U.S. patent application number 14/577645 was filed with the patent office on 2015-06-25 for tracheostomy tube and technique for using the same.
The applicant listed for this patent is COVIDIEN LP. Invention is credited to Robert W. Flagler, Carl Kling, Michael H. Vardanega.
Application Number | 20150174353 14/577645 |
Document ID | / |
Family ID | 38776203 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150174353 |
Kind Code |
A1 |
Flagler; Robert W. ; et
al. |
June 25, 2015 |
TRACHEOSTOMY TUBE AND TECHNIQUE FOR USING THE SAME
Abstract
A molded tracheostomy tube may provide enhanced comfort for a
patient. A unitary molded coating over areas of the tracheostomy
tube that come into contact with the patient's skin may prevent
irritation. Further, the overmolding manufacturing process may
allow the tracheostomy tube assembly to incorporate features that
allow for greater ease of movement for a patient, such as features
that allow flexing at the connection point of the tracheostomy tube
to other medical devices.
Inventors: |
Flagler; Robert W.;
(Pleasanton, CA) ; Kling; Carl; (San Ramon,
CA) ; Vardanega; Michael H.; (Livermore, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
COVIDIEN LP |
Mansfield |
MA |
US |
|
|
Family ID: |
38776203 |
Appl. No.: |
14/577645 |
Filed: |
December 19, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11527070 |
Sep 26, 2006 |
8936025 |
|
|
14577645 |
|
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Current U.S.
Class: |
128/200.26 ;
128/202.27; 128/204.18; 128/207.15; 128/207.17; 264/273 |
Current CPC
Class: |
A61M 2207/10 20130101;
A61M 16/0057 20130101; A61M 16/0465 20130101; A61M 16/0497
20130101; B29L 2023/00 20130101; B29L 2031/753 20130101; A61M
2205/0216 20130101; A61M 16/0816 20130101; A61M 16/0875 20130101;
A61M 16/0418 20140204; A61M 16/0427 20140204; A61M 16/0434
20130101; B29C 45/1676 20130101; B29C 45/14598 20130101 |
International
Class: |
A61M 16/04 20060101
A61M016/04; A61M 16/08 20060101 A61M016/08; A61M 16/00 20060101
A61M016/00 |
Claims
1. A tracheostomy tube comprising: a cannula comprising a distal
end and a flared proximal end, the distal end being adapted to be
inserted into a patient's trachea; a flange member molded over the
flared proximal end of the cannula such that the flared proximal
end is embedded in the flange and wherein the flange member is
configured to support the tracheostomy tube via engagement with the
patient's neck to maintain the flange member outside of the
patient's trachea; and a conduit disposed on the flange member in
communication with the cannula, wherein the conduit is adapted to
operatively connect to a medical device.
2. The tracheostomy tube of claim 1, comprising an inflatable cuff
disposed on cannula.
3. The tracheostomy tube of claim 1, wherein the medical device
comprises a ventilator.
4. The tracheostomy tube of claim 1, comprising a disposable
cannula lining adapted to be slidably insertable into the
cannula.
5. The tracheostomy tube of claim 1, wherein the conduit comprises
a grooved portion adapted to allow the conduit to flex relative to
the flange member.
6. The tracheostomy tube of claim 1, wherein the conduit is adapted
to be substantially orthogonal relative to the flange member absent
any deforming forces.
7. The tracheostomy tube of claim 1, wherein the flange member
comprises a flexible radial section substantially surrounding the
conduit adapted to allow the conduit to flex relative to the flange
member.
8. The tracheostomy tube of claim 1, wherein the flange member
comprises at least one groove adapted to allow the conduit to flex
relative to the flange member.
9. The tracheostomy tube of claim 1, wherein the flange member
comprises a thermoplastic elastomer, a polyvinylchloride, or a
polyurethane.
10. The tracheostomy tube of claim 9, wherein the thermoplastic
elastomer comprises at least one of a styrenic block copolymer,
thermoplastic vulcanizate alloy, thermoplastic polyurethane,
silicone, ethyl vinyl acetate, elastomer alloy, or a combination
thereof.
11. The tracheostomy tube of claim 1, wherein the conduit is
integral with the flange member.
12. The tracheostomy tube of claim 1, wherein the flange member is
permanently coupled to the proximal end of the cannula.
