U.S. patent application number 13/876150 was filed with the patent office on 2013-09-26 for artificial airway device.
This patent application is currently assigned to The Laryngeal Mask Company Limited. The applicant listed for this patent is Archibald Ian Jeremy Brain. Invention is credited to Archibald Ian Jeremy Brain.
Application Number | 20130247907 13/876150 |
Document ID | / |
Family ID | 43243374 |
Filed Date | 2013-09-26 |
United States Patent
Application |
20130247907 |
Kind Code |
A1 |
Brain; Archibald Ian
Jeremy |
September 26, 2013 |
ARTIFICIAL AIRWAY DEVICE
Abstract
The invention relates to an artificial airway device (1) to
facilitate lung ventilation of a patient, comprising an airway tube
(2) and a mask (3) canned at one end of the airway tube, the mask
(3) having a distal end (4) and a proximal end (5) and a peripheral
formation (6) capable of conforming to, and of fitting within, the
actual and potential space behind the larynx of the patient so as
to form a seal around the circumference of the laryngeal inlet, the
peripheral formation (6) surrounding a hollow interior space or
lumen (7) of the mask (3) and the airway tube (2) opening into the
lumen (7) of the mask, the mask having a conduit (8) for receiving,
in use, oesophageal matter, an outer, in use, surface of the
peripheral formation (6) defining a channel (10) for use in
facilitating drainage of oesophageal matter.
Inventors: |
Brain; Archibald Ian Jeremy;
(Victoria, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Brain; Archibald Ian Jeremy |
Victoria |
|
SC |
|
|
Assignee: |
The Laryngeal Mask Company
Limited
Victoria, Mahe
SC
|
Family ID: |
43243374 |
Appl. No.: |
13/876150 |
Filed: |
September 29, 2011 |
PCT Filed: |
September 29, 2011 |
PCT NO: |
PCT/GB2011/001420 |
371 Date: |
June 7, 2013 |
Current U.S.
Class: |
128/202.16 |
Current CPC
Class: |
A61M 16/0493 20140204;
A61M 16/0443 20140204; A61M 16/0463 20130101; A61M 16/0488
20130101; A61M 16/0409 20140204; A61M 16/0415 20140204 |
Class at
Publication: |
128/202.16 |
International
Class: |
A61M 16/04 20060101
A61M016/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 2010 |
GB |
1016562.9 |
Claims
1. An artificial airway device to facilitate lung ventilation of a
patient, comprising at least one airway tube and a mask earned at
one end of the airway tube, the mask having a distal end and a
proximal end and a peripheral formation capable of forming a seal
around the circumference of the laryngeal inlet, the peripheral
formation surrounding a hollow interior space or lumen of the mask
and the at least one airway tube opening into the lumen of the
mask, the mask having a conduit for receiving, in use, oesophageal
matter, characterised in that an outer, in use, surface of the
peripheral formation defines a channel for use in facilitating
drainage of oesophageal matter.
2. The device according to claim 1, wherein the peripheral
formation comprises an inflatable cuff
3. The device according to claim 1, the channel comprising a C- or
U- shaped channel formed in and/or by the material from which the
peripheral formation is formed.
4. The device according to claim 3, wherein the peripheral
formation comprises PVC.
5. The device according to claim 1 to wherein the channel extends
from the distal end of the mask towards the proximal end of the
mask and is in fluid communication with a drainage tube of the
mask.
6. The device according to claims 1, wherein the channel extends
from the distal end of the mask towards the proximal end of the
mask and is in fluid communication with a drainage tube of the
airway tube.
7. The device according to claim 5, wherein the channel is closed
over by an extension of the drainage tube of the mask or of the
airway tube, which extension extends therefrom to a point short of
the distal end of the channel and terminates in a substantially
smooth and rounded end.
8. The device according to claim 1, wherein the channel facilitates
drainage of oesophageal matter by defining a path through which a
drainage tube of the mask and/or the airway tube can extend.
9. The device according to claim 1, wherein the mask describes a
substantially convex curve, from the proximal to distal end.
