Gastro-laryngeal mask

Abstract

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.

Description

RELATED CASE[0001]This application is a continuation of original application, Ser. No. 08 / 609,521, filed Mar. 1, 1996, now abandoned.BACKGROUND OF THE INVENTION[0002]This 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.[0003]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 o...

AI Technical Summary

Benefits of technology

[0011]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.

[0013]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.

Problems solved by technology

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.

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