[Abolition of hypotension following spinal anaesthesia by dihydroergotamine (DHE) (author's transl)].

The conduction block of the preganglionic sympathetic fibres in spina anaesthesia leads to peripheral vasodilation. Such a loss of tone in blood vessels is also pronounced on the venous side. Therefore the effects of intravenously administered DHE (10 microgram/kg i.v.) on 25 healthy patients undergoing spinal anaesthesia were studied. Though all patients were preinfused with 500 ml Ringer there was a sustained decrease in arterial and pulmonary artery pressures (p less than 0.001). However, the heart rate remained unaffected. After DHE the pressure changes were completely reversed whereas heart rate was significantly decreased (p less than 0.001). The effects of DHE can largely be explained by its powerful and selective action on the capacitance vessels in the peripheral circulation. The increased venous return to the heart augments ventricular filling. Perfusion pressure is increased without any concomitant myocardial stimulation. The results indicate that DHE can have a beneficial effect in patients undergoing spinal anaesthesia.