Method and apparatus for correlating the display of information contained in two information signals

• US 4,958,640 A
• Filed: 12/23/1988
• Issued: 09/25/1990
• Est. Priority Date: 12/23/1988
• Status: Expired due to Fees

• Current Assignee: Spacelabs, Inc. (OSI Systems Incorporated)
• Original Assignee: Spacelabs, Inc. (OSI Systems Incorporated)
• Inventors: Logan, Charles H.
• Primary Examiner(s): Jaworski, Francis
• Assistant Examiner(s): Manuel, George
• Application Number:
  US07/289,386
• Time in Patent Office: 641 Days
• Field of Search: 128/671, 128/706, 128/708, 128/710, 364/413.13, 364/413.04, 364/413.05, 364/413.06
• US Class Current: 600/484
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/339 Displays specially adapted therefor
• CPC Class Codes: A61B 5/7445 Display arrangements, e.g. multiple display units
• CPC Class Codes: G06F 2218/10 by analysing the shape of a waveform, e.g. extracting parameters relating to peaks

Abstract

Apparatus for displaying first and second information signals includes detection circuitry for detecting the first and second signals to be displayed as well as detecting the occurrence of a predetermined phenomenon with respect to the first information signal. The first and second information signals are processed in conjunction with a timing signal to provide a display signal, wherein the display signal is adapted to be displayed using known display circuitry. Detection of the predetermined phenomenon provides an interrupt to the processing of the information signals such that the occurrence of the predetermined phenomenon can be recorded, in time correlation with the occurrence of the first and second information signals. The information signals are thereafter processed so that the ocurrence of the predetermined phenomenon can be displayed in time correlation with either the first or second information signal.

Claims

1. An apparatus for displaying first and second information signals, each with reference to the occurrence of a predetermined phenomenon, comprising:

detection means for monitoring the first information signal to detect the predetermined phenomenon and for providing an interrupt signal in response thereto;

timing circuit means for providing at least one timing signal to create a timing reference frame;

data display means, responsive to a display signal, for providing a visual indication of a predetermined characteristic of the first and second information signals; and

data processing means for receiving the first and second information signals and the at least one timing signal to provide the display signal, said data processing means being responsive to the interrupt signal and the at least one timing signal to alter the display signal such that the display of the second information signal is also altered thereby to indicate the occurrence of the predetermined phenomenon in real-time relationship with the display of the predetermined characteristic of the second information signal.

2. The apparatus of claim 1 wherein said data processing means comprises input means for receiving user provided input signals, said data processing means being responsive to the user provided input signals for providing the first information signal at a first sweep rate and for providing the second information signal at a second sweep rate such that the first sweep rate is a multiple of the second sweep rate, said data processing means being also adapted to maintain a time correlation between the occurrence of the predetermined phenomenon and the second information signal.

3. The apparatus as recited in claim 2 wherein the first and second information signals have voltage magnitudes and wherein the predetermined characteristic is the magnitude of voltage of the first and second information signals, said data processing means including means for providing the display signal such that the first and second information signals are displayed as graphs of continuous signals.

4. The apparatus as recited in claim 3 wherein said data display means includes means for providing a variable intensity display in response to the display signal and wherein selected portions of the variable intensity display of the second information signal are intensified in response to the display signal to indicate the occurrence of the predetermined phenomenon.

5. The apparatus as recited in claim 4 wherein the first and second information signals comprise heart rate and respiration rate signals of a patient, respectively, said apparatus further comprising sensor means for providing a heart rate output signal indicative of the heart rate of the patient, said sensor means being further adapted to provide a respiration rate output signal indicative of the respiration rate of the patient.

6. The apparatus as recited in claim 5 wherein the heart rate signal is indicative of a QRS complex and wherein the predetermined phenomenon is the occurrence of the QRS complex indicated by the heart rate signal, said detection means further comprising means for detecting the QRS complex.

