U.S. patent number RE37,861 [Application Number 09/654,222] was granted by the patent office on 2002-09-24 for laryngoscope blade.
Invention is credited to Cary N. Schneider.
United States Patent |
RE37,861 |
Schneider |
September 24, 2002 |
Laryngoscope blade
Abstract
An improved laryngoscope blade for use with a conventional
laryngoscope handle and conventional means for illumination. The
improvements to the blade include a small reverse curve at the tip
of the blade to better visualize the depth of insertion of the
blade, include a greater width of the portion of the blade proximal
to the handle to provide improved means for controlling the tongue,
and include a more gradual curvature of the blade to better conform
to the shape of the airway opening when the patient is properly
positioned for laryngoscopy. The blade may also include a vertical
wall which may be thickened to serve as a bite block, and raised
areas to define grooves on the surface of the blade for insertion
of an endotracheal tube and/or a suction catheter.
Inventors: |
Schneider; Cary N. (Plano,
TX) |
Family
ID: |
21952570 |
Appl.
No.: |
09/654,222 |
Filed: |
August 31, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
048068 |
Mar 26, 1998 |
05888195 |
Mar 30, 1999 |
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Current U.S.
Class: |
600/199; 600/191;
600/194 |
Current CPC
Class: |
A61B
1/06 (20130101); A61B 1/267 (20130101) |
Current International
Class: |
A61B
1/267 (20060101); A61B 001/267 (); A61B
001/06 () |
Field of
Search: |
;600/199,191,194,190 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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522807 |
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Oct 1953 |
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BG |
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0184588 |
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Jun 1986 |
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EP |
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2102294 |
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Feb 1983 |
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GB |
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2102679 |
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Feb 1983 |
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GB |
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94/03101 |
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Feb 1994 |
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WO |
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97/17885 |
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May 1997 |
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WO |
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Primary Examiner: Hirsch; Paul J.
Claims
I claim:
1. An improved blade for a laryngoscope having a handle,
comprising: a) an arcuate body having a proximal portion including
a proximal end and a distal portion including a distal end, the
body being substantially flat, having a convex top surface and a
concave bottom surface, said proximal portion being configured and
dimensioned to the width of a patient's mouth in order to depress
and control the tongue of a patient during insertion of an
endotracheal tube, said distal portion tapering in width from the
proximal portion to the distal end, the distal portion being
configured and dimensioned to enter a throat of the patient in
order to raise the epiglottis for insertion of the endotracheal
tube, wherein a median axis extending longitudinally through the
proximal portion of the bottom surface of said arcuate body and a
median axis extending longitudinally through the distal portion of
the bottom surface of said arcuate body intersect to define an
angle between and inclusive of 5 and 25 degrees; b) means for
connection to the laryngoscope handle connected to the proximal end
of said arcuate body; c) a tip at the distal end of said arcuate
body, the tip having a point of inflection and a short tip
extension from said point, the extension being substantially
concave upwards; and d) means for illuminating the distal end of
said arcuate blade.
2. The improved blade for a laryngoscope according to claim 1,
wherein the top surface and the bottom surface of said arcuate body
have a proximal portion having a width greater than 2 cm, the
proximal portion having a substantially oblong shape, and a distal
portion which tapers in width from the proximal portion to a width
of not greater than 2 cm at the distal end of said arcuate
body.
3. The improved blade for a laryngoscope according to claim 1,
wherein the top surface and the bottom surface of said arcuate body
have a proximal portion having a width of between 2 cm and 6 cm,
the proximal portion having a substantially oblong shape, and a
distal portion which tapers in width from the proximal portion to a
width not greater than 2 cm at the distal end of said arcuate body,
wherein the proximal portion of said arcuate body is configured and
dimensioned to the width of a patient's mouth and the distal
portion is configured and dimensioned to enter the patient's
throat.
4. The improved blade for a laryngoscope according to claim 1,
further comprising at least one raised area on the convex top
surface of said arcuate body defining a plurality of grooves
whereby the larynx may be visualized and whereby and endotracheal
tube or suction catheter may be passed over the blade and inserted
into the trachea.
5. The improved blade for a laryngoscope according to claim 4,
further comprising a vertical wall having its bottom edge attached
to an edge of the proximal portion of said arcuate body.
6. The improved blade for a laryngoscope according to claim 5,
wherein said vertical wall is dimensioned and configured in
thickness to serve as a bite block whereby the patient is prevented
from damaging his teeth by biting said blade and from preventing
intubation by biting the tube.
