Pulse detection apparatus, software, and methods using patient physiological signals

• US 20050240234A1
• Filed: 06/27/2005
• Published: 10/27/2005
• Est. Priority Date: 09/30/1999
• Status: Active Grant

• Current Assignee: Physio-Control Incorporated (Stryker Corporation)
• Original Assignee: Medtronic Physio-Control Manufacturing Corp. (Medtronic Plc), Medtronic Emergency Response Systems Inc (Stryker Corporation)
• Inventors: Taylor, James W., O'Hearn, Patricia, Jayne, Cynthia P., Stickney, Ronald E., Joo, Tae H., Yerkovich, Daniel, Hampton, David R., Lank, Paula, Crone, William E.
• Granted Patent: US 7,917,209 B2
• Time in Patent Office: Days
• US Class Current: 607/6
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: A61N 1/39044 in combination with cardiopulmonary resuscitation [CPR] therapy
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

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 two or more different physiological signals, such as phonocardiogram (PCG) signals, electrocardiogram (ECG) signals, patient impedance signals, piezoelectric signals, and accelerometer signals for features indicative of the presence of a cardiac pulse. 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

1-33. -33. (canceled)

34. An electrotheraphy device, comprising:

(a) a sensor configured to sense a phonocardiogram (PCG) signal in a patient;

(b) an electrotherapy generator for delivering electrotherapy to the patient; and

(c) processing circuitry configured to analyze the PCG signal for a feature indicative of the presence of a cardiac pulse in the patient and determine the presence of a cardiac pulse based on said feature.

35. The electrotherapy device of claim 34, further comprising an electrode adapted to sense electrocardiogram (ECG) signals in the patient, the processing circuitry being further configured to analyze the patient'"'"'s ECG signal for ventricular tachycardia and prompt the delivery of defibrillation therapy to the patient if the patient is determined to be pulseless and experiencing ventricular tachycardia.

36. The electrotherapy device of claim 35, in which the processing circuitry is further configured to prompt the delivery of defibrillation therapy if the patient is determined to be pulseless and experiencing ventricular tachycardia with a rate exceeding 100 beats per minute.

37. The electrotherapy device of claim 34, further comprising an electrode adapted to sense electrocardiogram (ECG) signals in the patient, the processing circuitry being configured to analyze the patient'"'"'s ECG signal for at least ventricular fibrillation (VF), ventricular tachycardia (VT), and asystole, and if the patient is determined to be pulseless and not in a VF, VT, or asystole condition, the processing circuitry being further configured to prompt delivery of electrotherapy to the patient designed specifically for pulseless electrical activity (PEA).

38. The electrotherapy device of claim 34, the processing circuitry being further configured to report the return of spontaneous circulation in the patient if a cardiac pulse is determined present in the patient after delivery of defibrillation therapy to the patient.

39. The electrotherapy device of claim 34, further comprising an electrode adapted to sense electrocardiogram (ECG) signals in the patient, the processing circuitry being configured to analyze the patient'"'"'s ECG signal for one or more of ventricular fibrillation (VF), ventricular tachycardia (VT), asystole, and pulseless electrical activity (PEA), the processing circuitry being further configured to prompt a report of VF, VT, asystole, or PEA, if detected and if the patient is determined to be pulseless.

40. The electrotherapy device of claim 34, in which the sensor adapted to sense a PCG signal is a first sensor, the electrotherapy device further comprising a second sensor adapted to receive an impedance-sensing signal that has been communicated through a patient, in which the processing circuitry is configured to analyze each of the PCG and impedance-sensing signals for features indicative of the presence of a cardiac pulse in the patient and determine the presence of a cardiac pulse based on said features.

41. The electrotherapy device of claim 40, in which the processing circuitry is further configured to analyze the impedance-sensing signal to determine the presence of respiration in the patient, the processing circuitry prompting the delivery of rescue breathing therapy to the patient if respiration is determined not present in the patient.

42. The electrotherapy device of claim 40, in which the processing circuitry is further configured to prompt the delivery of chest compressions or cardiopulmonary resuscitation to the patient if the patient is determined to be pulseless.

43. The electrotherapy device of claim 34, in which the electrotherapy generator and the processing circuitry are implemented in an automated external defibrillator.

44. A method for delivering electrotherapy to a patient in which the electrotherapy is comprised of pacing stimuli and seeks capture of a cardiac pulse in the patient, the method comprising:

(a) delivering a pacing stimulus to the patient;

(b) from the surface of the patient'"'"'s body, sensing a physiological signal in the patient; and

(c) analyzing the physiological signal to determine whether a cardiac pulse occurred in the patient after delivery of the pacing stimulus.

45. The method of claim 44, further comprising increasing the current of further pacing stimuli to be delivered to the patient if a cardiac pulse did not occur in the patient after delivery of the pacing stimulus.

46. The method of claim 44, in which the physiological signal is a phonocardiogram (PCG) signal, the method comprising analyzing the PCG signal for a feature indicative of a cardiac pulse and determining whether a cardiac pulse occurred in the patient after delivery of the pacing stimulus.

47. The method of claim 44, further comprising repeating steps (a)-(c) and increasing the current of further pacing stimuli to be delivered to the patient until a cardiac pulse occurs after delivery of the each pacing stimulus.

48. The method of claim 44, in which the pacing stimuli is delivered to the patient two or more times and the physiological signal is analyzed to determine whether a cardiac pulse occurred after the delivery of each pacing stimulus, in which the current of further pacing stimuli to be delivered to the patient is increased if a cardiac pulse does not consistently occur in the patient after the delivery of each pacing stimulus.

49. The method of claim 48, further comprising repeating the delivery of pacing stimuli and increasing the current of the pacing stimuli until a cardiac pulse consistently occurs in the patient after the delivery of each pacing stimulus.

