[Effects of isoflurane on bleeding in microsurgery of the middle ear]

40 patients undergoing middle ear microsurgery were anaesthetized with a narconeuroleptanalgesia (droperidol, phenoperidine, thiopentone) associated with a randomly selected halogenated volatile anaesthetic, either halothane or isoflurane at a concentration of 1 MAC. Clinical and haemodynamic tolerance was perfect. Respiratory and haemodynamic parameters were not significantly different in either series at the different moments that were common to all the operations. There was less bleeding in the isoflurane group, and it was stable (p less than 0.01). Isoflurane would seem to have the double advantage of maintaining anaesthesia and producing a bloodless surgical field, so avoiding the use of added hypotensive agents.