7. The improved blade for a laryngoscope according to claim 1,
wherein said means for connection to the laryngoscope handle is
attached to the bottom surface of said arcuate body and pivotally
mounts the blade to the laryngoscope handle so that the blade is
substantially parallel to the handle when not in use and
substantially perpendicular to the handle to form an L-shape in
use..Iadd.
8. An improved blade for a laryngoscope having a handle,
comprising: a) an arcuate body having a proximal portion including
a proximal end and a distal portion including a distal end, the
body being substantially flat, having a convex top surface and a
concave bottom surface, said proximal portion being configured and
dimensioned to the width of a patient's mouth in order to depress
and control the tongue of a patient during insertion of an
endotracheal tube, said distal portion tapering in width from the
proximal portion to the distal end, the distal portion being
configured and dimensioned to enter the throat of a patient in
order to raise the epiglottis for insertion of the endotracheal
tube, wherein a median axis extending longitudinally through the
proximal portion of the bottom surface of said arcuate body and a
median axis extending longitudinally through the distal portion of
the bottom surface of said arcuate body intersect to define an
angle between and inclusive of 5 and 25 degrees; b) means for
connection to the laryngoscope handle connected to the proximal end
of said arcuate body; and c) means for illuminating the distal end
of said arcuate blade..Iaddend..Iadd.
9. The improved blade for a laryngoscope according to claim 8,
wherein the top surface and the bottom surface of said arcuate body
have a proximal portion having a width greater than 2 cm, the
proximal portion having a substantially oblong shape, and a distal
portion which tapers in width from the proximal portion to a width
of not greater than 2 cm at the distal end of said arcuate
body..Iaddend..Iadd.
10. The improved blade for a laryngoscope according to claim 8,
wherein the top surface and the bottom surface of said arcuate body
have a proximal portion having a width of between 2 cm and 6 cm,
the proximal portion having a substantially oblong shape, and a
distal portion which tapers in width from the proximal portion to a
width not greater than 2 cm at the distal end of said arcuate body,
wherein the proximal portion of said arcuate body is configured and
dimensioned to the width of a patient's mouth and the distal
portion is configured and dimensioned to enter the patient's
throat..Iaddend..Iadd.
11. The improved blade for a laryngoscope according to claim 8,
further comprising at least one raised area on the convex top
surface of said arcuate body defining a plurality of grooves
whereby the larynx may be visualized and whereby an endotracheal
tube or suction catheter may be passed over the blade and inserted
into the trachea..Iaddend..Iadd.
12. The improved blade for a laryngoscope according to claim 11,
further comprising a vertical wall having its bottom edge attached
to an edge of the proximal portion of said arcuate
body..Iaddend..Iadd.
13. The improved blade for a laryngoscope according to claim 12,
wherein said vertical wall is dimensioned and configured in
thickness to serve as a bite block whereby the patient is prevented
from damaging his teeth by biting said blade and from preventing
intubation by biting the tube..Iaddend..Iadd.
14. The improved blade for a laryngoscope according to claim 8,
wherein said means for connection to the laryngoscope handle is
attached to the bottom surface of said arcuate body and pivotally
mounts the blade to the laryngoscope handle so that the blade is
substantially parallel to the handle when not in use and
substantially perpendicular to the handle to form an L-shape in
use..Iaddend..Iadd.
15. The improved blade for a laryngoscope according to claim 8,
wherein the distal end of said arcuate body includes a tip having a
point of inflection and a short tip extension from said
point..Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to laryngoscopes, and particularly to
an improved blade for a laryngoscope.
2. Description of the Related Art
While a laryngoscope may be used to visually examine the larynx,
its more important function is to aid endotracheal intubation. The
need for intubation may arise during a controlled situation, such
as surgery, or in a crisis situation when the patient is unable to
breathe adequately and requires a resuscitation bag or mechanical
ventilation. During intubation, a flexible tube is inserted through
the nasal or oral cavity, passed through the larynx, and into the
trachea for the administration of gases. The larynx may be viewed
as a chamber bounded superiorly by the epiglottis, inferiorly by
the vocal cords which cover the opening to the trachea, anteriorly
by the thyroid cartilage or Adam's apple, and posteriorly by a
portion of the pharynx. The epiglottis is a lamella or leaf-like
plate of cartilage which extends dorsally like a loose lid over the
larynx, helping to protect the trachea by preventing food from
entering the trachea during swallowing.
In order to intubate the patient, the intubator (either a physician
or paramedic) must visualize the epiglottis and the vocal cords to
watch the tube go past the vocal cords of the patient. The
laryngoscope generally comprises a handle, a blade which is used to
move the patient's tongue out of the way and to lift the epiglottis
to expose the vocal cords, and a light source to illuminate the
glottis and vocal cords.
