first embodiment, the distal end portion130of the body member110is divided so as to form a pair of elongated extension walls140and141which are operative to seat deep in the patient's hypopharynx and surround the patient's epiglottis and glottis (seeFIGS. 2 and 3), thereby to hold the patient's soft tissue away from the patient's air channel opening.

A U-shaped or V-shaped opening or notch150is formed in the distal end portion130of the body member110so as to form the two elongated extension walls140and141and into which the epiglottis and glottis are positioned. The elongated extension walls140and141at the distal end portion preferably, but not necessarily, expand outward laterally to allow for sufficient space in which to accommodate the epiglottis and glottis within the U-shaped or V-shaped opening150. The extreme distal ends160and161of the elongated extension walls140and141, respectively, may be angled inwardly slightly, thereby providing a smooth contour. The purpose of the inwardly angled extreme distal ends is to allow the ends to be safely inserted past the tonsillar pillars at the back of the patient's mouth. By forming the inwardly-shaped surface, the slightly narrower most distal end can push up against very large tonsils and move them laterally to the sides as the perilaryngeal oral airway is inserted.

The elongated lateral extension walls140and141are preferably, but not necessarily, formed to be relatively flexible and soft so that there is at least some “give” as the perilaryngeal oral airway is inserted into the patient. The particular firmness of the walls must strike a balance between the need to hold the hypopharyngeal and perilaryngeal structures away from the glottis, the need to move the soft tonsillar and oro-pharyngeal structures to the side as the oral airway is inserted, and the desire for the oral airway to be able to bend inwardly when inserted through the back of the patient's mouth. Likewise, the body member110of the perilaryngeal oral airway100is preferably, but not necessarily, of sufficient softness and pliability to bend during insertion and to accommodate different angles once it is successfully inserted into the patient, since a given patient's head and neck may be slightly flexed or extended to provide optimal positioning for mask ventilation. The most proximal end portion120of the oral airway is much harder than the distal end portion130in order to prevent occlusion by the patient biting down thereon.

FIGS. 5A and 5Bshow a further embodiment of the perilaryngeal oral airway according to the present invention wherein the distal end portion230is modified in comparison to the oral airway of the previous embodiment. Note that like elements are denoted with like reference numerals, but preceded by the reference number “2”. In particular, in this embodiment, the distal end portion230has a “filled-in” distal posterior wall235in order to better hold tissue away from the larynx. The anterior wall includes a notched portion250as in the previous embodiment. The body member210of the oral airway preferably, but not necessarily, is of sufficient softness and pliability to bend during insertion and to accommodate different angles once successfully inserted into the patient.

FIGS. 6A and 6Billustrate a still further embodiment of the perilaryngeal oral airway according to the present invention. Again, like elements are denoted with like reference numerals, but preceded by the number “3”. In particular, holes or fenestrations385may be formed through the distal anterior wall of the body member310of the oral airway in order to provide ventilation should the distal end portion330be positioned directly over the glottic opening of the patient, as might occur if the practitioner has selected too large of an oral airway for a particular patient, or where the patient has an abnormally high (rostrally) placed glottic opening.

Moreover, holes380and381may be formed through the anterior surface of the elongated extension walls340and341, respectively, and which function to allow ventilation should the oral airway be situated at an abnormal angle such that one of the elongated extension walls covers the glottis.

Still further, additional air holes or fenestrations390may be formed through the posterior wall395of the body member310of the oral airway at the region of curvature which is adapted to be positioned at the back of the oropharynx and which allows passage of air through the nasal passages of the patient and into the oral airway per se.

Of course, while the holes and fenestrations are shown in connection with the first embodiment of the present invention which includes the elongated extension walls340and341, the holes or fenestrations may likewise be used with the second embodiment which includes the filled-in distal posterior wall. Of course, the holes can be dispensed with entirely in both the first and second embodiments if desired.

