U.S. patent application number 09/753288 was filed with the patent office on 2001-05-31 for endotracheal tube for use during fiberoptic assisted intubation and with other intubating stylets.
Invention is credited to Allgeyer, Dean O..
Application Number | 20010001957 09/753288 |
Document ID | / |
Family ID | 27068321 |
Filed Date | 2001-05-31 |
United States Patent
Application |
20010001957 |
Kind Code |
A1 |
Allgeyer, Dean O. |
May 31, 2001 |
Endotracheal tube for use during fiberoptic assisted intubation and
with other intubating stylets
Abstract
An endotracheal tube for use with a fiberoptic bronchoscope or
other intubation stylet is described. There are ventilation holes
located on the tapering section on the distal tip such that
ventilation may occur while using the fiberoptic scope and such
that resistance to ventilation is minimized with the scope removed.
The endotracheal tube is particularly useful for difficult
intubations as the distal tip is tapered which facilitates passage
through the larynx.
Inventors: |
Allgeyer, Dean O.; (Los
Angeles, CA) |
Correspondence
Address: |
FULWIDER PATTON LEE & UTECHT, LLP
HOWARD HUGHES CENTER
6060 CENTER DRIVE
TENTH FLOOR
LOS ANGELES
CA
90045
US
|
Family ID: |
27068321 |
Appl. No.: |
09/753288 |
Filed: |
December 29, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09753288 |
Dec 29, 2000 |
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08645144 |
May 13, 1996 |
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6196225 |
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08645144 |
May 13, 1996 |
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08546681 |
Oct 23, 1995 |
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Current U.S.
Class: |
128/207.15 ;
128/207.14; 604/96.01 |
Current CPC
Class: |
A61M 16/04 20130101;
A61M 16/0488 20130101 |
Class at
Publication: |
128/207.15 ;
128/207.14; 604/96.01 |
International
Class: |
A61M 016/00 |
Claims
What is claimed is:
1. An endotracheal tube for use with a fiberoptic bronchoscope or
other intubating stylet, comprising: a) a unitary tube with a
proximal portion of generally constant cross section; and b) a
tapered end portion of said tube, disposed distally on said tube,
said tube having at least one hole situated on said tapered distal
end, whereby ventilation is accomplished without undue
resistance.
2. The tube of claim 1, further comprising a tracheal balloon
disposed on said tube generally proximate to said tapered end.
3. The tube of claim 2, wherein said tapered end is configured as a
mammalian nipple.
4. The tube of claim 2, wherein said tapered end is configured as a
truncated conical section.
5. An endotracheal tube adapted for use with a fiberoptic
bronchoscope, comprising: a) a tracheal balloon; b) a unitary
flexible tube, passing through said balloon, comprising a proximal
portion of generally constant cross section, said proximal portion
being disposed on one side of said balloon; c) a tapered distal
portion of said flexible tube, disposed on said balloon oppositely
of said proximal portion; and d) at least one ventilation aperture
disposed on said flexible tube distally of said balloon.
6. The endotracheal tube of claim 5 wherein said ventilation
aperture is disposed on said tapered distal portion.
7. The endotracheal tube of claim 7 wherein said tapered distal
portion is generally configured similar to a mammalian nipple.
8. The endotracheal tube of claim 7 wherein said tapered distal
portion is generally configured as a truncated conical section.
9. The endotracheal tube of claim 5 wherein said ventilation
aperture is disposed partially on said tapered portion and
partially on a constant cross-sectioned portion distal to said
balloon.
10. An endotracheal tube for use with a fiberoptic bronchoscope or
other intubating stylet, comprising: a) a tracheal balloon; b) a
tube disposed proximal to the balloon for ventilation and for
relative movement between the tube and the stylet; c) a tube
disposed distal to the balloon, having an exterior wall surface and
an interior wall surface defining a lumen for ventilation and for
relative movement between the tube and the stylet, the lumen having
an axis disposed generally along its centerline; d) a ventilation
aperture, disposed in the distal tube for ventilation and for
relative movement between the tube and the stylet; and e) a tapered
tip disposed on the distal tube and distal to the balloon, whereby
the exterior wall surface of the tube tapers toward the lumen axis
to avoid forming a significant leading edge.
