Pulse detection using patient physiological signals

• US 9,216,001 B2
• Filed: 10/30/2012
• Issued: 12/22/2015
• Est. Priority Date: 08/26/2002
• Status: Expired due to Fees

• Current Assignee: Physio-Control Incorporated (Stryker Corporation)
• Original Assignee: Physio-Control Incorporated (Stryker Corporation)
• Inventors: Owen, James M., Jayne, Cynthia P., Crone, William E.
• Primary Examiner(s): D'ANGELO, MICHAEL J
• Application Number:
  US13/664,205
• Publication Number:
  US 20130060148A1
• Time in Patent Office: 1,148 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 comprising:

transmitting light into a patient at a first intensity;

receiving light transmitted into the patient at the first intensity at a light detector;

generating a first light detection signal based on the received light transmitted into the patient at the first intensity;

transmitting light into the patient at a second intensity;

receiving light transmitted into the patient at the second intensity at the light detector;

generating a second light detection signal based on the received light transmitted into the patient at the second intensity;

extracting a dc component of the first light detection signal;

adjusting a gain of the light detector based on the extracted dc component; and

processing the first and second light detection signals to detect a physiological parameter indicative of presence of a cardiac pulse in the patient.

2. The method of claim 1, further comprising providing at least one of treatment and information concerning treatment based on the physiological parameter.

3. The method of claim 1, further comprising:

setting one or both of the first intensity and the second intensity according to the extracted dc component.

4. A medical device comprising:

a light source that transmits light into a patient at a first intensity and a second intensity;

a light detector that receives the light transmitted into the patient at the first intensity to generate a first light detection signal and receives the light transmitted into the patient at the second intensity to generate a second light detection signal; and

a processor configured to extract a dc component of the first light detection signal and to adjust a gain of the light detector according to the extracted dc component, the process further configured to process the first and second light detection signals to detect a physiological parameter indicative of presence of a cardiac pulse in the patient.

5. The medical device of claim 4, in which the processor is configured to provide at least one of treatment and information concerning treatment based on the physiological parameter.

6. The medical device of claim 4, in which the processor is further configured to control the light source to set the second intensity according to the extracted dc component.

7. A system, comprising:

means for transmitting light into a patient at a first intensity;

means for receiving light transmitted into the patient at the first intensity at a light detector;

means for generating a first light detection signal based on the received light transmitted into the patient at the first intensity;

means for transmitting light into the patient at a second intensity;

means for receiving light transmitted into the patient at the second intensity at the light detector;

means for generating a second light detection signal based on the received light transmitted into the patient at the second intensity;

means for extracting a dc component of the first light detection signal;

means for adjusting a gain of the light detector based on the extracted dc component; and

means for processing the first and second light detection signals to detect a physiological parameter indicative of presence of a cardiac pulse in the patient.

8. The system of claim 7, further comprising means for providing at least one of treatment and information concerning treatment based on the physiological parameter.

9. The system of claim 7, further comprising means for setting one or both of the first intensity and the second intensity according to the extracted dc component.