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Description  |
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FIELD OF THE INVENTION
This invention relates generally to blood testing systems and particularly
to those used in a combination with a catheter or the like.
Background of the Invention
Medical practitioners have, throughout history, faced a variety of risks
associated with the practice of their professions. The danger of
contamination or infection from substances handled and people treated has
virtually always threatened medical practitioners. Despite this,
practitioners have, for the most part, willingly assumed this risk while
observing certain precautions and preventative measures. However, the
recent dramatic increase in the nature and types of risks to which medical
practitioners are exposed has, in many instances, rendered standard
precautionary measures insufficient to protect the practitioner. Of
particular danger is the dramatic increase in blood and fluid born
infectious diseases such as AIDS or the like. The potential infection for
medical practitioners in contact with blood and other body fluids of their
patients has required the use of sometimes elaborate and cumbersome
protective measures.
One source of great risk arises from the variety of needles and cutting
instruments used by medical practitioners. The great number of hypodermic
needles, syringes and catheters used places the medical practitioner in
virtually constant danger of being infected by an inadvertent piercing of
the practitioner's skin with a contaminated needle.
Of the many types of medical needles used by medical practitioners, those
known generally as catheters may pose a significantly greater danger of
infection or contamination to the practitioner due to the increased
handling required in their use. The most common catheters utilize an
elongated hollow intravenous tube having a small housing which receives an
elongated pointed catheter needle which extends beyond the tube end. A
housing coupled to the opposite end of the needle defines a small chamber
and a suitable coupling mechanism which may be used to provide connection
to a intravenous feeding tube or the like.
In its normal use, the catheter unit having the catheter needle received
therein is used to pierce the skin and the wall of the target blood vessel
to a sufficient depth that the intravenous tube end is carried into the
target blood vessel. Thereafter, finger pressure is applied to preclude
blood flow as the piercing needle is withdrawn. A small amount of blood is
allowed to flow outwardly through the catheter tube into the housing in a
process known as "flashing" prior to the removal of the needle to assure
that the catheter has been properly placed within the target vessel.
Thereafter, finger pressure is again applied and the needle is completely
withdrawn afterwhich connection is made between the catheter unit housing
and the supply of intravenous material solution which is sought to be
introduced into the patient's bloodstream.
In many situations, such as emergency treatment by paramedics or other
emergency response practitioners, additional operations are carried
forward to obtain blood sample testing at the emergency scene or in route
to the hospital as advance information is forwarded to the response team
waiting at the hospital. Such tests may include, for example, vital
information such as blood sugar or blood pH and so on. These tests are
conducted by obtaining a blood sample during the flashing operation which
is smeared upon a test strip and then after a predetermined waiting period
wiped from the test strip and visually compared to standard criteria such
as color charts and so on.
The problems of providing such intricate and careful handling of blood
contaminated articles in the confusing, noisy and excited environment of
the trauma site or the ambulance ride back to the hospital greatly
increase the chance of infection or contamination of the medical
practitioner.
Various systems have been provided by practitioners in the art for
measuring elements of blood chemistry as well as preventing infection of
medical practitioners handling needles.
For example, U.S. Pat. No. 4,883,461 issued to Sawyer sets forth a SAFETY
NEEDLE SHEATH IN ANTI-REFLUX CATHETER HAVING NOVEL VALVE MEANS in which a
catheter includes a tubular structure together with a anti-reflux valve
which responds to the blood reflux to close while opening in response to
positive fluid pressure within the tubular structure.
U.S. Pat. No. 4,643,192 issued to Fiddian-Green sets forth HOLLOW VISCUS
TONOMETRY. The apparatus relies upon the fact that ischemia in a hollow
internal organ can be detected in its incipient stages by obtaining a
carbon dioxide sample from within the organ of interest and measuring the
carbon dioxide partial pressure therein. This measurement together with
measurement of bicarbonate concentration and the pH of the organ wall
provide an indication of the onset of ischemia. The apparatus used
includes an elongated probe received within the blood vessel of concern.
