U.S. patent application number 11/958946 was filed with the patent office on 2008-06-19 for gastro-laryngeal mask.
This patent application is currently assigned to The Laryngeal Mask Company Limited. Invention is credited to Archibald Ian Jeremy Brain.
Application Number | 20080142017 11/958946 |
Document ID | / |
Family ID | 24441146 |
Filed Date | 2008-06-19 |
United States Patent
Application |
20080142017 |
Kind Code |
A1 |
Brain; Archibald Ian
Jeremy |
June 19, 2008 |
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.
Inventors: |
Brain; Archibald Ian Jeremy;
(Les Bons Villers, BE) |
Correspondence
Address: |
WILMERHALE/BOSTON
60 STATE STREET
BOSTON
MA
02109
US
|
Assignee: |
The Laryngeal Mask Company
Limited
London
GB
|
Family ID: |
24441146 |
Appl. No.: |
11/958946 |
Filed: |
December 18, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09803452 |
Mar 8, 2001 |
RE39938 |
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11958946 |
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08609521 |
Mar 1, 1996 |
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09803452 |
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08921169 |
Aug 29, 1997 |
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Current U.S.
Class: |
128/207.15 |
Current CPC
Class: |
A61M 16/0459 20140204;
A61M 16/0463 20130101; A61M 16/0415 20140204; Y10T 156/10 20150115;
A61M 16/0434 20130101; A61M 16/0456 20140204; A61M 16/0445
20140204; A61M 16/0409 20140204; A61M 16/04 20130101 |
Class at
Publication: |
128/207.15 |
International
Class: |
A61M 16/04 20060101
A61M016/04 |
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.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of and claims priority
under 35 U.S.C. .sctn. 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. .sctn. 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 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 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.
[0004] 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.
[0005] 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 INVENTION
[0006] It 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] 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:
[0014] FIG. 1 is a simplified view, generally in side elevation,
for the presently preferred embodiment of an artificial airway
device, having at its distal end a laryngeal mask with a
gastric-drainage feature of the invention, the same being shown in
position for use in a patient;
[0015] FIG. 2 is a fragmentary plan view, to an enlarged scale
showing the back or pharynx-facing side of the mask of FIG. 1;
[0016] FIG. 3 is a plan view to the scale of FIG. 2, showing a
softly compliant moulded inflatable component of the mask, as seen
from the aspect of FIG. 2;
[0017] FIG. 4 is a plan view to the scale of FIG. 2, showing a
relatively stiffly compliant rigidising or reinforcing back-plate
component of the mask, as seen from the aspect of FIG. 2;
[0018] FIG. 5 is a longitudinal section of the softly compliant
component of FIG. 3, to the scale of FIGS. 2 to 4 and taken
generally in the vertical plane 5-5 of substantial symmetry, but
prior to an inside-out deformation step, to create the appearance
of FIG. 3;
[0019] FIG. 5A is a section, taken at 5A-5A in FIG. 5;
[0020] FIG. 6 is another view in longitudinal section, to the scale
of FIGS. 2 to 5 and in the vertical plane 5-5 of FIG. 3, showing
the relatively stiff component of FIG. 4 in assembled relation to
the softly compliant component of FIG. 3;
[0021] FIG. 7 is an end view, being a proximally directed view, of
the distal end of the rigidising component of FIG. 4;
[0022] FIG. 8 is a simplified cross-sectional view of the inflated
mask of FIG. 2, taken at 8-8 in FIG. 2;
[0023] FIG. 9 is a simplified cross-sectional view of the deflated
mask of FIG. 2, taken at 8-8 in FIG. 2;
[0024] FIG. 10 is a view similar to FIG. 2, to show a first
modification;
[0025] FIG. 11 is a view similar to FIG. 4, to show the back-plate
component in the modification of FIG. 10;
[0026] FIG. 12 is a sectional view, taken at 12-12 in FIG. 11;
and
[0027] FIG. 13 is a plan view to the scale of FIG. 2 to illustrate
an intermediate product which is a modification of that shown in
FIGS. 5 and 6.
