[Continuous alfentanil infusion in surgical interventions of intermediate and long duration]

Alfentanil, a new short-acting narcotic analgesic, was studied as a continuous infusion for surgical procedures of medium and long duration in 80 patients. Anaesthesia was induced with thiopentone immediately followed by 1 mg of alfentanil to attenuate the stress response to intubation. Alfentanil 100 micrograms/kg was then slowly given as a loading dose before surgery started and anaesthesia maintained by a continuous infusion at a rate of 0.5-1 micrograms/kg/min. Patients were ventilated with a 66% nitrous oxide in oxygen. The course of anaesthesia was good in 76 of the patients, while 27 needed small increments of alfentanil on top of the infusion. Cardiovascular stability was a feature in almost all patients. Recovery was extremely rapid and without complications. Naloxone to reverse respiratory depression was only used twice.