Patent EA-003314-B1 (EA)
Title: Laryngeal mask with large-bore gastric drainage
IPC: A61M25/04
Filed: 2000-10-09
Abstract: 1. A laryngeal-mask airway device (20) which may be used to ventilate the lungs of an unconscious patient, the device comprising: an expandable mask (52) including a generally elliptical inflatable/deflatable masking ring (55) for sealingly surrounding the laryngeal inlet (50) of the patient when expanded to obstruct communication between the laryngeal inlet (50) and the oesophagus (37); one or more airway tubes (125,127) connected to the mask (52) to provide a fluid flow-path from the exterior of the patient to a portion (57) of the mask arranged to communicate with the laryngeal inlet (50) when the masking ring (55) sealingly surrounds the laryngeal inlet; and a gastro-tube (75) connected to the mask (52) to provide a fluid flow-path to a portion of the mask facing the oesophagus (37) when the masking ring (55) sealingly surrounds the laryngeal inlet, the gastro-tube (75) and the airway tube (s) (125,127) being hermetically sealed in side-by-side abutting adjacency to one another and to the mask so as to define an inner space (57) between transversely spaced walls of the masking ring (55) and gastro-tube (75) and airway tube (125,127) and to obstruct fluid flow between the oesophagus and the trachea (35). 2. A device according to claim 1, wherein the airway tube comprises a pair of airway tubes (125,127) laterally disposed on opposite sides of the gastro-tube (75), longitudinal portions of the outer surfaces of each of the airway tubes being sealed to the masking ring (55). 3. A device according to claim 2, wherein the gastro-tube (75) is in such laterally squeezed adjacency to and between the airway tubes (125,127) in the region of the sealed closure of the inner space (57) that at least on the anterior side of the sealed closure the squeezed portion of the gastro-tube projects in the anterior direction to define a stop to prevent its epiglottis (45) of the patient from interfering with airway-tube communication with the laryngeal inlet. 4. A device according to any one of claims 1 to 3, wherein the cross sectional area of the gastro-tube (75) is greater than that of the airway tube (s) (125,127). 5. A device according to any one of claims 1 to 3, wherein the cross-sectional area of the gastro-tube (75) is not less than about 75% of the total cross-sectional area of the airway tube (s) (125,127). 6. A device according to claim 4 or claim 5, wherein each of the air tubes (125,127) has an inner diameter of about 6 to 10 mm and the gastro-tube (75) has an inner diameter of about 10 to 15 mm. 7. A device according to claim 6, wherein the inner diameter of each of the air tubes is about 8 mm and the inner diameter of the gastro-tube is about 10 mm. 8. A device according to any one of claims 1 to 7, wherein the or each airway tube (125,127) has a distal end thereof truncated (139, 142) at an angle to the longitudinal axis of the tube to define an elongated opening facing towards the inner space (57), the portions of the airway tube adjacent the opening thereof being sealed to the masking ring (55) and to the gastro-tube (75). 9. A device according to claim 8, wherein the distal end (77) of the gastro-tube (75) extends through the distal portion (62) of the masking ring (55) and is collapsible, the portions of the masking ring (55) adjacent the gastro-tube being sealed to the exterior of the gastro-tube. 10. A device according to claim 9, wherein the gastro-tube (75) is (i) of relatively great wall thickness through at least traverse of the proximal region (65) of the masking ring (55) and (ii) of relatively thin wall thickness throughout passage of the gastro-tube through the distal region (62) of the masking ring such that, when the masking ring is deflated, the distal region (62) thereof is rendered into a substantially flattened flexible shape enabling the distal region to smoothly ride posterior contours of the throat and pharynx and to assure that the deflated masking ring enters and locates within the upper sphincteral region of the oesophagus so that, upon inflation of the masking ring following its insertion into the patient, the flexible distal region (62) will inflate to open the distal end of the gastro-tube (75) within the upper sphincteral region of the oesophagus. 11. A device according to claim 9 or claim 10, further comprising a pair of porous collapsible support plugs (85) disposed within the distal portion (62) of the masking ring (55), each support plug (85) being disposed on one side of the collapsible tube (77), having one outer surface thereof sealed to an interior surface of the masking ring and having a second outer surface thereof forming a portion of or sealed to a portion of the outer surface of the collapsible tube. 12. A device according to claim 11, wherein each support plug (85) is wedge-shaped having a concave surface conforming to or forming the outer surface of the collapsible tube (77) and a convex surface conforming to an adjoining inner surface of the distal portion (62) of the masking ring (55). 13. A device according to claim 9, wherein the collapsible tube (77) has a pair of lateral hinges (87,90) defined by the radial thickness of the collapsible tube and positioned on generally opposite sides thereof, each lateral hinge extending generally longitudinally of the collapsible tube and including a flexible base contiguous with the interior surface of the collapsible tube and a pair of edges extending generally radially outwardly from the base to the exterior surface of the collapsible tube, each lateral hinge being such that the angle between the edges thereof is greater when the masking ring (55) is in a collapsed configuration than when the masking ring (55) is in an expanded configuration. 14. A device according to claim 13, wherein the lateral hinges (87,90) terminate proximally of the extreme distal end (80) of the collapsible tube (77), and the extreme distal end of the collapsible tube defines a substantially continuous outer surface that is sealed to the masking ring. 15. A device according to any one of claims 9,13 and 14, wherein the collapsible tube (77) has a pair of medial hinges (92,95) defined by the radial thickness of the collapsible tube and positioned on generally opposite sides thereof, each medial hinge extending generally longitudinally of the collapsible tube and including a flexible base contiguous with the exterior surface of the collapsible tube and a pair of edges extending generally radially inwardly from the base to the interior surface of the collapsible tube, each medial hinge being such that the angle between the edges thereof is greater when the masking ring (55) is in a collapsed configuration than when the masking ring (55) is in an expanded configuration. 16. A device according to any one of claims 1 to 15, comprising also an inflatable flexible cover (149) positioned on the posterior side of the airway tube (s) and the gastro-tube, the cover being sealed along its peripheral edges to anterior portions of the masking ring (55), the airway tube (s) and the gastro-tube. 17. A device according to claim 16, wherein the cover (149) is elastomeric. 18. A device according to claim 16 or claim 17, wherein the cover is sized so that, when the masking ring (55) is deflated, the cover lies in juxtaposition with underlying portions of the masking ring, the airway tube (s) and the gastro-tube without folding portions of the cover. 19. A device according to any one of claims 16 to 18, wherein the proximal portion of the cover (149) is bonded to the masking ring in regions closely adjacent the proximal portions of the airway tube (s) and the gastro-tube and extending distally of the proximal end of the masking ring to prevent ballooning of the proximal portion of the cover when the cover is inflated.