10. The device according to claim 1, wherein the mask body
comprises a plate, the plate having a dorsal side and a ventral
side, the dorsal side being substantially smooth and having a
convex curvature across its width.
11. The device according to claim 10, wherein the dorsal surface of
the airway tube corresponds in curvature to the curvature across
the width of the plate.
12. The device according to claim 1, wherein the airway tube
comprises a relatively more rigid material than the mask body.
13. The device according to claim 1, the airway tube being adapted
to include a relatively softer wall portion adjacent a point that
in use will be adjacent the patient's teeth.
14. The device according to claim 13, the airway tube including
dorsal and ventral surfaces and that the relatively softer wall
portion being disposed at one or both of the dorsal or ventral
surfaces.
15. The device according to claim 14, the relatively softer portion
comprising a relatively softer material.
16. The device according to claim 14, the relatively softer portion
comprising an unsupported portion of the airway tube.
17. The device according to claim 13, the airway tube including a
bite-block that supports the airway tube against biting by the
patient, the relatively softer portion being provided by a cutaway
of the bite block.
Description
[0001] The present invention relates to an artificial airway
device.
[0002] Artificial airway devices such as the laryngeal mask airway
device are well known devices useful for establishing airways in
unconscious patients. In its most basic form a laryngeal mask
airway device consists of an airway tube and a mask carried at one
end of the airway tube, the mask having a peripheral formation
often known as a "cuff" which is capable of conforming to and of
fitting within, the actual and potential space behind the larynx of
the patient so as to form a seal around the laryngeal inlet. The
cuff can be inflatable, and in most variants it surrounds a hollow
interior space or lumen of the mask, the at least one airway tube
opening into the lumen. U.S. Pat. No. 4,509,514 is one of the many
publications that describe laryngeal mask airway devices such as
this. Such devices have been in use for many years and offer an
alternative to the older, even better known endotracheal tube. For
at least seventy years, endotracheal tubes comprising a long
slender tube with an inflatable balloon disposed at the tube's
distal end have been used for establishing airways in unconscious
patients. In operation, the endotracheal tube's distal end is
inserted through the mouth of the patient, past the patient's
trachea. Once so positioned, the balloon is inflated so as to form
a seal with the interior lining of the trachea. After this seal is
established, positive pressure may be applied to the tube's
proximal end to ventilate the patient's lungs. Also, the seal
between the balloon and the inner lining of the trachea protects
the lungs from aspiration (e.g., the seal prevents material
regurgitated from the stomach from being aspirated into the
patient's lungs).
[0003] In contrast to the endotracheal tube, it is relatively easy
to insert a laryngeal mask airway device into a patient and thereby
establish an airway. Also, the laryngeal mask airway device is a
"forgiving" device in that even if it is inserted improperly, it
still tends to establish an airway. Accordingly, the laryngeal mask
airway device is often thought of as a "life saving" device. Also,
the laryngeal mask airway device may be inserted with only
relatively minor manipulation of the patient's head, neck and jaw.
Further, the laryngeal mask airway device provides ventilation of
the patient's lungs without requiring contact with the sensitive
inner lining of the trachea and the size of the airway established
is typically significantly larger than the size of the airway
established with an endotracheal tube. Also, the laryngeal mask
airway device does not interfere with coughing to the same extent
as endotracheal tubes. Largely due to these advantages, the
laryngeal mask airway device has enjoyed increasing popularity in
recent years.
[0004] U.S. Pat. Nos. 5,303,697 and 6,079,409 describe examples of
prior art devices that may be referred to as "intubating laryngeal
mask airway devices." The intubating device has the added advantage
that it is useful for facilitating insertion of an endotracheal
tube. After an intubating laryngeal mask airway device has been
located in the patient, the device can act as a guide for a
subsequently inserted endotracheal tube. Use of the laryngeal mask
airway device in this fashion facilitates what is commonly known as
"blind insertion" of the endotracheal tube. Only minor movements of
the patient's head, neck and jaw are required to insert the
intubating laryngeal mask airway device, and once the device has
been located in the patient, the endotracheal tube may be inserted
with virtually no additional movements of the patient. This stands
in contrast to the relatively large motions of the patient's head,
neck and jaw that would be required if the endotracheal tube were
inserted without the assistance of the intubating laryngeal mask
airway device. Furthermore, these devices permit single-handed
insertion from any user position without moving the head and neck
of the patient from a neutral position, and can also be put in
place without inserting fingers in the patient's mouth. Finally, it
is believed that they are unique in being devices which are airway
devices in their own right, enabling ventilatory control and
patient oxygenation to be continuous during intubation attempts,
thereby lessening the likelihood of desaturation.
