COSTA, CALDAS, NUNES ET AL. commended 7 . In contrast, the discontinuation of drugs, such as angiotensin-converting enzyme inhibitors (ACE inhibitors) on the day of the surgery based on reports of significant hypotension after induction of anesthesia suggesting a deleterious interaction between ACE inhibitors and anesthetics in general has been questioned or suggested by some authors 8,9 . However, discontinuation of drugs used for a long time, such as antihypertensives, can implicate on a higher risk of intraoperative hypertensive peaks with harmful consequences for the patient 7 . This has generated controversies among anesthesiologists and, occasionally, conflicts with the physician in charge. The objective of this preliminary study was to evaluate the influence of the preoperative use of ACE inhibitors on the incidence of clinically significant hypotension (hypotension requiring intervention by the anesthesiologist) after anesthetic induction.
METHODSAfter approval by the Ethics Committee of the hospital, a case-control, retrospective study in which the study group was composed by all patients who presented significant hypotension after anesthetic induction during the study period, i.e., one year, was undertaken. Cases of hypotension that required intervention such a volume expansion and use of vasopressors by the anesthesiologist responsible for the case were considered significant. Patients underwent orthopedic, neurosurgical, reconstructive plastic surgery, urologic, and thoracic procedures. Electronic medical records were reviewed for data on anesthetic induction, the moment the patient developed hypotension, therapeutic measures, and evolution of the case. The control group was composed by four patients, randomly selected, for each study patient, to increase the power of the statistical analysis 10 . Patients in the control group were in the same age range, underwent the same type of surgery and at the same time as the study patients, and did not develop hypotension after anesthetic induction. Patients younger than 18 years and those who received local anesthetics or sedation as the only technique were excluded from the study. Parameters analyzed were as follows: age, gender, size of the surgery, prior diagnosis of hypertension, use of ACE inhibitors, physical status (ASA), intraoperative bleeding, anesthetic technique, and duration of the surgery. Analysis of Variance was used for numerical parameters and Fisher's Exact test for categorical parameters. For categorical parameters with significant association, the degree of increase in risk was determined by odds ratio. Univariate and multiple analyses were also undertaken using logistic regressions. Data were processed by SPSS for Windows, version 13.0.