U.S. Pat. No. 4,703,756 issued to Gough, et al. sets forth a COMPLETE
GLUCOSE MONITORING SYSTEM WITH AN IMPLANTABLE TELEMETERED SENSOR MODULE in
which a module having two oxygen sensors is situated in an oxygen
permeable housing in a tandem relationship. The module includes a
communication capability for transmitting measurement information to an
external recording device outside the body.
U.S. Pat. No. Re.31,879 issued to Lubbers, et al. sets forth a METHOD AND
ARRANGEMENT FOR MEASURE THE CONCENTRATION OF GASES in which a
monochromatic light beam is generated having a predetermined color
characteristic. An indicator generates light signals indicative of the
concentration of gases in a sample to be measured which includes a light
transmissive surface positioned to be impinged by the monochromatic light
beam.
U.S. Pat. No. 4,871,351 issued to Feingold sets forth an IMPLANTABLE
MEDICAL INFUSION SYSTEM including an implantable unit, a refillable
reservoir, a catheter connected thereto and a pumping mechanism activated
by a microcomputer for pumping medication from the reservoir through the
catheter into the body.
While the foregoing described prior art devices have provided some
assistance to medical practitioners and while other devices have been
devised directed primarily at preventing the inadvertent piercing of the
skin surface of a medical practitioner handling contaminated needles,
little if any attention has been provided by practitioners in the medical
arts to the problem of making the handling of blood sampling under
emergency conditions safer for medical practitioners.
Summary of the Invention
Accordingly, it is a general object of the present invention to provide an
improved blood tester. It is a more particular object of the present
invention to provide an improved and safer blood tester for use under
emergency circumstances.
In accordance with the present invention, there is provided for use in
testing a blood sample during the insertion of a catheter within a blood
vessel, an integral catheter and blood tester comprises: a catheter having
a hollow tube; a needle unit having a needle unit housing partially
receivable within the catheter defining an interior chamber and having a
needle extending from the chamber terminating in a piercing end; a blood
tester having a blood tester housing couplable to the needle unit and a
test strip supporting a test patch, the test patch extending into the
interior chamber when the blood tester housing is coupled to the needle
unit; valve means supported by the needle unit for receiving the test
strip and test patch and for wiping blood from the surfaces thereof when
the blood tester housing and the needle unit are separated; and shield
means supported by the blood tester housing partially surrounding the test
strip and test patch.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention, which are believed to be novel, are
set forth with particularity in the appended claims. The invention,
together with further objects and advantages thereof, may best be
understood by reference to the following description taken in conjunction
with the accompanying drawings, in the several figures of which like
reference numerals identify like elements and in which:
FIG. 1 sets forth a side view of an integral catheter and blood tester
constructed in accordance with the present invention;
FIG. 2 sets forth an assembly view of an integral catheter and blood tester
constructed in accordance with the present invention;
FIG. 3A and 3B set forth partially sectioned side views of the present
invention embodiment of FIG. 1 in connected and disconnected relationship
respectively;
FIGS. 4A and 4B set forth partial sectioned views of an alternate
embodiment of the present invention integral catheter and blood tester in
connected and disconnected relationships respectively;
FIGS. 5A and 5B set forth partially sectioned side views of a still further
alternate embodiment of the present invention integral catheter and blood
tester in connected and disconnected orientation respectively; and
FIGS. 6A, 6B and 6C set forth partially sectioned side views of a still
further alternate embodiment of the present invention integral catheter
and blood tester in connected and disconnected orientation respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 sets forth a side view of an integral catheter and blood tester
constructed in accordance with the present invention and generally
referenced by numeral 10. Catheter and blood tester 10 includes a catheter
unit 12 having a generally cylindrical housing 15 coupled to an elongated
cylindrical hollow intravenous tube 13. Intravenous tube 13 defines an end
portion 14. A needle unit 20 includes an outwardly extending flange 21, a
cylindrical housing 24 (seen in FIG. 2) and an elongated cylindrical
catheter needle 22. Catheter needle 11 extends beyond end 14 of
intravenous tube 13 in the assembled position shown in FIG. 1 and defines
a pointed end 23. A tester housing 30 defines a generally cylindrical
viewing portion 32 coupled to needle unit 20 and a cylindrical grip end
31. FIG. 1 shows the assembled position of catheter and blood tester 10
appropriate to the insertion of catheter and blood tester into the target
blood vessel of a patient. During this insertion, the extended pointed end
23 of catheter needle 22 provides the implement for piercing the patient's
skin and underlying tissue as well as the blood vessel wall forming a
pierced hole therein through which end portion 14 of intravenous tube 13
may be passed. In its typical use, catheter and blood tester 10 are
inserted in the assembled position shown until end portion 14 and pointed
end 23 are reliably positioned within the target blood vessel.