[0005] Artificial airway devices of the character indicated are
exemplified by the disclosures of U.S. Pat. No. 4,509,514; U.S.
Pat. No. 5,249, 571; U.S. Pat No. 5,282,464; U.S. Pat. No.
5,297,547; U.S. Pat. No. 5,303,697; and by the disclosure of UK
Patent 2,205,499.
[0006] Furthermore, devices with additional provision for
gastric-discharge drainage are exemplified by EP 0 794 807; U.S.
Pat. No. 4,99,5388(FIGS. 7 to 10); U.S. Pat. No. 5,241,956; and
U.S. Pat. No. 5,355,879 and commonly known as gastro-laryngeal
masks. These masks make provision for airway assurance to the
patient who is at risk from vomiting or regurgitation of stomach
contents whilst unconscious. From a reading of these prior art
documents it will be appreciated that gastro-laryngeal masks
present numerous and often conflicting requirements of design and
manufacture to achieve designs that do not sacrifice any of the
benefits of the more simpler designs described above.
[0007] Thus, in general, laryngeal mask airway devices aim to
provide an airway tube of such cross-section as to assure more than
ample ventilation of the lungs. Designs with provision for gastric
drainage have been characterized by relatively complex internal
connections and cross-sections calculated to serve in difficult
situations where substantial solids could be present in a gastric
discharge. As a result, the provision of a gastric discharge
opening at the distal end of the mask applicable for direct service
of the hypopharynx has resulted in a tendency for such masks to
become bulky and unduly stiff, thus making for difficulty in
properly inserting the mask. Undue bulk and stiffness run contrary
to the requirement for distal flexibility for tracking the
posterior curvature of the patient's anatomy on insertion, in such
manner as to reliably avoid traumatic encounter. Moreover,
manufacturing is made much more difficult and costly and the risks
of device failure may be increased.
[0008] Problems such as these can be especially actute in devices
formed from relatively rigid materials, like PVC, as opposed to the
more traditional Liquid Silicon Rubber (LSR). In general, devices
formed from materials such as PVC are attractive because they are
cheaper to make, and can be offered economically as "single-use"
devices. However, there are material differences in PVC and PVC
adhesives, such as increased durometer hardness as compared to LSR,
which affect how devices perform in use. For example, it has been
observed that for a given volume of air, an LSR cuff will expand to
a larger size than a comparable PVC cuff. This superior elasticity
allows the LSR cuff to provide an anatomically superior seal with
reduced mucosal pressure. To close the performance gap, the PVC
cuff must be of reduced wall thickness. However, a PVC cuff of
reduced wall thickness, deflated and prepared for insertion, will
suffer from poor flexural response as the transfer of insertion
force through the airway tube to cuff distal tip cannot be
adequately absorbed. The cuff assembly must deflate to a thickness
that preserves flexural performance i.e. resists epiglottic
downfolding, but inflate so that a cuff wall thickness of less than
or equal to 0.4 mm creates a satisfactory seal. And where mask
backplates are formed from PVC, as well as cuffs, the fact that the
increased durometer hardness of PVC is inversely proportional to
flexural performance (hysterisis) means that the flexural
performance of the device in terms of reaction, response and
recovery on deformation is inferior to a comparable LSR device.
[0009] The above described problems are particularly acute in
devices which incorporate an oesophageal drain. As mentioned above,
in any such device regardless of the material from which it is
formed, adding an oesophageal drain in itself adds greatly to
complexity of manufacture and can also affect the performance of
devices, in terms of ease of insertion, seal formation and
prevention of insufflation. These problems can be exacerbated still
further if PVC or similarly performing materials are used. For
example, the skilled worker will appreciate that in terms of
manufacture, the need to provide a drain tube which is sealed from
the airway, and which must pass through the inflatable cuff poses a
particularly difficult problem. In terms of effects on
functionality, the provision of a drain tube can cause unacceptable
stiffening of the mask tip area and occlusion/restriction of the
airway passage.
