PULSE DETECTION USING PATIENT PHYSIOLOGICAL SIGNALS

The presence of a return of spontaneous circulation (ROSC) in a patient is determined by evaluating physiological signals in the patient. In one embodiment, methods and devices device evaluate 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 methods and devices determine whether pulsatile blood flow is present in the patient and also whether the patient has ROSC based on whether the pulsatile blood flow is present. Some examples of the methods and devices indicate that the patient has ROSC if the patient's pulsatile blood flow is detected after defibrillation therapy has been delivered to the patient. Other example methods and devices either prompt a user to deliver additional defibrillation therapy to a patient or automatically deliver additional defibrillation therapy to a patient if the patient does not have ROSC.