Method and apparatus for monitoring body conditions

Body monitoring apparatus for use with a catheter tube having an outlet opening and a drainage tube having a male connector engageable with the outlet opening of the catheter tube. The apparatus comprises a tubular body member having at one end a male connector engageable with the outlet opening of the catheter tube, at the other end an outlet opening engageable with the male connector of the drainage tube, and an exit from the body member between the connector and the outlet opening. A flexible transmission line extends from a condition sensing transducer such as a temperature sensor through the body member from the male connector thereof through the exit to a point outside the body member. The exit is sealed to prevent leakage of fluid at the point of egress of the transmission line. In another embodiment, the intermediate tube has a window to permit outside observation of the interior of the tube. One or more temperature responsive visual indicators are located in the intermediate tube at the window. The indicators respond to different temperatures.

BACKGROUND OF THE INVENTION 
This invention relates to the measurement of body conditions and, more 
particularly, to a method and apparatus for monitoring body conditions, 
such as core temperature. 
Core body temperature is an important indicator of a patient's body 
functions and conditions, such as for example, shock. A thermometer placed 
in the ear, nose, mouth, or rectum measures peripheral temperature, which 
is affected by extraneous factors such as ambient temperature and body 
circulation. Therefore, peripheral temperature is not an accurate 
indicator of core temperature. In order to provide an accurate indication 
of core temperature, it has been proposed to embed a temperature sensor in 
the wall of a urinary catheter at the extremity thereof inserted into the 
bladder. Electrical leads extend longitudinally through the wall of the 
catheter to an indicator outside the patient's body. The described 
catheter with embedded temperature sensor is substantially more expensive 
than a conventional catheter. For this reason it is desirable to use the 
described catheter selectively only on patients who require core 
temperature monitoring. However, it is commonly not known at the time the 
catheter is inserted in a patient whether or not core temperature 
monitoring should be prescribed. 
SUMMARY OF THE INVENTION 
The invention permits core temperature or other body function to be 
measured after a conventional urinary catheter has been inserted in a 
patient. 
One aspect of the invention is a method comprising the steps of feeding a 
flexible transmission line having a sensor connected to its end into the 
outlet opening of a catheter until the sensor lies near the inlet thereof, 
connecting the other end of the transmission line to an indicator outside 
the catheter, and connecting a drainage tube to the outlet of the catheter 
without fluid leakage at the point of egress of the transmission line. 
Thus, when the decision is made to monitor a body condition, such as core 
temperature, a sensor can be set into place after the catheter has been 
inserted into the patient. The sensor can be removed at any time and 
reused if desired. 
Another aspect of the invention is body monitoring apparatus for use with a 
catheter tube having an outlet opening and a drainage tube having a male 
connector engageable with the outlet opening of the catheter tube. The 
apparatus comprises a tubular body member having at one end a male 
connector engageable with the outlet opening of the catheter tube, at the 
other end an outlet opening engageable with the male connector of the 
drainage tube, and an exit from the body member between the connector and 
the outlet opening. A flexible transmission line extends from a condition 
sensing transducer such as a temperature sensor through the body member 
from the male connector thereof through the exit to a point outside the 
body member. The exit is sealed to prevent leakage of fluid at the point 
of egress of the transmission line. 
Another aspect of the invention is a temperature monitoring system in which 
an intermediate tube is removably connectable between the outlet of a 
catheter and the inlet of a drainage tube. The intermediate tube has a 
window to permit outside observation of the interior of the tube. One or 
more temperature responsive visual indicators are located in the 
intermediate tube at the window. The indicators respond to different 
temperatures. Since urine temperature flowing through the intermediate 
tube is being measured by this technique, it is not as accurate as 
measurement with a temperature sensor near the inlet end of the catheter.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS 
In FIGS. 1 and 2, a conventional urinary retention catheter tube 10 is 
shown. A commercially available Curity Foley catheter manufactured by the 
Kendall Company, Code No. 2710, is typical of this type of catheter tube. 
Catheter tube 10 comprises in a one-piece, molded and bonded rubber 
construction a urine passage 12 and a balloon filling conduit 14. Catheter 
tube 10 has an interior end 16 adapted to be inserted into the urethra of 
a patient until it lies in the bladder and an external end 18 lying 
outside the patient. Eye openings 20 at internal end 16 serve as an inlet 
to urine passage 12. The outlet of urine passage 12 is at external end 18. 
