VECTOR CONTOUR PLOT OF PHYSIOLOGICAL PARAMETERS

• US 3,811,040 A
• Filed: 09/27/1972
• Issued: 05/14/1974
• Est. Priority Date: 09/27/1972
• Status: Expired due to Term

• Current Assignee: Marquette Electronics (General Electric Company)
• Original Assignee: Phillip T. Weinfurt, Robert P. Lijewski
• Inventors: Weinfurt, Phillip T., Lijewski, Robert P.
• Primary Examiner(s): Ruggiero, Joseph F.
• Application Number:
  US05/292,605
• Time in Patent Office: 594 Days
• Field of Search: 235/193,151.3,151 444/1 128/2.6V,2.6R 340/324A,324AD
• US Class Current: 702/67
• CPC Class Codes: A61B 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/7242 using integration
• CPC Class Codes: G01R 13/208 Arrangements for measuring with C.R. oscilloscopes, e.g. vectorscope
• CPC Class Codes: G01R 17/00 Measuring arrangements involving comparison with a reference value, e.g. bridge
• CPC Class Codes: G06G 7/60 for living beings, e.g. their nervous systems ; for problems in the medical field

Abstract

Equiangularly spaced vectors correspond respectively with physiological parameters such as heart rate, blood pressure and others. The ends of the vectors are connected and preferably form a circular contour on an oscilloscope display screen or printed readout. Variation of the vectors from their reference or normalized value causes the contour to change. Converse operation is also explained. Limit markers for each vector parameter are displayed. An algorithm for representing the parameters as a contoured figure is presented. The plot generator may be built with analog or digital devices or both.

Claims

1. Apparatus for producing a visible contour plot representative of a plurality of presently measured parameter values compared with initially selected parameter values, comprising:

a. first means for receiving a sequence of electric signals which correspond with the respective presently measured parameter values, each signal being designated P(t) and each being representative of a particular parameter value, b. second means for receiving and storing said sequence of signals at a time characterized as initializing and normalizing time, each such signal for a particular parameter being designated P(TN), c. subtraction means for receiving said signals from the first and second means and for sequentially subtracting the signals so that a difference signal corresponding with each parameter is represented by (P(t) - P(TN)), d. means for adding to each signal for a parameter a selectable constant value RN where RN equals the predetermined vector radius length for a normalized circular contour plot, thereby producing a final set of signals which are each represented by (P(t) - P(TN)) + RN which is a vector designated R(t), the instantaneous signal value representative of each parameter in a sequence including all of the signals, and e. display means for receiving said signals R(t) and for producing visible representations thereof about respective intersecting axes which axes correspond with each parameter.

2. The apparatus set forth in claim 1 including:

a. means for multiplying each difference signal, (P(t) - P(TN)), respectively, by a predetermined unique sensitivity factor K so as to produce a sequence of signals in which each parameter is represented by K(P(t) - P(TN)) for thereby producing a final set of signals which are each represented by K(P(t) - P(TN)) + RN when RN is added to each signal.

3. The invention set forth in claim 1 including:

a. means for producing electric signals corresponding with predetermined limits of said respective parameter values, said limit signals being introduced in said first means and being designated L(t), b. said limit signals each also having subtracted therefrom in said subtraction means in sequence a corresponding initial parameter value P(TN) to produce difference signals represented by (L(t) - P(TN)), c. said adding means also adding to each of the last named signals the selectable constant value RN to produce a sequence of signals represented by (L(t) - P(TN)) + RN which is a vector designated RL(t), the instantaneous limit values for each parameter in a sequence, said signals RL(t) being displayed substantially concurrently with said parameter representing signals R(t).

4. The apparatus set forth in claim 3 including:

a. means for multiplying each difference signal, (L(t) - P(TN)), respectively, by a predetermined unique sensitivity factor K to produce a sequence of signals in which said limits are represented by K(L(t) - P(TN)) for thereby producing a final set of limit signals which are each represented by K(L(t) -P(TN)) + RN when RN is added to each signal.

5. The invention set forth in claim 1 including:

a. switching means selectively operable to switch initial parameter value representing signals P(TN) into said second storage means.

6. The invention set forth in claim 3 wherein:

a. said display means comprises writing means operable in response to parameter and limit signals and including means for effecting visible writing on a medium, and including b. first and second multiplier means for receiving said sequence of RL(t) and R(t) signals and being coupled with said display means, c. a cosine waveform signal generator connected to one multiplier means and a sine waveform signal generator connected to another of said multiplier means, said sine and cosine waveforms having the frequency designated theta , the final sets of signals also being supplied to each of said multiplier means, the output of said multiplier means constituting voltages, respectively, controlling said writing means, said waveform generators being for causing a Lissajou circle to be plotted on said medium when said parameter corresponding signals in said final set are equal and said plot being non-circular when any signal in said final set is not equal to the others.

7. The invention set forth in claim 6 wherein:

a. said display means comprises an oscilloscope.

8. The apparatus set forth in claim 1 including:

a. latch means for receiving the output difference signals from said signal subtracting means in a predetermined sequence, and b. means for inhibiting said second storage means from receiving parameter value representing signals when said latch means is accepting difference signals from said subtracting means.

