Pulse detection using patient physiological signals
First Claim
1. A method comprising:
- transmitting light into a patient from a light source positioned external to the patient;
receiving the transmitted light at a sensor positioned external to the patient;
generating a light detection signal in response to the received light, the light detection signal having a first amplitude and a first shape at a first time;
monitoring, over a period of monitored time, the light detection signal for changes in at least one of the first amplitude and the first shape;
detecting, at a second time, at least one of a second amplitude and a second shape of the light detection signal;
comparing the at least one of the second amplitude and the second shape with a corresponding at least one of the first amplitude and the first shape;
analyzing, with a processor, the compared at least one of the second amplitude and the second shape to detect a trend that the patient'"'"'s pulse is detected and is becoming weaker over the period of monitored time;
determining that the patient'"'"'s pulse is weakening over the period of monitored time based on the detected trend; and
providing at least one of treatment and information concerning treatment based on the determined-weakening patient pulse.
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Accused Products
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.
119 Citations
19 Claims
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1. A method comprising:
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transmitting light into a patient from a light source positioned external to the patient; receiving the transmitted light at a sensor positioned external to the patient; generating a light detection signal in response to the received light, the light detection signal having a first amplitude and a first shape at a first time; monitoring, over a period of monitored time, the light detection signal for changes in at least one of the first amplitude and the first shape; detecting, at a second time, at least one of a second amplitude and a second shape of the light detection signal; comparing the at least one of the second amplitude and the second shape with a corresponding at least one of the first amplitude and the first shape; analyzing, with a processor, the compared at least one of the second amplitude and the second shape to detect a trend that the patient'"'"'s pulse is detected and is becoming weaker over the period of monitored time; determining that the patient'"'"'s pulse is weakening over the period of monitored time based on the detected trend; and providing at least one of treatment and information concerning treatment based on the determined-weakening patient pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method comprising:
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transmitting light into a patient from a light source positioned external to the patient; receiving the transmitted light at a sensor positioned external to the patient; generating a light detection signal in response to the received light, the light detection signal having a first amplitude and a first shape at a first time; monitoring, over a period of monitored time, the light detection signal for changes in at least one of the first amplitude and the first shape; detecting, at a second time, at least one of a second amplitude and a second shape of the light detection signal; comparing the at least one of the second amplitude and the second shape with a corresponding at least one of the first amplitude and the first shape; analyzing, with a processor, the compared at least one of the second amplitude and the second shape to detect that the patient'"'"'s pulse is detected and is becoming weaker over the period of monitored time; determining that the patient'"'"'s pulse is weakening over the period of monitored time based on the detection of the patient'"'"'s pulse and the detection that the patient'"'"'s pulse is become weaker over the period of monitored time; and providing at least one of treatment and information concerning treatment based on the determined-weakening patient pulse. - View Dependent Claims (13)
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14. A method, comprising:
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generating light at a first wavelength corresponding to a first level of tissue and blood absorption; generating light at a second wavelength corresponding to a second level of tissue and blood absorption; transmitting the light at the first wavelength into a patient at a first time; transmitting the light at the second wavelength into the patient at a second time; receiving the transmitted first light and the transmitted second light; generating a first light detection signal based on the received first light and a second light detection signal based on the received second light; monitoring, over a period of monitored time, the first light detection signal and the second light detection signal for changes in at least one of an amplitude and a shape of at least one of the first light detection signal and the second light detection signal; detecting a change in the at least one of the amplitude and the shape of the at least one of the first light detection signal and the second light detection signal, the detected change detected within the period of monitored time; and analyzing, with a processor, the detected change for an indication of a trend that the patient'"'"'s pulse is detected and is becoming weaker over the period of monitored time; and determining that the patient'"'"'s pulse is weakening over the period of monitored time based on the indication of the trend. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification