Haemodynamic effects of infusions of diisopropyl phenol (ICI 35 868) during nitrous oxide anaesthesia in man.

The haemodynamic effects of diisopropyl phenol in cremophor EL at infusion rates of 50-55 and 100 micrograms kg-1 min-1 in combination with inhalation of 67% nitrous oxide have been studied during spontaneous and controlled ventilation in patients premedicated with morphine and atropine. Under all the conditions studied diisopropyl phenol supplementation of nitrous oxide anaesthesia was associated with a decreased arterial pressure (-20% to -31%) compared with the awake patient, related to a decrease in cardiac output (-27% to 29%) and an increase in systemic vascular resistance (+8% to +30%) during surgery, but to a decrease in cardiac output (-19%) and a decrease in systemic vascular resistance (-17%) during anaesthesia without surgery. Doubling the infusion rate of diisopropyl phenol caused no significant haemodynamic changes during either spontaneous or controlled ventilation. The haemodynamic manifestations of sympathetic nerve activity in response to laryngoscopy and intubation were poorly suppressed by diisopropyl phenol.