A cellular transtelephonic defibrillator for management of cardiac arrest outside the hospital.
A cellular transtelephonic defibrillator facilitates early defibrillation in remote areas and involves electrocardiographic diagnosis and defibrillation control by a physician remote from but in voice contact with the patient-unit operator. The patient unit contains a microprocessor, microphone, defibrillator, electrocardiogram/defibrillator electrode pads and cellular telephone. Activation of the patient-unit initiates automatic dialing and contact with the remotely sited base station within 35 to 50 seconds. The physician at the base station identifies the rhythm and controls defibrillator charging and discharge. The minimal interaction required between the system and the local operator makes it suitable for use by minimally trained first responders. The cellular transtelephonic defibrillator has been tested in 211 calls responded to by a physician-manned mobile coronary care unit over distances up to 15 miles in an urban area. Satisfactory electrocardiographic transmission and voice communication were established in 172 of 211 calls (81.5%). In 39 (18.5%), connection with the base station either could not be established or maintained mainly because of geographic location or battery failure. One hundred direct current shocks of 50 to 360 J were effectively administered to 22 patients with 48 episodes of ventricular fibrillation or ventricular tachycardia with successful correction of 46 of 48 episodes using 1 to 4 shocks per episode. Widespread distribution of such devices could improve survival in patients with cardiac arrest outside the hospital.