How long is too long? The effect of the duration of anaesthesia on the incidence of non-urological complications after surgery

OBJECTIVE To examine the association between the duration of anaesthesia and non-urological complication (NUC) rates after surgery, as the increasing complexity of minimally invasive and laparoscopic procedures in urology has resulted in longer surgery and anaesthesia, and information on the effect of this on NUC rates is limited. PATIENTS AND METHODS We identified 2196 patients who had open radical nephrectomy or nephron-sparing surgery at our institution between 1989 and 2002. Patients were subdivided into groups I, II, and III according to the duration of general anaesthesia (< 4, 4-6 and >= 6 h, respectively). NUCs after surgery, and mortality during and after surgery, were evaluated. RESULTS There were 1340, 723, and 133 patients in groups I, II and III, respectively. The incidences of any NUC were 3.1%, 5.8% and 13.5%, respectively. The odds ratios for the likelihood of a NUC were 1.91 (P = 0.004) and 4.84 (P < 0.001) for groups II and III, respectively. These differences remained significant even after adjusting for patient and tumour characteristics. Perioperative mortality was highest in group III, at 2.3%, vs 0.4% in groups I and II. CONCLUSIONS Longer anaesthesia is associated with an increase in the incidence of perioperative complications and mortality, especially when the duration of anaesthesia is > 6 h. This increase appears to be independent of patient's preoperative health status, tumour extent and blood loss.