11. The endotracheal tube of claim 10, further comprising a second
ventilation aperture disposed in the distal tube more proximal to
the balloon than the first ventilation aperture.
12. The endotracheal tube of claim 10, wherein the tapered tip is a
truncated cone.
13. The endotracheal tube of claim 10, wherein the tapered tip
further includes a guide tip.
14. The endotracheal tube of claim 10, wherein the ventilation
aperture is perpendicular to the axis of the lumen.
15. The endotracheal tube of claim 11, wherein the second
ventilation aperture includes an axis defined by centers in
openings in the interior and exterior wall surfaces.
16. The endotracheal tube of claim 15, wherein the axis of the
second aperture is perpendicular to the axis of the distal
endotracheal tube.
17. The endotracheal tube of claim 10, wherein the proximal and
distal tubes comprise a unitary tube.
18. The endotracheal tube of claim 10, wherein the tapered tip is a
mammalian nipple.
Description
[0001] This application is a continuaton-in-part of Ser. No.
08/546,681 filed Oct. 23, 1995.
BACKGROUND OF THE INVENTION
[0002] This invention relates to medical equipment used in the
fields of anesthesiology and emergency airway management. More
particularly, the invention relates to an endotracheal tube used in
conjunction with a fiberoptic bronchoscope, or other stylet, to
overcome intubation difficulties.
[0003] Provision of anesthesia to patients during surgical
procedures requires ensuring adequate respiratory function. This is
most often accomplished by use of an endotracheal tube (ETT).
Placement of an endotracheal tube for support of respiration is a
critical step in the provision of anesthetic patient care.
Placement of the ETT is performed most often under direct
visualization using a laryngoscope. However, this procedure can be
difficult to accomplish due to anatomic anomalies. Often, a
fiberoptic bronchoscope (FOB), or other intubating stylet, is used
to overcome these instances of difficult intubations. Use of an FOB
allows visualization of the upper airway structures and visual
confirmation that the trachea has been entered. Once the trachea
has been entered, the FOB is used as a stylet guide to place an
ETT. The ETT is slid over the FOB into the trachea. Once the ETT
has been successfully placed in the trachea, the FOB is withdrawn
and the patient can be ventilated. Other types of stylets are also
known.
[0004] The currently utilized ETTs were originally designed for
intubation under direct visualization and without consideration of
use in conjunction with an FOB or other intubating stylet. Their
design incorporates a constant diameter tube with a leading edge.
When using a standard ETT over an FOB, or other intubating stylet,
the leading edge can become impacted on the laryngeal structures
causing trauma, delay, or failed intubation.
[0005] Endotracheal tubes are in general flexible breathing
conduits constructed of medical grade plastics that are adapted to
be placed in the patient's trachea. The proximate end of the ETT
has a standard fitting allowing connection to a source of
pressurized gas such as oxygen and anesthetic gases. The distal end
is open to deliver these gases to the trachea and lungs of the
patient. The distal end usually has a side hole to aid in equal
ventilation of both lungs should the ETT be inaccurately
positioned. This side hole is not intended to, nor does it,
decrease ventilatory resistance in an ETT that is correctly
positioned. The ETT typically has an inflatable bladder or balloon
which can be inflated once the ETT is in place within the trachea.
This seals the trachea allowing positive pressure ventilation to
the lungs and protecting them from secretions and gastric contents.
During the intubation process the ETT traverses the mouth, pharynx,
larynx, and trachea of the patient and is ultimately placed in the
correct position within the trachea without causing damage to
bodily structures. Various devices are available to assist with
this process, the most important of them being the fiberoptic
bronchoscope.
