Nausea: the most important factor determining length of stay after ambulatory anaesthesia. A comparative study of isoflurane and/or propofol techniques

Speed of recovery and length of stay in hospital were studied in 95 ambulatory patients undergoing laparoscopy or arthroscopy. The patients were divided into three groups regarding maintenance of anaesthesia. Group A (n = 32) received isoflurane 0.7% end-tidally, group B (n = 31) propofol infusion for 25 min and thereafter isoflurane, and group C (n = 32) received an infusion of propofol throughout the procedure. Recovery was assessed by a combination of the Maddox-Wing, the Choice Reaction Time test and p-deletion. The awakening period was somewhat shorter in group A, but psychomotor recovery was somewhat slower compared to groups B and C. The length of stay in hospital depended on whether the patient was nauseated or not. In group A, 44% suffered from nausea requiring medical intervention compared to 13% and 19% in groups B and C, respectively. The stay in hospital was 235 ± 90 min (mean ± standard deviation) in group A compared to 184 ± 56 min and 197 ± 55 min in groups B and C, respectively. The non-nauseated patients in group A had a stay in hospital of 188 ± 55 min compared to 184 ± 52 and 184 ± 37 in the non-nauseated patients in groups B and C, respectively. In total, the nauseated patients (n = 24) stayed 267 ± 95 min compared to 185 ± 47 min for the non-nauseated patients (n = 71), P < 0.001. We found nausea to be the most important factor determining length of stay after ambulatory anaesthesia. Propofol in a dose higher than a normal induction dose decreases the incidence of nausea and thus the length of stay in hospital.