50. The method of claim 44, further comprising prompting a user to increase the current of the pacing stimuli if a cardiac pulse did not occur in the patient after delivery of the pacing stimulus.

51. An electrotheraphy device, comprising:

(a) a sensor configured to sense a physiological signal in a patient;

(b) an electrotherapy generator for delivering pacing stimuli to the patient; and

(c) processing circuitry configured to analyze the physiological signal and determine whether a cardiac pulse occurred in the patient following the delivery of a pacing stimulus to the patient, the processing circuitry increasing the current of further pacing stimuli to be delivered to the patient if a cardiac pulse did not occur in the patient following the delivery of the pacing stimulus.

52. The electrotherapy device of claim 51, in which the physiological signal is a phonocardiogram (PCG) signal and the processing circuitry is configured to analyze the PCG signal for a feature indicative of a cardiac pulse and determine whether a cardiac pulse occurred in the patient after delivery of the pacing stimulus.

53. The electrotherapy device of claim 51, in which the electrotherapy device is configured to deliver pacing stimuli to the patient two or more times and the processing circuitry is configured to analyze the physiological signal to determine whether a cardiac pulse occurred after the delivery of each pacing stimulus, the current of further pacing stimuli to be delivered to the patient being increased if a cardiac pulse does not consistently occur in the patient after the delivery of each pacing stimulus.

54. The electrotherapy device of claim 51, in which prior to the current of the pacing stimuli being increased, the processing circuitry is configured to prompt a user of the device to increase the pacing stimuli current.

55-78. -78. (canceled)

79. An article comprising a storage medium having device-executable instructions stored thereon, in which when the instructions are executed by at least one device, they result in:

(a) delivering a pacing stimulus to the patient;

(b) from the surface of the patient'"'"'s body, sensing a physiological signal in the patient; and

(c) analyzing the physiological signal to determine whether a cardiac pulse occurred in the patient after delivery of the pacing stimulus.

80. The article of claim 79, in which the instructions when executed further result in increasing the current of further pacing stimuli to be delivered to the patient if a cardiac pulse did not occur in the patient after delivery of the pacing stimulus.

81. The article of claim 79, in which the physiological signal is a phonocardiogram (PCG) signal, the instructions when executed further resulting in analyzing the PCG signal for a feature indicative of a cardiac pulse and determining whether a cardiac pulse occurred in the patient after delivery of the pacing stimulus.

82. The article of claim 79, in which the instructions when executed further result in repeating steps (a)-(c) and increasing the current of further pacing stimuli to be delivered to the patient until a cardiac pulse occurs after delivery of the pacing stimulus.

83. The article of claim 79, in which pacing stimuli is delivered to the patient two or more times and the physiological signal is analyzed to determine whether a cardiac pulse occurred after the delivery of each pacing stimulus, the instructions when executed further resulting in increasing the current of further pacing stimuli to be delivered to the patient if a cardiac pulse does not consistently occur in the patient after the delivery of each pacing stimulus.

84. The article of claim 83, in which the instructions when executed further result in repeating the delivery of pacing stimuli and increasing the current of the pacing stimuli until a cardiac pulse consistently occurs in the patient after the delivery of each pacing stimulus.

85. The article of claim 79, in which the instructions when executed further result in prompting a user to increase the current of the pacing stimuli if a cardiac pulse did not occur in the patient after delivery of the pacing stimulus.

86-109. -109. (canceled)

110. A device for providing treatment to a patient, comprising:

a pulse sensor;

a controller to determine a defibrillation therapy protocol based on a first input from the pulse sensor; and

a defibrillator configured to operate according to the protocol.

111. The device of claim 110, further comprising:

a breathing detection device to determine whether the patient is breathing; and

an output device configured to issue a prompt to provide rescue breathing in the event the breathing detection device determines that the patient is not breathing.

112. The device of claim 110, in which the pulse sensor comprises a phonocardiogram (PCG) electrode configured to sense PCG signals in the patient.

113. The device of claim 110, in which the pulse sensor comprises a light source and a photodetector.

114. The device of claim 110, further comprising:

a motion detection device to detect a motion of the patient.

115. The device of claim 114, in which the motion detection device includes a patient impedance measuring device to measure a patient impedance.

116. The device of claim 114, in which the motion detection device transmits a second input to the controller, and in which the controller inhibits the defibrillator from delivering a defibrillation shock when the controller determines that there is motion based on the second input.

117. The device of claim 114, further comprising:

an output device to issue a prompt to reduce motion when the the controller determines that there is motion based on the second input.

118. A method for providing treatment to a patient, comprising:

sensing a pulse of the patient;

determining a defibrillation therapy protocol based on the sensed pulse; and

applying defibrillation therapy to the patient according to the protocol.

119. The method of claim 118, further comprising:

determining whether the patient is breathing; and

prompting a caregiver to provide rescue breathing when the patient is not breathing.

120. The method of claim 118, further comprising:

determining whether the patient is moving; and

performing one of inhibiting defibrillation and prompting a caregiver to reduce motion when the patient is moving.

121. The method of claim 120, in which determining whether the patient is moving comprises measuring a patient impedance.

122. A device for providing treatment to a patient, comprising:

a patient impedance measuring device to measure a patient impedance; and

a controller to determine whether CPR is being administered based on the patient impedance.

123. The device of claim 122, further comprising:

an output device to prompt a caregiver to provide CPR when the controller determines that no CPR is being administered.

124. A method for providing treatment to a patient, comprising:

measuring a patient impedance; and

determining whether CPR is being administered based on the patient impedance.

125. The method of claim 124, further comprising:

prompting a caregiver to provide CPR when it is determined that no CPR is being administered.