[0006] An FOB consists of three basic parts, a proximal control
assembly which includes an eyepiece for viewing, an elongated shaft
housing fiberoptic bundles, channels, and control wires, and a
distal tip containing optics. In use, a high intensity light source
is connected via the proximal control assembly for transmission
through the fiberoptic bundles. The fiberoptic bundles transmit the
light to the distal tip where it is used to illuminate the object
to be viewed. Optics located in the distal tip transmit the image
through another fiberoptic bundle to the proximal control assembly
where the image can be viewed with ones eye or transmitted to a TV
monitor for viewing.
[0007] In certain situations an FOB is used in conjunction with an
ETT to intubate a difficult airway. This is sometimes anticipated
prior to anesthetizing a patient but more often is an emergency
procedure in a patient who is discovered to have a difficult airway
after being anesthetized. In either situation, an appropriate size
ETT for the patient is chosen and threaded onto the proximal shaft
of the FOB. The tip is of the ETT is lubricated with a water
soluble medical lubricant. The procedure for using an FOB as an
intubating stylet is the same whether one is using a standard ETT
or the described tapered ETT. The upper airways are traversed with
the distal tip of the FOB and the laryngeal structures are
visualized and identified. The distal tip of the FOB is advanced
through the vocal cords and into the trachea. Once entrance of the
FOB into the trachea is visually confirmed, the ETT is slid down
the shaft of the FOB, using the FOB as an intubating stylet. The
tip of the ETT must traverse the larynx prior to entering the
trachea, and it is at this point resistance and obstruction to
advancement is not infrequently encountered. Thereafter the ETT
must be positioned accurately within the trachea and is done so
either by direct visualization of the bronchi and carina (the first
division of the trachea) through the FOB, or by using predetermined
norms for ETT position and listening to breath sounds. Once
positioned and the tracheal balloon inflated, the FOB is removed
from the ETT. The proximal end of the ETT is then connected to a
pressurized gas source and the patient is ventilated.
[0008] Trauma from ETT placement may cause bleeding, swelling,
laryngospasm, patient discomfort and hoarseness. Delayed or failed
intubation can cause brain damage and/or death. This cause of
delayed, traumatic, or failed intubation when using an FOB/ETT
combination is not infrequent and is documented in the anesthesia
literature. For example, Ovassapian states: "In 20-30% of patients,
even though the fiberscope has entered the trachea, the
endotracheal tube impinges on the larynx and cannot be advanced
into the trachea. It is postulated that the tube catches on the
epiglottis or on the vocal cords or that it lodges in the pyriform
sinus."
[0009] Benumof states: "The free lumen of the endotracheal tube
predisposes the tube to move away from the the insertion cord of
the FOB and catch the laryngeal structures, therefore interfering
with the smooth entrance of the tube into the trachea." Brull et al
report that fully 13 of 20 FOB assisted intubations using a
standard ETT were unsuccessful on the first attempt. Moreover, 7 of
20 patients were unable to be intubated using this technique
(standard ETT over an FOB) on the third attempt. They state:
"Furthermore, repeated attempts at passage may result in airway
bleeding, damage to the arytenoid cartilages or epiglottis, or
swelling of the airway, making subsequent endotracheal intubations
attempts more difficult." Failed intubation is a significant cause
of anesthetic related brain damage, death, and malpractice
litigation.
[0010] The same problem has been described when using standard
ETT's over other intubation stylets. The problem is most severe in
the instance of retrograde intubation. Retrograde intubation
involves placing a guide wire through the crico-thyroid membrane
and bringing it out through the patient's mouth. The wire is then
used as a stylet guide for an ETT. Because of the relatively large
discrepancy between the thin wire (0.038-inch outer diameter) and
the ETT (7-8 millimeters internal diameter), the tip of the ETT
often impinges upon the larynx.