FIG. 2 sets forth an assembly view of catheter and blood tester 10. As
described above, catheter 12 includes a generally cylindrical housing 15
and an extended generally cylindrical hollow intravenous tube 13. The
latter terminates in an end portion 14. Needle unit 20 defines a generally
cylindrical housing 24 having an outwardly extending flange 21. Needle
unit 24 further includes an elongated generally cylindrical catheter
needle 22 extending from housing 24 and terminating in a pointed end 23.
Needle unit 20 further includes a generally cylindrical sleeve 25
extending from housing 24 and terminating in an end portion 27. A valve 26
is supported at end 27 of sleeve 25 and is shown below in greater detail.
A tester housing 30 defines a generally cylindrical viewing portion 32 and
an end grip portion 31. Tester housing 30 supports a test strip 40 within
viewing portion 32 which in turn supports a test patch 41.
In operation, tester housing 30 is received upon sleeve 25 in the manner
set forth below in greater detail to couple tester housing 30 to needle
unit 10 in the manner shown in FIG. 1. The combined structure of tester
housing 30 and needle unit 20 are received within catheter 12 such that
catheter needle 22 extends through intravenous tube 13 and beyond to
expose point end 23 of catheter needle 22 in the manner shown in FIG. 1.
Thereafter, catheter and blood tester 10 may be used in the
above-described manner to pierce the patient's skin, underlying tissue and
the wall of the target blood vessel. Once the piercing has been completed,
a quantity of the patient's blood is permitted to flow through catheter
needle 22, housing 24 and into sleeve 25. By means set forth below in
greater detail, test strip 40 and valve 26 cooperate to preclude the
further flow of blood beyond sleeve 25 at valve 26. Once the desired
quantity of blood has been introduced into housing 24 and sleeve 25 of
needle unit 20, further blood flow is precluded by common measures such as
appropriate finger pressure upon the blood vessel. In accordance with an
important aspect of the present invention, test patch 41 is exposed to the
blood flash within sleeve 25 during the above-described flashing
operation. Once it has been determined that the intravenous tube and
catheter needle have been properly placed within the target blood vessel,
needle unit 20 and tester 30 may be withdrawn as a single unit from
catheter 12. Thereafter, needle unit 20 and tester housing 30 may be
separated and needle unit 20 discarded in accordance with appropriate
safety techniques of needle handling. The appropriate coupling to catheter
12 may be then completed permitting the desired intravenous fluid
introduction to take place.
In accordance with an important aspect of the present invention described
below in greater detail, valve 26 and test strip 40 cooperate to remove
excess blood from test strip 40 and test patch 41 as needle unit 20 and
tester housing 30 are separated. As a result, tester housing 30 maintains
test strip 40 and test patch 41 within the enclosure of housing 30.
Because test patch 41 has been exposed to the blood flash within needle
unit 20, it may be utilized in the above-described blood testing such as
measuring the pH of the patient's blood. In its preferred form, tester
housing 30 is fabricated of a transparent material such as molded plastic
or the like and thus test patch 41 may be readily observed within the
interior of tester housing 30 without exposing the practitioner to contact
with the blood contaminated test strip or test patch. Thus, the
practitioner is able to clearly view test patch 41 through the transparent
material of viewing portion 32 while holding tester housing 30 at a
convenient point upon grip end portion 31.
It will be apparent to those skilled in the art that the convenient manner
in which catheter and blood tester 10 is utilized and the avoidance of any
handling by the medical practitioner of a blood contaminated element
during the blood testing process provides substantial safety for the
medical practitioner while facilitating the desired blood testing. It will
be equally apparent to those skilled in the art that while test patch 41
is described as having a pH testing material such as litmus or the like,
other test media may be utilized to perform other blood tests without
departing from the spirit and scope of the present invention.
