Canadian Journal of Anesthesia, Vol 44, 946-954, Copyright © 1997 by Canadian Anesthesiologists' Society

ARTICLES

Risk of unanticipated intraoperative events in patients assessed at a preanaesthetic clinic

A Lee, ME Lum, M Perry, SJ Beehan, KM Hillman and A Bauman
Department of Anaesthetics and Intensive Care, Liverpool Hospital, NSW, Australia.

PURPOSE: To determine the risk of unanticipated intraoperative events (UIE) in patients assessed at a preanaesthetic clinic compared with those not assessed at the clinic. METHODS: Preoperative and intraoperative data were collected on 6130 elective surgical patients by procedural anaesthetists over a 12-month-period at an Australian tertiary referral hospital. The procedural anaesthetists rated the level of preparation and identified predefined unanticipated intraoperative events. A logistic regression model was used to identify significant risk factors of UIE and was further validated on another sample of 482 patients (one month) by a goodness-of-fit test. RESULTS: Of the 6130 elective surgical patients, 2000 (33%) had been assessed at the preanaesthetic clinic. There was a greater proportion of ASA II to IV patients seen at the clinic than patients not assessed at the clinic (chi 2(3) = 689.92, P < 0.001). Nonclinic patients were more likely to be inadequately prepared than clinic patients (RRunadjusted = 1.61, 95% CI: 1.25 to 2.04, P < 0.001). The overall incidence of intraoperative events was 4.14% (95% CI: 3.64% to 4.64%). Despite adjusting for the preparation level, type of anaesthesia, admission category, ASA physical status and duration of anaesthesia, clinic patients were 1.94 (95% CI: 1.42 to 2.64) times more likely to experience an UIE than nonclinic patients (P < 0.001). CONCLUSION: Although clinic patients were more often optimally prepared, their adjusted risk of UIE was higher than nonclinic patients. The procedural anaesthetist needs to be vigilant with these high risk patients, even if they have been assessed at a preanaesthetic clinic.