The two most widely used blades in the current state of the art are
known as the Miller blade and the Macintosh blade. The Miller blade
is a substantially straight blade with a curved tip, the curve
commencing approximate 2 inches from the end of the blade. The
Macintosh blade is a blade which is curved for substantially its
entire length (U.S. Pat. No. 2,354,471 issued Jul. 25, 1944). In
use the Miller blade is inserted along the longitudinal axis of the
larynx past the epiglottis to lift it enough to visualize the vocal
cords and slip the tube through the cords into the trachea. The
Macintosh blade is inserted on a combination of the axis of the
oral cavity and the longitudinal axis of the larynx, the tip being
placed in the vallecula, which are shallow depressions in the
membranous folds and tissue between the epiglottis and the root of
the tongue. By applying an upward pressure at the vallecula, the
epiglottis is raised enough to visualize the vocal cords.
While intubation may be done with the existing blades, several
shortcomings in the existing blades have prompted various efforts
to improve the blades. Efforts to improve the curvature of the
blade are shown in U.S. Pat. No. 5,003,962, issued Apr. 2, 1991 to
Choi, and U.S. Pat. No. 5,406,941 issued Apr. 18, 1995 to Roberts.
Choi describes a blade having three straight segments, the second
segment at a 20 degree angle to the first, and the third at a 30
degree angle to the second. The Roberts patent describes a flat,
flexible blade, having a cam attached to one side of the blade so
the curvature may be adjusted by rotating the cam. U.S. Pat. No.
3,856,001 issued to O. C. Phillips Dec. 24, 1974 describes a
Jackson or straight blade having a U-shaped cross-section and a tip
similar to the Miller blade, curving about 2 inches from its
end.
Efforts to improve the tip are shown in U.S. Pat. No. 4,573,451,
issued Mar. 4, 1986 to Bauman, and U.S. Pat. No. 5,603,688 issued
Feb. 18, 1997 to Upsher. The Bauman patent describes a blade made
of plastic or metal, thinned or hinged at the tip, with a push rod
and a ratchet to change the angle of the tip. Upsher's patent shows
a blade having a hollow tube in the blade for insertion of the
endotracheal tube, with an extension of one side of the tip to
prevent the natural curve of the endotracheal tube from causing the
end of the endotracheal tube to leave the field of vision after
exiting the hollow tube in the blade.
Efforts to improve the illumination of the larynx and vocal cords
are shown in U.S. Pat. No. 3,638,644 issued Feb. 1, 1972 to Reick,
and U.S. Pat. No. 3,771,514 issued Nov. 13, 1973 to Huffman, et al.
The Reick patent shows a light bulb in the handle with a plastic
light conduit extending through the blade. The Huffman patent shows
a one-piece handle and blade, the blade having a prism mounted
thereon for reflecting and diffusing the light.
U.S. Pat. No. 5,036,835 issued Aug. 6, 1991 to Filli describes a
blade which slides to adjust the length of the blade. U.S. Pat. No.
5,065,738 describes a sheath fitting over the blade to protect the
patient's teeth, gums, oral mucosa and epiglottis from damage
during insertion of the laryngoscope.
Various patents show a disposable blade, including European Patent
0184588 published Jun. 18, 1986, describing a disposable blade with
a light source in the handle; International Patent 94/03101
published Feb. 17, 1994, describing a disposable blade with the
light source in the blade; and International Patent 97/17885
published May 22, 1997, showing a disposable blade with a channel
in the blade for the passage of fluids.
Construction techniques for incorporating a channel or path for a
bulb and light cable or guide are shown in U.K. Patent 2,102,294
published Feb. 2, 1983, describing two L-shaped members pull
together in overlapping fashion to form a channel for the light and
cable, and U.K. Patent 2,102,679 describing a blade made by placing
a fiber optic bundle in an injection mold and forming a plastic
blade by injecting the mold with plastic.
None of the above inventions and patents, taken either singularly
or in combination, is seen to describe the instant invention as
claimed. Thus an improved laryngoscope blade solving the
aforementioned problems is desired.
The present invention exploits the principle used by health care
providers to widen the airway in preparation of intubation. When
the head is in the normal anatomic position, the airway is narrow.