13. The tracheostomy tube of claim 1, wherein the flange member is
chemically bonded to the proximal end of the cannula.
14. A tracheostomy tube, comprising: a cannula having a first
passageway extending between a distal end and a proximal end of the
cannula, the distal end being configured to be inserted into a
trachea; a conduit having a second passageway being substantially
in line with the first passageway at the proximal end of the
cannula; and a flange member that couples the first passageway to
the second passageway, wherein the proximal end of the cannula is
embedded in the flange member and wherein at least a portion of the
conduit is integral with the flange member.
15. The tracheostomy tube of claim 14, wherein the flange member is
integrally coupled to the proximal end of the cannula via injection
molding, insert injection molding, or two-shot molding.
16. The tracheostomy tube of claim 14, wherein the flange member is
formed from a material having a lower durometer than a material
forming the conduit.
17. A method of forming a tracheostomy tube, comprising: providing
a cannula having a distal end and a proximal end, the distal end of
the cannula being configured to be inserted into a trachea; molding
a first material over the proximal end of the cannula to form a
flange member, wherein the flange member is configured to support
the tracheostomy tube via engagement with a patient's neck to
maintain the flange member outside of the trachea; and forming a
conduit having a first passageway being communicatively coupled to
the proximal end of the cannula, the conduit being configured to
attach to an external medical device, wherein the conduit is formed
from a second material.
18. The method of claim 17, wherein the first material forms the
flange member by being molded through one or more perforations.
19. The method of claim 17, wherein the first material is softer
than the second material.
20. The method of claim 17, wherein the proximal end is flared.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of patent application
Ser. No. 11/527,070, entitled "Tracheostomy Tube and Technique for
Using the Same" filed Sep. 26, 2006, which is herein incorporated
by reference in its entirety for all purposes.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to medical devices, and more
particularly, to airway devices, such as tracheostomy tubes.
[0004] 2. Description of the Related Art
[0005] This section is intended to introduce the reader to various
aspects of art that may be related to various aspects of the
present invention which are described and/or claimed below. This
discussion is believed to be helpful in providing the reader with
background information to facilitate a better understanding of the
various aspects of the present invention. Accordingly, it should be
understood that these statements are to be read in this light, and
not as admissions of prior art.
[0006] In the course of treating a patient, a tube or other medical
device may be used to control the flow of air, food, fluids, or
other substances into the patient. For example, medical devices,
such as tracheal tubes, may be used to control the flow of one or
more substances into or out of a patient. In many instances, it is
desirable to provide a seal between the outside of the tube or
device and the interior of the passage in which the tube or device
is inserted. In this way, substances can only flow through the
passage via the tube or other medical device, allowing a medical
practitioner to maintain control over the type and amount of
substances flowing into and out of the patient.
[0007] More specifically, tracheal tubes may be used to control the
flow of air or other gases through a patient's trachea. Such
tracheal tubes may include endotracheal tubes or tracheostomy
tubes. While patients may be intubated using endotracheal tubes
during emergencies or shorter hospital stays, tracheostomy tubes
are more typically used for prolonged ventilation, as the use of a
tracheostomy tube is generally more comfortable for a patient.
[0008] A typical tracheostomy tube is generally inserted into the
trachea via a surgical incision in the neck. After insertion of the
tube into the trachea, a portion of tube remains outside the
patient. This portion extends outwards from the neck and may
connect the tracheostomy tube to a ventilator or other medical
device. Generally, this exterior portion of the tube is held in
place by a flange that rests on the patient's neck and is further
secured by straps to the patient. The inserted portion of the
tracheostomy tube is generally mechanically coupled to the flange,
typically by a snap or screw mechanism on the underside of the
flange, which rests on the patient's neck. As such, the mechanical
connection point may display angled edges that may irritate a
patient's skin. Certain devices attempt to address this problem by
providing pillow or fabric protectors for the neck that may lift
the flange slightly off the neck to avoid skin irritation. However,
these devices may compromise the secure attachment of the
tracheostomy tube to the patient by providing a less stable base
for the tube at the patient's neck.