7. An apparatus for monitoring and displaying the respiration and heart rate of a patient, comprising:

sensor means for providing a heart rate output signal indicative of the heart rate of the patient, said sensor means being also for providing a respiration rate output signal indicative of the respiration rate of the patient, wherein both the heart rate and respiration rate output signals comprise alternating current voltage signals having a varying voltage magnitude;

QRS signal detector means responsive to said sensor means for detecting the occurrence of a QRS complex and for providing in response thereto a QRS interrupt signal;

timing signal generator means for providing a timing signal, said timing signal comprising a periodic signal having a predetermined period;

data processing means for storing the output from said sensor means, said data processing means being responsive to the timing signal to obtaining store a plurality of respiration rate data samples and a plurality of heart rate data samples, wherein each said respiration rate data sample is indicative of the value of the voltage of the respiration rate output signal at the time the respiration rate data sample is obtained and wherein each heart rate data sample is indicative of the value of the voltage of the heart rate output signal at the time the heart rate data sample is obtained, said data processing means being further responsive to the QRS interrupt signal for providing a timing byte signal wherein the timing byte signal indicates the timing of the occurrence of the QRS complex relative to the timing signal; and

data display means for providing a visual indication of the respiration and heart rate of the patient, said data display means including a display medium for providing a variable intensity display and being responsive to the timing signal and the plurality of heart rate and respiration rate data samples for displaying a heart rate and respiration rate signal on said display medium such that the positioning of the signals is indicative of the sensed heart rate and respiration rate, said data display means being further responsive to the timing byte signal to alter the intensity of a portion of the respiration signal to thereby indicate the times of the occurrences of the QRS complex.

8. The apparatus as recited in claim 7 wherein said data display means comprises input means for receiving user provided input signals, said data display means being responsive to the user provided input signals for displaying the heart rate and respiration rate signals at different sweep speeds, said data display means being further adapted to maintain correlation between the timing byte and the respiration signal to thereby maintain correlation between the occurrence of the QRS complex and the respiration signal.

9. The apparatus as recited in claim 8 wherein said data processing means comprises:

a multiplexer coupled to said sensor means and adapted to selectively provide either the heart rate output signal or the respiration rate output signal as said multiplexer output signal;

an analog-to-digital converter coupled to receive the output from said multiplexer and to provide in response thereto the heart rate and respiration rate data samples; and

first microprocessor circuit means for controlling said multiplexer and said analog-to-digital converter, said first microprocessor circuit means being also adapted to receive and store the heart rate and respiration rate data samples, said first microprocessor circuit means being responsive to the QRS interrupt signal for providing the timing byte signal.

10. The apparatus as recited in claim 8 wherein said timing signal generator means comprises first and second timing circuits, said first timing circuit being adapted to provide a first clock signal at a rate of 56 cycles per second and said second timing circuit being adapted to provide a second clock signal at a rate of 448 cycles per second, the first and second clock signals comprising the timing signal, the first clock signal being used to indicate the beginning of a timing byte and the second clock signal being used to indicate a period during the timing byte wherein the QRS interrupt signal is provided.

11. The apparatus as recited in claim 8 wherein said data display means further comprises means for providing the display signal such that the displayed heart and respiration rate signals do not appear jagged.

12. An apparatus for monitoring and displaying the respiration and heart rate of a patient, comprising:

first, second and third sensors each adapted to be coupled to the patient;

an electrocardiograph amplifier coupled to said first and second sensors for generating a heart rate signal indicative of the heart rate of the patient and amplifying the heart rate signal to provide an amplified heart rate signal as its output wherein the time rate of change of the voltage magnitude of the amplified heart rate signal is indicative of the heart rate of the patient;

a respiration amplifier coupled to said first and third sensors for generating a respiration rate signal indicative of the respiration rate of the patient and for amplifying the respiration rate signal to provide an amplified respiration signal as its output, wherein the time rate of change of the amplified respiration rate signal is indicative of the patient'"'"'s respiration rate;

a QRS signal detector coupled to receive the amplified heart rate signal and adapted to provide in response thereto a QRS interrupt indicating the occurrence of the QRS complex;

a multiplexer coupled to receive the amplified heart rate signal and the amplified respiration signal and responsive to a multiplexer control signal to provide a single multiplexer output corresponding to either the amplified heart rate signal or the amplified respiration signal;

an analog-to-digital converter responsive to an A/D control signal for receiving the multiplexer output from said multiplexer and providing a multiple bit digital output indicative of the voltage magnitude of the multiplexer output, wherein each said multiple bit digital output provided comprises a data sample being a heart rate sample if the multiplexer output is the amplified heart rate signal and the data sample being a respiration rate sample if the multiplexer output is the amplified respiration signal;

a timing generator for providing first and second clock signal outputs, said first and second clock signals each comprising periodic signals having first and second predetermined periods, respectively, wherein said first period is an integral multiple of said second period;