[0010] It is an object of the present invention to seek to mitigate
problems such as these.
[0011] According to a first aspect of the invention there is
provided an artificial airway device to facilitate lung ventilation
of a patient, comprising at least one airway tube and a mask
carried at one end of the at least one airway tube, the mask having
a distal end and a proximal end and a peripheral formation capable
of forming a seal around the circumference of the laryngeal inlet,
the peripheral formation surrounding a hollow interior space or
lumen of the mask and the at least one airway tube opening into the
lumen of the mask, the mask having a conduit for receiving, in use,
oesophageal matter, an outer, in use, surface of the peripheral
formation defining a channel for use in facilitating drainage of
oesophageal matter. In this way, the invention provides a device
that is simpler and easier to manufacture because the requirement
for the conduit to pass through the peripheral formation is
avoided.
[0012] The peripheral formation may be inflatable, such as for
example an inflatable cuff. The channel may be for example a C- or
U-shaped channel formed in and/or by the material from which the
peripheral formation is formed, such as PVC, which is
thermoformable. The channel will preferably extend from the distal
end of the mask towards the proximal end of the mask and may
connect with a drainage tube of the mask, or of the airway tube.
The channel may be closed by an extension of the drainage tube of
the mask or of the airway tube, which extension may extend to a
point short of the distal end of the channel and terminate in a
substantially smooth and rounded end. It has been found that such
an end formation helps avoid the possibility of trauma during
insertion of the device.
[0013] In an alternative embodiment, the channel may perform its
function of facilitating drainage of oesophageal matter by defining
a path through which a drainage tube of the mask and/or the airway
tube can extend.
[0014] It is preferred that the mask describes a substantially
convex curve, from the proximal to distal end. It is further
preferred that the mask body comprises a plate, the plate having a
dorsal side and a ventral side, the dorsal side being substantially
smooth and having a convex curvature across its width. It is also
preferred that the dorsal surface of the airway tube corresponds in
curvature to the curvature across the width of the plate. MI of
these expedients assist in making insertion of the mask easier.
[0015] The airway tube preferably comprises a relatively more rigid
material than the mask body. Both the airway tube and the mask body
preferably comprise a plastics material.
[0016] The airway tube may be adapted to include a relatively
softer wall portion adjacent a point that in use will be adjacent
the patient's teeth. It is preferred that the airway tube includes
dorsal and ventral surfaces and that the relatively softer wall
portion is disposed at one or both of the dorsal or ventral
surfaces. The relatively softer portion may comprise a relatively
softer material, or may comprise an unsupported portion of the
airway tube. It is preferred that airway tube includes a bite-block
that supports the airway tube against biting by the patient and
that the relatively softer portion is provided by a cutaway of the
bite block. For the avoidance of doubt, the airway device may or
may not have means for removal of oesophageal material.
[0017] The invention will further be described by way of example
and with reference to the following drawings, in which,
[0018] FIG. 1 is an underplan, or ventral view of a device
according to the invention;
[0019] FIG. 2 is an exploded view of a part of the device of FIG.
1;
[0020] FIG. 3 is a perspective ventral view of the mask of the
device of FIG. 1;
[0021] FIG. 4 is a front end view of the mask shown in FIG. 3 in a
first position;
[0022] FIG. 5 is a front end view of the mask shown in FIG. 3 in a
second position;
[0023] FIG. 6 is a side view of the device of FIG. 1; and
[0024] FIG. 7 is a plan, or dorsal view of the device of FIG.
1.
