[Multifactorial index of the risk of complications related to anesthesia].

Anaesthetic risk has been studied until now only in terms of mortality rates, and by single factor analysis. A multifactorial index of anaesthetic risk, taking into account all major complications related to anaesthesia that occur during--or within 24 hours of--surgery is proposed. Data were collected in a prospective survey among a representative sample of anaesthesias. The logistic model included a sample of 232 complications and a control group of 1 642 anaesthesias with no complications. Eight factors related to the patient's condition, and to the kind of surgery performed, were considered. Only six were found to have prognostic value, and--among them--the "previous complications" factor stood out. There was a good concordance between predicted and observed risk. The index may be used for a preoperative estimate of anaesthetic risk.