PULSE DETECTION USING PATIENT PHYSIOLOGICAL SIGNALS

• US 20150173689A1
• Filed: 03/02/2015
• Published: 06/25/2015
• Est. Priority Date: 09/02/2003
• Status: Active Grant

• Current Assignee: West Affum Holdings DAC
• Original Assignee: Physio-Control Incorporated (Stryker Corporation)
• Inventors: Owen, James M., Jayne, Cynthia P., Crone, William E.
• Granted Patent: US 11,419,508 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• 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 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/082 Evaluation by breath analysis, e.g. determination of the chemical composition of exhaled breath A61B5/083, A61B5/091 take precedence
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/4848 Monitoring or testing the effects of treatment, e.g. of medication
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/488 involving Doppler signals
• CPC Class Codes: A61N 1/3625 External stimulators
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: A61N 1/36557 controlled by chemical substances in blood
• CPC Class Codes: A61N 1/3904 External heart defibrillators [EHD]
• CPC Class Codes: A61N 1/39044 in combination with cardiopulmonary resuscitation [CPR] therapy
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock

Abstract

The presence of a cardiac pulse in a patient is determined by evaluating physiological signals in the patient. In one embodiment, a medical device evaluates optical characteristics of light transmitted into a patient to ascertain physiological signals, such as pulsatile changes in general blood volume proximate a light detector module. Using these features, the medical device determines whether a cardiac pulse is present in the patient. The medical device may also be configured to report whether the patient is in a VF, VT, asystole, or PEA condition, in addition to being in a pulseless condition, and prompt different therapies, such as chest compressions, rescue breathing, defibrillation, and PEA-specific electrotherapy, depending on the analysis of the physiological signals. Auto-capture of a cardiac pulse using pacing stimuli is further provided.

Claims

1. A method of detecting a blood flow in a patient, comprising:

receiving a first data segment corresponding to a first physiological parameter of the patient;

receiving a second data segment corresponding to a second physiological parameter of the patient;

calculating a first blood flow detection characteristic from the first data segment;

calculating a second blood flow detection characteristic from the second data segment;

determining a blood flow for the patient based on the first blood flow detection characteristic and the second blood flow detection characteristic; and

analyzing the determined blood flow of the patient to determine if the patient has good blood flow, marginal blood flow, or no blood flow.

2. The method of claim 1, wherein the first physiological parameter and the second physiological parameter are the same and wherein the first data segment is different from the second data segment.

3. The method of claim 1, wherein the first physiological parameter and the second physiological parameter are each at least one of a phonocardiogram signal, an electrocardiogram signal, an impedance signal, a piezoelectric signal, an accelerometer signal, an optical signal, a pulse oximetry signal, a CO₂ waveform signal, and a Doppler probe signal.

4. The method of claim 1, wherein the first physiological parameter and the second physiological parameter are different.

5. The method of claim 1, further comprising weighting at least one of the first blood flow detection characteristic and the second blood flow detection characteristic.

6. The method of claim 1, wherein the calculating the first blood flow detection characteristic from the first data segment and the calculating the second blood flow detection characteristic from the second data segment occur at approximately the same time.

7. The method of claim 1, further comprising prompting an operator to select the first physiological parameter and the second physiological parameter from a group of multiple physiological parameters.

8. The method of claim 1, further comprising determining at least one of treatment and information relating to treatment for the patient based on the analysis of the blood flow of the patient.

9. The method of claim 1, further comprising identifying a threshold for the first blood flow detection characteristic and comparing the calculated first blood flow detection characteristic to the threshold and wherein the determining the patient has a blood flow based on the first blood flow detection characteristic and the second blood flow detection characteristic includes determining whether the comparison of the calculated first blood flow detection characteristic to the threshold results in the first blood flow detection characteristic meeting or exceeding the threshold or falling below the threshold.

10. The method of claim 9, wherein if the first blood flow detection characteristic meets or exceeds the threshold, then determining that the first blood flow detection characteristic is indicative of the patient having a good blood flow and if the first blood flow detection characteristic falls below the threshold, then determining that the first blood flow detection characteristic is indicative of the patient having a marginal blood flow or no blood flow.

11. The method of claim 1, wherein at least the first data segment is monitored over a period of monitored time and wherein the patient is determined to have a blood flow at least at a first time and a second time during the monitored period of time.

12. The method of claim 11, further comprising comparing the detected blood flow of the patient at the first time and the second time and analyzing the compared detected blood flow of the patient to detect a trend in the blood flow over the period of monitored time.

13. The method of claim 12, further comprising generating an alert if the trend in the blood flow of the patient is detected to be becoming weaker over the period of monitored time.

14. The method of claim 13, further comprising determining whether the weakening blood flow falls below a marginal blood flow threshold in which the patient has a blood flow that is determined insufficient to support life.

15. The method of claim 1, wherein the determining a blood flow for the patient based on the first blood flow detection characteristic and the second blood flow detection characteristic includes determining a pulse for the patient based on the first blood flow detection characteristic and the second blood flow detection characteristic.

16. The method of claim 1, wherein the method of detecting the blood flow in the patient occurs while cardiopulmonary resuscitation (CPR) is being administered to the patient.

17. A medical device, comprising:

a first sensor configured to sense a first physiological parameter of a patient and output a first data segment based on the sensed physiological parameter;

a second sensor configured to sense a second physiological parameter of the patient and output a second data segment based on the sensed second physiological parameter;

a processor arranged to;

analyze the first data segment to determine a first blood flow detection characteristic;

analyze the second data segment to determine a second blood flow detection characteristic;

determine a blood flow level for the patient based on the analyzed first data segment and the analyzed second data segment; and

analyze the determined blood flow level to determine if the blood low level for the patient is good blood flow, marginal blood flow, or no blood flow.

18. The medical device of claim 17, wherein the processor is further arranged to determine at least one of treatment and information relating to treatment for the patient based on the analysis of the determined blood flow level of the patient.

19. The medical device of claim 17, wherein the processor is further arranged to generate an alert if the determined blood flow for the patient is marginal blood flow or no blood flow.

20. The medical device of claim 17, wherein at least one of the first sensor and the second sensor includes a sensor configured to be attached to a forehead of the patient.