Note: Descriptions are shown in the official language in which they were submitted.
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IN~ELLIGENT 8EN80R APPARATU~ AND METUOD FOR
INTE~LIGENTLY COMMUNICATING INFORMATION AND DATA
To AND FROM A VITAL 8IGN8 MONITO~
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a
method and apparatus for monitoring a patient's vital
physiological signs. More particular, the invention
relates to a method and apparatus for monitoring a
patient's vital signs by use of at least one portable
remote sensing unit.
2. Description of the Related Art
Vital sign monitors are used extensively in
patient care environments. Conventional monitors are able
to measure and store data for vital signs such as blood
pressure, pulse rate, respiration rate and temperature.
For example, conventional automatic electronic blood
pressure monitors are used routinely to quickly, easily
and accurately measure the blood pressure of a patient.
The blood pressure measurement data are maintained in
nurses logs and/or in the memory of the monitor.
Conventional integrated monitors providing a full
range of vital sign sensing present a number of serious
drawbacks from an ease of usage standpoint. First,
conventional vital sign measuring sensors merely sense the
vital signs of a patient and generate signals which must
be communicated back to the main monitor for processing.
Second, in order to provide a full range of information,
vital signs from a variety of areas of the body are
sensed, preventing the sensors from being located in a
single module. Finally, measuring vital signs requires
sensors which must be in contact with the patient.
Accordingly, in a conventional integrated vital
signs monitor, a cable for each sensor must be provided to
connect the main monitor to the sensors, which are
attached to the patient at a variety of locations. These
cables are a nuisance for the doctors, nurses and others
involved in the patient's care, interfere with access to
the patient, and are easily tangled or damaged, thereby
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hindering the monitor~s ability to gather the vital signs
data.
For 2xample, U.S. Patent 4,981,139 to Pfohl
discloses a vital signs monitoring system with sound
sensor 18, blood pressure sensor 22 and esophageal
catheter 14 connected by cables to the monitor 12 and
attached to the patient. While Pfohl discloses an infra-
red transmitter and receiver which provides communication
between the monitor and a remote unit carried by a physi-
cian, none of the problems inherent in the conventional
vital signs monitors are avoided by Pfohl.
In contrast U.S. Patents. 4,966,154 to Cooper et
al. and 4,909,260 to Salem et al. describe devices which
are able to monitor a number of vital signs without
connection to a central monitor device. In Cooper et al.,
a harness system containing a number of vital signs
sensors is disclosed. The raw data from the sensors is
transmitted by a radio frequency transmitter to a receiver
system 200. The receiver system 200 contains a plurality
of converters which supply outputs to a computer system
208. The computer system 208 stores the data, makes the
requisite calculations, feeds the information to a display
monitor 210 of printer 212 and an alarm unit 214. Salem
et al discloses a belt-like device containing a number of
vital sign sensors, a volatile memory, a nonvolatile
memory and a radio frequency transmitter. The device of
Salem et al., outputs a radio frequency signal only when
preset alarm conditions are encountered. When an alarm
condition is encountered, the data from the sensors is
dumped into the nonvolatile memory, where it is stored for
later analysis by a physician. However, both Cooper et
al. and Salem et al. merely transmit the raw, analog data
instead of a cleaned, processed data waveform. In addi-
tion, the system of Cooper at al. is highly susceptible to
noise or interference from other electronic devices and
requires a large number of receivers to maintain constant
contact with the patient unit. Eurthermore, both Salem
et al. and Cooper et al. are limited to the kinds of
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sensors that can be provided and the sensing locations
available due to the single patient unit they disclose.
SUMMARY OF THE INVENTION
In the vital physiological signs monitor of the
present invention, at least one patient unit, each unit
comprising a vital sign sensor for sensing blood pressure
or the like, is stored in a patient unit retaining means
of the monitor. The vital sign sensor is connected with
the monitor solely through a communications means. The
patient unit also comprises a battery as a power source.
The battery may be a rechargeable-type battery recharge-
able through a rechargeable battery connection to the
monitor.
To use the patient unit, the patient unit is
removed from the retaining means and attached and secured
on an appropriate location on the patient. While the
patient unit is attached to the patient, a sensor
generates a signal indicative of the patient's vital signs
and outputs the signal to a control means of the patient
unit. The control means determines an instantaneous
quantitative value of the patient's vital signs from the
signal and stores it in a memory means.