Passage 12 extends continuously between ends 16 and 18. Conduit 14 also 
extends continuously between a one-way valve 22 at end 18 and a thin 
walled sleeve 24 at end 16, which serves as a retention balloon when 
inflated. After catheter 10 is inserted into the patient's urethra until 
end 16, including sleeve 24, lies in the patient's bladder, a fluid, 
preferably sterilized water, is injected by a syringe into tube 14 via 
valve 22, thereby inflating sleeve 24 and retaining catheter 10 in place. 
End 18 is coupled to a drainage tube 30, which leads to a urine drainage 
bag 32. 
End 18 has an outlet opening into which a male connector 34 on the end of 
tube 30 removably fits to engage the outlet opening with connector 34. The 
invention involves monitoring the core temperature of a patient with 
catheter tube 10 in plae by means of body monitoring apparatus insertable 
in the fluid line between catheter tube 10 and drainage tube 30. In the 
embodiment of FIGS. 1 and 2, the apparatus comprises an intermediate tube 
36, a temperature sensor 38, and a transmission line 40. 
Sensor 38 could comprise a thermistor operating in the self-heated mode. As 
depicted in FIG. 2, transmission line 40 could comprise a pair of 
electrically conductive mutually insulated leads 42 inside a sheath 44. 
Leads 42 could be insulated from each other by dipping them individually 
into an electrically insulative varnish. Sensor 38 is bonded to the end of 
sheath 44 which could be made of a plastic tubing. 
Body member 36 could comprise a flexible transparent plastic tube 54 and a 
rigid molded plastic piece 46 having a male connector 48 at one end, a 
stepped reduced diameter portion 50 at the other end, and an exit opening 
52 therebetween. Tube 54 is secured to portion 50, such as for example by 
bonding. Connector 48 is identical to connector 34 so it can removably 
engage the outlet opening of catheter 10 and the inside diameter of tube 
54 is the same as the outlet opening of catheter 10 so it can removably 
engage connector 34. Transmission line 40 extends from sensor 38 through 
piece 46 from connector 48 to exit 52, which serves as the point of egress 
of transmission line 40 from body member 36. A plug of water impervious 
epoxy 56 fills the space in exit 52 around transmission line 40, thereby 
sealing exit 52 and securing transmission line 40 to piece 46. Sheath 44 
ends at a convenient point outside body member 36 and leads 42 are 
connected to a digital indicator 58 of conventional construction. 
To measure core body temperature after catheter 10 has been inserted into 
the urethra of a patient, connector 34 of drainage tube 30 is first 
disconnected from the outlet opening of catheter tube 10. Second, sensor 
38 is introduced into the outlet opening of catheter tube 10 and advanced 
through catheter 10 to its inlet by feeding transmission line 40 into 
catheter tube 10. Third, connector 48 is made to engage the outlet opening 
of catheter tube 10. Finally, connector 34 is made to engage the outlet 
opening of body member 36. The portion of transmission line 40 extending 
from connector 48 is sufficiently long for sensor 38 to lie near the inlet 
of catheter tube 10, preferably between eyes 20 and sleeve 24 when body 
member 36 is installed between catheter tube 10 and drainage tube 30, to 
insure that sensor 38 lies within the bladder of the patient. Sensor 38 
produces an electrical output that is transmitted by leads 42 to digital 
indicator 58. Sensor 38 can be removed for reuse simply by disconnecting 
body member 36 from the line between catheter tube 10 and drainage tube 30 
and reconnecting the latter directly together once again. 
In the embodiment of FIG. 3, body member 36 has no exit opening because no 
transmission line is required. In this case the urine temperature is 
measured within body member 36. A temperature indicator 60, in the form of 
a plastic substrate for example, has a plurality of dot shaped indicating 
elements 62 thereon. Indicator 60 is bonded to the inner side wall of tube 
54. Each of elements 62 provides a visual indication responsive to a 
different temperature, as indicated by a number directly below such 
element. Thus, the element above "number 98" provides a visual indication 
when the urine temperature is 98.degree., etc. Indicator 60 is mounted in 
body member 36 at a window in the form of the transparent walls of tube 
54. Indicator elements 62 could comprise commercially available 
temperature recorders sold by Telatemp Corporation, of Fullerton, Calif., 
or liquid cholesteric crystals. It is preferable to so orient body member 
36 as to collect urine therein for measurement purposes rather than to 
measure continuously flowing urine. 
The described embodiment of the invention is only considered to be 
preferred and illustrative of the inventive concept; the scope of the 
invention is not to be restricted to such embodiment. Various and numerous 
other arrangements may be devised by one skilled in the art without 
departing from the spirit and scope of this invention.