Physiological parameter measuring system

• US 4,232,682 A
• Filed: 08/21/1978
• Issued: 11/11/1980
• Est. Priority Date: 08/21/1978
• Status: Expired due to Term

• Current Assignee: United States Surgical Corporation (Medtronic Plc)
• Original Assignee: United States Surgical Corporation (Medtronic Plc)
• Inventors: Veth, George J.
• Primary Examiner(s): Michell, Robert W.
• Assistant Examiner(s): Jaworski, Francis J.
• Application Number:
  US05/935,642
• Time in Patent Office: 813 Days
• Field of Search: 73/359 R, 73/362 AR, 73/362 SC, 364/415, 364/417, 364/557, 364/577, 364/723, 364/853, 128/670, 128/671, 128/689, 128/724, 128/736
• US Class Current: 600/484
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: G01K 13/20 Clinical contact thermometers for use with humans or animals

Abstract

A system for measuring physiological parameters such as temperature, pulse rate, and respiration rate employs specialized algorithms in combination with a digital processor to provide accurate measurements in a short period of time which are then displayed to the system operator. Mathematical curve fitting principles and a specialized algorithm are employed by the digital processor to implement the measurements. Automatic error signals and alarm signals are produced whenever a reading is determined to be inaccurate or abnormal. The system is entirely self-contained and, upon completion of a measuring cycle, actuation of the appropriate function key, will visually display the desired measurement to the operator.

Claims

1. A portable electronic apparatus capable of being transported to, and successively and rapidly servicing, individually a plurality of patients by simultaneously measuring temperature, pulse rate, and respiration rate for each successive patient, comprising:

a plurality of sensing means for measuring said temperature, pulse and respiration, respectively, and each simultaneously providing a signal corresponding to said temperature, pulse, and respiration, respectively;

converting means for receiving and converting said signals corresponding to said temperature, pulse and respiration, respectively, to produce corresponding digital data signals, said corresponding digital data signals including a series of measurement values leading to a single measurement value;

processing means for receiving and processing said corresponding digital data signals so as to calculate said single measurement value for temperature before said single measurement value for temperature is reached, and so as to calculate a pulse rate and a respiration rate, and for determining, by analysis of said corresponding digital data signals, invalidity of at least one of the temperature, pulse and respiration calculations, said processing means generating indication signals indicating said invalidity of said at least one of the temperature, pulse and respiration calculations;

indicator means responsive to said indication signals for alerting an operator of said portable electronic apparatus each time said invalidity of said at least one of the temperature, pulse and respiration calculations is indicated; and

display means connected to said processing means for displaying said single measurement value for temperature, said calculated pulse rate, and said calculated respiration rate.

2. The apparatus of claim 1 wherein said sensing means for providing a signal corresponding to temperature comprises a thermistor and a voltage controlled oscillator.

3. The apparatus of claim 2 wherein said converting means for producing a digital output signal representing temperature sensed further comprises means for determining when said temperature reaches ninety-four degrees Fahrenheit.

4. The apparatus of claim 1 wherein said processing means further comprises means for implementing a predetermined algorithm utilizing said pulse and respiration digital data signals to determine the validity thereof, comprising the steps of (1) setting a first average equal to a preselected value, and setting an upper limit to a maximum value and a lower limit to a minimum value;

(2) generating a second new average utilizing said pulse and respiration digitial data signals which are less than the upper limit and greater than the lower limit;

(3) comparing the first selected average with said second new average;

(4) if the two values are within a preselected variance, then determining the number of data points used to generate the second new average;

(5) if this number determined in step (4) is greater than a preselected value, labeling the average valid;

(6) if the number determined in step (4) is not greater than said preselected value, labeling the average invalid, and supplying a signal to said indicator means for producing said indication of said invalidity of said at least one of the pulse and respiration digital data signals; and

(7) calculating a further new average, and repeating steps (2)-(7) above.

5. Electronic apparatus for simultaneously measuring temperature, pulse rate, and respiration of a patient, said apparatus comprising:

a plurality of sensing means for providing signals corresponding to temperature, pulse, and respiration;

oscillator means connected to receive said temperature signal for producing a signal having a frequency proportional to the temperature sensed;

first and second amplification and filtering means connected to receive said pulse signal and said respiration signal respectively for amplifying said received signals and for producing output signals only upon the occurrence of a signal corresponding to a pulse or respiration of the patient;

means connected to receive said frequency signal proportional to temperature for producing a digital output signal representing the temperature sensed;

clock means for producing a synchronizing signal having a first preselected frequency, a gate signal having a preselected frequency less than said first preselected frequency, and binary output signals representing preselected time intervals;

interrupt means connected to receive said clock signal, said gate signal and said output signals from said first and second amplification and filtering means for producing an interrupt signal and a pulse flag signal each time a pulse signal is received and for producing said interrupt signal and a respiration flag signal each time a respiration pulse is received and for producing said interrupt signal each time said gate signal is received;

digital processing means connected to receive said interrupt signals, said flag signals, and said synchronizing signals, said digital signal representing temperature, and said binary signal representing preselected time intervals, for calculating a final temperature value prior to reaching said final temperature, said calculation being made according to a first algorithm based on a least square fit to a hyperbolic curve, said digital processing means serving also for calculating a pulse rate and a respiration rate according to a second algorithm including steps for determining if pulse rate and said respiration rate data are within certain tolerances in order to determine validity of such data; and

display means connected to said digital processing means for selectively displaying said final temperature value, said calculated pulse rate, and said calculated respiration rate.

6. The apparatus of claim 5 wherein said first and second amplification and filtering means each comprises:

at least two amplification stages for amplifying all input signals to a preselected upper level; and

mono-stable multivibrator means for producing a pulse having a predetermined pulse width for eliminating noise signals from said amplification and filter means output signals.

7. The apparatus of claim 5 wherein said means for producing a digital output signal representing the temperature sensed comprises:

a first coincidence gate having a first input receiving said frequency signal proportional to temperature and a second input receiving said synchronizing signal and producing a pulsed output signal;

binary counter means connected to said pulsed output signal for producing on parallel output lines a binary value of the pulses in said pulsed output signal; and

a second coincidence gate connected to receive at least two of said parallel output lines for producing an output signal upon the occurrence of signals representing a predetermined temperature.

8. The apparatus of claim 7 wherein said predetermined temperature is 94°

F.

9. The apparatus of claim 5 wherein said digital processing means utilizes said binary output signals representing preselected time intervals, said interrupt signals and said flag signals in connection with said second algorithm to determine an average of the time occurring between successive pulses and respiration of the patient and to check the time between each respective successive pulse or respiration occurrence with said average in order to determine the validity of the detected data.