This document relates to systems and techniques for the treatment of a cardiac arrest victim via electromagnetic stimulation of physiologic tissue.

An apparatus for assisting a rescuer in performing chest compressions during CPR on a victim, the apparatus comprising a pad or other structure configured to be applied to the chest near or at the location at which the rescuer applies force to produce the chest compressions, at least one sensor connected to the pad, the sensor being configured to sense movement of the chest or force applied to the chest, processing circuitry for processing the output of the sensor to determine whether the rescuer is substantially releasing the chest following chest compressions, and at least one prompting element connected to the processing circuitry for providing the rescuer with information as to whether the chest is being substantially released following chest compressions.

Systems and methods related to the field of cardiac resuscitation, and in particular to devices for assisting rescuers in performing cardio-pulmonary resuscitation (CPR), are described herein. In one aspect, a method for managing cardiopulmonary resuscitation (CPR) treatment to a person in need of emergency assistance includes monitoring a parameter that indicates a fatigue level of a rescuer and providing an indication that a different person should perform the CPR component if the rescuer is exhibiting fatigue.

Technologies and implementations for a wearable medical device (WMD). The technologies and implementations facilitate incorporating a blood oxygen saturation level device with the WMD. Additionally, the technologies and implementations include wearable cardioverter device (WCD) incorporating a blood oxygen saturation level device.

In an aspect, a system for treating a patient in cardiac arrest is described and includes memory, one or more electronic ports for receiving signals from sensors for obtaining indications of an electrocardiogram (ECG) of the patient, one or more sensors for obtaining a transthoracic impedance of the patient, and a patient treatment module executable on one or more processing devices that is configured to generate, from the ECG, transform values that represent magnitudes of two or more frequency components of the ECG, and modify, based on at least one transform value, at least one shock delivery parameter.

A medical system includes an implantable cardiac monitoring device (ICMD) configured to monitor one or more physiological signals of a patient and in response to detecting a current or imminent arrhythmia in the patient, transmit first data to an external user device. The external user device is configured to: in response to receiving the first data from the ICMD, outputting a notification of the current or imminent arrythmia; confirm the presence of the current or imminent arrhythmia in the patient; and in response to confirming the current or imminent arrhythmia in the patient, cause an external defibrillator device to deliver a shock to the patient.

A guide system for indicating an activator of a defibrillator to a user including a motion detection circuit which determines motion of the defibrillator and generates at least one defibrillator motion mode signal, and a guide circuit which receives the defibrillator motion mode signal and causes the activator to be indicated to the user of the defibrillator.

An external defibrillator, such as a wearable defibrillator can have a heart rhythm detector to detect the heart rhythm of a patient. The defibrillator can also have a synchronous shock operating mode and an asynchronous shock operating mode. A controller can set the defibrillator in the synchronous shock operating mode or the asynchronous shock operating mode. The defibrillator can also include a shock module to cause the defibrillator to deliver shock therapy to the patient according to the operating mode of the defibrillator and a sync module configured to identify a first portion of the heart rhythm detected from a first ECG lead with which to time the delivery of the shock therapy to the patient when the operating mode of the defibrillator is in synchronous shock operating mode. A comparator module can compare timing of a QRS complex detected from the first ECG lead with the timing of the QRS complex detected by the second EGG lead.

A wearable defibrillator system includes a support structure with one or more electrodes in an unbiased state. A monitoring device monitors, for the long term, a parameter of the person that is not the person's ECG; rather, the monitored parameter can be the person's motion, a physiological parameter, or both. When a value of the monitored parameter reaches a threshold, such as when the person is having an actionable episode, the electrode becomes mechanically biased against the person's body, for making good electrical contact. Then, if necessary, the person can be given electrical therapy, such as defibrillation. As such, the electrodes of the wearable defibrillator system can be worn loosely for the long term, without making good electrical contact. This can reduce the person's aversion to wearing the defibrillation system.

A system for facilitating resuscitation includes: a first electrode assembly having a therapy side and a first motion sensor; a second electrode assembly having a therapy side and a second motion sensor; processing circuitry operatively connected to and programmed to receive and process signals from the first and second motion sensors to estimate at least one of a chest compression depth and rate during administration of chest compressions and to compare the chest compression depth or rate to a desired range; and an output device for providing instructions to a user to administer chest compressions based on the comparison of the estimated chest compression depth or rate to the desired range. One or both of the electrode assemblies may be constructed so that the conductive therapeutic portion is able to maintain substantial conformance to the anatomy of the patient when coupled thereto. For example, at least a portion of the flexible electrode pad may be able to flex from a more rigid sensor housing, or the sensor housing itself may be relatively small compared to the flexible electrode pad so as not to cause lift off of the therapeutic side from the patient.