[0011] Several ETTs and other devices have been designed for
specific functions and to overcome specific difficulties related to
the difficult airway. For example, Ring, Adair, and Elwyn, in U.S.
Pat. No. 3,964,488, seek to overcome the problems of ETT kinking
and obstruction by incorporating a preformed angle in the shaft of
an ETT. Carden, in U.S. Pat. No. 4,041,936, describes an ETT
designed for use during fiberoptic bronchoscopy of the lungs which
simplifies the procedure. Vilasi, in U.S. Pat. No. 3,968,800
describes a "Device For Insertion Into A Body opening." One
embodiment is an endotracheal tube with an adjustable external
circumference which seeks to overcome the need to stock multiple
size ETTs and to supplant the need for a tracheal balloon. Adair,
in U.S. Pat. No. 5,329,940 describes an "Endotracheal Tube
Intubation Assist Device" which couples an FOB with a television
monitor to assist with the problem of difficult intubation. Cook
Medical markets a retrograde intubation kit, which also seeks to
address the problem of the difficult airway.
[0012] Vilasi describes a device which generally suffers from
complexity, and is therefore more expensive to manufacture, is more
user dependent in its correct operation and application than a
simpler device, and is more time consuming to operate than a
simpler device designed for the same purpose. Using this device as
an ETT would raise safety issues as well. One can see that an FOB
placed through this device in the non-expanded configuration would
significantly interfere with ventilation. This is a serious
drawback of the design for use with an FOB, as the ability to
visualize anatomic structures while maintaining sufficient
ventilation is often necessary or desirable, such as when one is
checking for correct placement of the ETT within the trachea. This
is accomplished by using an FOB bronchoscopy adaptor which allows
the FOB and pressurized gases to be delivered through the ETT at
the same time. Attempting to intubate a patient or position the
device by moving it in the expanded configuration (intentionally or
unintentionally), within the trachea, would risk laceration of the
trachea or other upper airway structures, a potentially disastrous
complication. Using the device of Vilasi in solelyrthe closed
configuration would be limited by the increase in resistance to gas
flow caused by narrowing the distal end according to Poiseuille's
law which states resistance is inversely proportional to the inside
radius of the conduit to the 4th power. Hence, small decreases in
ETT size give large increases in airway resistance. Therefore, the
more useful the device of Vilasi is for intubating difficult
airways over a stylet, the less useful the device becomes as a
breathing conduit due to the increase in airway resistance.
[0013] Adair utilizes a standard ETT in conjunction with his device
for assisted intubations. The standard ETT depicted in Adair is not
tapered, has a leading edge, and an opening at the distal end which
aids in the equal dispersion of oxygen into the lungs. Its use with
a standard ETT is therefore subject to the same problems described
above, stemming from size discrepancy and the leading edge.
[0014] Others in the art teach using a standard ETT for instances
when an intubating stylet of one type or another are used. Examples
of intubating stylets include FOB's, tracheal tube changers,
tracheal tube introducers and guides, and wires used in retrograde
intubation kits. For example, the ETT illustrated in the retrograde
intubation and tracheal tube changer literature is of standard
design. Olympus, the leading FOB manufacturer, depicts a standard
ETT in their literature.
[0015] The problem of the tube tip catching on the laryngeal
structures is in part a function of the discrepancy between the
diameter of the intubating stylet and the ETT, causing the leading
edge to be oriented incorrectly as the distal tip approaches the
larynx. Attempts to overcome this problem have been made. For
example, Cook Medical includes an obturator sheath which functions
as a spacer in its retrograde intubation kit. The spacer is fitted
over the wire after a retrograde intubation wire has been placed,
after which the ETT is slid down the combined-wire/spacer assembly.
