Note: Descriptions are shown in the official language in which they were submitted.
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INTERCHAN~EABLB PNEUMATIC CONNECTOR
FOR B~OOD PR~URE MONITOR8
Field of the Invent$on
The present invention relates to patient monitoring
device6 and, in particular, to fittings for providing
interchangeable connection of such devices to the operable
patient portions of the devices.
Bac~around of the Invention
Many devices have been developed for the non-invasive
determination of blood pressure in a patient. These
devices comprise a bladder in the form of an attachable,
adjustable cuff which is placed in a surrounding
relationship on a patient's limb juxtaposed an artery for
providing the pressure measurement, and a microprocessing
device for reading the data generated through the cuff or
bladder. The cuff or bladder is connected to the
microprocessor throuqh a tubing set and a transducer. In
operation, the device inflates the cuff by supplying
pressurized air through the tubing to the bladder in order
to occlude the artery. Various manipulations of the air
pressure within the cuff are provided by adjusting the
pressure within the cuff and reading the response through
the transducer to such reductions in the pressure. The
transducer converts the pressure manipulations into
electri~al signals for computation by the microprocessor.
In order to appropriately measure the blood pressure in a
variety of patients, different cuff sizes are provided.
These cuff sizes may range from a very small neonatal cuff
to a large thigh cuff for an adult. Each of these cuffs
must be attachable to a monitoring device for determining
the blood pressure of the patient. Although the cuffs are
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relatively universal in size and construction, the devices
and the method by which they manipulate the information
received through the pressurization of the cuff are
different. These different devices have different set-ups
for attaching the cuff to the monitoring device. These
attachment devices may be a threaded, bayonet style
connector or, for example, a male luer fitting at the end
of a tube extending from the basic processing unit. This
required maintaining an inventory of cuffs which were
particularly suited for the particular monitoring device.
Thus, the interchangeability of cuffs was greatly limited.
~ummarv of tho Inventio~
It has been found desirable to have an interchangeable
fitting on a blood pressure cuff such that a patient may
be attached to a specific type of monitoring device,
detached from that device for transportation or for
exchange of device and reattached to a different type of
device without removing the cuff. In order to provide for
this, a fitting is provided at the end of the tubing which
extends from the cuff. The fitting is adapted to receive
a tube associated with a pneumatic device and includes a
first end having a tube attachment means formed thereon
and a second end which comprises an external surface
defining a male thread and an internal surface defining a
female taper. Advantageously, the internal surface may
define a female luer fitting for receiving an associated
male luer fitting from the monitoring device.
Alternatively, the second end may further include an
internal cylindrical surface which receives an associated
bayonet fitting which is clamped in place by the external
surface which defines the male thread.
The tube attachment means provided at the first end of the
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fitting may be a tapered external surface or may be a
barbed formation for holding the tubing thereon.
Additionally, the surface may merely be cylindrical if
fiufficient interference fit is provided between the
fitting and the tubing in order to maintain the connection
under the pressure which will be applied to the cuff
through the tubing.
Additionally, a shoulder portion of widened diameter may
be provided intermediate the first and second ends in
order to provide a gripping section to the fitting. This
gripping section may be provided in order to assist in the
threading of the connections of the second end or the
insertion of the luer fittings into the second end of the
fitting.
Thus provided, the f itting creates a blood pres6ure cuff
apparatus for use with a non-invasive blood pressure
monitor which apparatus includes a bladder for inflation
in the cuff. A tube communicates with the bladder at a
first end of the tube for inflation and deflation of the
bladder, and a fitting is received at a second end of the
tubing set. This fitting includes a threaded attachment
~eans on an outer surface of a second end and a second
attachment means for selective attachment to a blood
pressure determining device.
The threaded attachment mean~ is preferably a male thread,
and the fitting may define an internal cylindrical surface
which, in connection with the male thread, receives and
attaches a bayonet-type fitting. Alternatively, the
second attachment means may be an internal tapered surface
whic~ forms a female luer fitting which receives a male
luer fitting at the end of a tubing set or extending from
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the body of a monitoring device. The luer fitting may be
spaced from the end of the fitting in order to provide the
space necessary for the cylindrical surface of the
associated bayonet-type fitting.
Brief Description of the Dra~in~s
Figure 1 is a perspective view of a fitting for a tubing
set according to the present invention;
Figure 2 is a longitudinal cross-sectional view of the
fitting of Figure 1; and
Figure 3 is a perspective view of a cuff tubing set with
fitting.