DETAILED DESCRIPTION
[0028] Referring first to the preferred embodiments of FIGS. 1 to
9, the invention is shown in application to an airway system
comprising a laryngeal-mask unit 10 and its airway tube 11,
installed through the mouth 12 of a patient. The mask unit 10 may
be generally as described in any of the above-identified U.S.
patents and therefore need not now be described in detail. It
suffices to say that mask unit 10 comprises a relatively stiff body
or backing-plate member, generally indicated at 13, and an
apertured relatively thin body-membrane portion or panel 13' having
an aperture or lumen 14 through which the airway tube 11 can
establish a free externally accessible ventilation passage, via the
patient's mouth 12 and throat 15, and past the epiglottis 16 to the
larynx 17. The body member 13 of mask 10 may be described as
generally dome-shaped, with its concave side terminating in a
generally elliptical footing, and facing the laryngeal inlet; and
its convex side faces the backwall of the pharynx. Body 13 is
suitably of an elastomer such as silicone rubber and relatively
stiff; and body member 13 is surrounded by an inflatable ring 18
which is generally elliptical and which is circumferentially united
to body member 13 in essentially a single plane. The inflatable
ring 18 may also be of silicone rubber, although preferably
relatively soft and flexible compared to body member 13. An
externally accessible tube 19 is the means of supplying air to the
inflatable ring 18 and of extracting air from (and therefore
collapsing) ring 18 for purposes of insertion in or removal from
the patient; check-valve means 21 in tube 19 will be understood to
hold a given inflation or to hold a given deflation of ring 18.
[0029] In the installed position of FIG. 1, the projecting but
blunted distal end 27 of ring 18 is shaped to conform with the base
of the hypopharynx where it has established limited entry into the
upper sphinctral region of the oesophagus 24. The back side of body
member 13 is covered by a thin flexible panel 25 (FIG. 2) which is
peripherally bonded to the inflatable ring 18 (FIG. 1) and in
sealed engagement at peripheral line 25' around the entrance of
tubes 11 and 23 to the mask structure to define an inflatable back
cushion which assures referencing to the back wall of the pharynx
and thus is able to load the mask unit forward for enhanced
effectiveness of inflated-ring sealing engagement to the laryngeal
inlet. The inflated ring, thus-engaged to the laryngeal inlet,
orients the distal-end of the airway tube 11 at an acute angle to
the general plane of ring 18 and in substantial alignment with the
axis of the laryngeal inlet, for direct airway communication only
with the larynx 17.
[0030] The laryngeal-mask unit 10 is of the GLM variety in which an
evacuation tube 23 (FIG. 2) serves for extraction and external
removal of gastric-discharge products from the oesophagus. Tube 23
follows the general course of the airway tube 11, with sealed entry
alongside airway tube 11, beneath the back-cushion panel 25, and
with passage through the interior of ring 18, near the distal end
of the mask; in FIG. 3, the distally open end of the evacuation
tube 23 is defined by a re-entrant tubular conduit formation 26
integrally formed with the relatively soft material of ring 18. As
explained in U.S. Pat. No. 5,241,956, inflation-air supply to the
back cushion may be the same (19) as for ring 18, or separate
inflating means (not shown) may be provided for these separate
inflatable means.
[0031] 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 FIG. 5, following the technique described in U.S. Pat. No.
5,305,743, to which reference is made for detailed description. It
suffices here to identify the inflation-air inlet formation 28,
directed inwardly on a central axis 29 which also includes the
outwardly directed distal-end formation of the evacuation tube 26;
the central axis 29 may also be understood as identifying the
equator plane (perpendicular to the drawing of FIG. 5) which
applies to the inflatable annular ring 18, after evacuation tube 26
has been swung upward (counterclockwise), in the sense suggested by
arrow 30, and generally for 180.degree. of rotation about an axis
31, which (axis 31) is normal to the plane of the drawing of FIG.
5. This 180.degree. rotation tucks tube 26 into the flange
relatively large edge 32 of the open skirt of the moulded
intermediate product of FIG. 5 and makes it a simple matter to turn
the remainder of the skirt inside-out, thus defining ring 18, with
the edge flange 32 seated on a ledge 33 of the upper dome-shaped
feature (body-membrane portion or liner 13') of the moulded
intermediate product.
[0032] In the preferred form shown, the mask body member 13 (FIGS.
4 and 7) is a separately moulded component of relatively stiff
nature as compared to the moulded intermediate product of FIG. 5.
Stiffness vs. softness will be understood to be relative terms and
not necessarily to imply that these components are formed from
different materials.
