Gastro-Laryngeal Mask
A gastro-laryngeal mask features softly compliant construction of the distal half of the mask, wherein the mask is of generally elliptical configuration, with an inflatable peripheral cuff to seal and support the mask around the laryngeal inlet. A back cushion is inflatable to engage the back wall of the pharynx and thus to forwardly load the peripheral-cuff seal to the laryngeal inlet. An evacuation tube for external removal of a possible gastric discharge completes an evacuation or discharge passage contained within the mask and opening through the distal end of the peripheral cuff. Special provision is made for assuring integrity of the discharge passage within the flexible distal half of the mask, i.e., assuring against collapse of the distal-end half of the softly compliant evacuation tube in the distal region of the mask, such that inflation of the mask does not compromise viability of the evacuation tube by compressing softly compliant material of the evacuation tube during periods of mask inflation. The special provision also favors such collapse of the mask when deflated as to provide a leading flexible edge for piloting a safe and correct advancing insertional advance of the deflated mask in the patient's throat, in avoidance of epiglottis interference and to the point of locating engagement in the upper sphincter of the oesophagus.
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This application is a continuation of and claims priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 09/803,452, now U.S. Pat. No. RE39938, filed on Mar. 8, 2001, entitled Gastro-Laryngeal Mask, the entire contents of which are incorporated herein by reference, which is a reissue of patent application Ser. No. 08/921,169, now U.S. Pat. No. 5,878,745, filed on Aug. 29, 1997, entitled Gastro-Laryngeal Mask, the entire contents of which are incorporated herein by reference, which is a continuation of and claims priority under 35 U.S.C. § 120 to U.S. patent application Ser. No. 08/609,521, filed on Mar. 1, 1996, entitled Gastro-Laryngeal Mask, now abandoned.
BACKGROUND OF THE INVENTIONThis invention relates to a laryngeal-mask airway (LMA) device, which is an artificial airway device designed to facilitate lung ventilation in an unconscious patient by forming a low-pressure seal around the laryngeal inlet. An inflatable-ring seal surrounds an appropriately shaped mask which fits into the lower pharynx and is attached to a tube which emerges from the mouth, as for connection to medical gas-supply tubing.
More particularly, the invention relates to a variety of laryngeal masks, known as gastro-laryngeal masks (GLM), wherein provision is made for airway assurance to the patient who is at risk from vomiting or regurgitation of stomach contents while unconscious. U.S. Pat. No. 5,241,956 deals with this problem by providing an evacuation tube which is open through the center of the inflatable seal of the laryngeal mask, thus utilizing the distal end of the inflatable ring as an inflatable-cuff formation which establishes peripherally sealed engagement to the upper sphinctral region of the oesophagus and centrally supports the distal end of the evacuation tube. In addition, said U.S. Pat. No. 5,241,956 discloses a further inflatable cuff carried by the laryngeal mask and by the evacuation tube, for referencing inflation against the back wall of the pharynx, thus making it possible to establish the laryngeal-inlet seal with reduced inflation pressure, as compared with prior structures not having such an additional inflatable cuff.
U.S. Pat. No. 5,305,743 discloses moulding techniques for manufacture of a variety of laryngeal masks, including a gastro-laryngeal mask, wherein an inflatable back cushion provides such referencing inflation against the back wall of the pharynx as to widely distribute the back-wall reference, over substantially the full area of the laryngeal mask. Such a back-cushion construction has been found to be mechanically simple and highly effective, and U.S. Pat. No. 5,355,879 discloses such a back cushion for each of several representative laryngeal-mask constructions.
In practice, although a gastro-laryngeal-mask as described in said U.S. Pat. No. 5,355,879 works well, it has the disadvantage that the gastric evacuation channel needs to be sufficiently stiff to prevent its collapse under the influence of the increased pressure within the back-cushion cuff, when it is inflated in the pharynx. A suitably stiff tube is readily provided, but the whole device is then more difficult to insert into the patient's throat, since insertion involves flexing the device around the angle at the back of the tongue. Provision of a pre-curved airway tube facilitates passage around the back of the tongue, but the advancing distal tip end of the device is then more likely to collide with the glottis (or entrance to the larynx), and indeed it may block the larynx by so doing, with consequent danger to the patient.