This adds another step and time to a procedure in which time is of
the essence but is deemed necessary to address the size discrepancy
problem. It also does not necessarily solve the problem, only
lessens it by degree. Brull et al. describe having greater success
using a spiral wound, more flexible ETT than a standard ETT for
fiberoptic assisted intubations. They postulate that improved
performance was due to the increased flexibility of the ETT, and to
a less acute angle of the leading edge relative to the longitudinal
axis of the ETT as opposed to the standard ETT. They also note that
the Spiral Wound ETT was 10-20 times the cost of a standard ETT and
that 5% of the time intubation using the spiral wound ETT and an
FOB was unsuccessful in their series. The described ETT of the
present invention represents an improvement over the prior art for
this purpose.
SUMMARY OF THE INVENTION
[0016] The objectives of the invention are accomplished by
providing a distally tapering endotracheal tube, with no
significant leading edge, that has ventilation holes placed on the
tapering portion of the ETT to mitigate what would otherwise be a
prohibitive increase in the resistance to gas flow. Additionally,
the tube is typically constructed of polyvinyl chloride and
otherwise manufactured in the same fashion as a standard ETT. The
tapered ETT may be constructed of various sizes to match patient
needs. Similarly, the distal aperture for passage of the FOB may be
of various sizes to complement the diameter of the FOB in use. The
ideal aperture would be only slightly larger in diameter than the
FOB in use, such that the ETT slides easily upon the shaft of the
FOB yet is closely contoured to the shaft in order to prevent
difficulty of passage of the ETT at the level of the larynx. The
ventilation holes are distal to the tracheal balloon and are
preferrably placed mainly or wholly on the tapered portion of the
ETT. This allows adequate ventilation when the FOB is in use and
protruding through the distal aperture. Ventilation is accomplished
by attaching a fiberoptic bronchoscopy adaptor to the proximate end
of the ETT which allows connection to a pressurized gas source and
passage of an FOB through a diaphragm.
[0017] This new feature can be critical in the following
situations. Difficult intubations are those instances most likely
to lead to aspiration of gastric contents into the lung. This will
cause hypoxemia with its attendant problems of cardiovascular
instability and brain damage if not reversed. Aspiration is best
diagnosed by viewing the bronchi with an FOB, looking for bile,
food particles, and erythema. While one is interested in making the
diagnosis rapidly in order to institute the correct therapy, one
does not want to interrupt ventilation which will exacerbate
hypoxemia. Additionally, when hypoxemia occurs, one of the first
maneuvers is to check for correct placement of the ETT, as
misplacement is a frequent cause of hypoxemia. This ETT will allow
continued ventilation while the FOB is in use and will address this
dilemma.
[0018] With the FOB removed from the ETT, the combination of side
holes and the distal aperture provide for ventilation through the
ETT without a significant increase in ventilatory resistance
relative to a standard ETT. Thus, this invention accomplishes the
objectives of making difficult intubations safer, less traumatic,
and quicker when using this ETT in conjunction with an FOB or
intubating stylet, but without a significant increase in
ventilatory resistance that would otherwise limit its usefulness.
Additionally it allows ventilation through a tapered ETT while the
FOB is in use and so has the added feature of combined ventilatory
support and diagnostic capacity.
[0019] Accordingly, there are several objects and advantages of my
invention.
[0020] One advantage provides an endotracheal tube that when used
in conjunction with a fiberoptic bonchoscope, or other intubating
stylet, will result in safer intubations.
[0021] Another provides an endotracheal tube that when used in
conjunction with a fiberoptic bronchoscope, or other intubating
stylet, will result in less trauma to the airway during
intubation.
[0022] Yet another benefit of my invention is to provide an
endotracheal tube that when used in conjunction with a fiberoptic
bronchoscope will result in fewer instances of failed
intubations.
[0023] Yet another benefit of my invention is to provide an ETT
that when used in conjunction with an FOB or other intubation
stylet will result in quicker intubations.
[0024] Another benefit of my invention is to provide an
endotracheal tube that will facilitate intubations over an FOB or
intubating stylet yet will not significantly increase resistance to
ventilation when the ETT is in use with the FOB or stylet
removed.