Desaription o~ the Preferred Embodiments
Referring to Figure 1, the fitting of the present
invention will be described and below the operation and
use of the fitting will be described in connection with
Figure 3. The fitting 1 has a tubing end 2 with an
external surface 3. The external surface 3 has barbs 4
formed thereon for retaining a tubing set thereover. The
barbs 4 are formed in a known manner at a maximum external
diameter slightly larger than the internal diameter of the
tubing set. The tubing set has the tubing end 2 of the
fitting inserted therein thus deforming the tubing set
radially outward in order to provide a frictional fit over
the barbs 4.
The device end 5 has a surface 6 which defines a series of
male threads 7. The male threads 7 are adapted to receive
the female threads of a connector from a blood pressure
monitoring device. This device may be of any known type
and should have female threads of like pitch and depth to
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the male threads of the fitting. The male threads of the
fitting should be chosen so as to provide a sufficient
hermetic seal with the supply tubes of the device to
operatively connect the fitting to the device and,
S therefore, operatively connect the cuff.
Referring to Figure 2, the internal construction of the
fitting is easily seen. The fitting defines an internal
cylindrical surface 8 at a distal end of the fitting.
This cylindrical surface 8 is sized to receive the bayonet
portion of the threaded connector described above. The
bayonet portion is received internally of the fitting
while the female threaded portion of the device attachment
mechanism threads on the external surface of the fitting.
Thus, the combination of the threaded attachment and the
receipt of the bayonet within the internal cylindrical
surface 8 provides the necessary hermetic seal to the
device.
The internal construction further defines an internal
taper of a female luer fitting 9 which is adapted to
receive a luer fitting on the device tubing set. Thus,
the female luer fitting and the threaded male connection
of the fitting end may be used in an alternative fashion.
That is, if the device to be attached to the cuff has a
male luer fitting, it is received within the fitting and
sealed to the female luer fitting 9. However, if the
device has a female threaded attachment mechanism, the
bayonet of the attachment mechanism is received adjacent
the internal cylindrical surface 8 with the female
threaded portions of the attachment mechanism being
threadedly received on the outer surface of the fitting.
A passage 10 is defined by the remainder of the fitting în
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order to provide communication from one end of the fitting
to the other end of the fitting. The passage and the
sizing of the internal formations on the device end of the
fitting are adapted to permit sufficient air flow through
the fitting so as not to interfere with the operation of
the monitoring device. That is, the passage must be
shaped and sized so as not to provide a significant
constriction to the passage of the air therethrough either
during the inflate or deflate portions of the cycle.
The fitting is formed out of an engineering metal or a
plastic, for example, brass and polycarbonate.
Conveniently, the fitting may be injection molded from
plastic which, once formed, is rigid with respect to the
tubing set. A representative fitting may have a length of
approximately 0.875 inch and an internal passage diameter
of 0.125 inch. The threaded end is formed with an
external diameter of 0.390 inch and a thread pitch of 24
threads per inch.
Referring now to Figure 3, the use of the device is shown.
A cuff 11 is provided with a tubing set 12 extending from
the cuff and in communication with a bladder within the
cuff. The fitting 1 is received in interference fit at an
end of the tubing set extending from the cuff. The second
end of the fitting receives a threaded-type female
connector 13 which extends from a tubing set attached to
and in communication with the monitoring device. This
tubing set is shown as having a free end 14 as it may be
attached to any known type of pneumatic monitoring device.
Without removing the cuff 11 from a patient, the fitting
1 may be detached from the monitoring device by
unthreading the connection with the tube extending to the
pati~nt monitoring device. The patient may then be
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transported or merely have a different device attached.
If the patient i8 transported, a transportable monitoring
device may be used or a different monitoring device at the
end of the transportation. The transport monitoring
S device or the second monitoring device need not have the
same type of threaded fitting as is shown in Figure 3 but
rather may have a luer-type fitting for attachment to the
cuff. Thus, the cuff may be attached to different types
of tubing sets without removing the cuff from the patient.
In order to easily grip the fitting 1, a shoulder 15 is
formed having a grip surface 16. The grip surface may be
serrated to provide better grip. The wide diameter of the
shoulder 15 increases the grip leverage and provides a
stop for the tubing 12 to abut.
The invention will now be described with reference to the
accompanying claims. It should be understood that the
description given herein is merely representative, and the
scope of the invention claims should be determined with
reference to the attached claims.
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