U.S. patent number 3,785,367 [Application Number 05/234,267] was granted by the patent office on 1974-01-15 for arterial blood sampler.
This patent grant is currently assigned to Pharmasel Division of American Hospital Supply Corporation. Invention is credited to Robert F. Fortin, Larry A. Sims.
United States Patent |
3,785,367 |
Fortin , et al. |
January 15, 1974 |
ARTERIAL BLOOD SAMPLER
Abstract
A blood sampler with an arterial needle and a collapsed flexible
blood pouch that snaps into inflated condition with arterial blood
pressure but not with venous blood pressure. This provides a visual
indication that an artery and not a vein has been punctured.
Inventors: |
Fortin; Robert F. (Santa Paula,
CA), Sims; Larry A. (Hermosa Beach, CA) |
Assignee: |
Pharmasel Division of American
Hospital Supply Corporation (Glendale, CA)
|
Family
ID: |
22880649 |
Appl.
No.: |
05/234,267 |
Filed: |
March 13, 1972 |
Current U.S.
Class: |
600/576; 600/580;
600/584 |
Current CPC
Class: |
A61B
5/1535 (20130101); A61B 5/15003 (20130101); A61B
5/150244 (20130101); A61B 5/150259 (20130101); A61B
5/150732 (20130101); A61B 5/150213 (20130101); A61B
5/150236 (20130101); A61B 5/150519 (20130101); A61B
5/150389 (20130101); A61B 5/150221 (20130101) |
Current International
Class: |
A61B
5/15 (20060101); A61b 005/14 () |
Field of
Search: |
;128/2F,2R,DIG.5,2.5D,214F,216,215,218R,276 ;73/409 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
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32,825 |
|
Jan 1924 |
|
DK |
|
279,270 |
|
Jan 1965 |
|
AU |
|
Primary Examiner: Howell; Kyle L.
Attorney, Agent or Firm: Barger; Larry N. Merrick; Robert
T.
Claims
We claim:
1. An artery-vein distinguishing blood collection device
comprising: a flexible pouch with an interior surface for contact
with blood and an exterior surface for contact with atmospheric
air; a needle of sufficient length for puncturing a human artery,
which needle has a blunt rear end connected in flow communication
with the interior surface of the pouch, said needle extending
outwardly therefrom to a sharpened artery-puncturing forward end of
the needle; a rigid transparent sleeve surrounding the pouch;
adapter means rigidly mounting the needle on the rigid sleeve; said
device having atmospheric vent means communicating with the
exterior surface of the pouch; said flexible pouch having a
structure that defines a first visible position relative to the
rigid sleeve at a pressure drop from the internal surface to the
external surface of the pouch in the range of 3.7 to 8 mm. Hg, and
the pouch has structure defining a substantially different second
visible position relative to the sleeve when there is a pressure
drop from the inner surface to the outer surface of the pouch in
the range of 90 to 150 mm. Hg, whereby the two substantially
different structural positions are readily visible through the
transparent sleeve to distinguish whether the needle is in an
artery or a vein.
2. The combination as set forth in claim 1, wherein the first
structural position includes a space between the flexible pouch and
the rigid sleeve at a pressure drop of 3.7 to 8 mm. Hg.
3. The combination as set forth in claim 2, wherein the second
structural position includes annular physical contact between the
flexible pouch and the rigid sleeve at a pressure drop of 90 to 150
mm. Hg.
4. The combination as set forth in claim 1, wherein the first
structural position includes a toggle cone section of the pouch
with a convex inner surface facing the needle's rear end, with
structure resists inversion of its convex inner surface into a
concave structure with a pressure drop of 3.7 to 8 mm. Hg applied
from the inner surface to the outer surface of the pouch.
5. The combination as set forth in claim 4 wherein the second
structural position includes the cone section with its inner
surface inverted to a concave structure with a pressure drop of 90
to 150 mm. Hg applied from the inner surface to the outer
surface.