Referring toFIG. 3, the anterior and posterior U- or V-shaped grooves or notches receive an endotracheal tube E. When a patient is presently intubated with the endotracheal tube E, the body member110can receive a proximal end of the endotracheal tube and be axially inserted into the mouth and pharynx of a patient over the endotracheal tube and seated as illustrated inFIG. 3. When intubation is no longer required, the endotracheal tube E can be removed and body member110is properly seated to retain the surrounding soft tissue and maintain an oral airway as may be necessary.

FIG. 7shows yet a further embodiment which includes an inflatable cuff415placed just above the distally positioned anterior notch450.FIG. 7Afurther includes a plurality of bars452forming a grate over the leading opening454. Again, like elements are denoted with like reference numerals, but preceded with the number “4”. The grate or bars452cause the epiglottis to slide into abutment with an anterior portion of the end portion430of the body member410. As discussed below with reference toFIG. 11, the bars are rigid enough to support the epiglottis but flexible enough to allow an endotracheal tube to be inserted therebetween. The cuff415is designed to be inflatable using a pilot tube416which includes a self-sealing proximal valve (not shown).

Upon inflation, the more distally positioned inflated cuff of the present invention is located within the hypopharynx and thereby allows the perilaryngeal oral airway of the present invention to be held in place without external means and avoids the airway leakage which can occur at the base of the tonsillar pillars and soft palate when using the conventional cuffed oro-pharyngeal airway.

As shown inFIG. 8, in order to allow the cuffed airway400to be attached to an anesthesia circuit or other airway circuit, an adapter425is inserted into the flanged proximal end portion420of the oral airway. In the embodiment ofFIGS. 7 and 8, the adapter425is placed inside the flanged proximal end portion420of the oral airway400and held in by means of friction. However, many other mechanisms (e.g., Luer-lock, notched, snap, etc.) may be utilized to retain the adapter425in the proximal end420of the oral airway. Alternatively, the adapter may be made so as to fit over the end of the perilaryngeal oral airway and still accomplish the desired purpose. Of course, the proximal end piece for permitting attachment to an anesthesia circuit or other airway circuit may be molded into the oral airway itself.

With respect to all of the above-discussed embodiments, the actual lumen or hollow portion of the perilaryngeal oral airway of the present invention may be dome-shaped (convex) at the posterior wall of the body member at least through the portion which is operative to be positioned within the patient's mouth in order to better approximate the anatomy of the oral passageway.

Moreover, as an alternative, the oral airway may terminate in the hypopharynx (below the base of the tongue) but still end above the epiglottis, so that it would function to hold soft tissues away from the air passageway. A further embodiment of this particular alternative might have both the anterior and posterior notch absent since it could terminate just above the epiglottis.

FIGS. 9,10,11,14and15relate to another embodiment of the perilaryngeal oral airway according to the present invention. Note that inFIGS. 14 and 15as well asFIG. 16, like elements are denoted with like reference numerals with reference to the patient's oral airway.

The embodiment of the perilaryngeal oral airway illustrated inFIG. 9will be referred to herein as the grated oral airway or the grated PLA510. The grated PLA510consists of an elongate tubular member512having a proximal end514and a distal end516. Attached to the distal end516of the elongate tubular member512is a wedge-shaped housing520. The wedge-shaped housing520has an anterior wall522, a posterior wall524and sidewalls526,528extending therebetween. The anterior wall abuts an anterior portion of a patient's hypopharynx and the posterior position abuts a posterior portion of patient's hypopharynx when seated as illustrated inFIGS. 14–16. As best viewed inFIG. 17, the anterior and posterior walls522,524form an enlarged proximal portion530of the wedge-shaped housing which tapers to a smaller distal portion532. The housing is sized to seat deep in the patient's hypopharynx. The leading opening534separates the anterior and posterior walls from the distal end of the housing and extends from the distal end of the posterior wall524to a recess in the anterior wall at536. In this manner, the opening534is inclined between the distal end of the posterior wall and the recess536in the anterior wall. A grate537covers the leading opening, with the grate being inclined between the posterior and the anterior walls. In the embodiment illustrated inFIG. 9, the grate comprises a plurality of parallel bars538separated by a plurality of gaps540extending between the posterior wall524and anterior wall522.

