We investigated the influence of intravenous clonidine 2, 4 and 6 μg kg−1 on the electroencephalogram and on the minimal alveolar concentration of isoflurane in 40 patients aged 20–60 years undergoing elective surgery. Minimal alveolar concentration was determined using the Dixon ‘up-and-down’ method. Thirty min after the clonidine infusion anaesthesia was induced with etomidate, 0.25 mg kg−1. Skin incision was made after stable end-tidal isoflurane concentrations had been maintained for at least 15 min. Clonidine caused significant decreases in the spectral edge (95%) and median power frequency of the electroencephalogram and in the bispectral index. The minimal alveolar concentration of isoflurane decreased in a dose-dependent manner from 1.32% (95% CI, 1.28%–1.36%) in the control group to 1.03% (0.9%–1.18%) in patients given clonidine 6 μg kg−1. Clonidine 4 and 6 μg kg−1 was associated with a moderate reduction in heart rate and arterial systolic blood pressure. We recommend the use of clonidine intravenously as an adjunct to general anaesthesia in a dose of 4 μg kg−1 given 15 min before induction of anaesthesia.

Desflurane is a new inhalation anaesthetic with a low blood/gas solubility which should allow a fast emergence from anaesthesia. In a prospective open randomized study, desflurane was compared with isoflurane paying special attention to recovery and the quality of the post-operative period. The occurrence of pain and post-operative nausea and vomiting (PONV) was recorded during the first 20 post-operative hours. Seventy women ASA Grade I-II scheduled for elective gynaecological laparoscopic procedures were studied. Patients receiving desflurane were extubated earlier than patients receiving isoflurane, 5±1 and 9±1 min respectively (P < 0.05) and the patients anaesthetized with desflurane were able to tell their name and date on average 5 min earlier than those who had received isoflurane; however, time in the recovery room was the same for both groups of patients. Twenty-two of 35 patients receiving desflurane, and 18 of 35 receiving isoflurane required analgesia. PONV was recorded in 18 patients anaesthetized with desflurane and 12 patients anaesthetized with isoflurane. In both groups PONV was more frequently observed in patients after leaving the recovery room. PONV in the recovery room was associated with a delayed discharge, 139 vs. 114 min respectively. Desflurane seems to be an useful alternative to isoflurane for laparoscopic procedures.