6. An artery-vein pressure distinguishing blood collecting device
comprising in combination:
deformable pouch means having an interior surface for contact with
a pressurized blood sample and an exterior surface subject to
atmospheric pressure;
tubular needle means of a length sufficient to puncture an artery
and having a distal end sharpened to penetrate an artery and an
opposite end portion connected in flow communication with the
interior surface of the deformable pouch means for subjecting the
same to arterial blood pressure, said pouch means being constructed
and arranged to be deformable to one condition when subject to
internal pressures in the range of 3.7 to 8 mm. Hg and being
constructed and arranged to be snap-action deformable to another
readily discernable condition when subject to internal pressures in
the range of 90 to 150 mm. Hg, which ranges of pressures
respectively comprise the venous and arterial pressures normally to
be distinguished;
adapter means including means for mounting the needle means in an
operative position;
a rigid sleeve circumposed about said pouch means and including
means so that the pouch can be observed in any of its deformed
conditions.
7. The structure as claimed in claim 6 in which said pouch
comprises an elongated flexible, resilient sack extending
longitudinally of said sleeve from said needle means and
substantially the length of said sleeve, said sack having a normal
substantially reduced cross section as compared with said sleeve
cross section, said sack in the one condition when subjected to
internal pressure ranging from 3.7 to 8 mm. Hg being greater in
cross section than its normal relaxed condition and substantially
spaced from the inner surface of said sleeve, said sack having
another deformed condition when subject to internal pressures
ranging from 90 to 150 mm. Hg in which the sack cross section
substantially conforms to the cross section of said sleeve.
8. The structure as claimed in claim 7 in which said sleeve is open
at the end opposite said needle, said sack protruding toward and
disposed adjacent the open end thereof, the open end of said sleeve
subjecting the outer surface of said sack to atmospheric pressures,
said rigid sleeve and adapter including means rigidly and
detachably connecting the sleeve to the adapter means.
9. The structure as claimed in claim 6 in which said flexible pouch
comprises a conical barrier extending transversely of the sleeve
and closing off the same and forming a compartment open to the
needle means for receiving pressurized blood therein, said conical
barrier having a normal position in which an apex portion thereof
is directed towards and substantially closes the compartment in the
direction toward which it is directed, said conical barrier being
invertible upon itself axially of the sleeve to substantially
double the capacity of said compartment when subject to pressures
in the range of 90 to 150 mm. Hg.
10. The structure as claimed in claim 9 in which said sleeve
includes an open rear end for receiving piston means whereby a
blood sample in said compartment may be expressed therefrom.
11. The structure as claimed in claim 10 in which said sleeve
includes vent means for communicating atmospheric pressure into
said sleeve and at the outer surface of said pouch opposite the
compartment.
12. The structure as claimed in claim 11 in which said vent means
includes closure means for closing off the vent means whereby said
piston means can express the blood sample from the compartment by
re-reversing the conical barrier.
13. The structure as claimed in claim 9 in which said adapter means
comprises a conical portion having an inner surface substantially
complementary to the inner surface of said conical barrier, the
axial length of said conical barrier being such that the barrier
has a substantially toggle action when subjected to the range of
pressures from 90 to 150 mm. Hg whereby axial inversion thereof
occurs due to arterial blood pressures and observation is readily
discernable.
14. The structure as claimed in claim 13 in which said conical
barrier includes a peripheral portion sandwiched between a
peripheral portion of said adapter and an end portion of said
sleeve.
Description
BACKGROUND
In diagnosing a patient's illness, blood samples are often taken
and analyzed in a laboratory. By far the most common blood sample
taken is a "venous" blood sample. This sample is usually taken with
an evacuated vial connected to a hypodermic needle or with a
hypodermic syringe. The vacuum in these devices sucks the blood
from the patient into the vial or syringe.