FIG. 3A sets forth a section view of catheter and blood tester 10 in the
assembled or connected configuration corresponding to FIG. 1. A needle
unit 20 defines a generally cylindrical housing 15 having an outwardly
extending flange 21. Housing 15 further defines an internal generally
cylindrical cavity 29 having a closed end 19. Housing 15 further supports
an extending elongated catheter needle 22. As is set forth in FIG. 1,
catheter needle 22 terminates in a pointed end 23 at the outer end
thereof. The remaining end of catheter needle 22 extends through closed
end 19 of housing 15 and terminates within cavity 29 in an open end 28. An
elongated generally cylindrical sleeve 25 defines an interior flash
chamber 33 and is sealingly received within and secured to the interior
surface of cavity 29 of housing 15. A portion of sleeve 25 extends
outwardly from cavity 19 beyond flange 21 and terminates in an end portion
27. End portion 27 supports a valve 26 having a sealing orifice 35 formed
at the center portion thereof.
A tester housing 31 preferably formed of a clear transparent molded plastic
material or the like defines a generally cylindrical viewing portion 32
and a grip end 31. Tester housing 30 further defines a cylindrical
interior cavity 34 having a closed end 27. An elongated test strip 40 is
supported within cavity 34 of tester housing 30 and extends into cavity 34
from the interior end of cavity 34. Test strip 50 supports a test patch 41
on the end portion thereof. In its preferred form, test strip 40 and test
patch 41 are formed having a generally cylindrical cross section which
cooperates with sealing orifice 35 of valve 26 to permit test strip 40 to
be inserted through orifice 35 and into flash chamber 33 in a sealing
engagement when tester housing 40 is coupled to needle unit 20 by the
insertion of end 27 of sleeve 25 into cavity 34. Thus, in the assembled
position shown in FIG. 3A, tester housing 40 is received upon sleeve 2 and
secured thereto by a frictional fit between cavity 34 and sleeve 25. The
cooperation of valve 26 and test strip 40 provide a sealing closure of
flash chamber 33 and prevent leakage from flash chamber 33 so long as
tester housing 30 is secured to needle unit 20. In accordance with an
important aspect of the present invention, test strip 40 supports test
patch 41 within flash chamber 33 to expose test patch 41 to the blood flow
into chamber 33 during the above-described flashing process.
Catheter 12 includes an intravenous tube 13 and cylindrical housing 15.
Housing 15 receives catheter housing 24 while intravenous tube 13 receives
catheter needle 22 in the above-described assembly.
In operation, the above-described insertion process is carried forward
placing catheter needle 22 and intravenous tube 13 in communication with
the target blood vessel. Thereafter, the above-described blood flashing
process permits a quantity of the patient's blood to flow outwardly
through catheter needle 22 from end 28 thereof into the interior of flash
chamber 33. This blood fills flash chamber 33 and immerses test patch 41
within the patient's blood. Thereafter, once the medical practitioner has
observed the blood flashing within chamber 33 and thereby confirmed the
proper placement of catheter needle 22 and intravenous tube 13, the
combined structures of needle unit 20 and tester housing 30 may be removed
from catheter 12 in the above-described procedure.
FIG. 3B sets forth catheter and blood tester 10 following the removal of
needle unit 20 and tester housing 30 from catheter 12 and the separation
of tester housing 30 from needle unit 20. As described above, needle unit
20 is discarded in accordance with appropriate safety precautions and
techniques. In accordance with an important aspect of the present
invention, tester housing 30 is separated from needle unit 20 by drawing
housing 30 axially and thereby withdrawing the extending portion of sleeve
25 from cavity 34. The separation of tester housing 30 from needle unit 20
also withdraws test strip 40 and test patch 41 outwardly through orifice
35 of valve 26. Because valve 26 provides a sealing engagement between
orifice 35 and test strip 40 as well as test patch 41, the withdrawal of
test strip 40 and test patch 41 outwardly through orifice 35 provides a
wiping action upon test strip 40 and test patch 41 which removes
substantially all of the excess blood therefrom. Once test strip 40 and
test patch 41 have been removed through orifice 35, valve 26 closes
orifice 35 which restores the seal of flash chamber 33 and captivates the
blood within flash chamber 33 to avoid any contact therewith by the
medical practitioner.
