RESUMO
Two groups of patients were studied. In group A, propofol was used alone, given by repeat injections of 2.5 mg X kg-1 in 30 s, in 5 patients undergoing percutaneous thermocoagulation of the Vth cranial nerve. In group B, a series of 12 patients undergoing lumbar disc hernia surgery, propofol was given as a bolus of 2.5 mg X kg-1 in 60 s followed by an infusion of 7 to 12 mg X kg-1 X h-1 together with vecuronium and fentanyl. The EEG recording was carried out during the whole length of anaesthesia and for 1 h after its end. The recordings were all stereotyped, within five successive phases: the awake physiological pattern (phase 0) was desynchronized a mean 52 s after the start of the propofol injection; it was followed by an increase in amplitude of the alpha rhythm (phase I); within a mean of 132 s were seen phases II to V. Phase V corresponded to surgical anaesthesia and could be kept up by a rate of infusion of 9 mg X kg-1 X h-1 propofol. An increase in this rate gave rise to burst suppressions which lasted as much as 15 s or more, and disappeared very quickly when the infusion rate was slowed. After stopping the anaesthesia, the EEG phases were quickly reversed, V to 0: in a mean of 11.1 min, the EEG pattern had returned to the awake state (extremes 4.3 to 19 min).(ABSTRACT TRUNCATED AT 250 WORDS)