[0009] A stable attachment of the tracheostomy tube to the patient
is advantageous for preventing motion of the tube within the
trachea. Because the exterior portion of the tracheostomy tube is
connected to the inserted portion, when the exterior portion of the
tube is shifted or moved, these movements may be translated to the
interior potion of the tube. These movements may cause some
discomfort for the patient if the tracheostomy tube shifts position
within the trachea.
SUMMARY
[0010] Certain aspects commensurate in scope with the originally
claimed invention are set forth below. It should be understood that
these aspects are presented merely to provide the reader with a
brief summary of certain forms the invention might take and that
these aspects are not intended to limit the scope of the invention.
Indeed, the invention may encompass a variety of aspects that may
not be set forth below.
[0011] There is provided a tracheostomy tube that includes a
cannula including a distal end and a proximal end, the distal end
being adapted to be inserted into a patient's trachea; a flange
member molded over the proximal end of the cannula; and a conduit
disposed on the flange member in communication with the cannula,
wherein the conduit is adapted to operatively connect to a medical
device.
[0012] There is also provided a method of manufacturing a
tracheostomy tube that includes providing a cannula comprising a
distal end and a proximal end, the distal end being adapted to be
inserted into a patient's trachea; molding a flange member over the
proximal end of the cannula such that the proximal end of the
cannula is coupled to the flange member; and disposing a conduit
disposed on the flange member in communication with the cannula,
wherein the conduit is adapted to operatively connect to a medical
device.
[0013] There is also provided a method of sealing a patient's
trachea that includes inserting a tracheostomy tube into a
patient's trachea, wherein the tracheostomy tube comprises: a
cannula comprising a distal end and a proximal end, the distal end
being adapted to be inserted into a patient's trachea; a flange
member molded over the proximal end of the cannula; and a conduit
disposed on the flange member in communication with the cannula,
wherein the conduit is adapted to operatively connect to a medical
device.
[0014] There is also provided a tracheostomy tube mold form that
includes: a mold cavity defining a flange member; a mold cavity
defining a conduit adapted to be disposed on the flange member in
communication with the cannula; and an opening in the mold form
adapted to receive a cannula comprising a distal end and a proximal
end, wherein the proximal end of the cannula is adapted to be
inserted into at least a portion of the mold cavity defining the
flange member.
[0015] There is also provided a unitary molded tracheostomy tube
assembly that includes: a cannula adapted to be inserted into a
patient's trachea comprising a distal end and a proximal end; a
flange member disposed on the proximal end of the cannula; and a
conduit disposed on the flange member in communication with the
cannula, wherein the conduit is adapted to operatively connect to a
medical device, and wherein the cannula, the flange member, and the
conduit comprise a unitary molded structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Advantages of the invention may become apparent upon reading
the following detailed description and upon reference to the
drawings in which:
[0017] FIG. 1A illustrates a side perspective view of an overmolded
tracheostomy tube with bellows and a notched flange in accordance
with aspects of the present technique;
[0018] FIG. 1B illustrates a side perspective view of a disposable
inner cannula lining and an overmolded tracheostomy tube with
bellows and a notched flange in accordance with aspects of the
present technique;
[0019] FIG. 2 illustrates a cross-sectional view of the
tracheostomy tube of FIG. 1;
[0020] FIG. 3 illustrates an alternative configuration of a flange
according to the present techniques;
[0021] FIG. 4 illustrates another alternative configuration of a
flange according to the present techniques;
[0022] FIG. 5 illustrates yet another alternative configuration of
a flange according to the present techniques; and
[0023] FIG. 6 illustrates an exemplary flange mold according to the
present techniques.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0024] One or more specific embodiments of the present invention
will be described below. In an effort to provide a concise
description of these embodiments, not all features of an actual
implementation are described in the specification. It should be
appreciated that in the development of any such actual
implementation, as in any engineering or design project, numerous
implementation-specific decisions must be made to achieve the
developers' specific goals, such as compliance with system-related
and business-related constraints, which may vary from one
implementation to another. Moreover, it should be appreciated that
such a development effort might be complex and time consuming, but
would nevertheless be a routine undertaking of design, fabrication,
and manufacture for those of ordinary skill having the benefit of
this disclosure.