first microprocessor circuit means for receiving and storing the heart rate samples and the respiration rate samples, said first microprocessor circuit means being adapted to receive the first and second clock signals and being responsive to the first and second clock signals to provide the multiplexer control signal and the A/D control signal such that a heart rate sample is provided from said analog-to-digital converter with each occurrence of the second clock signal and a respiration rate sample is provided from said analog-to-digital converter with each occurrence of the first clock signal, said first microprocessor circuit means including random access memory and being further adapted to store the heart and respiration rate samples provided from said analog-to-digital converter in said memory, said first microprocessor circuit means being responsive to the QRS interrupt for providing a timing byte wherein the timing byte indicates the occurrence of the QRS complex relative to the first and second clock signals;

display means responsive to a display signal for providing a visual indication of the respiration and heart rate of the patient; and

second microprocessor circuit means for providing the display signal in response to the heart and respiration rate samples, the first and second clock signals and the timing byte, said second microprocessor circuit means being adapted to retrieve a plurality of heart rate and respiration rate samples and a plurality of timing bytes from said memory, said second microprocessor circuit means being responsive to the plurality of heart rate and respiration rate data samples for creating the display signal wherein the display signal contains information for reconstructing heart and respiration signals and for positioning the reconstructed heart signal and the reconstructed respiration signal on said display means such that the positioning of the signals indicates their voltage magnitude, said second microprocessor circuit means being further responsive to the timing byte to alter the display signal such that the respiration signal is intensified upon each occurrence of the QRS complex.

13. The apparatus as recited in claim 12 wherein said second microprocessor circuit means comprises input means for receiving user provided input signals, said second microprocessor circuit means being responsive to the user provided input signals for averaging a plurality of the respiration rate samples to provide a plurality of averaged respiration rate samples and for providing the display signal such that the sweep rate at which the heart rate signal is displayed is a multiple of the sweep rate at which the respiration rate signal is displayed, said second microprocessor circuit means being further adapted to maintain a time correlation between the averaged respiration rate samples and the occurrences of the timing bytes so that the occurrence of the QRS complex is also maintained in time correlation with the averaged respiration rate samples.

14. An apparatus as recited in claim 13 wherein said timing generator includes first and second timing circuits, said first timing circuit being adapted to provide the first clock signal at a rate of 56 cycles per second and said second timing circuit being adapted to provide the second clock signal at a rate of 448 cycles per second.

15. An apparatus as recited in claim 14 wherein said second microprocessor circuit means further comprises means for providing the display signal such that the displayed heart and respiration rate signals do not appear jagged.

16. A method for displaying first and second information signals, comprising the steps of:

providing at least one timing signal to create a timing reference frame;

detecting a predetermined phenomenon indicated by a first predetermined characteristic of the first information signal and providing an interrupt signal in response to the detection of the first predetermined phenomenon;

providing a timing byte to indicate a real-time correlation between the occurrence of the predetermined phenomenon and the status of a second predetermined characteristic of the second information signal;

responding to a display signal to provide a visual indication of a third predetermined characteristic of the first information signal and to provide a visual indication of the second predetermined characteristic of the second information signal, wherein the visual indication is provided on a display medium;

providing the display signal in response to the first and second information signals and the timing signal wherein the display signal includes information for building raster lines on the display medium and wherein each raster line contains information relative to the positioning of the first and second information signals on the display medium and the combination of raster lines cooperate to provide the visual indication of the first, second and third predetermined characteristics; and

responding to the timing byte and the timing signal to alter the display signal such that the display of the second information signal is altered thereby to indicate the occurrence of the predetermined phenomenon in real-time relationship with the second predetermined characteristic of the second information signal.

17. The method as recited in claim 16, further comprising the steps of:

receiving user provided input signals and responding to the user provided input signals for providing the display signal such that the sweep rate at which the first information signal is displayed is a multiple of the sweep rate at which the second information signal is displayed; and

maintaining correlation between a multiple of timing bytes and the respiration signal to maintain real-time correlation between occurrence of the predetermined phenomenon and the respiration signal.

18. The method as recited in claim 17 wherein the third and second predetermined characteristics are the voltage magnitude of the first and second information signals, respectively.

19. The method as recited in claim 18 wherein the step of providing the display signal comprises the substep of altering the display signal such that the second information signal is intensified to indicate the occurrence of the predetermined phenomenon.

20. The method as recited in claim 19 wherein the first and second signals comprise heart rate and respiration rate signals of a patient, respectively, said method further comprising the step of sensing the heart rate and respiration rate and providing the first and second information signals indicative of the heart rate and the respiration rate of the patient,

21. The method as recited in claim 20 wherein the predetermined phenomenon is a QRS complex in the heart rate signal and wherein the step of detecting the predetermined phenomenon comprises the substep of detecting the QRS complex.