The grated PLA510including the elongate tubular member and the wedge-shaped housing520may be integrally formed in a single manufacturing step from polyvinyl chloride or another suitable thermoplastic. In the preferred embodiment, however, the wedge-shaped housing is manufactured in two pieces divided substantially along the line10—10ofFIG. 9. Referring toFIG. 10, internal supports542are integrally formed with each position of the housing and define circular orifices544that receive the distal end of the elongate tubular member512therein. The elongate tubular member is heat staked, sonic welded or otherwise permanently bonded to the housing. In the embodiments illustrated inFIGS. 9–18, the tubular member is shown as having a round cross-section, although the tubular member may have a number of cross-sectional configurations including oval, square or rectangular, provided the elongate tubular member includes a hollow lumen. The tubular member can be slightly contoured as illustrated inFIG. 9or straight. The tubular member is preferably made of a material such as polyvinyl chloride or other thermoplastic that is substantially axially rigid yet radially flexible so that when inserted within the mouth, oral cavity and pharynx of a patient, it may follow the anatomical contours. It is also preferably sufficiently flexible so that a surgeon operating on the oral cavity or pharynx with the grated PLA in place can axially deflect the tubular member out of the operating theater. The tubular member further is radially robust to not kink during insertion or manipulation. As illustrated inFIG. 18, the tubular member may include wire reinforcing546wound into its wall.

The wedge-shaped housing520further includes an inflatable cuff548that surrounds the wedge-shaped housing520radially about the enlarged proximal portion530of the wedge-shaped housing520. As illustrated inFIGS. 9 and 10, the inflatable cuff548extends both proximal and distal of the largest effective diameter of the enlarged proximal portion530. Alternatively, the inflatable cuff548may be located on the tubular member proximate the proximal end of the wedge-shaped housing520as illustrated with the embodiment ofFIG. 7. A pilot tube550extends from the cuff along the elongate tubular member so as to be able to extend out of the mouth of a patient and terminates at its proximal end with a self-sealing proximal valve552. With the cuff in its uninflated state, it closely envelops the exterior surface of the wedge-shaped housing520. When in its inflated state, as illustrated inFIG. 14, the cuff extends radially sufficiently to fully occlude the surrounding pharynx or hypopharynx so as to enable a practitioner to apply positive pressure ventilation.

The grated PLA510preferably further includes a temperature sensor554shown mounted to the anterior wall522of the wedge-shaped housing520inFIG. 9. Alternatively, the temperature sensor554can be located on one of the sidewalls526,528, the posterior wall524or even on the inflatable cuff548. The temperature sensor554is connected to a lead556which extends along the length of the elongate tubular member512coupling to an external display or monitor (not shown).

At the proximal end514of the elongate tubular member is a bite block560having a flanged end561. The bite block560can be integrally formed from a thickened side of the tubular member512or be a more rigid plastic or metal collar that is slid over the proximal end514and held in place by friction or an adhesive. In addition, an adaptor562may be placed inside the flanged end561of the bite block560and may be permanently affixed or releasably held in place by means of friction or other mechanisms such as a Luer-lock, notch, snap or the like. It may also be integrally formed with the bite block560in a single manufacturing step.

FIG. 12illustrates an alternate embodiment of the wedge-shaped housing referred to herein as the hinged grated PLA566. This embodiment is identical to that described above with regard toFIGS. 9 and 10except the grate568is attached only to the anterior wall522by a hinge570. By virtue of the hinge, the grate568can be pivoted open as illustrated inFIG. 16. As illustrated inFIG. 12, the hinged grate572has a plurality of vertically extending bars572. Alternatively, as illustrated inFIG. 13, the hinged grate can be a solid flap with a plurality of holes574therein. Although not shown, the grate could also be a solid flap as opposed to a perforated grate. The hinge570can be a separate structure joining the grate568onto the anterior wall522or a living hinge, under which circumstances the anterior wall522and the grate568are integrally formed in a single manufacturing step.