Once tester housing 30 has been fully separated from needle unit 20, the
condition of test patch 41 may be observed through the transparent wall of
viewing portion 32. It should be noted that in accordance with an
important aspect of the present invention, test patch 41 remains enclosed
within the interior of cavity 34 of tester housing 30. Thus, the
surrounding surface of viewing portion 32 of tester housing 30 provides a
protective covering for the blood contaminated surfaces of test patch 41
and test strip 40. As a result, tester housing 30 may be easily and
conveniently handled by the medical practitioner without undue risk of
contact with the contaminated test patch. Once the examination of test
patch 41 is completed, tester housing 30 may be discarded in accordance
with appropriate precautionary techniques.
It will be apparent to those skilled in the art that the present invention
integral catheter and blood tester provides a convenient easy to use
catheter structure which permits blood testing such as pH measurement or
the like by exposing a test patch to the flashed blood sample during
catheter insertion while facilitating the safe handling of the exposed
test patch using transparent tester housing 30 as a protective housing and
shield for the contaminated test patch.
FIG. 4A sets forth a partial section view of an alternate embodiment of the
present invention catheter and blood tester generally referenced by
numeral 70. Catheter and blood tester 70 utilizes catheter 12 and needle
unit 20 together with sleeve 25 in the same configuration as shown in the
embodiment of FIGS. 1 through 3B. The difference between catheter and
tester 70 shown in FIGS. 4A and 4B with the above-described catheter and
blood tester referenced by numeral 10 is found in the structure of tester
housing 50 which provides an alternate structure for producing additional
shielding and protection of the contaminated test strip and which permits
the utilization of an extended length test strip 60 and an extended test
patch 61.
Specifically, catheter 12 includes a cylindrical housing 15 and an
extending intravenous tube 13. Needle unit 20 includes a generally
cylindrical housing 24 having an outwardly extending flange 21 and
supporting an extending pointed catheter needle 22 having an interior end
28. Housing 24 defines an interior cavity 29 which receives and supports a
generally cylindrical sleeve 25. sleeve 25 is tightly received within
cavity 29 in a sealing attachment and secured thereto by conventional
methods such as thermal welding, adhesives or the like. In the
alternative, housing 24 and sleeve 25 may be fabricated of a single molded
plastic part with the essential requirement being the cylindrical
extension of end 27 of sleeve 25. Housing 24 further defines a closed end
19 while sleeve 25 defines an interior flash chamber 33. A resilient valve
26 defines a constricting orifice 35 which, under the resilience of valve
26, tends to expand in a inwardly directed radial manner to converge and
seal orifice 35 and provide closure of flash chamber 33.
Tester housing 50 defines a generally cylindrical member having a
cylindrical grip end 51 and a cylindrical reduced diameter portion 53.
Reduced diameter portion 53 defines an outer diameter 58 and an interior
cavity 54. In its preferred form, tester housing 50 is formed of a
transparent material such as clear molded plastic and thus forms a viewing
portion 52 through which the interior of flash chamber 33 may be viewed.
Cavity 54 receives end 27 of sleeve 25 during the assembly of tester 50 to
needle unit 20 in the manner described above. This fit is preferably a
reasonably secure slide fit which tends to maintain the attachment between
housing 50 and needle unit 20 but which may be readily overcome when the
practitioner desires to separate tester housing 50 from needle unit 20 in
the manner described above for the preceding embodiment. Tester housing 50
further includes an inwardly extending test strip 60 supporting a test
patch 61 at the end portion thereof. Test patch 61 is formed of a suitable
visual indicator type material such as litmus or the like which exhibits a
visual change in response to the to-be-examined blood criteria in
accordance with conventional blood testing techniques such as pH testing
or the like. During the assembly of tester housing 50 to needle unit 20,
test strip 60 and test patch 61 are forced through orifice 35 of valve 26.