When the doctor or nurse needs to review the
patient's vital sign, the patient unit is detached from
the patient and returned to the patient unit retaining
means. The monitor detects the return of the patient unit
to the retaining means. A communications means is estab-
lished with the patient unit. The patient unit then
transmits the quantitative data (which was stored in the
memory means) indicative of the instantaneous level of the
vital sign being monitored to the main monitor. The
patient unit may also transmit time data indicating when
the vital sign was measured, and status data for verifying
the accuracy of the data. The main monitor then stores
this transmitted quantitative data (and the other data if
provided) for later display and/or immediately displays
it.
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Accordingly, it is a primary object of the present
invention to provide a vital sign measurement system
having a main monitor and at least one portable patient
unit for remotely and intelligently measuring and storing
a vital sign of a patient.
It another object of the present invention to
provide a vital sign measurement system wherein each of
the at least one patient unit comprises a portable sensor
which generates measurement data and a control means which
processes the measurement data into quantitative data
prior to transmitting the data to the main monitor.
It is a further object of the invention to provide
a vital sign measurement system comprising a memory means
in the patient unit for storing the quantitative data
prior to transmission.
It is yet another object of the invention to
provide a vital signs measurement system comprising at
least one portable sensor which wirelessly transmits data
to and receives data from the main monitor.
These and other objects, features and advantages
of the present invention are described in and are apparent
from the following details description of the preferred
embodiments of the invention.
RIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiments will be described with
reference to the drawings, in which like elements have
been denoted with like reference numerals throughout the
figures, and in which:
Figure 1 is a perspective view of the main moni-
tor;
Figure 2A is a perspective view of a first surface
of a tympanic temperature patient unit of a first pre-
ferred embodiment of the present invention;
Figure 2B is a perspective view of a second
3S surface of the tympanic temperature patient unit of the
first preferred embodiment of the present invention;
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Figure 2C is a perspective view of a first surface
of a tonometric blood pressure patient unit of a fourth
preferred embodiment of the present invention;
Figure 2D is a perspective view of a second
surface of a tonometric blood pressure patient unit of the
fourth preferred embodiment of the present invention;
Figure 3 is a block diagram of a retaining means
of the main monitor of the present invention;
Figure 4 is a block diagram of the components of a
patient unit of the present invention; and
Figure 5 is a block diagram of the components of
the main monitor of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figures 1, 2a, 2b and 3, in a first
preferred embodiment, a main monitor 10 comprises at least
one patient unit retaining means 12 (designated 12-1
through 12-N), a microprocessor 20 and associated memory
22, other blood pressure device electronics 24 and display
means 26. Each patient unit retaining means 12 comprises
a communications means 14 and holding means 16. In the
first preferred embodiment the communication means 14
comprises an infrared detector or receiver 14A. In a
second preferred embodiment, the patient unit retaining
means 12 also comprises a pair of rechargeable battery
charging terminals 18 for connecting a rechargeable
battery to a recharging source. In a third preferred
embodiment, the communication means 14 comprises a plug
receptacle.
As shown in Fig. 5, the microprocessor 20 is
connected to a receiver buffer 14C, which is in turn
connected to the receiver 14A. The microprocessor 20 may
also be connected to a memory means 22, which comprises a
RAM 22A and a ROM 22B. The display means 26 is connected
to the microprocessor and can be a cathode ray tube, an
LED display, a printer or the like. Finally, the micro-
processor 20 is connected to the other blood pressure
device electronics 24. As shown in Figs. 2A and 2B, in
the first preferred embodiment, the patient unit is a
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tympanic temperature patient unit, and the main monitor is
a standard blood pressure monitor. The main monitor has a
blood pressure sensor (not shown) which, in a conventional
manner, is connected to the main monitor by appropriate
sensor cables and senses blood pressure. The main
monitor's blood pressure electronics 24 controls the
sensor and processes the signals outp~t by the blood
pressure sensor. The blood pressure sensor may be any
conventional blood pressure sensor, including a tonometric
blood pressure sensor.
In a fourth preferred embodiment shown in Figs. 2C
and 2D, the conventional blood pressure sensor and the
blood pressure electronics are replaced by a tonometric
blood pressure patient unit, which tonometrically senses
blood pressure, and processes the sensor signal in the
same manner as the tympanic temper patient unit. In this
fourth embodiment other vital signs patient units, such as
the tympanic temperature patient unit of the first pre-
ferred embodiment, can also be provided.