FIG. 14is a simplified anatomical cross-section of a patient's head and neck with the various anatomic features indicated by the same references numbers used withFIG. 1. Additional relevant anatomic features include the vocal chords8and the glottis or larynx generally indicated at9. The various cartilage and muscular tissue comprising the glottis or larynx, with the exception of the vocal chords8, has been eliminated for the sake of clarity.

In use, the wedge-shaped housing520of the grated PLA510is axially inserted in the mouth1of a patient and the elongated tubular member512bends to conform to the anatomical contours of the oral cavity2, pharynx7A, hypopharynx7so that the wedge-shaped housing520rests within the hypopharynx as illustrated inFIG. 14. The housing is made of a material that is flexible and soft to provide some give as it is inserted into a patient so as to prevent damage to the soft tissue of the pharynx and hypopharynx. However, the housing is sufficiently rigid to prevent its collapse by this same tissue as it is inserted into and seated within a patient. Likewise, the grate must be of sufficient rigidity to separate these tissues and to allow the epiglottis to ride up it.

The grate537is inclined so that as the grate encounters the epiglottis4, the epiglottis rides up the grate and comes to rest abutting the anterior wall522of the wedge-shaped housing520. More particularly, as viewed inFIG. 14, the epiglottis abuts the inflatable cuff548. The axial insertion of the wedge-shaped housing is intended to be arrested by the sidewalls of the enlarged proximal portion530coming into abutment with the aryepiglottic folds576as illustrated inFIG. 17. As illustrated inFIGS. 14–16, with the grated PLA510or the hinged grated PLA566properly seated, the epiglottis abuts the anterior wall of the wedge-shaped housing and the leading opening534is adjacent to the vocal chords8and the glottis or larynx9. In addition, the distal end of the housing may abut the tissue578dividing the trachea5and esophagus6. In this manner, all the soft tissue surrounding the hypopharynx and larynx is held back from the leading opening534and an unobstructed airway is provided to the trachea5for unassisted patient breathing.

The PLA illustrated inFIG. 14can also be used to provide respiratory assist or anesthesia of a patient. In this application, once the PLA is seated as illustrated inFIG. 14, the inflatable cuff548is inflated so as to form a seal in the patient's hypopharynx7. In fact, the cuff is shown so inflated inFIG. 14. A principle advantage of placing the cuff at the enlarged portion of the housing is less air is required to inflate it to occlude the pharynx. Also, by having the cuff on the housing as it inflates it further serves to spread tissue and keep the airway formed by the PLA open. A respiratory circuit or anesthesia circuit (not shown), as conditions require, is attached to the distal end of the elongate tubular member by the adaptor14.

The grated PLA510is also intended to allow blind intubation of a patient with an endotracheal tube580having an inflatable cuff582or to insert some other instrument into the trachea of a patient. Referring toFIG. 11, the bars538of the grate537are flexible enough so that an endotracheal tube can be inserted into a gap540between adjacent bars and deform the bars as shown at584inFIG. 11to extend axially therebetween. Referring toFIG. 15, the distal end516of the tubular member512is received with in the housing so that as the endotracheal tube574is axially advanced through the bars538of the grate537, it is directed anteriorly into the trachea5of a patient. In this manner, a patient may be reliably blindly intubated with a high degree of confidence that the endotracheal tube will be properly seated in the trachea.

FIG. 16illustrates the hinged grate embodiment566of the wedge-shaped housing520being used to intubate a patient with a endotracheal tube580. In this embodiment, as the endotracheal tube580is axially advanced into contact with the hinged grate568it pivots the hinged grate open anteriorly so that the endotracheal tube580can extend into the patient's trachea5as illustrated.