The resilience of valve 26 causes a sealing constriction of orifice 35
about test strip 60 which maintains the sealing closure of flash chamber
33.
Tester housing 50 further supports a generally cylindrical sliding sleeve
62 having an inner diameter 63 which is sufficiently large to permit
sliding sleeve 62 to be freely movable upon outer diameter 58 of reduced
diameter portion 53. Sliding sleeve 62 is preferably formed of a
transparent material such as clear transparent molded plastic or the like.
Tester housing 50 further defines a shoulder portion 55 forming an annular
shoulder transition between reduced diameter 53 and the larger diameter of
grip end 51. A coil spring 56 is captivated between shoulder 55 and the
end portion of sliding sleeve 62. In the assembled position shown in FIG.
4A, spring 56 is compressed between shoulder 55 and the end of sleeve 62
and thus provides a spring force urging sleeve 62 in the direction
indicated by arrow 57. In the assembled position, however, the frictional
attachment of tester housing 50 to sleeve 25 is sufficient to withstand
this spring force and thus spring 56 and sleeve 62 remain captivated in
the positions shown in FIG. 4A.
In operation, the practitioner carries forward the above-described process
of catheter insertion and blood vessel piercing as well as the
above-described process of flashing in which a small quantity of blood is
permitted to flow through needle 22 partially filling flash chamber 33.
Once the visual indication and confirmation of proper catheter placement
has been provided by the flashing process, the quantity of blood within
flash chamber 33 is in contact with test patch 61 of test strip 60. Test
patch 61 undergoes the visual change described above as the to-be-tested
chemicals within the blood sample begin reacting upon test patch 61.
Thereafter, the practitioner is able to remove the assembled combination of
tester housing 50 and catheter needle unit 20 by withdrawing the assembly
outwardly from catheter 12 leaving intravenous tube 13 in place in
accordance with conventional practices. Once needle unit 20 and tester
housing 50 are removed, the practitioner may then attach suitable
intravenous fluid devices to catheter 12 in accordance with conventional
methods.
FIG. 4B sets forth the configuration of catheter and tester 70 once needle
unit 22 is separated from tester housing 50 in order to discard needle
unit 20. This separation is carried forward by producing a drawing force
between flange 21 of needle unit 20 and grip end 51 of tester housing 50
which separates sleeve 25 from cavity 54. During the separation of tester
housing 50 from needle unit 20, the axial motion as tester housing 50 is
drawn outwardly along sleeve 25 simultaneously draws test strip 60 and
test patch 61 outwardly through orifice 35 of valve 26. It should be noted
that the resilient constriction of orifice 35 provided by valve 26 serves
to provide a wiping action upon test strip 60 and test patch 61 which
removes excess blood therefrom and permits the ready viewing of test patch
61 substantially free of excess blood which would otherwise obscure the
viewing of the test patch. In its preferred form, test strip 60 and test
patch 61 are formed in a generally cylindrical shape corresponding to the
circular constriction provided by orifice 35 of valve 26. However, it will
be apparent to those skilled in the art that other combinations of valve
26, orifice 35 and shapes of test strip 60 and test patch 61 may be
utilized without departing from the spirit and scope of the present
invention. The essential character of valve 26, orifice 35, test strip 60
and test patch 61 is to provide the wiping action upon test patch 61 and
test strip 60 as they are withdrawn through orifice 35.
In addition, as tester housing is removed from needle unit 20, the
captivation of spring 56 is released permitting the spring force of spring
56 to urge sleeve 62 in the direction indicated by arrow 57. As seen in
FIG. 4B, the repositioning of sleeve 62 provides an extended shield which
surrounds test patch 61 of test strip 60 and thus provides additional
protection which precludes inadvertent touching of the blood contaminated
portions of test patch 60 and test strip 61. As mentioned above, sleeve 62
as well as reduced diameter portion 53 are formed of a transparent clear
material such as transparent molded plastic. Thus, the visual condition of
test patch 60 having been exposed to the flashed blood sample in the above
procedure may be easily observed through the clear material of sleeve 62
and reduce diameter portion 53. The extent of movement of sliding sleeve
62 may be limited in accordance with conventional fabrication techniques
such as providing cooperating tabs or the like. However, in the present
embodiment, it has been found desirable to secure one end of spring 56 to
the interior end of sleeve 62 and thereby limits its motion to the full
extension of spring 56. Once the desired examination of test patch 61 has
been carried forward, the practitioner may simply discard tester housing
50 in accordance with established procedures. It should be noted that
during the entire handling procedure of catheter and blood tester 70, the
practitioner has not been required to touch or otherwise contact
contaminated blood while performing the above-described testing procedure.
