Processing pulse signal in conjunction with ECG signal to detect pulse in external defibrillation

1 . An external defibrillator for delivering a defibrillation waveform to a patient, the defibrillator comprising:

chest electrodes for detecting at least one ECG signal on the patient and for delivering the defibrillation waveform to the patient;

a defibrillation circuit for shaping and delivering the defibrillation waveform;

a pulse sensor for detecting the presence of a cardiac pulse in the patient, wherein the pulse sensor has a pulse signal as its output;

memory and processing circuits for analyzing the pulse signal in conjunction with the ECG signal to determine whether the patient has a pulse.

2 . The subject matter of claim 1 wherein the pulse rate of the pulse signal is compared to the pulse rate of the ECG signal.

3 . The subject matter of claim 1 wherein the pulse signal is processed to isolate the pulsatile component of the signal.

4 . The subject matter of claim 1 wherein the pulse signal is examined for a peak during a window initiated at the occurrence of an R-wave in the ECG signal.

5 . The subject matter of claim 1 wherein a comparison is made of the energy in discrete frequency bands of the pulse and the ECG signals.

6 . The subject matter of claim 1 wherein a peak frequency corresponding to the peak of one of the pulse and ECG signals is determined, and the other of the pulse and ECG signals is examined for a peak within a frequency band surrounding the peak frequency.

7 . The subject matter of claim 1 wherein a frequency domain transformation of the pulse signal is processed.

8 . The subject matter of claim 1 wherein frequency domain transformations of the pulse and ECG signal are processed.

9 . The subject matter of claim 1 wherein a decision whether to deliver a defibrillation waveform to the patient is based in part on whether processing of the ECG and pulse signals determines that the patient has a pulse.

10 . The subject matter of claim 1 wherein the defibrillator comprises an automatic external defibrillator (AED).

11 . The subject matter of claim 10 further comprising the capability to provide the user with prompts for performing CPR, and wherein the prompts are dependent at least in part on whether the processing of the pulse signal determines that the patient has a pulse.

12 . The subject matter of claim 1 wherein a determination of whether the patient has a pulse is undertaken after delivery of the defibrillation waveform, and the user is informed of the outcome of the determination.

13 . The subject matter of claim 1 wherein the pulse sensor is mechanically connected to at least one of the defibrillation electrodes.

14 . The subject matter of claim 13 wherein there are two defibrillation electrodes, each supported on a substrate, and the pulse sensor is supported on the same substrate

15 . The subject matter of claim 14 wherein the wires connected to the pulse sensor are bundled with wires connected to the defibrillation electrodes to form a combined bundle of wires extending from the defibrillator to the electrodes and sensor.

16 . The subject matter of claim 1 wherein the pulse sensor is mechanically separate from the defibrillation electrodes.

17 . The subject matter of claim 16 wherein the pulse sensor comprises an optical sensor, and the optical sensor is configured to be attached to the forehead of the patient.

18 . The subject matter of claim 16 wherein the pulse sensor comprises an optical sensor, and the optical sensor is configured to be attached to the ear lobe of the patient.

19 . The subject matter of claim 16 wherein the pulse sensor comprises an optical sensor, and the optical sensor is configured to be attached to the nasal septum

20 . The subject matter of claim 16 wherein the pulse sensor comprises an optical sensor, and the optical sensor is configured to be attached to the nasal bridge.

21 . The subject matter of claim 16 wherein the pulse sensor comprises an optical sensor, and the optical sensor is configured to be attached to the finger.

22 . The subject matter of claim 1 wherein the pulse sensor comprises an optical sensor, and the optical sensor is configured so that its output may also be used for pulse oximetry

23 . The subject matter of claim 1 wherein the pulse sensor comprises an optical sensor, and the optical sensor is configured so that its output is not useful for pulse oximetry.

24 . The subject matter of claim 1 wherein determining whether the patient has a pulse includes determining whether the pulse, if present, is correlated with the R-wave of the patient's heart rhythm.

25 . The subject matter of claim 1 wherein a determination whether to administer CPR to the patient is based on whether it is determined that the patient has a pulse.

26 . The subject matter of claim 1 further comprising using the pulse sensor to determine the efficacy of CPR treatment of the patient.

27 . The subject matter of claim 1 wherein the pulse sensor is an optical sensor.

28 . The subject matter of claim 14 wherein the pulse sensor is an optical sensor.

29 . The subject matter of claim 1 wherein analyzing the pulse signal in conjunction with the ECG signal comprises analyzing whether there is a correlation between the two signals indicative of the presence of a pulse.

30 . The subject matter of claim 1 wherein the pulse sensor is a non-optical sensor.

31 . The subject matter of claim 1 wherein the pulse sensor comprises an acoustic (heart sounds) sensor.

32 . The subject matter of claim 1 wherein the pulse sensor comprises an ultrasonic blood flow sensor.

33 . The subject matter of claim 1 wherein the pulse sensor comprises a pressure sensor on a limb-compressing pneumatic cuff.

34 . The subject matter of claim 1 wherein the pulse sensor comprises a at least one mechanical or ultrasonic sensor configured to detect arterial wall motion caused by blood flow in an artery.

35 . The subject matter of claim 34 wherein the sensor is piezoelectric-based.

36 . The subject matter of claim 1 wherein the pulse sensor comprises one or more sensors for measuring body impedance variation from blood flow.