U.S. patent number 3,628,536 [Application Number 04/850,530] was granted by the patent office on 1971-12-21 for tourniquet.
Invention is credited to Otto N. Glesne.
United States Patent |
3,628,536 |
Glesne |
December 21, 1971 |
TOURNIQUET
Abstract
A tourniquet for restricting the venous flow of blood is formed
by a strip of elastic material having a series of spaced apertures
adapted for selective engagement with an upstanding stud for
holding the tourniquet tightened around a body member. The
apertures are unevenly spaced to compensate for the stretch of the
strip so that substantially the same constricting pressure is
applied regardless of the size of the body member.
Inventors: |
Glesne; Otto N. (Fort Dodge,
IA) |
Family
ID: |
25308392 |
Appl.
No.: |
04/850,530 |
Filed: |
August 15, 1969 |
Current U.S.
Class: |
606/203 |
Current CPC
Class: |
A61B
17/1322 (20130101) |
Current International
Class: |
A61B
17/12 (20060101); A61B 17/132 (20060101); A61b
017/12 () |
Field of
Search: |
;128/327 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pace; Channing L.
Claims
I claim:
1. A tourniquet adapted to be placed in encircling relation on a
body member for restricting the venous flow of blood comprising a
strip of elastic material, fastening means carried by the strip
adjacent to a first end portion thereof, said strip having a
plurality of spaced apertures extending lengthwise thereof from a
point spaced from the fastening means and thence towards the second
end portion of the strip, said apertures being adapted for
selective engagement with the fastening means for exerting on a
body member a constricting pressure for restricting the venous flow
of blood, the optimum constricting pressure being provided when the
strip is tightened around a body member with the aperture nearest
to the fastening means in engagement therewith, the remaining
apertures being unevenly spaced to compensate for the stretch of
the strip when it is tightened around body members of larger sizes,
the spacings between successive apertures increasing in length
progressively by a substantially fixed increment beginning with the
spacing nearest to the fastening means whereby substantially the
same optimum predetermined constricting pressure will be exerted on
a body member regardless of its circumference.
Description
BACKGROUND OF THE INVENTION
This invention relates to constricting devices for medical usages
and more particularly it has reference to a tourniquet which is
wrapped and tightened around an arm or limp of a person in order to
distend the veins, generally the superficial but sometimes the
deeper veins. This is necessary in order to facilitate the puncture
of the veins with a needle for extracting a sample of blood or
effecting intravenous injection of desired material. Under prior
art practices, various types of tourniquets have been used such,
for example, as a piece of rubber tubing or strip which is wrapped
around a body member and tied or held in place with a clamp. Such
devices, however, have been unsatisfactory since they do not
consistently provide the optimum pressure to produce adequate
distension of the veins to permit easy and accurate insertion of a
needle, especially in the hands of relatively unskilled persons. In
addition, some of the prior art tourniquets are reliable and
cumbersome in use and frequently cause discomfort to the
patient.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a tourniquet of
the type described which will, when in use, apply to the arm or
limb substantially the same predetermined optimum constricting
pressure regardless of the size of the arm or limb so that the
veins will be adequately distended to permit accurate and easy
insertion of a needle. Other objects are to provide a tourniquet
which will be relatively simple in structure yet efficient in
operation and constructed so that it may be quickly and easily
applied to or removed from a body member.
In accordance with the invention, a tourniquet is formed of a flat
strip of elastic plastic material having fastening means such as an
upstanding stud secured thereto adjacent to one end thereof. The
strip is provided with a plurality of spaced apertures which extend
lengthwise of the strip from a point spaced from the stud and are
adapted for selective engagement with the stud for holding the
tourniquet in constricting relation around a body member. In order
to compensate for the greater stretch of the strip when applied to
body members of larger sizes, the spacings between successive
apertures increase progressively beginning with the aperture
nearest to the stud. Because of this arrangement of the spacings
and apertures, the tourniquet will, when in use, consistently
provide substantially the same predetermined optimum constricting
pressure, within a small range, so that adequate distension of the
veins is produced regardless of the circumference of the body
member to which it is applied.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a plan view of the tourniquet embodying the
invention.
FIG. 2 is an edge view thereof.
FIG. 3 is a perspective view showing the relation of the parts when
the tourniquet is in use.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the invention is shown in the drawing
wherein 10 indicates a tourniquet which is formed of a flat strip
of elastic material. Secured to the end portion 11 of the strip is
suitable fastening means such as the upstanding metal stud 12. A
plurality of spaced apertures 13 are formed in the strip in
substantial alignment with the stud 12 and extending lengthwise of
the strip 10 from a point spaced from the stud 12 and thence
towards the end portion 14 of the strip. The apertures 13 are
adapted to be selectively engaged with the stud 12 to hold the
strip 10 in tightened encircling relation with a body member. The
spacings between successive apertures increase progressively in
length beginning with the aperture which is nearest to the stud 12,
for a purpose to be described hereinafter.
In use, the tourniquet is wrapped around a body member with
portions of strip 10 in side-by-side parallel relation snugly
engaging the member and with an aperture substantially adjacent to
the stud 12. With an end of the strip 10 held in each hand, the
strip is tightened by an amount which is produced by moving the
strip a distance equivalent to about 2 or 21/2 spacings, for
example, and then securing the strip in tightened position by
forcing the adjacent aperture down over the stud 12. The tourniquet
may be quickly released by raising the strip 10 to move the engaged
aperture off the stud 12.