[0025] Another benefit of my invention is to accomplish the above
goals by providing an ETT which is simple to use and cost effective
to manufacture.
[0026] Further objects and advantages of this invention will become
apparent from a consideration of the drawings and ensuing
description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In the drawings, closely related figures have the same
number but different alphabetic suffixes.
[0028] FIG. 1A is a perspective view of the endotracheal tube.
[0029] FIG. 1B is a detailed drawing of the distal end of the ETT
showing the novel features of the invention in a perspective
view.
[0030] FIG. 2 is a cross section of a human head showing the
endotracheal tube in use with a fiberoptic bronchoscope (the
proximal control and eyepiece assembly is not shown).
PREFERRED EMBODIMENT OF THE INVENTION
[0031] Referring now to FIGS. 1-2, an endotracheal tube 16 for use
during fiberoptic assisted intubations and with other intubating
stylets is shown. The manner of using the tapered ETT 16 utilizes
the same technique now being used with conventional ETT's for FOB
assisted intubation of the trachea. Specifically, one first places
the shaft of the FOB 20 (proximal control assembly not shown)
through the lumen of the ETT 16. Standard features incorporated
include a pilot balloon 12 that communicates with a tracheal
balloon 10 via tubing 14. The combined apparatus is placed in the
pharynx and the laryngeal structures are visually identified with
the FOB 20. The FOB 20 is passed through the vocal cords into the
trachea under bronchoscopic visualization. The ETT 16 can now be
slid down the shaft of the FOB 20 into the trachea using the shaft
of the FOB 20 as a stylet guide as depicted in FIG. 2. This last
maneuver is often where difficulty is encountered with a
conventional ETT due to its non-tapered shape and leading edge. Not
uncommonly, the leading edge will impinge on the laryngeal
structures. This may cause trauma, and or delay, and or abandonment
of the procedure. The tapered tip 8 of the described ETT is less
traumatically and more quickly placed, with greater success rates
due to the combination of (a) a smaller diameter distal end 8 which
is more closely contoured to the shaft of the FOB 20, and (b) the
absence of a leading edge. A tapered tip should be understood as a
structure whose distal end is significantly smaller in diameter
than that of the tube. There is no precise dimensional relationship
between the tube and distal end diameters, although an example is
provided below. The emphasis here is in avoiding a leading edge and
in reducing the size of the ETT'S distal end so that the previously
discussed problems are minimized or eliminated, all while still
providing respiratory function with no complicating resistance.
[0032] The ventilation holes 6 situated on the tapering portion of
the ETT allow ingress and egress of respiratory gases without undue
resistance to flow. They do so by a) increasing the cross sectional
area available for passage of respiratory gases, and b) when the
ETT 16 is in place within the trachea, by allowing enough clearance
between the tracheal wall and the ventilation holes 6 such that gas
exchange is not significantly impeded. Placing the ventilation
holes 6 on the tapered portion of the distal end 8, as opposed to
the non-tapered portion of the ETT 16 distal to the balloon 10,
also removes the holes 6 from the proximity of the balloon 10 and
thus the possibility of obstruction due to balloon 10 herniation.
Less preferred embodiments place the holes 6 partially on or just
off the tapered portion of the tube. Herniation can occur when the
balloon 10 covers and thus obstructs ventilation through holes 6
due to overexpansion. All functions that may be performed with a
conventional ETT, e.g. passage of a suction catheter or application
of positive end expiratory pressure, can be performed with the ETT
16. Additionally, ventilation can be performed through the holes 6
while the FOB 20 is in use and protruding through, and therefore
obstructing, the distal aperture 4. This would be impossible with a
standard, non-tapered ETT whose internal diameter is only slightly
greater than the FOB 20.