9. The apparatus set forth in claim 1 wherein:

a. said second and first signal receiving means are adapted to stor digital signals and said subtraction means is adapted to process digital signals, b. latch means receiving the output digital difference signals from said subtraction means, said latch means being responsive to consecutive reading control signals by reading the instantaneous difference signals in a repeatable sequence from said subtraction means, and c. a digital-to-analog converter receiving the digital output signals from said latch means and converting said signals to a sequence of analog signals.

10. The apparatus set forth in claim 9 including:

a. first order integrator means connected to the output of said means for adding a selected constant signal value, RN, to each in the set of difference signals, said integrator means converting said analog signals from a stepped waveform to a smoothed waveform.

11. The apparatus set forth in claim 6 wherein:

a. said means for subtraction is adapted to process digital signals, b. a digital-to-analog converter, c. means for producing read initiating signals, d. latch means adapted to respond to consecutive read signals by gating said digital difference signals in a predetermined Sequence to said converter, said converter producing a sequence of analog signals corresponding with the difference signals, e. third and fourth multiplier means, the third being adapted to multiply a new sequence of signals by Sin 2 theta and the fourth being adapted to multiply a near preceding old sequence of signals by Cos 2 theta , where 2 theta is twice the frequency of theta , f. means for summing the output signals from said third and fourth multipier means, and g. means for applying said summed signals simultaneously to said first and second multiplier means and concurrently with the signals at frequency theta from said sine and cosine waveform generators.

12. The apparatus set forth in claim 1 including means for producing fiducial lines dividing said plot into sectors in said display where said fiducial lines are equiangularly spaced from each other, said fiducial line producing means comprising:

a. means for generating consecutive pairs of control signals occurring in time frames, respectively, equal in number to the number of fiducial lines to be written, b. means for coupling said control signals simultaneously to said display means, said display means responding by displaying said fiducial lines.

13. Apparatus for producing a visible contour plot representative of a plurality of presently measured parameter values, comprising:

a. first means for receiving a sequence of electric signals which correspond with the respective presently measured parameter values, each signal being designated P(t) and each being representative of a particular parameter value, b. second means for receiving and storing a selected sequence of signals which correspond respectively with prospective parameter values and are designated P(ideal), c. subtraction means for receiving said signals from the first and second means and for sequentially subtracting the signals so that a difference signal corresponding with each parameter is represented by (P(t) - P(TN)), d. means for adding to each signal for a parameter a selectable constant value RN where RN equals the predetermined vector radius length for a normalized circular contour plot, thereby producing a final set of signals which are each represented by (P(t) - P(ideal)) + RN which is a vector designated R(t), the instantaneous signal value representative of each parameter in a sequence including all of the signals, and e. display means for receiving said signals R(t) and for producing visible representations thereof about respective intersecting axes which axes correspond with each parameter.

14. The apparatus set forth in claim 1 including:

a. a first order integrator means having as one input an existing final set of electric signals and as another input a previously existing final set of signals, said integrator means integrating the existing and next preexisting signals to produce an electric signal waveform having sharp transition points coincident with each parameter, b. a pair of electric signal multipliers each having an input for simultaneously receiving said electric signal waveform, c. a sine wave signal generator supplying its signal to another input to one of said multipliers, d. a cosine wave signal generator supplying its signal to another input to the other of said multipliers, e. the output signals from said multipliers being applied to said display means.

15. The apparatus set forth in claim 1 including:

a. a sine wave signal generator and a cosine wave signal generator, whose output signals have a frequency theta , b. a multiplier having an input for said sine wave signals and another multiplier having an input for said cosine wave signals, c. sine and cosine wave signal generators whose output signals have the frequency 2 theta , d. a second pair of multipliers each having at least two inputs, an input of one receiving the sine 2 theta signals and a corresponding input of the other receiving the cosine 2 theta signals, e. the multiplier in the second pair receiving said sine 2 theta signals also receiving the next preexisting signals Rn(t) representative of said parameters, f. the multiplier in the second pair receiving said cosine 2 theta signals also receiving the existing set of signals Rn 1(t) representative of said parameters, g. means summing the output signals from said second pair of multipliers, and h. means applying the summed signals to each of said first pair of multipliers, whereby to produce a smooth transition set of electric signals for driving said display device.

16. The invention set forth in claim 1 including:

a. means for detecting the absence of a signal in said sequence of signals which corresponds with the absence of a parameter, and b. means responsive to said detecting means for interrupting said visible representation of said absent signal on said display device.

17. The invention set forth in claim 1 including:

a. means for detecting the absence of a signal in said sequence of signals, which corresponds with the absence of a parameter, and b. means responsive to said detecting means for interrupting the visible display of an axis associated with that part of said contour plot for which the parameter signal is absent.

18. The invention set forth in claim 3 including:

a. means for detecting a signal indicative of a parameter limit having been exceeded, b. and means responsive to said detecting means for controlling said display means to repeatedly interrupt the display of said limit signal which corresponds with the parameter which has been exceeded.