[0033] In FIG. 4, the body component 13 is seen to comprise an
apertured panel which is essentially a moulded dome or bowl 34
having a concave inner surface which conforms to the convex moulded
contour of the dome shape 35 of the relatively soft (i.e.,
thin-walled) component of FIG. 5, these components being shown in
FIG. 6 in assembled relation. Relative stiffness (thickness) in the
bowl or dome 34 of FIG. 4 is generally in the range 2 to 5 mm, with
gradually reducing thickness for greater flexibility in approach to
the lower or distal end. The bowl or dome 34 has a peripheral edge
which terminates in a single plane, for adhesively bonded seating
to the ledge 33 of the relatively soft component of FIG. 5, after
making the inside-out inversion.
[0034] 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 FIG. 3. Relative stiffness of
body member 13 is also enhanced (i) by the fact that its distal
half features a slot 38 of width less than the diameter of the
re-entrant distal-end tube 26, (ii) by the fact that the re-entrant
tube 26 is adhesively retained in cradled support by and between
confronting edges of slot 38, and (iii) by the fact that the distal
end of evacuation tube 23 is preferably preformed (as seen in FIG.
2) with a quarter-turn helical advance to track the course of slot
38 in the upper or proximal half of body member 13. The evacuation
tube 23 is preferably relatively stiff, e.g., stiffness (thickness)
in the order of magnitude of the material at the upper (proximal)
half of body member 13, and is seen in FIG. 2 to have telescoping
fit to the proximally directed upper end of re-entrant tube 26;
this is an adhesively sealed fit.
[0035] 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 FIGS. 2, 3, and
6. Furthermore, as seen in FIG. 4, the distal half of backing-plate
member 13 is essentially straight, thus determining a straight
proximal direction of tubular conduit 26 for substantially the
distal half of the longitudinal extent of the mask.
[0036] As also seen in FIG. 2, the back-cushion panel 25 covers a
substantial part of the posterior surface of the mask, being
peripherally sealed around the generally elliptical course of
inflatable ring 18, and also being centrally adhered to the
re-entrant tube 26 for substantially the entire length of tube 26,
as suggested by cross-hatching 39. Finally, to assure integrity of
the inflatable ring 18, the re-entrant tube 26 is adhesively sealed
to the adjacent edges of tube-26 local passage through ring 18 at
the distal location designated 40 in FIG. 3; for purposes of
avoiding undue complexity in the drawings, this adhesively sealed
region is not shown but will be understood to be along the line of
tube-26 intercept with locally adjacent walls of inflatable ring
18. In FIG. 5, this intercept line is accounted for by a local
cut-out 40' at the distal end of the skirt of the intermediate
product of FIG. 5.
[0037] The simplified sectional diagram of FIG. 8 illustrates the
functional cooperation of described component parts and features of
the described gastro-laryngeal mask construction, in inflated
condition, to account for diametrically opposite section cuts
through right and left halves of the inflatable ring 18, spaced by
sealed fit of body member 13 to the inner profile of ring 18. The
back-cushion panel 25, being centrally adhered at 39 to the upper
central region of re-entrant tube 26, provides a lifting force
which is in the direction to hold open the evacuation tube and,
therefore, not to collapse tube 26 when the back cushion is
inflated; without this force, in opposition to a retaining force
attributable to adhesive connection to body member 13 (along edges
of slot 38), there would be no tendency to hold a softly compliant
tube 26 against collapse, in that the cushion panel would outwardly
expand itself to a bowed shape 25' suggested by phantom outline in
FIGS. 6 and 8.
[0038] 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 FIG. 8. Preferably also, the
adhesive connection of tube 26 along the straight edges of the
distal half of slot 38 accounts for a corresponding range of
support of tube 26 against collapse in the circumstance of
back-cushion inflation. In other words, inflation of the ring 18
and back cushion 25 will assure developed vertical forces to hold
the evacuation passage of re-entrant tube 26 in substantially open
condition, but the transversely opposed arcuate regions (each of
approximately 90.degree. arcuate extent) between these adhesively
connected regions are vulnerable to compressionally inward bowing,
thus reducing the sectional area of tube 26 while the mask is
inflated. The invention resolves this vulnerability by providing
axially spaced stiffening ribs or ridges 42 as integral formations
of the re-entrant tube 26, in the initially moulded intermediate
product of FIG. 5. As shown, there are three mutually opposed pairs
of ridges 42, at axial spacings which are in the order of the
unstressed bore diameter of tube 26. For the indicated
silicone-rubber material of the product of FIG. 5, the incremental
local thickness at ridges 42 is suitably twice or three times the
otherwise uniformly thin moulded product of FIG. 5, as seen in FIG.
5A.