[0033] A preferred embodiment of a fiberoptic endotracheal tube 16
is illustrated in FIG. 1A. A standard universal adaptor 18 is
seated into a unitary endotracheal tube 16. The ETT 16 is
manufactured by a plastic injection technique using a soft medical
grade polymer such as polyvinyl chloride in the same fashion as are
standard ETT's. The most useful sizes for the ETT 16 (in adults)
are from 6.5 mm to 8.5 mm internal diameter, increasing in 0.5 mm
increments. FOB 20 are manufactured with a variety of standard
shaft sizes, 3.7 or 4.0 mm diameter being the most versatile and
common for adults. Therefore, for example, with a 3.7 mm FOB 20
protruding through the distal aperture 4, of a 8.0 mm ETT 16, fully
79 percent of the cross sectional luminal area of the non-tapered
portion of the ETT 16 remains available for ventilation. The
remaining cross sectional luminal area is 39.5 square millimeters,
which is slightly greater than a standard 7.0 ETT (38.47 square
millimeters). Endotracheal tubes for pediatric use, for example,
would be proportionately smaller.
[0034] Utilizing an ETT with a distal aperture 4 approximately 0.3
mm in diameter greater than the FOB 20 used as a stylet allows for
smooth action of the ETT 16 upon the FOB 20. Therefore, for use
with a 3.7 mm FOB , the distal aperture 4 can be manufactured with
an internal diameter of 4 mm. One can see, for example, using an
ETT 16 of standard internal diameter 8.0 mm allows a 50% reduction
in distal aperture 4 internal diameter relative to a non-tapered
ETT. These dimensions are by way of example only. They are subject
to variance based upon preferences of manufacturers and physicians.
The principle requirement in the different diameters of the ETT and
the FOB is smooth action between the two.
[0035] The distance from the distal tip of the ETT 16 to the distal
border of the balloon 10 when inflated is variable and is a
function of style of taper employed, i.e. straight or nipple shape.
In general the distance is approximately 22 mm, which is currently
utilized in a standard adult ETT.
[0036] FIG. 1B is a detailed illustration including the features of
this invention in a preferred embodiment. The distal tapered end 8
is shown terminating in a circular aperture 4 which is oriented
perpendicular to the long axis of the endotracheal tube. Therefore,
the ETT 16 does not have a leading edge. The ventilation holes 6
are situated on the tapering portion of the distal tapered end
8.
[0037] FIG. 2 is an illustration of the endotracheal tube 16 in use
with a fiberoptic bronchoscope 20 (control and eyepiece assembly
not shown), during the intubation process.
[0038] While my above description contains many specificities,
these should not be construed as limitations on the scope of the
invention, but rather as an exemplification of one preferred
embodiment thereof. Many other variations are possible. For
example, the distal aperture 4 need not be perfectly perpendicular
to the long axis of the ETT and consequently need not be perfectly
circular. The ETT itself need not be perfectly circular for that
matter and could be elliptical, for example. The requirement is
there not be a significant leading edge such that there is a risk
of the leading edge impinging on the larynx with regularity. The
aperture 4 may be of various sizes and shapes. The tapered end 8
can be of various shapes as opposed to the mammalian nipple shape
shown in the drawings. It could be, for example, a truncated
conical section, with or without a generally cylindrical, short
guide at the very tip of the taper.
[0039] The ventilation holes 6 can be of various number, size,
shapes, and locations, etc., so long as the structural integrity of
the ETT is maintained. Thus, for example, there could be two,
three, or four holes on the tapered portion. Those holes could be
circular, elliptical, or even triangular. In the instance where the
tapered tip comprised a mammalian nipple, the hole may even be
located on an untapered portion of the nipple. Still another
embodiment of the invention contemplates that the ventilation holes
are disposed on the constant diameter portion of the ETT, between
the tracheal balloon and the tapered tip. Thus the scope of the
invention should be determined by the appended claims and their
legal equivalents, rather than by the examples given.
* * * * *