BRIEF STATEMENT OF THE INVENTIONIt is an object of the invention to provide an improved gastro-laryngeal mask. A specific object is to meet the above object with a construction that specifically avoids problems or difficulties with constructions of said U.S. patents.
Another specific object is to provide for ready compression and flexure of a gastric passage within a back-cushioned or cuffed gastro-laryngeal mask, when the mask is in deflated condition for insertion into the patient's throat.
Furthermore, for the deflated condition of the mask, i.e., in readiness for insertion into the patient's throat, it is an object to enable formation of a flattened flexible leading distal-end edge to self-adapt to and resiliently ride the outer limit of curvature of the patient's airway, throughout the insertional course of the deflated mask and into its locating engagement with the hypopharynx.
It is a further specific object, in conjunction with the foregoing specific objects, to provide for assurance of full patency of the gastric passage within the mask, when the mask has been inflated.
These objects are realized in the present invention by utilizing two structural mechanisms, both of which are operative when the device is inflated; one of these mechanisms prevents lateral compression of the wall of the gastric tube, while the other of these mechanisms prevents antero-posterior compression of the wall of the gastric tube; the result is to assure a substantially circular section within relatively soft portions of the evacuation passage, as long as the device is inflated and in installed position.
In a preferred embodiment of the invention, an artificial airway device to facilitate a patient's lung ventilation comprises an airway tube, an evacuation tube, and a laryngeal mask at one end of both tubes. The mask is of generally elliptical configuration and comprises a body or backplate of relatively stiffly compliant nature, and an inflatable annular cuff or ring of relatively softly compliant nature is connected to and surrounds the body or backplate. When inflated, the annular cuff adapts to and seals around the laryngeal inlet, and an inflatable cushion on the exterior of the inflated annulus bears against the back wall of the pharynx, to thereby forwardly load the inflated annulus into sealed relation with the laryngeal inlet, with the backplate dividing the mask between a laryngeal-chamber side and a pharyngeal-chamber side. The relatively stiff backplate is formed for connection to the airway tube for exclusive communication to the larynx through an opening in the backplate; and the backplate is also configured to guide and support a relatively soft flexible evacuation tube within the pharyngeal-chamber side, from a distally open end for reception of gastric products, to a proximal end for connection to an externally discharging evacuation tube.
It is a feature of the invention that along an aligning path for the flexible evacuation tube within the pharyngeal-chamber side of the mask, a first significant angular fraction of the periphery of the flexible tube is bonded to a stabilizing portion of the backplate, and that a second angular fraction of the periphery of the flexible tube is continuously bonded to the inner surface of the flexible back cushion, such that generally opposite unbonded further angular regions exist between the bonded regions. These unbonded further regions are provided with external stiffening ribs at a succession of axial intervals, to reinforce the unbonded regions against lateral compression when the back cushion and the inflatable ring are under inflation pressure. In this way, inflation of the annular laryngeal-inlet sealing ring and of the flexible back cushion will assure a maximally open evacuation passage within the mask in inflated condition, essentially without antero-posterior or lateral compression of the passage. And it is further assured that upon deflation of the mask, evacuation-passage compression will be essentially in the sense of achieving a squeezing and somewhat flattening deformation of the discharge passage against the formed back-plate area of evacuation-passage support; such flattening is maximal at the oesophageal end of the discharge passage, so that, when correctly deflated, the device forms a wedge shape for correct insertion.