[0025] Provided herein are tracheostomy tubes in which a flange
portion is permanently attached to a cannula portion. Such tubes
may allow for increased patient comfort. Typical tracheostomy tubes
contain a curved cannula portion that is mechanically connected to
an outer flange that is designed to rest on a patient's neck. This
mechanical connection may include exposed notches or edges that may
cause discomfort against a patient's skin. The tracheostomy tubes
according to the present techniques may be molded or cast to
provide a comfortable coating over the flange/cannula connection
point that reduces the chance of such discomfort. Further, the
coating results in a more robust tracheostomy tube assembly in
which the flange portion is substantially permanently connected to
the cannula portion without sacrificing patient comfort for
increased durability. In specific embodiments, the tracheostomy
tubes may also contain features that reduce the outside forces that
may be transferred to inserted portion of the tube, which may cause
discomfort if the tube shifts position and contacts the trachea.
For example, the exterior flange and other patient exterior
assemblies may include regions that allow for flexing or bending of
the tracheostomy tube to reduce or eliminate the translation of
movement to the interior portion of the tube.
[0026] FIGS. 1A and 1B show a side perspective view of an exemplary
overmolded tracheostomy tube assembly 10 according to the present
techniques. In the depicted embodiment, a portion of a cannula 12
is permanently embedded in a portion of a flange 20 member through
an overmolding technique, described in detail below. Generally, a
region of a preformed cannula 12 may be inserted into a mold
suitably sized and shaped to form the flange member 20. A flange
material may be injected into the mold so that as the flange
material cools and hardens around the cannula 12, it permanently
attaches itself to any portion of the cannula 12 that is contained
in the mold. Alternatively, as provided herein, a tracheostomy tube
assembly 10 may be formed from a single mold. In any case, a flange
member 20 may be permanently attached to a cannula 12, without
employing a mechanical coupling, such as a snap or screw.
[0027] The tracheostomy tube assembly 10 may include an arcuate
cannula 12 having a distal end 14, which is generally sized and
configured to be inserted through a patient tracheostomy. When the
tracheostomy tube assembly 10 is in use, the distal end 14 as well
as the major portion of the length of the cannula 12 will reside
within the trachea, with the proximal end 16 being generally flush
with the anterior surface of the patient's neck. The cannula 12 may
also feature a small lumen (not shown) within the wall, accessed by
notches 18a and 18b. This lumen is an airway that may be used to
fill a balloon type sealing cuff 13 at the patient insertion end.
The cuff 13 may be a urethane balloon bonded to the exterior of the
cannula 12 such that the notch 18b is encompassed. A user may
inject air into the lumen through its access point at notch 18a,
which transfers air to the cuff. The cuff 13 may inflate within the
patient airway to provide an additional seal.
[0028] The tracheostomy tube assembly 10 also features a flange 20
connected to the proximal end 16 of the cannula 12. The flange 20
is designed to rest on the neck of a patient and may feature
openings 22a and 22b designed to accommodate attachment straps that
may further secure the tracheostomy tube assembly 10 to the neck.
The flange 20 may feature a conduit 24 that is substantially
in-line with the proximal end 16 of the cannula 12. Generally, the
conduit 24 may be adapted to connect the tracheostomy tube 10 to
any suitable medical device. For example, the conduit 24 may serve
as an insertion point for a disposable cannula lining 17 (shown in
FIG. 1B) or may be suitably sized and shaped to connect the
tracheostomy tube 10 via medical tubing or other devices to a
mechanical ventilator.
[0029] In certain embodiments, the flange 20 may include features
that allow the conduit 24 to move or flex to accommodate outside
forces. Because the conduit 24 may be manipulated by healthcare
providers to attach or detach a medical device, it may be
advantageous for the conduit 24 to have some freedom of movement.
For example, if a healthcare worker exerts force on the conduit 24
to connect a medical device, the conduit 24 may transmit some of
that force into a bending or flexing motion so that the cannula 12,
which is mostly inside the patient's trachea, does not experience
the full force exerted on the conduit 24. As such, the cannula's 12
movements may be reduced, which may result in less irritation of
the tracheal walls. Additionally, a flexible medical device
connection point, i.e. the conduit 24, may increase possible
patient room layout options. Such a feature may be advantageous in
emergency room or operating room settings, where larger medical
devices may be difficult and time-consuming to move. As depicted in
FIG. 1, an annular notch or recess 26 that substantially surrounds
the conduit 24 may allow the conduit 24 to have flexibility in
several directions. Further, the conduit 24 may also feature a
grooved region 28 that may allow additional degrees of freedom to
the conduit 24. In certain embodiments, the grooved region 28 may
include support ribs 30 to assist in supporting the conduit 24 in a
substantially orthogonal position relative to the flange 20 absent
any deforming forces applied to the conduit 24.