[0025] Referring now to the drawings, there is illustrated an
artificial airway device 1 to facilitate lung ventilation of a
patient, comprising at least one airway tube 2 and a mask 3 carried
at one end of the at least one airway tube, the mask 3 having a
distal end 4 and a proximal end 5 and a peripheral formation 6
capable of conforming to, and of fitting within, the actual and
potential space behind the larynx of the patient so as to form a
seal around the circumference of the laryngeal inlet, the
peripheral formation 6 surrounding a hollow interior space or lumen
7 of the mask 3 and the at least one airway tube 2 opening into the
lumen 7 of the mask, the mask having a conduit 8 for receiving, in
use, oesophageal matter, an outer, in use, surface 9 of the
peripheral formation 6 defining a channel 10 for use in
facilitating drainage of oesophageal matter.
[0026] As can be seen from the drawings, the device 1, in terms of
overall appearance is somewhat similar to prior art devices, in
that it consists of the basic parts which make up most if not all
laryngeal mask airway devices, i.e. an airway tube 2 and mask 3.
The mask 3 includes two components, a body part 11 often referred
to as a backplate (shown in FIGS. 6 and 7), and a peripheral
formation 6 which here takes the form of an inflatable cuff with an
inflation line 12.
[0027] For the purposes of description it is convenient to assign
reference names to areas of the device 1 (as opposed to its
constituent parts) and accordingly with reference to FIGS. 6 and 7,
the device 1 has a dorsal side 14, a ventral side 15, a proximal
end 16 (in a sense that this is the end nearest the user rather
than the patient) a distal end 17 and right and left sides 18 and
19.
[0028] Referring firstly to the airway tube 2, in the illustrated
embodiment the tube 2 comprises a relatively rigid PVC material
such as a shore 90A Colorite PVC moulded into an appropriately
anatomically shaped curve. The tube 2 has, some flexibility such
that if it is bent it will return to its original shape. Although
it is resiliently deformable in this way, it is also sufficiently
rigid to enable it to assist in insertion of the device 1 into a
patient, acting as a handle and guide for positioning the mask. The
airway tube 2 does not have a circular cross-section as in many
prior devices, but instead is compressed in the dorsal/ventral
direction which assists in, correct insertion of the device 1,
helps prevent kinking, and assists in comfortable positioning for
the patient as the shape generally mimics the shape of the natural
airway. In this embodiment each side 18, 19 of the airway tube 2
also includes a groove or channel 20 extending for most of the
tube's length from the proximal to distal ends. These grooves 20
further assist in preventing crushing or kinking of the airway tube
2. Internally the grooves 20 form ridges along the inner surfaces
of the sides 18 and 19, but this not essential to their
operation.
[0029] A further feature of the airway tube 2 is oesophageal drain
tube 41. This drain tube 41 is located within airway tube 2,
extending centrally through it from the proximal end to the distal
end, and in this embodiment it is disposed in contact with the
inner surface of the dorsal wall 2b of the airway tube 2, and
bounded on each side by raised, smooth walls (not shown) which form
a shallow channel through which it runs. At the proximal end of the
airway tube 2, the drain tube 41 exits the airway tube 2 via branch
42a of a bifurcated connector 42, to which a suction line may be
attached.
[0030] Bifurcated connector 42 also allows for connection of the
airway tube to a gas supply via branch 42b. Here it is formed from
a relatively rigid plastics material (when compared with the airway
tube 2) to enable easy connection of air lines and suction.
Referring to FIG. 2, connector 42 comprises a hollow somewhat
flattened, conical connector body 43 defining an atrium having
branches 42a and 42b extending from its narrower, proximal end.
Conical body 43 includes a circumferential flange 42c from which
extends tab 42d in a direction generally normal to the longitudinal
axis of the connector. An insert section 44 extends longitudinally
from the distal end of the conical body 43. The insert section 44
can be described as a tube, flattened in the dorsal to ventral
direction and having two sections of wall removed leaving gaps 44e
and "arms" 44a. The insert section 44 corresponds in shape and
dimension with the internal shape of the proximal end of the airway
tube 2 such that it fits inside it, with arms 44a providing support
and rigidity to the sides of the airway tube. As a result of the
removed wall sections 44e the support for the parts of the airway
tube 2 adjacent the removed sections is reduced. A sleeve 45 of a
soft and compliant material is bonded in placed around the outside
of the airway tube 2, covering the area into which the insert
section 44 locates, and the thickness of the airway tube wall at
this point can be reduced to accommodate this such that the overall
thickness at this point 46 is not increased. Thus, it will be
appreciated that this configuration provides a bite block that not
only supports the airway tube 2 at a point where the patient's
teeth are normally located when the device is in use, but also
guards against damage to the teeth by virtue of the less rigid
parts. It will be appreciated that this form of connector can also
be applied to airway devices that do not include an oesophageal
drain.
