[The effect on barbiturates on hemodynamics during extracorporeal circulation: thiopental versus methohexital]

We studied the effects of thiopentone (3 vs 6 mg/kg) and methohexitone (1 vs 2 mg/kg) on TPR during hypertensive episodes (m BP greater than 80 mmHg) under the conditions of ECC and hypothermia: T led to an initial shortlasting increase of TPR up to 114% and 125% from baseline for the dosages tested. This was followed by a decrease to 67% and 56% respectively. After 5 min TPR returned to control. The effect of M on TPR is less pronounced (maximum reduction of 35%) but of longer duration. In contrast to thiopentone we did not observe a biphasic course of TPR following administration of methohexitone.