[0030] FIG. 2 is a cross-section view of the tracheostomy tube 10
of FIG. 1. As depicted, a flared portion 32 of the proximal end 16
of the cannula 12 is embedded in the flange member 20. The flange
member 20 may also include guides 34 that may provide additional
support to the proximal end 16 of the cannula 12. The conduit 24
defines a passageway 36 into which respiratory gases may flow.
Passageway 36 may be connected with a passageway 38, defined by the
cannula 12, to allow flow of respiratory gases into the trachea.
Although the conduit 24 may bend or flex, the passageway 36 will
remain substantially in-line with the passageway 38.
[0031] The grooved region 28 may include grooves with a
substantially V-shaped cross-section with sloping sides that meet
in a point, as shown. In other embodiments, the grooves in the
grooved region 28 may have different configurations. For example,
the grooves may include non-sloping sides that are connected by a
substantially flat bottom region. In any case, the grooved region
28 allows the conduit 24 to bend at the area that includes the
grooves. Further, in certain embodiments, the grooved region 28 may
include semi-annular grooves that may allow flexibility only in
certain directions where the grooves are located. Similarly, the
notch 26 may also include any suitably shaped annular or
semi-annular notch or groove that allows the flange to bend in the
area surrounding the conduit.
[0032] The flexibility of the conduit 24 may be altered according
to the needs of the patient or healthcare workers by altering the
configuration of the flange member 20. For example, the flange
member 20 illustrated in FIG. 3 includes a grooved region 28 with
support ribs 30 without a notch 26 surrounding the conduit 24. Such
a configuration may provide increased support to a heavier or
larger conduit 24, which may be appropriate for a larger patient,
while maintaining some degree of flexibility. The flange member 20
depicted in FIG. 4 includes a grooved region 40 substantially
surrounding the conduit 24. Such an embodiment may confer increased
degrees of freedom to the conduit 24, which may be advantageous for
an active patient. In other embodiments (not shown), a grooved
region (e.g. 28 or 40) may contain more or fewer grooves in order
to alter the flexibility characteristics of the conduit 24. In
other embodiments, a flange member 20 may contain no flexibility
features, such as grooves or notches, if a healthcare worker is not
particularly concerned about outside forces being transmitted to
the tracheal walls. The flange member 20 may also include a certain
degree of flexibility through the choice of an appropriate mold
material, such as a thermoplastic elastomer. Such an embodiment may
be appropriate for a stable patient in an intensive care setting,
where the patient is not being moved very often.
[0033] In addition, as depicted in FIG. 5, increased flexibility
for the conduit 24 may be achieved by molding portions of the
flange member 20 into thin or membranous regions of thermoplastic
material, such as a membranous region 42 surrounding the conduit
24. Such flexible regions may allow a greater range of motion for
the conduit 24. In certain embodiments, the membranous region may
be 0.03-0.05 inches in thickness, while the outer rim 44 of the
flange member may be 0.1''-0.2'' thick. In an alternative
embodiment the conduit 24 may exhibit an outer wall thickness of
0.07''-0.11'' be internally ribbed and may include ribs or grooves
(not shown) molded into the interior passageway. The support ribs
30, may be 0.03''-0.1'' inches in thickness depending on material
flexural modulus and may, for example, vary in number from 3 to
6.
[0034] The proximal end 16 of the cannula 12 may include a region
that is embedded in the flange member 20 through an overmolding
process. As noted above, in certain embodiments of the present
technique, the tracheostomy tube 10 is overmolded to form a unitary
or integral assembly in which the cannula 12 is integrated into the
flange member 20 during the manufacturing process. Such overmolded
embodiments may result in an assembly in which the tracheostomy
tube 10 is completely or partially coated with a thermoplastic
material, discussed in more detail herein. For example, the flange
member 20 and conduit 24 may be formed by an injection molding
process. In one example of such a process, the proximal end 16 of
the cannula 12 may be positioned within a die or mold 48, shown in
FIG. 6 of the desired shape for the flange member 20 and conduit
24. In certain embodiments, the mold 48 may include cavities
defining the guides 34 on either side of an opening in the mold 48
designed to accommodate the proximal end 16 of the cannula 12. The
mold 48 may also include an opening 50 into which the mold material
may be injected. The guides 34 may help properly position the
proximal end 16 of the cannula 12 in the mold. Additionally, the
tracheostomy tube 10 may also include a second or distal conduit
extension (not shown) that may be inserted into the proximal end 16
of the cannula 12 and radio-frequency welded to the cannula 12.