Referring to Figs. 2A-2D, each patient unit 30
comprises a housing 28 which encloses the-sensor 38 and
all of the related electronics. A shown in Figs. 2C and
2D, an attachment means 32, such as a belt, a clip or the
like, for attaching the patient unit 30 to the patient may
be provided. As shown in Figures 2A-2D, the patient unit
30 comprises a second communication means 34 having an
infrared transmitter 34A. The infrared transmitter 34A
preferably is arranged on the patient unit 30 such that
when the patient unit 30 is in one of the retaining means
12, the infrared transmitter 34A is opposite the infrared
receiver 14A. However, if data is to be transmitted
solely when the patient unit is remote from the main
monitor, the second communication means 34 can be located
anywhere on the patient unit 30.
In the second preferred embodiment, the patient
unit 30 also includes a rechargeable-type battery and
rechargeable battery terminals 36 which are arranged on
the patient unit 30 such that when the patient unit 30 is
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in retaininq means 12, the rechargeable battery terminals
36 are in direct contact with rechargeable battery termi-
nals 18 provided in the retaining unit 12. The battery
terminals 18 and 36 establish a circuit between the
rechargeable-type battery 52 (shown in Fig. 4) and the
rechargeable battery recharging means (not shown) of main
monitor 10. In the third preferred embodiment, the second
communication ~eans 34 comprises a plug, and the communi-
cation means 1~ comprises a plug receptacle.
As shown in Figure 4, the sensor 38, which is
placed in contact with a patient, senses a vital sign of a
patient, such as temperature, blood pressure, respiration
rate, pulse rate, blood gases, respired gases or the like,
and generates an analog signal indicative of the vital
sign being measured.
For example, the sensor 38 could be a tympanic
temperature sensor, or a tonometric blood pressure sensor
such as is described in U.S. Patent 4,802,488 to Eckerle,
which is incorporated herein by reference. The sensor 38
which is connected to an electrical transducer 40 which in
turn is connected to a signal conditioning means 42. The
signal conditioning means conditions the raw data signal
generated by the transducer 40 by providing any necessary
amplification/scaling, filtering and offset correction to
the raw data signal. Each different sensor will generally
require different types and amounts of conditioning, but a
fuller explanation of this is beyond the scope of this
invention.
The signal conditioning means 42 is connected to
an analog-to-digital (A/D) converter 44 which converts the
analog data signal to a digital data signal. The A/D
converter is connected to a control means 46. The control
means 46 converts the digital data signal to a quantita-
tive value indicative of the instantaneous value of the
vital sign, and stores the quantitative value to a RAM 48A
of a first memory means 48. The control means may also
add status data and time data, indicative of the time
the measurement of the vital sign was made, to the
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quantitative data. The quantitative data is in the form
of a single numerical value of the vital sign sensed. For
example, a temperature sensing patent unit may store a
quantitative datum of 98.6, which is indicative of a
normal temperature. The first memory means 48 also
contains a ROM 48B for storing a control program for the
control means 46.
Also connected to the control means 46 is the
second communication means 34. The patient unit 30 also
comprises a detection means 54 for detecting whether the
sensor is in one of the retaining means 12. Finally, the
patient unit 30 has a battery 52 which supplies power to
all of the other components of the patient unit 30.
In operation, the patient unit 30 is stored in one
of the retaining means 12 when not in use. In the second
preferred embodiment, while in the retaining means, the
rechargeable-type battery 52 is connected through
rechargeable battery terminals 36 and 18 to the
rechargeable battery recharging means and is kept in a
fully charged state.
When a physician, nurse or the like needs to
measure one of a patient's vital signs, such as
temperature, the appropriate patient unit 30 is removed
from one of the retaining means 12 and placed into an "ON"
2S mode. For example, to measure a patient's temperature, a
temperature sensing patient unit is selected. In a
preferred embodiment, the temperature sensing patient unit
comprises a tympanic temperature patient unit, which is
inserted into the patient's ear. In the first preferred
embodiment, the tympanic temperature patient unit is held
by the physician, nurse or the like, and placed in contact
with the patient and a single measurement made. In the
fourth preferred embodiment, the tonometric blood pressure
patient unit is attached to the patient so that a number
of measurements can be made. In further preferred embodi-
ments, a vital sign patient unit may be adhesively
attached to the patient, or simply placed upon the
patient.