This, of course, provides enhanced safety for the medical practitioner.
FIG. 5A sets forth a still further alternate embodiment of the present
invention catheter and blood tester generally referenced by numeral 80.
Catheter and blood tester 80 utilizes catheter 12 and needle unit 20
together with sleeve 25 and valve 26 in the fabrication described above.
Catheter and blood tester 80 differs from the preceding embodiments in the
structure of tester housing 90 which utilizes a translating rod assembly
to withdraw the contaminated test patch into the tester housing and
thereby provide improved shielding of the blood contaminated test patch
during handling by the practitioner.
Specifically, catheter 12 includes cylindrical housing 15 and intravenous
tube 13 as described above. Similarly, needle unit 20 includes cylindrical
housing 24, flange 21, closed end 19 and interior cavity 29, also
described above. Cylindrical sleeve 25 is received within cavity 29 and
defines an interior flash chamber 33 therein. Sleeve 25 extends outwardly
beyond flange 21 terminating in an end 27. Valve 26 formed of a resilient
material defines a constricting orifice 35 proximate end 27 of sleeve 25.
Tester housing 90 defines a generally cylindrical member formed of a clear
transparent material such as clear molded plastic or the like and defines
a cylindrical bore 95 together with a generally cylindrical cavity 94. The
interior of cylindrical bore 95 defines a plurality of detent recesses 96
through 99 positioned along cylindrical bore 95 in accordance with the
descriptions that follow. However, suffice it to note here that certain
ones of recesses 96 through 99 are formed closer to cavity 94 while others
are formed more remote therefrom.
A cylindrical rod 100 is sized to fit within cylindrical bore 95 in a
sliding fit and defines a pair of outwardly extending projections 101 and
102. Projections 101 and 102 are configured to be receivable within
detents 96 through 99. Rod 100 further includes an extended enlarged grip
portion 91 at its outer end and an inwardly extending test strip 103 at
the remaining end. Test strip 103 supports a test patch 104 which may, for
example, comprise conventional litmus testing material or the like.
In the assembled position shown in FIG. 5A, tester housing 90 is received
upon sleeve 25 and maintained in attachment to needle unit 20 by the
frictional fit between inner diameter 93 of housing 90 and the outer
surface of sleeve 25. Rod 100 is shown in FIG. 5A in its inserted testing
position in which grip portion 91 abuts the outer edge of housing 90 and
in which test strip 103 and test patch 104 extend through orifice 35 of
valve 26 and into flash chamber 33. The position of rod 100 is maintained
by the extension of projections 101 and 102 into detent recesses 96 and 97
respectively.
In operation, the above-described catheter insertion and blood flashing
processes carried forward result in the introduction of a blood sample
into flash chamber 33 which surrounds and wets test patch 104 producing
the desired chemical reaction and visible changes of test patch 104. As
mentioned above, this test may be a conventional reactive test in which
the pH of the blood sample is tested using conventional litmus material
for test patch 104. Alternatively, virtually any visual indicating test
material may be utilized for test patch 104. Once the flashing process has
confirmed the proper placement of the catheter needle, needle unit 20 and
tester housing 90 may be withdrawn as a combined unit leaving catheter 12
in place for eventual coupling to a suitable intravenous unit in
accordance with conventional practices.
