Successful defibrillation in water: a preliminary study.
Mild hypothermia (32-34 deg C) treatment alleviates vital organ damage after cardiac arrest. A new cooling device, the Thermosuit operates by applying of a thin layer of water directly to the body surface. Hypothermic patients may experience sequential fibrillation. Therefore, we examined whether defibrillation could be administered safely and effectively in water. A 35 kg swine was anesthetized and placed inside the Thermosuit system. This consists of a water containing surround and pumping system. Conventional AED disposable defibrillation electrodes were applied to the animal's chest. Fibrillation was created by applying a 50-volt signal to a pacing wire introduced into the heart. Following a 30-second period of fibrillation, defibrillation was attempted using Medtronic AED 1000 defibrillator. Defibrillation voltage and current were measured. There were three test cases: dry in the system, wet in the functioning system, and damp. Cooling water in the system was contaminated with saline to simulate potential conditions in clinical application. In each fibrillation-defibrillation sequence, the heart was restarted successfully; this required less than 220 joules. Only a small difference was measured in the overall defibrillation voltage and current as applied to the electrodes for the different cases. Thus, underwater defibrillation is safe and can be performed effectively.
Klock-Frézot
J C
JC
Dept. of Electr. & Comput. Eng., Rhode Island Univ., Kingston, RI 02881, USA.
Ohley
W J
WJ
Schock
R B
RB
Cote
M
M
Schofield
L
L
D001145:Arrhythmias, Cardiac / Q000628:therapy*; D002307:Cardiography, Impedance; D047548:Defibrillators; D004554:Electric Countershock / Q000379:methods*; D005334:Fever / Q000503:physiopathology*; D006321:Heart / Q000502:physiology / Q000503:physiopathology*; D006323:Heart Arrest / Q000503:physiopathology / Q000628:therapy*; D006329:Heart Conduction System; D006801:Humans; D014693:Ventricular Fibrillation; D014867:Water
D014867:Water