It is therefore recommended that the intubator align the laryngeal
and pharyngeal axes; unlike the present invention, in this position
neither the Miller blade nor the Macintosh blade present the
optimum angle for viewing and intubating the patient. Although the
Macintosh blade is curved, the curvature is greater than the
curvature of the airway, hence it does not permit optimal
visualization of the vocal cords because the intubator can't see
around the curvature of the blade. Moreover, with both the Miller
blade and the Macintosh blade, the intubator has difficulty
visualizing the tip of the blade, again due to the shape of the
blade and the shape of the airway. Consequently the intubator has
difficulty determining when the tip is in proper position.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the invention to provide
an improved laryngoscope blade which produces better visualization
of the larynx through adjusting the curvature of the blade.
The present invention is a laryngoscope blade which is generally
curved throughout its length. However, the curvature is more
gradual than the curvature of the conventional Macintosh blade.
The invention also provides the tip of the blade with a small
reverse curve at the tip of the blade, in order to permit better
visualization of the position of the end of the blade.
The laryngoscope blade of the present invention further includes a
proximal part which is contoured to the width and shape of the
mouth, having a width of up to 6 cm., in order to provide better
control of the tongue during laryngoscopy. This configuration is
unlike the part of a conventional laryngoscope blade proximal to
its connection with the handle, which is used to move the tongue
away from the airway and prevent the tongue from obstructing
visualization of the larynx. Therefore, present laryngoscope blades
have a maximum width of approximately 2 cm.
It is a further object of the invention to provide improved
elements and arrangements thereof for the purposes described which
is inexpensive, dependable and fully effective in accomplishing its
intended purposes.
These and other objects of the present invention will become
readily apparent upon further review of the following specification
and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a right side view of the improved laryngoscope blade
according to the present invention.
FIG. 2 is a top plan view of the improved laryngoscope blade
according to the present invention.
FIG. 3 is a top perspective view of the improved laryngoscope blade
according to the present invention.
FIG. 4 is an end view of the improved laryngoscope blade according
to the present invention.
FIG. 5 is an environmental perspective view of an alternative
embodiment of the invention showing a "bite block".
FIG. 6 is an end view of an alternative embodiment of the invention
showing a "bite block" and raised areas on the surface of the blade
defining grooves.
FIG. 7 is a top perspective view of an embodiment of the invention
with a vertical wall and a raised area defining grooves on the
blade.
Similar reference characters denote corresponding features
consistently throughout the attached drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention relates to a laryngoscope with an improved
blade. A conventional laryngoscope typically comprises a handle, a
blade, and a light source. The blade is usually pivotally mounted
on the blade so that the blade is substantially parallel to the
handle when not in use, and is substantially perpendicular to the
handle to form an L-shape in use.
A variety of arrangements may be used to provide a light source.
Power for the light source is usually provided by batteries in the
handle. The light source itself may be in the handle with a conduit
mounted on the blade, or the light source itself may be mounted on
the blade. The connector used to mount the blade may vary depending
on the nature of the light source.
The improvement of the present invention does not relate to the
handle, the light source, or the means connecting the blade to the
handle. As shown more particularly in FIGS. 1 through 4, the
present invention relates to the laryngoscope blade 10. The
improved blade is designed to be used with a conventional handle 12
(shown in phantom in the drawings), means for illumination 14, and
means 16 for connecting the blade 10 to the handle 12, all of which
are well known in the prior art. Although the light source 14 is
shown mounted on the top surface of the blade 10 in FIGS. 1 through
3, it will be appreciated that the light source 14 may be mounted
alternatively on the edge of the blade 10, or in the handle 12 with
a light-transmitting conduit towards the end of the blade 10, etc.
The nature and location of the means for illumination 14 are not
critical, provided that there are some means for illuminating the
distal end of the blade 10 and an appropriate means 16 for
connecting the blade 10 to the handle 12 adapted to the particular
light source used.
The improved blade 10 has an arcuate body 20 having a proximal end
22 and a distal end 24, the body 20 being substantially flat,
having a top surface 26 which is convex upwards as seen from a side
view, and a bottom surface 28 concave downwards. The means 16 for
connecting the blade 10 to the handle 12 is connected to the bottom
surface 28 of the proximal end 22 of the body 20. The blade 10 has
a tip 30 at the distal end 24 of the body 20, the tip 30 having a
point of inflection as seen from a side view, most clearly seen in
FIG. 1, and a short tip extension 32 being concave upwards. The tip
extension 32 provides the physician or other person performing the
intubation with a visual means for determining the depth to which
the blade 10 has been inserted into the patient's throat, and can
be rested on the top of the epiglottis, both features being an
improvement on prior laryngoscope blades.
