GB2465199A

GB2465199A - Insertion tool for laryngeal mask

Info

Publication number: GB2465199A
Application number: GB0820567A
Authority: GB
Inventors: Andrew John Thomas Bosworth
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-11-11
Filing date: 2008-11-11
Publication date: 2010-05-12
Also published as: GB0820567D0

Abstract

The tool comprises a relatively stiff curved, malleable or hinged shaft 2 whose ends are adapted to engage reversibly with the tube of the laryngeal mask (LMA). At one end the tool has a yoke 3 which engages the recess between the mask and tube of the airway. The other end of the tool is provided with a slot 8 which causes the tube to form an S shape. The distance between the two ends being such that when the LMA is loaded onto the tool, the tension along the tube keeps it in a horizontal plane. The tool may comprise slots 11 with rounded tops 12.

Description

TITLE

Device to assist insertion of a Laryngeal Mask Airway (LMA)

FiELD

Medical Devices -artificial airway devices.

INTRODUCTION

The LMA is an artificial airway device used in maintaining the patency of the airway in unconscious patients. It consists of a mask made of silicon, pvc, rubber or similar polymer attached to a silicon or pvc tube designed to fit into the lower part of the throat where it prevents the tongue from falling back and causing airway obstruction.

To be used successfully, it needs to be prepared and inserted in a particular fashion.

Part of the insertion procedure involves placing ones index fmger in the patients mouth to guide the device into place, In practice, many users are reluctant to do this, for hygienic and aesthetic reasons, users who have short index fingers cannot always advance it into place, with the results that the device is not optimally positioned.

A further difficulty arises from insertion of the index fmger in patients whose mouth is restricted and there is a danger of the fmger being bitten if anaesthesia is insufficient to prevent patient reaction. Another problem is that the bulk of the insertion finger may cause the tongue to be pushed backwards during insertion, with the result that the device becomes jammed at the back of the throat in some cases.

Yet another difficulty with the finger insertion is that the tip if the insertion finger must be located at the junction of the tube and the mask portions of the LMA, a position from which it may accidentally slip during insertion due to the presence of secretions or lubricant jelly used to assist passage of the device into the throat.

Finally, a new form of laryngeal mask tube has been developed for use in intra-oral surgery which is more flexible than the standard LMA tube. This high degree of flexibility makes it even more difficult to insert the device without inserting the index finger fully into the mouth, so that the users who do care to use this technique for the reasons stated above cannot use this new flexible tube LMA.

THE INVENTION

To overcome these problems an introducer tool was designed which performs the function of the index finger during insertion of the device and, like the index finger, is removed once the LMA is in place. This is achieved by splinting the tube of the LMA so that the force can be applied to the correct point on the tube (see position of the ball of index finger in drawing B) from outside the patient's mouth. The invention consists of a shaft of substantially rigid material, for example hard plastics, carbon fibre, soft metals or rubber coated plastic or metals, said shaft being preferably curved or malleable in its long axis and having a flattened and / or curved cross -section whose wider diameter is normal to the radius of the curvature of the shaft, said cross-section when curved having its concave surface lying on the convex side of the longitudinal curvature of the shaft, said shaft being of appropriate length, having shape or form by one or more angle, curve or hinge so as to accommodate an LMA tube when lightly stretched along the long axis of the convex side of said shaft, said shaft having two ends of which is adapted to form reversible frictional attachment to an LMA tube, one of said ends form a two-pronged yoke whose arms lie substantially in the long axis of said shaft, the configuration of said yoke being such as to permit its snug and secure engagement into correspondingly shaped recess present at the junction of the tube and mask of the LMA, the other of said ends being formed into a semi circular slot cut into one side of said shaft for reversible frictional engagement with outer flanged end of the LMA tube. Optionally, a shaft of an introducer tool for LMA insertion may additionally extend beyond the point of attachment to the outer end of the LMA tube to form a guiding handle for ease of insertion and removal.

A working form of the invention will now be described in detail with reference to the accompanying drawings, in which A is a schematic view of an LMA in place in a patient, B is a schematic view of index finger insertion of an LMA mask, C is a schematic view of a working model of an LMA introducing tool, I) and E are views of a working model in two planes, F is a schematic view of said model mounted on an LMA, and G is a schematic view of both introducer and LMA in a patient.

With reference to drawing F, the LMA (1) is mounted on an introducer tool (2) by fitting yoke (3) into saddle-shaped recess (4) situated at the junction of the LMA tube (5) with the mask (6) then slightly stretched tube (5) in direction shown by arrow (7) until tube (5) can be slipped into retaining engagement slot which is a semi circular slot forming an S shape to tube (5). The tension along tube (5) keeps the LMA and Introducer in a horizontal plane. The introducer has two slots (11) allowing movement of the fork being part of yoke (3) to move in a downward direction from the horizontal plane.

The yoke is prevented from moving in an upward direction from the horizontal plane because of the direction in which the slots have been cut and by the design of rounded top to the slots (12). Having a rounded top also removes any sharp features that would otherwise be present when the yoke moves in a downward direction from the horizontal plane.

The slot will allow any diameter of tube size up too LMA 6, and any length of tube (5) because once enough tension has pulled the Introducer too a horizontal plane then any of tube (5) is free beyond slot (8).

Yoke (3) is in either arrangement held firmly in place by the elastic tension in tube (5) and cannot easily slip out of position as long as slot (8) is gripping the outer circumference of tube (5). This is because yoke (3) is arranged substantially in the long axis of shaft (2) and cannot easily be disengaged accidentally by force applied perpendicular to such long axis, while semi circular cut out (8) is arranged so tube (5) becomes perpendicular to the long axis of shaft by creating an S shape as it engages within slot (8) and is designed to be readily engaged or disengaged by force applied perpendicular to shaft (2). In practice, accidental disengagement of the outer end is unlikely due to the perpendicular forces, but would easily occur inner or mask-bearing end were the tool not designed to prevent this, since the act of insertion requires exertion of forces perpendicular to the long axis of the LMA tube at point (13) where tube (5) is joined to mask (6).

Further tension and forces are applied by the insertion of the LMA at a point when the direction of insertion changes and causes the yoke (3) to move in a downward direction from the horizontal plane of the shaft (2) opening the slots (12) applying the tension to tube (5) as it stretches to meet the new position.

The assembly is inserted into the throat of the unconscious patient using the same approach as when the index finger is used as in drawing B, but tube (5) and shaft (2) are gripped between finger and thumb, it not being necessary due to the rigidity of the assembly to insert a finger into the mouth or throat. Just as the finger is withdrawn after LMA is inserted, the introducer tool should be removed as soon as insertion has been accomplished. However, before withdrawing the introducer tool, (8) must be slid out of engagement with outer end of tube (5), which holds yoke (3) in position.