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g
Once in contact with the patient, the patient unit
may make one, or a series, of vital si~n measurements. In
the first preferred embodiment, which uses an infrared
transmission system, it would not be necessary to return
the patient unit to the retaining means 12. Rather, the
patient unit is aimed at the main monitor. The doctor,
nurse or the like operates a switch (not shown) provided
on the patient unit 30 which causes the control means to
begin transmitting data to the main monitor. In this
embodiment, the second communication means 34 would have
to be aimed at the communication means 14 for communica-
tion between the patient unit and main monitor to be
established.
To take a measurement of a patient's vital signs,
the patient unit 30 is placed into an "ON" mode, placed in
contact with the patient and the sensor 38 begins sensing
a particular vital sign of the patient. As the sensor 38
senses the vital sign of the patient, it causes the
transducer 40 to produce an analog signal indicative of
this vital sign. The analog signal is conditioned by
running it through the signal conditioning means 42, then
converting to digital form by an A/D converter 44. The
digital signal is then transmitted to the control means
46, which generates a single quantitative or numerical
value of the instantaneous level of the patient's vital
sign from the digital signal. This quantitative value is
then stored in the RAM 48A. Alternatively, when only a
single measurement is to be made, the quantitative value
can be held by the microprocessor 46. As the guantitative
value is determined, the control means may also generate
time data indicative of the time period the quantitation
data relates to, and status data for verifying the
accuracy of the quantitative data. The time data and
status data are also then stored to the gAM 48A.
Once the desired number of vital sign measurements
have been taken, the data stored in the microprocessor 46
or RAM 48B is transmitted to the main monitor. In the
first preferred embodiment, the communication means 14 is
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open. The communication means 14 may be kept open contin-
uously, or may open (and close) automatically when the
patient unit is removed from (and returned to) the patient
unit holding means 16. To automatically open and close
the communication means 14, a detection means 56 for
detecting the presence and/or absence of the patient unit
30 is provided. In the first preferred embodiment, the
patient unit 30 transmits the data directly to the main
monitor 10, without any formal handshaking. To ensure the
data has been correctly received by the first communica-
tion means receiver 14A, the patient unit 30 transmits the
data 3 times.
In an alternative preferred embodiment, the data
is transmitted automatically upon returning the patient
unit 30 to the holding means 16. After detecting means 54
detects that patient unit 30 has been returned to the
retaining means, the control means 46 recalls the quanti-
tative data (and the time and status data if generated)
stored in the RAM 48A and loads it into the receiver
transmitter buffer 34C. As in the first preferred embodi-
ment, the detection means 56 detects the return of the
patient unit 30 and opens the communication means 14. The
quantitative data (and time and status data) stored in the
buffer 34C is then transmitted by infrared transmitter 34A
to an infrared receiver 14A which converts the infrared
signals to electrical signals, which are stored in the
receiver transmitter buffer 14C. The microprocessor 20
then removes the quantitative data (and time and status
data) from the buffer 14C and either immediately displays
the data on the display means 26 or stores it for later
display in the RAM 22A. The display means may comprise a
CRT, an LED or other usual means; a printer or plotter or
other graphical means; or an output means for transmitting
an electrical or optical signal to a further processing
means. This sequence is also repeated 3 times to ensure
the data has been properly transmitted.
In the second preferred embodiment, the recharge-
able battery would be automatically recharged when the
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patient unit 30 is returned to the retaining unit 12. In
the third preferred embodiment, communication between the
patient unit 30 and the main monitor 10 would be estab-
lished by inserting the plug on the patient unit 30 into
the receptacle of the retaining unit 12 to mechanically
complete the transmission circuit between the second
communication means 34 and the communication means 14.
In a fifth preferred embodiment, the main monitor
10 also includes a transmitter 14B, and the patient unit
30 also includes a receiver 34B. In this manner, fully
two way communication, including handshaking, is estab-
lished between the main monitor 10 and the patient unit
30. This allows for correction of erroneously transmitted
data, and for transmission of data to the control means of
the patient unit, such as alarm limits or data for
"tuning" the patient unit to the physiology of a
particular patient.
While this invention has been described in con-
junction with the specific embodiments thereof, it is
evident that many alternatives, modifications and varia-
tions will be apparent to those skilled in the art.
Accordingly, the preferred embodiments of the invention as
set forth herein are intended to be illustrative, not
limiting. Various changes may be made without departing
from the spirit and the scope of the invention as defined
in the following claims.
