RESUMO
BACKGROUND: Spinal anesthesia has been considered inappropriate for ambulatory surgery patients because of concern about voiding dysfunction. The purpose of this study was to analyze the relationship between voiding interval and type of surgery under spinal anesthesia with lidocaine and to identify other nonanesthetic risk factors for delayed voiding. PATIENTS AND METHODS: A prospective study of 406 patients undergoing to ambulatory surgery under spinal anesthesia with lidocaine was performed. Voiding interval was defined as the time in minutes from the injection of local anesthetic to the patient's first spontaneous voiding. Univariate and multivariate linear regression models were constructed to identify risk factors associated with length of voiding interval. RESULTS: A total of 187 patients underwent herniorrhaphy; 187 patients underwent lower limb surgery; and 32 patients went benign anorectal surgery. The mean +/- sd voiding interval was 230 +/- 50.5 minutes. Factors associated with length of voiding interval in the univariate analysis were sex, body mass index (BMI), type and duration of surgery, lidocaine dose, and volume of fluid administered. Factors that remained significant in the multivariate model were sex, BMI, lidocaine dose and type of surgery: spontaneous voiding came later after inguinal herniorrhaphy surgery than after lower-limb surgery (regression coefficient 20 minutes; 95% confidence interval 11.5-29.8). Multivariate models performed for each type of surgery separately identified sex and lidocaine dose as factors related to length of voiding interval in all types of surgery. CONCLUSIONS: A longer voiding interval was associated with inguinal herniorrhaphy, spinal lidocaine dose, and male sex.
