Ventricular fibrillation during hypothermia successfully treated by rewarming and electroshock.

Ventricular fibrillation is one of the major complications which may arise during induced controlled hypothermia. In the absence of cardiac manipulations this condition may arise spontaneously at temperatures below 25° C., but even at temperatures around 280 C. ventricular fibrillation often follows intracardiac manipulaticns (Bigelow, Lindsay, Harrison, Gordon, and Greenwood, 1950). Various methods have been applied to prevent and treat ventricular fibrillation. Bigelow and his colleagues, operating on dogs, realized the importance of maintaning a normal blood pH, and attempted to obtain this by adding 5% CO2 to the anaesthetic mixture. Cookson, Neptune, and Bailey (1952) found that adding CO2 was of no importance. They found that adrenaline often produced ventricular fibrillation in dogs during hypothermia, but that by using the adrenolytic substance "benodaine" the onset of ventricular fibrillation was prevented when adrenaline was necessary for the treatment of cardiac arrest. Swan, Zeavin, Holmes, and Montgomery (1953) demonstrated experimentally the importance of hyperventilation and its accompanying high blood pH in the prevention of ventricular fibrillation. This has been confirmed by many other investigators. Niazi and Lewis (1956), during experiments on dogs, confirmed that spontaneous ventricular fibrillation did not arise so frequently when normal blood pH was maintained by the addition of 5% CO2. Prevedel, Montgomery, and Swan (1954) described the use of intravenous prostigmine for the prevention of ventricular fibrillation, and state that even if the condition is established the use of this drug will increase the chances of successful defibrillation.