Recently, it has become more prevalent to also take an "arterial"
blood sample for testing blood gases and pH, etc. When taking an
arterial blood sample it is very important to know that the blood
sample is from an artery and not a vein. The medical parameters of
arterial blood, such as the partial pressures of oxygen and carbon
dioxide are often sufficiently different from those of venous blood
so as to cause erroneous test results if venous blood is sampled by
mistake.
In the past, arterial blood has been taken with glass syringes with
precision ground barrels and plungers. Because the arterial blood
pressure was significantly greater than the venous blood pressure,
only the arterial pressure would push the plunger rearwardly in a
glass syringe. This gave a visual indication of whether an artery
or vein had been punctured. The precision ground glass syringes
were very costly and for this reason they were washed and
resterilized after each arterial blood sampling.
Inexpensive disposable plastic syringes with rubber stoppers failed
to give the visual indication that the needle was in the patient's
artery. This was because arterial pressure could not overcome the
frictional drag of the rubber stopper in the disposable plastic
syringe.
SUMMARY OF THE INVENTION
Our invention overcomes the problem of taking arterial blood
samples present in previous glass syringes and disposable plastic
syringes. We have provided an inexpensive disposable arterial blood
sampler that gives a quick and accurate indication that an artery
and not a vein has been punctured. Our invention has a collapsed
flexible blood reservoir that snaps into an inflated position with
arterial blood pressure but not with venous blood pressures. In a
first version of our invention an elongated collapsed blood pouch
resists inflation by venous pressure but will snap into an inflated
balloon-like position when arterial pressure is applied. A second
version of our invention includes a resilient cup member that
inverts with arterial pressure but not with venous pressure.
THE DRAWINGS
FIG. 1 is a side elevational view, partially in section, of a first
embodiment of our arterial blood sampler, showing the elongated
collapsed blood pouch being inserted into a rigid protector
housing;
FIG. 2 is a side elevational view, in section, of the first
embodiment showing the action of the pouch when the hypodermic
needle is in a vein;
FIG. 3 is a side elevational view, in section, of the first
embodiment, showing the action of the pouch when the hypodermic
needle is in an artery;
FIG. 4 is a side elevational view, in section, of a second
embodiment, showing a resilient cup as the collapsed blood
pouch;
FIG. 5 is a side elevational view, in section, of the second
embodiment showing how arterial blood pressure causes the resilient
cup to invert; and
FIG. 6 is a side elevational view, in section, of the second
embodiment showing how the blood sample is forced out of the blood
sampler and into testing equipment.
DETAILED DESCRIPTION
In FIG. 1, the first embodiment of the invention is shown as
including an arterial needle 1 that includes a cannula 2 and a hub
3. This needle is connected to a hollow adapter 4 which in turn is
connected to a collapsed flexible pouch 5. A ring 6 attached to the
pouch's rearward end is used to pull the pouch into a rigid
protector sleeve 7 and seat the adapter to the sleeve. A passage
extends through the cannula, hub, adapter and pouch for passage of
blood when a patient's artery is punctured with the cannula.
Once assembled as described above, the arterial blood sample is
ready for use. In FIG. 2, when a nurse or physician punctures a
vein with hypodermic needle 3 the flexible pouch 5 will resist
inflation by the venous blood pressure, equivalent to approximately
110 mm of H.sub.2 O (8 mm Hg). Even though collapsed flexible pouch
5 may expand very slightly to receive a small amount of venous
blood it is readily apparent to an operator that the needle is not
in an artery. When this occurs, the needle is withdrawn from the
patient's vein and another puncture made.
When the needle does enter an artery as shown in FIG. 3, the
arterial pressure equivalent to approximately 90 mm Hg will quickly
snap the flexible pouch 5 into an inflated condition against sleeve
7. Once the arterial blood sample has been taken the protector
sleeve 7 can be removed and the sack squeezed to expel the arterial
blood into blood testing equipment.
In FIGS. 4, 5 and 6 a second embodiment of the invention is shown.
