[Evaluation of the impact of guidelines for rationalizing the prescription of preop tests for patients ASA 1 and 2 undergoing elective surgery].
To evaluate the impact of implementation of guidelines aimed at reducing the use of laboratory and diagnostic preoperative tests in patients with low anesthesiologic risk, admitted to six public hospital of Ente Ospedaliero Cantonale in Cantone Ticino (Switzerland). Observational study. Time series analysis of patterns of use of preoperative tests, on 14,585 patients admitted to public hospitals form March 1996 to June 1998. PRINCIPAL OUTCOME MEASURE: Proportion of patients undergoing a laboratory or other diagnostic tests during three six months periods before guidelines implementation (baseline), during the six months of the implementation phase and during the following four months of adoption of the guidelines in the participating centres. During the four months following the implementation, we observed a reduction of 15% (95% CI: 1%-27%) in the use of azotemia, and a reduction of 34% (95% CI: 18%-50%) for coagulation tests. Corresponding figures for glycemia and chest x-ray indicated a reduction of 44% (95% CI: 32%-54%) and of 22% (95% CI: 8%-34%), respectively. As for other tests (creatinine, ECG), no statistically significant reduction was observed. Most of the observed effect was explained by a reduction in use in patients at a low risk (ASA 1 and 2). In addition, guidelines appeared to have a greater impact in the four small (i.e. < 200 beds) hospitals, as compared with the two centres of greater size. Consistently with the empirical evidence available in this area, this study suggests that guidelines can change clinical practice, when they are implemented through a strategy taking into account adaptation of the recommendations to local circumstances and involvement of health professionals.