The invention will be illustratively described in detail for a presently preferred embodiment, and for certain other embodiments, all in conjunction with the accompanying drawings, in which:
Referring first to the preferred embodiments of
In the installed position of
The laryngeal-mask unit 10 is of the GLM variety in which an evacuation tube 23 (
More specifically, for the particular construction shown, the relatively softly compliant flexible components may be integrally formed in a single moulding operation, in which the moulded intermediate product is an inside-out version of what will become the finished more flexible part of the finished mask unit 10. The moulded intermediate product may thus have the appearance shown in
In the preferred form shown, the mask body member 13 (
In
The stiffness of body member 13 is greatest in the region of proximal-end seating to ledge 33, above which an inlet-air formation 36 is oriented on an axis 37 which is not only inclined at an acute angle .alpha. to the plane of seating to ledge 33, but is also laterally offset from the central longitudinal plane of symmetry of the mask, denoted 5-5 in
Stated in other words and in explanation of the distal and proximal halves of the body member 13 and the relation of these halves to the relatively thin material and distal-half extent of re-entrant tubular conduit 26, said tubular conduit may be said to extend proximally to approximately 50 percent of the longitudinal extent of the inflatable ring 18; alternatively, said tubular conduit 26 may be said to extend proximally to at least substantially 50 percent of the longitudinal extent of the inflatable ring 18, consistent with the drawings of
As also seen in
The simplified sectional diagram of
Preferably, the effective arcuate extent of adhesive connection 39 is in the range 45.degree. to 90.degree. about the central axis of tube 26, as seen in
In
It will be appreciated that the GLM device described thus far has an airway tube 11 that is of larger diameter than the evacuation tube 23; in this circumstance, the airway tube 11 is large enough to accommodate guided insertion of an endotracheal tube. The tubes 11, 23 enter the described laryngeal mask 10 in side-by-side relation and are preferably adhesively secured to each other in this side-by-side relation, and along their full longitudinal extent, in order to provide a measure of torsional resistance against twisting, thereby aiding a medically qualified person in quickly and correctly installing a fully deflated GLM in a patient, with assurance that, upon inflation of ring 18 and the back-cushion panel 25, an exclusive and sealed airway connection will be established to the laryngeal inlet, via lumen 14 and from the airway tube 11; concurrently, a similarly exclusive evacuation connection is established to the upper sphinctral region of the oesophagus, via the distal-end opening 43 of tube 26, through the evacuation tube 23, and to suitable waste-collection means (not shown) external to the patient.
More specifically as to insertion of the fully deflated GLM device in a patient, it will be understood that a range of GLM sizes is available from which to select a sufficiently correct size for the patient. Deflation is accomplished via external means (not shown) and via check-valve means 21 to hold the deflated condition wherein the dome shape of body member 13 rises from within the dished peripheral lip 18′ of the collapsed ring 18. A skilled operator is quickly able to develop the desired appearance of the GLM in its deflated state; but for a uniformly correct deflated shaping, it is recommended to use a forming tool as described in U.S. Pat. No. 5,711,293.
When correctly shaped and in its deflated condition, and at the distal end of the GLM, the opening 43 will have been flattened, and this distal end merges with the peripheral lip 18′ of the collapsed ring 18. Noting that the entire distal half of the mask is of relatively soft material, stiffened only by indicated adhesive connection, the distal end projects distally and at its upwardly flared merge with lip 18′, for low acute-angle incidence to the posterior arcuate profile of the patient's throat passage. That being the case, a medical technician need only make sure that upon inserting the mask via the patient's mouth and throat, the flattened distal end rides the outer (posterior) arcuate contour of the patient's airway, in that the softly flexible nature of the distally projecting and somewhat flattened distal end will be flexibly self-adapting to local irregularities (if any) in the course of passage into the pharynx; final insertional location is noted by an increase in encountered resistance, upon distal-end engagement of the GLM with the upper sphinctral region of the oesophagus. At this juncture, inflation air supplied via line 19 and retained by check-valve means 21 establishes (i) the described seal of ring 18 to the laryngeal inlet, (ii) back cushion (panel 25) contact with the back wall of the pharynx, and (iii) full opening of the evacuation tube 26 for maximum accommodation of a possible gastric discharge from the oesophagus.
Beyond what has been described,
It will be understood that the inside-out technique described in connection with
Claims
1. A device including:
- (A) an inflatable mask, the mask being insertable, at least when deflated, through a mouth of the patient to an inserted location within a patient, the inserted location being near a laryngeal inlet of the patient;
- (B) an airway tube coupled to the mask, the airway tube extending from a proximal end located outside of the patient's mouth through an interdental gap to the mask when the mask is at the inserted location, the interdental gap being a space between the patient's lower teeth and the patient's upper teeth; and
- (C) an evacuation tube for communication with an esophageal inlet of the patient, the evacuation tube being coupled to the mask, the evacuation tube extending from a proximal end located outside of the patient's mouth through the interdental gap to the mask when the mask is at the inserted location.
Type: Application
Filed: Dec 18, 2007
Publication Date: Jun 19, 2008
Applicant: The Laryngeal Mask Company Limited (London)
Inventor: Archibald Ian Jeremy Brain (Les Bons Villers)
Application Number: 11/958,946
International Classification: A61M 16/04 (20060101);