[0035] In certain embodiments, the tracheostomy tube 10 may be
constructed, in whole or in part, from polymeric materials, such as
thermoplastics, capable of providing a suitable rigidity or
semi-rigidity. Examples of such suitable materials include
polyvinylchloride, polyurethane, polypropylene and silicone, though
other polymeric materials may also be suitable. In one
implementation, the overmolding or coating is a thermoplastic
elastomer or other conformable coating or material. In such
embodiments, the thermoplastic elastomer may include compositions
such as styrenic block copolymers, thermoplastic vulcanizate
alloys, silicone, thermoplastic polyurethane, and so forth.
Further, many elastomer alloys may be suitable as well. As will be
appreciated by those of ordinary skill in the art, the overmolding
composition may vary, depending on the varying degrees of
conformability, durability, wettability, elasticity, or other
physical and/or chemical traits that are desired. For example, in
certain embodiments, the thermoplastic elastomer is selected to
have a hardness between 30 and 60 Shore A to provide a robust yet
comfortable material to rest against a patient's skin. In one
embodiment, a suitable material having a hardness between 30 and 60
Shore A is employed to mold the flange member 20 while another
material having a hardness between between 50 and 70 Shore A is
employed to form the cannula 12. In embodiments in which the flange
member 20 and the cannula 12 are formed from different materials,
these materials may be selected based upon the desirability of a
chemical bond between the between the flange member 20 and the
cannula 12.
[0036] A molten or otherwise unset overmold material may then be
injected into the die or mold. For example, in one implementation,
a molten thermoplastic elastomer at between about 340.degree. F. to
about 430.degree. F. is injected into the mold. The overmold
material may then be set, such as by cooling for a period based
upon wall thickness where cooling may take place at 30 seconds per
0.100'' thickness of overmold material to form the tracheostomy
tube 10. In certain embodiments, shear-dependent overmold materials
may be advantageous for molding thin or more intricate parts.
[0037] In an alternative embodiment, the tracheostomy tube 10 may
be formed from a two-shot injection molding process in which a mold
is moved or rotated from one injection barrel to a second injection
barrel to allow two materials, which may be the same or different,
to be injected one after the other in the same mold. Such a process
may allow a first molded part to cool before the second molded part
is formed. In certain embodiments, the mold may not move or rotate,
but movable components within the mold may allow for molding shots
from different barrels. In one embodiment, a two-shot molding
process may involve injecting a higher durometer material for the
conduit and injecting a softer durometer material for the flange.
Additionally, insert injection molding techniques may also be
appropriate for forming the tracheostomy tube 10.
[0038] The cannula 12 may be a pre-formed assembly that may be
molded into the appropriate curved configuration or may be extruded
and curved into a "J" shape with heat-setting. The proximal end of
the cannula 12 may be flared using radio frequency energy. In
certain embodiments, it may be advantageous to form perforation or
depressions (not shown) into the flared region 32 of the cannula
12. In such an embodiment, the overmolding material may flow into
the perforations or depressions to create an improved bond with the
flared region 32.
[0039] The tracheostomy tubes 10 of the present techniques may be
incorporated into systems that facilitate positive pressure
ventilation of a patient, such as a ventilator. Such systems may
typically include connective tubing, a gas source, a monitor,
and/or a controller. The controller may be a digital controller, a
computer, an electromechanical programmable controller, or any
other control system.
[0040] While the invention may be susceptible to various
modifications and alternative forms, specific embodiments have been
shown by way of example in the drawings and have been described in
detail herein. However, it should be understood that the invention
is not intended to be limited to the particular forms disclosed.
Rather, the invention is to cover all modifications, equivalents,
and alternatives falling within the spirit and scope of the
invention as defined by the following appended claims.
* * * * *