Referring to FIG. 4 the resilient collapsible blood pouch has a
rubber cup-shaped member 10 with a mouth facing away from the
needle in FIG. 4, and facing toward the needle in FIG. 5. This
cup-shaped member fits inside a rigid housing 11 which has a
partially closed forward end attached to a hollow tapered adapter
12. Arterial needle 13 fits on hollow tapered adapter 12. Connected
to a rigid adapter 11 is a rigid barrel 14 which is secured to
housing 11 to form a structure similar to a hypodermic syringe
barrel. Within the barrel is an axially slidable conventional
hypodermic plunger 15 with a rubber stopper 16.
A very important aspect of this second embodiment is a side vent 17
opening in rigid barrel 14. The vent opening 17 has an upstanding
collar 18 surrounding it and as shown in FIG. 5 permits air to
escape from the rigid barrel 14 as the resilient cup-shaped member
inverts in response to arterial blood pressure. An annular space
17a between the barrel and cup-shaped member allows air to escape.
Because of the vent no internal pressure is built up inside barrel
14 to resist inversion of the rubber cup. The arterial blood
sampler of the second embodiment gives a very vivid visual
indication of whether the sampler is in a vein (FIG. 4) or in an
artery (FIG. 5).
Once the sample has been taken, the side vent 17 is closed off by a
removable cap 19 which is attached to collar 18 surrounding the
vent. The cap has an internal undercut groove that snaps over an
external rib on the collar. Forward motion of plunger 15 and
stopper 16 then forces the arterial blood collected in resilient
cup-shaped member 10 out through arterial needle 13 and into blood
testing equipment (not shown).
In both embodiments of this invention it is seen that the collapsed
flexible blood collecting pouch has an exterior surface that is
exposed to atmospheric pressure. During the arterial blood sampling
there is neither suction nor pressure applied to this pouch. In the
first embodiment the flexible collapsed pouch is preferably of a
stretchable rubber-like material with predetermined stretch
characteristics so as to not substantially inflate under venous
pressure, 8 mm Hg, but readily inflate when subjected to arterial
blood pressure, 90 mm Hg.
In the second embodiment the resilient cup-shaped member 10 can be
of a rubber or rubber-like material and have a shape and wall
thickness so as to remain in the FIG. 4 position with a convex
outer surface facing the needle when subjected to venous pressures
through arterial needle 13. However, when subjected to arterial
pressures as in FIG. 5 the cup will rapidly invert as shown.
Because venous and arterial pressures vary with patients it is
desired to have the snap action of the pouch occur at approximately
midway, 50 mm of Hg, between ranges of normal venous and normal
arterial blood pressures. Venous pressure ranges from 3.7 to 8 mm
Hg and arterial blood pressure ranges from 90 to 150 mm Hg. The
arterial pressure is normally reported as being in units of mm of
Hg, and venous pressure is usually measured in cm. of H.sub.2 O.
However, for ready comparison the pressures throughout the
application and claims have been expressed in mm Hg for both venous
and arterial pressures.
In either embodiment, the flexible pouch can contain an
anti-coagulant or other solution for treating the blood as soon as
it flows from the patient into the pouch. In the first embodiment
the adapter 4 and rigid sleeve are preferably made of a
conventional thermoplastic material. Likewise in the second
embodiment the rigid adapter 11, barrel 14 and cap 19 are also made
of conventional thermoplastic materials. The flexible pouch is
preferably sufficiently thin and sufficiently transparent or
translucent to visibly show blood entering the pouch.
Throughout the specification and claims we have used the word
"snap" to describe the quick inflation of the flexible pouch when
subjected to arterial blood pressure. We intend this word to
describe an action of the pouch that is significantly great in
speed and volume of inflation so as to clearly distinguish an
arterial puncture from a venous puncture with its slow seeping
blood which does not substantially inflate the flexible pouch.
In the foregoing description we have used specific examples to
describe our invention. However, it is understood that those
persons skilled in the art can readily make certain modifications
to these embodiments without departing from the spirit and scope of
the invention.
* * * * *