The average arterial blood pressure for a adult varies between
about 100-200 mm. of mercury whereas the average venous pressure
for an adult is about 15-25 mm. of mercury. In order to produce
adequate distention of the superficial veins for the easy and
accurate insertion of a needle, the tourniquet should not produce a
constricting pressure greater than about 90 mm. Hg. since such a
greater pressure would unduly impede or stop the arterial flow of
blood. The tourniquet must, however, produce a pressure which
exceeds the venous pressure and also overcomes the resistance
provided by tissue, such as fat, in the body member to which it is
applied. The optimum pressure produced by a tourniquet for the
adequate distention of the superficial veins to permit easy and
accurate insertion of a needle varies from about 60-90 mm. Hg. for
an adult.
For optimum results, the constricting pressure of 60-90 mm. Hg.
should be provided consistently whether the tourniquet is applied
to a body member having a large or small circumference. The
predetermined optimum constricting pressure on a body member of any
size can be obtained by tightening the strip 10 through relative
movement of adjacent parts of the encircling strip 10 a distance
equal to, for example, two or two and one-half spacings between
successive apertures 13.
When the tourniquet is applied to and tightened on a large arm, the
strip 10 will be stretched or expanded more than when applied to a
smaller arm. Hence, if substantially the same constricting pressure
of 60-90 mm. Hg. is to be applied to an arm regardless of its
circumference, it is essential that some compensation or allowance
be made for the additional stretch of the strip 10. This is
accomplished by spacing the apertures 13 unevenly so that beginning
with aperture A, nearest the stud 12, the spacings between
successive apertures increase progressively. Since the stretch of
the material in strip 10 substantially varies directly as the force
applied, the optimum results are provided by making the spacings
between successive apertures 13 increase by a substantially fixed
increment, such, for example, as 0.015 inch in the specific
embodiment of the invention hereinafter described. Spacings between
apertures may be varied depending on the size and material of the
strip but it is essential that there be some progressive increase
in spacing lengths between at least some of the apertures with the
longest spacing being near to the end portion 14 of the strip.
In one embodiment of the invention which has been made and used
successfully, the tourniquet is formed of a flat extruded strip of
polyurethane 80A Durometer. The strip is 24 inches long, 0.656
inches wide and 0.078 inches thick. The upstanding metal stud 12 is
located about 4 inches from the strip end 11 and the apertures 13
each have a diameter of about 0.156 inches so that they may be
forced into releaseable holding engagement with the head on stud
12. The row of apertures 13 extends lengthwise of and along the
central portion of the strip 10 and in alignment with stud 12. The
aperture indicated at A is nearest to and about 7 inches from the
stud 12. The distance between the centers of A and the next
aperture B is 0.530 inches; the distance between the centers of
aperture B and the next aperture C is 0.545 inches; the distance
between the aperture C and the next aperture D is 0.560 inches and
so on with the distance between successive apertures increasing
progressively by a substantially constant increment of 0.015
inches.
In order that the optimum constricting pressure of 60-90 mm. Hg.
will be provided when the tourniquet of the next preceding
paragraph is tightened around a body member of minimum size with
the aperture A engaged over the stud 12, the elasticity of the
plastic strip is modified by providing eight parallel pairs of
holes 15 each having a diameter of 0.109 inches and located between
the aperture A and the stud 12. Suppose, for example, that the
tourniquet is wrapped around a larger body member so that the strip
snugly engages the member and the aperture A is adjacent to the
stud 12. Then a tightening of the tourniquet by pulling the ends of
the strip so that the aperture C is engaged over the stud 12 will
serve to produce the optimum constricting pressure of 60-90 mm. Hg.
Because of the progressively increasing lengths of the spaces
between the apertures 13, beginning with the first aperture A, a
substantially constant predetermined pressure, within a range of
60-90 mm. Hg., will be provided regardless of the circumference of
the body member to which the tourniquet is applied. The structural
dimensions and data for the above-described tourniquet were
determined experimentally and resulted in a device which has been
very successful in use.
The tourniquet may be made of any suitable elastic material and the
strip may be made in any suitable thickness, width and length. A
plastic material such as polyurethane has proven to be highly
satisfactory because of its resistance to deterioration and
consequent retention of its elastic properties. Whether in the
hands of skilled or unskilled technicians, the tourniquet of the
invention will consistently provide a predetermined optimum
constricting pressure on a body member regardless of its size. The
tourniquet is wrapped snugly around a body member with the end
portions of the strip in side-by-side relation and, using the stud
12 as a guide, the strip is tightened by pulling the ends of the
strip to move a distance of a substantially fixed number of spaces
to consistently provide the optimum constricting pressure. For the
tourniquet which has been described specifically herein, the
optimum pressure is provided by tightening the strip by a movement
equivalent to two or two and one half spaces between apertures.
The series of apertures may be serially numbered on the strip 10 to
facilitate the application of the tightening pull by moving the
parts a certain fixed number of spaces such as two to two and one
half in the example herein given. The number of spaces to be moved
to provide a consistent predetermined optimum constricting pressure
will of course, depend on the dimensions and material of the strip
10 and the spacings between the apertures. For use on a child, the
tourniquet would, of course, be appropriately modified in
structure. Various modifications may be made without departing from
the spirit of the invention as pointed out in the appended
claims.
* * * * *