Haemodynamic effects of fenoterol for labour inhibition during spinal or epidural anaesthesia.

Haemodynamic investigations, partly using invasive monitoring, concerning interactions between the beta-mimetic effect of fenoterol and the alpha-sympathetic blockade of spinal or epidural anaesthesia were made in a total of 49 patients during pregnancy, during caesarean section and in non-pregnant women. Haemodynamic effects of fenoterol during regional anaesthesia were compared with those during general anaesthesia (n = 17). Epidural or spinal anaesthesia enhance vascular beta-mimetic reactions at the start of tocolysis, leading to a profound but short-lasting decrease in blood pressure. This initial hypotension is more pronounced after regional than after general anaesthesia.