[0039] In FIG. 8, a section taken near the location of tube 26
connection to the more stiffly compliant evacuation tube 23, the
inflated condition of the GLM mask of the invention is seen to have
an overall "height" dimensions H.sub.1, meaning front-to-back
(i.e., laryngeal inlet-to-pharynx back wall). When the mask is
deflated, this dimension H.sub.1 is seen to be reduced by
approximately 50 percent, as shown at H.sub.2 in FIG. 9 for the
deflated condition of the same mask. When deflated, as has been
pointed out in U.S. Pat. No. 5,297,547, the ring 18 collapses into
flattened double walls (marked 18') which are upwardly dished; and
although deflation does little to compress tube 26 other than at
the region 39' of adhesion to the back-cushion panel 25, the
overall deflated extent H.sub.2 is essentially unchanged from the
dimension H.sub.2 which applies for collapse of ring 18. On the
other hand, at the distal end of the mask, the collapse of ring 18
is operative upon the formed distal-end opening 43 of tube 26 to
somewhat flatten the opening 43, into a generally shovel-shaped
distal lip feature which merges smoothly into the adjacent upwardly
dished double-wall. shape 18' shown in the longitudinal mid-section
of FIG. 9.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] Beyond what has been described, FIG. 10 illustrates at
phantom outline 26' that the flexible length of the re-entrant tube
26 may be of even greater length than the approximately half-mask
length shown by the solid lines of FIG. 5. In that event, arcuate
stiffener ridges as described at 42 will be preferred, as long as
lateral support is needed to prevent side-wall collapse of the
extended tube 26', in the inflated condition of the mask, i.e.,
including inflation of back-cushion panel 25.
[0044] FIGS. 10 to 12 illustrate another GLM embodiment wherein an
airway tube 50 and an evacuation tube 51 are of equal size, adhered
(as suggested at 52) to each other in side-by-side relation for
torsionally resistant and symmetrically positioned entry into
corresponding side-by-side ports 53, 54 of the dome like moulded
backing plate or body member 55 of FIGS. 11 and 12. The backing
plate 55 may be similar to plate 13 of FIG. 4, except that in FIG.
11 the somewhat helically arcuate conduit path from the inserted
distal end of evacuation tube 51 to the point 56 of softly
compliant re-entrant tube (26) connection is provided by an
integral passage formation 57 of the backing plate 55. At point 56
in FIG. 11, the formation 57 is seen to be in the central vertical
plane 58 of symmetry of the bowl or dome-shape of backing plate 55
and in alignment for accepted proximal-end insertional
accommodation of a re-entrant tube 26 of thin-walled material to
which backing plate 55 is to be assembled, with edges of the
straight slot 38' supporting tube 26 in the manner already
described. Also integrally formed with backing plate 55 is an
inlet-connection counterbore for coupled connection of airway tube
50 to the laryngeally exposed side of the mask. Features in FIG.
10, such as the back-cushion panel 25, the inflatable ring 18, and
the adhesively bonded connection 39 of panel 25 to tube 26 are all
as previously described.
[0045] It will be understood that the inside-out technique
described in connection with FIGS. 5 and 6 for initially moulding
and then inverting the skirt of the moulded product, is but one
illustration of a way to create the mask and its inflatable ring,
in which case the flexible drainage conduit does not get inverted.
That being the case, the reinforcement ribs 42 are initially formed
portions of the outer surface of the moulded product. On the other
hand, another technique for forming the mask with its inflatable
ring, involves moulding the mask bowl integrally with an
elliptically configured product as shown in FIG. 13, wherein
completion of inflatable-ring (18) integrity requires only an
adhesively bonded completion of the ring peripherally around the
inner substantially elliptical profile, where backing-plate (13)
connection is also adhesively secured. In that case, the drainage
tube 26 is integrally-moulded with the non-invertible ring (18), so
that an inversion of tube 26 is necessary, to have it project
re-entrantly, in the proximal direction, and the moulded product
which is to become inflatable ring 18 must be cut away as at 40, to
permit inverted tube 26 to "pass through" the inflatable ring, in
order to develop a relationship which is suggested by FIG. 5. Of
course, if tube 26 is to be inverted, the reinforcement ribs 42 are
preferably integrally formed as radially inward rib reinforcements
or discontinuities in the moulded bore of tube 26. Inversion of
tube 26 places these rib reinforcements on the outer surface of
tube 26, so that the bore of tube 26 is inherently smooth.
* * * * *