The top surface 26 and the bottom surface 28 of the blade 10 have a
proximal portion 22a towards the proximal end 22 of the body 20
having a width of between 2 cm and 6 cm in the preferred
embodiment, the proximal portion 22a having a substantially oblong
shape, so the that proximal portion 22a conforms to the width of an
adult patient's mouth. The top surface 26 and the bottom surface 28
have a distal portion 24a towards the distal end 24 of the body 20.
The width of the blade 10 tapers from the proximal portion 22a to a
width not greater than approximately 2 cm at the distal end 24, so
that the distal end 24 may be inserted in the patient's throat.
It is contemplated that the blade 10 will be made in various sizes,
with perhaps the width of the proximal portion of the body 20
ranging between 2 cm and 6 cm in 0.5 cm increments, while the
distal end 24 perhaps ranges in width from 0.5 cm to 2 cm for the
adult patient. For children and infants, the widths may be
proportionally shorter, e.g., 1 cm for children and 0.5 cm f or
infants. In an alternative embodiment, the proximal end 22 of the
block 10 may have a width greater than 6 cm to accommodate patients
with a very large oral cavity. The greater width of the improved
blade 10 at its proximal end 22 provides the physician or other
intubator an improved means for controlling the patient's tongue
during the intubation procedure.
In order to derive full advantage from the improved tip 30 and tip
extension 32 of the present invention, the curvature of the arcuate
body 20 should fall within certain limits. The conventional
Macintosh blade has a rather steep curvature in order to facilitate
passage over the tongue and to avoid depression of the tongue which
might otherwise cause restriction of the visible aperture of the
larynx. However, the conventional Macintosh is curved too much.
Occasionally the physician or intubator can't see around the
curvature of the Macintosh blade to view the larynx.
The blade of the present invention has a gentle curvature. When
intubating a patient, it is recommended that the patient be
positioned to align an axis extending through the pharynx with an
axis extending through the larynx, or in other words, the opening
to the airway is widened by straightening the throat. When so
positioned, the angle between the pharyngeal axis and the laryngeal
axis is approximately 5.degree. to 25.degree.. The blade 10 of the
present invention is designed to conform with this angle.
Viewing the blade 10 from the side, a median axis M extending
longitudinally through the bottom surface of the proximal portion
22a of the arcuate body 20 intersects with a median axis A
extending longitudinally through the distal portion 24a of the body
20 to define an angle .theta.. In the blade 10 of the present
invention, this angle .theta. is between 5.degree. and 25.degree.,
preferably approximately 15.degree.. The more gradual curvature of
the blade 10 of the present invention facilitates viewing the tip
extension 32 when the blade 10 is inserted in the patient's
throat.
The blade 10 of the present invention is further improved by the
addition of raised areas 40 defining grooves on the top surface 26
of the blade 10, as seen in FIGS. 6 and 7. One of the grooves
defined by the medial raised area 40 shown in the Figures may be
used for guiding a tube over the top surface 26 of the blade 10 for
insertion into the trachea, while the other groove preserves a line
of sight to visualize the larynx and glottis.
The blade may be further improved by the addition of a vertical
wall 50 having its bottom edge attached to the edge of the proximal
portion 22a of the arcuate body 20 as shown in FIGS. 6 and 7. The
vertical wall 50 may serve as a convenient location for mounting of
the means for illumination 14. When the vertical wall is thickened,
it serves as a bite block to prevent the patient from damaging his
teeth or preventing intubation by involuntarily biting the blade 10
or the tube. The additional raised area 40 shown adjacent to the
vertical wall 50 in FIG. 6 might be used for insertion of a suction
catheter to move any liquids in the mouth or throat obstructing
visualization of the larynx.
In operation, for an endotracheal intubation, the patient's
position is adjusted to align the airway for intubation. Unlike the
Macintosh and Miller blades, which are inserted in the right side
of the patient's mouth, the blade 10 of the present invention is
inserted medially towards the center of the mouth, by virtue of the
width of the blade 10 approaching the width of the mouth.
In further contrast, the tip of the Macintosh blade is inserted in
the vallecula between the epiglottis and the base of the tongue,
while the curved tip of the Miller blade is inserted behind the
posterior edge of the epiglottis. The blade 10 of the present
invention may be used in either manner, depending on the anatomy of
the patient and the preference of the physician. Once the tip 30 is
inserted in the proper location, the epiglottis is raised to open
the airway to permit the insertion of the tube. The proper
positioning of the tube in the airway is verified by x-ray or other
means.
It is to be understood that the present invention is not limited to
the embodiments described above, but encompasses any and all
embodiments within the scope of the following claims.
* * * * *