To evaluate the quality of intra-operative anaesthesia and recovery characteristics of two different anaesthesia regimens, 60 healthy women undergoing ultrasound guided oocyte retrieval for in vitro fertilization procedures were randomly allocated to receive either a propofol/fentanyl or a midazolam/remifentanil based anaesthesia. The surgical procedure was successful in all patients and no severe side effects were reported by any patient. Four patients in the midazolam/remifentanil group (13%) would not accept the same anaesthetic procedure for further in vitro fertilization treatment due to intra-operative awareness, while all propofol/fentanyl patients were prepared to accept the same procedure again (P < 0.05). Patients in the propofol/fentanyl group required manual ventilation more frequently through a facemask than those patients treated with the midazolam/remifentanil combination (50% and 30%, respectively; P < 0.05). The time to achieve an Aldrete's score of 10 was shorter in the midazolam/remifentanil patients (2±2 min) than in those who received propofol/fentanyl (4±2 min) (P < 0.001), but no differences were observed in the time required to be ‘fit to discharge’ from the post-anaesthesia care unit. We conclude that the use of a midazolam/remifentanil regimen is as effective and safe as a fentanyl/propofol regimen in patients undergoing transvaginal oocyte retrieval for in vitro fertilization procedures.

It has been shown in healthy volunteers that a concentration of volatile anaesthetic lower than 1 minimum alveolar concentration provides unconsciousness. We tested the hypothesis that, using the electroencephalogram bispectral index, less than 1 minimum alveolar concentration of sevoflurane can produce unconsciousness in patients. Anaesthesia was induced and maintained with sevoflurane in N2O and O2 (33%) in 32 ASA I-II women undergoing laparoscopic tubal ligation. For the first patient, the sevoflurane concentration was adjusted to 1 minimum alveolar concentration with an end-tidal concentration of 0.7%. The electroencephalogram bispectral index values were used to determine the concentration to be used for the next patient. The ED50 (effective dose) measured using end tidal concentrations of sevoflurane for laparoscopic tubal ligation in a 40-year-old patient was 0.70% (CI 95%: 0.63–0.77) and ED95 0.83% (CI 95%: 0.75–0.90). None of the patients had any operation-associated recall. It is concluded that the sevoflurane concentration needed for laparoscopic tubal ligation is not lower than 1 minimum alveolar concentration.