[0031] Turning now to the mask 3, the mask 3 consists of two parts,
a body part 11 often referred to as a back plate, and a peripheral
cuff 6.
[0032] The back plate 11 is formed by moulding from a shore 50A
Vythene PVC+PU. This material is substantially softer and more
deformable than the material of airway tube 2. The back plate 11
comprises a generally oval moulding when viewed from the dorsal or
ventral directions, having a smooth dorsal surface 24, and a formed
ventral surface 24a (FIG. 5). The dorsal surface 24 has a convex
curvature from one side to the other, corresponding to the
curvature of the dorsal surface of the airway tube 2, and
longitudinally, the dorsal surface 24 is also curved, having a
curvature, beginning at the joining portion 24b and extending with
constant rate of curvature toward the distal tip. As a result the
tip is ventrally biased relative to the distal end of the airway
tube, in the assembled device 1, the extent of displacement of the
distal tip being approximately 20 mm or 10 degrees, in order to
produce a curvature in the mask that is suited to the anatomy of
the patient. On insertion, this displacement of the tip assists the
mask in "turning the corner" in the insertion path.
[0033] Backplate 11 includes an integrally moulded cylindrical
drain tube 20 that extends from its proximal to distal ends. At the
proximal end, the drain tube 11 is dimensioned such that it can be
joined to the drain tube of the airway tube. At its distal end, the
wall of the drain tube 20 has a cut away portion 21, and a smooth,
turned over edge.
[0034] The second part of the mask 3 is the peripheral cuff 6. The
cuff 6 is in this embodiment blow moulded PVC and takes the form of
a generally elliptical inflatable ring, a relatively deeper
proximal end 37 with an inflation port 38 and a relatively
shallower distal end tapering to a "wedge" profile 39. At the
distal end the cuff is formed with a channel 22 in its dorsal
surface, the channel being of an open C shape that runs in a
proximal to distal direction to the tip of the cuff. The cuff 6 is
integrally formed in one piece. The wedge profile is provided such
that the ratio of dorsal to ventral side surface areas favours the
dorsal side. Thus, when deflated the distal end of the cuff 6 will
curl with bias from dorsal to ventral side.
[0035] The cuff 6 is bonded to the backplate 11 such that the cut
away section of the drain tube 20 extends over the channel 22 in
the dorsal surface of the backplate 11, thereby forming a tube,
part of the wall of which is formed by the backplate and part by
the cuff 6. The tube terminates at or just before the distal
extremity of the cuff, the smooth edge flaring to some extent in a
dorsal direction.
[0036] In use, the deflated device 1 is inserted into a patient in
the usual manner with devices of this type. As noted above, the
relative rigidity of the airway tube 2 allows a user to grip it and
use it to guide the device 1 into the patient, whilst the
relatively softer, more compliant material of the back plate means
that the mask will more readily deform to negotiate the insertion
path without causing damage to the anatomy, and will return to its
optimum shape to ensure that a good seal is achieved at the
furthest extent of insertion. The ventral displacement of the
distal tip relative to the join between the back plate 11 and
airway tube 2 further enhances ease of insertion, because the
distal tip is thereby presented at the optimum angle to negotiate
the "bend" in the insertion path. In devices formed from relatively
rigid materials such as PVC, as opposed to the often used LSR these
features are particularly important in easing insertion and
providing for an enhanced seal. It will be appreciated that, as the
oesophageal drain tube does not pass through the interior of the
cuff as with prior designs, but instead resides in the channel
formed on its surface the device is both easier to manufacture and
more resistant to failure as the integrity of the cuff is
maintained.
* * * * *