Cardiovascular pharmacology I

The use of bicarbonate during cadiopulmonary resuscitation remains controversial. The present standards, suggested in large part by the investigations of Bishop and Weisfeldt, and the acknowledged toxicity of treatment with bicarbonate led to aggressive use of hyperventilation, the frequent monitoring of pH, and a reduction in bicarbonate administration. However, to date no studies have indicated an improvement in outcome to support the importance of these changes. Instead, controversy continues concerning the most appropriate buffer and whether the pH gradient induced between venous and arterial beds during CPR is of importance. To date, a viable alternative regimen has not been proposed. Thus, at present there is little new data upon which to base a major change in strategy, although the logic of reducing further the use of bicarbonate seems compelling. The choice of antiarrhythmic therapy is equally difficult. Initially, experimental studies suggested a more potent antifibrillatory effect for bretylium than for lidocaine. Subsequent studies have challenged these initial experimental results and clinical data have failed to indicate the benefit of one drug over the other. There is little information to suggest that these agents are more effective than the aggressive use of defibrillation alone in patients with ventricular fibrillation. It therefore seems improbable that a definitive decision concerning the use of one or another of these agents can be made.