FIG. 5B sets forth the disassembled configuration of catheter and blood
tester 80 following the separation of contaminated needle unit 20 from
tester housing 90 which is carried forward in order to discard needle unit
20. The separation process is carried forward preferably by the
practitioner gripping flange 21 and grip end 91 simultaneously and forcing
needle unit 20 and tester housing 90 outwardly to simultaneously withdraw
sleeve 25 from cavity 94 of tester housing 90. Concurrently, the
separating force operates to draw rod 100 outwardly within cylindrical
bore 95 and overcoming the detent action of projections 101 and 102 within
recesses 96 and 97 respectively. Thus, rod 100 slides outwardly to the
position shown in FIG. 5B until projections 101 and 102 are received
within detent recesses 98 and 99 which maintains the relative position
shown for tester housing 90 and rod 100. Once needle unit 20 is separated
from tester housing 90, valve 26 closes orifice 35 captivating the blood
sample within flash chamber 33. It should be noted that the constricting
action of orifice 35 of valve 26 produces a wiping action upon test strip
103 and test patch 104 during the separation process which removes excess
blood from test patch 104 permitting proper viewing of test patch 104 for
the visual evaluation which follows. It should also be noted that the
translating motion of rod 100 with respect to tester housing 90 causes
blood contaminated test patch 104 and test strip 103 to be further
withdrawn into the interior of tester housing 90 thereby further
protecting the practitioner from inadvertent contamination and contact
with potentially contaminated blood during the evaluation process. The
clear transparent material of tester housing 90 permits the practitioner
to easily view the condition of test patch 104 and thereby undertake the
desired evaluation and comparison to standard color charts or the like.
Once the evaluation has been completed, tester housing 90 may be discarded
in accordance with standard precautionary techniques.
It should be noted that during the above-described handling of catheter and
blood tester 80, the practitioner is protected from inadvertent contact
with contaminated blood by the shielding action of the translating
movement of rod 100 with respect to tester housing 90.
FIGS. 6A, 6B and 6C set forth the operation and structure of a still
further alternate embodiment of the present invention blood tester. FIGS.
6A through 6C are shown in cross-section taken generally in the same
manner set forth above in the above-described embodiments. FIG. 6A shows
the initial position of the blood tester at the time of initial needle
insertion. FIG. 61B sets forth the configuration of the blood tester
following the above-described flashing operation which exposes the test
patch to the patient's blood. FIG. 6C sets forth the final stage in the
use of the embodiment of FIGS. 6A through 6C in which the test patch is
withdrawn from the blood sample and is viewable while enclosed within the
blood tester housing.
Specifically, FIG. 6A sets forth a section view of a blood tester
constructed in accordance with the present invention and generally
referenced by numeral 110. Tester 110 is used in combination with a
catheter 12 constructed in accordance with conventional fabrication
techniques and comprising a housing 15 having a hollow intravenous tube 13
extending therefrom. A catheter needle unit 20 includes a needle housing
24 supporting an elongated generally cylindrical needle 22 having a
piercing end 23 (seen in FIG. 1) and an interior end 28. Needle housing 24
further defines an interior cavity 29 and a closed end 19 together with an
extending flange 21. Needle unit 20 and catheter 12 are formed in
accordance with conventional fabrication techniques.
Blood tester 110 includes a generally cylindrical housing 111 defining an
interior cylindrical bore 112. Housing 111 terminates at one end in an
open end 113 and at the remaining end in a reduced diameter portion 114.
Reduced diameter portion 114 is generally cylindrical and configured to be
received within cavity 29 of needle housing 24 in a tight generally
sealing coupling. Reduced diameter end 114 defines an interior flash
chamber 115.
A generally disk-shaped piston 130 is supported by an elongated generally
cruciform-shaped rod 122. Rod 122 is formed of a quartet of mutually
perpendicular webs 131, 132, 133 and a fourth web 134 (not seen). Rod 122
terminates at its outer end in a knob 135. In its preferred form, piston
130, rod 122 and knob 135 are integrally formed of a single molded plastic
unit. An elongated preferably cylindrical test strip 140 is integrally
formed with piston 130 and extends therefrom away from knob 135 toward
flash chamber 115 of reduced diameter end portion 114. Test strip 140
supports a test patch 141 at the distal end thereof. An absorbent element
120 is interposed between piston 130 and flash chamber 115 and defines a
center aperture 121. Absorbent element 120 i | | |
