Interactions between nimodipine and general anaesthesia--clinical investigations in 124 patients during neurosurgical operations.

Haemodynamic, respiratory, metabolic and endocrine investigations were performed in a total number of 124 patients, divided into four different groups, during opiate anaesthesia for neurosurgical operations in order to characterize general effects of nimodipine, a calcium channel blocking agent with a preferential cerebrovascular action. These studies led to the following conclusions: Nimodipine is a vasodilator drug with a hypotensive action, which is especially obvious in hypertensive patients and in combination with similarly acting agents, such as sodium nitroprusside or nitroglycerin. This vascular hypotensive effect may be also enhanced by combined cardiodepressive activity if nimodipine is applied together with inhaled anaesthetics, such as halothane or isoflurane. Nimodipine as well as other vasodilator drugs may lead to increased pulmonary shunting in patients with artificial ventilation, which, however, can be reduced by adequate positive end-exspiratory pressure. With high doses the decrease of oxygen extraction and consumption, seen with nimodipine, is accompanied by a moderate rise of lactate. Determination of stress hormones did not reveal analgesia potentiation of nimodipine, as has been assumed in other studies.