Prospective evaluation of anesthetic technique for anorectal surgery.

Purpose: Deep intravenous sedation plus local anesthesia for anorectal surgery in the prone position is used frequently at our institution, but is not widely accepted because of concerns regarding airway management. The purpose of this study was to prospectively evaluate the safety and efficacy of this anesthetic technique for anorectal surgery.

Methods: Data were collected prospectively on 413 consecutive patients (mean age, 47 years; mean weight, 80 kg) undergoing anorectal surgical procedures.

Results: Of the 389 patients who underwent anorectal procedures in the prone position, 260 (67 percent) received intravenous sedation plus local anesthesia, 125 (32 percent) received regional anesthesia (spinal or epidural), and 4 (1 percent) received general endotracheal anesthesia. Of the 24 patients who underwent anorectal procedures in the lithotomy position, 13 (54 percent) received intravenous sedation plus local anesthesia, 2 (8 percent) received regional anesthesia, 2 (8 percent) received general endotracheal anesthesia, and 7 (29 percent) received mask inhalational anesthesia. Forty-two adverse events attributable to the anesthetic occurred in 18 patients: nausea and vomiting (n = 17), transient hypotension, bradycardia, or arrhythmia (n = 8), transient hypoxia or hypoventilation (n = 7), urinary retention (n = 6), and severe patient discomfort (n = 2). These complications occurred in 4 percent (10/273) of patients receiving intravenous sedation plus local anesthesia and in 6 percent (8/127) of patients receiving regional anesthesia. Two of 260 patients (0.8 percent) receiving intravenous sedation plus local anesthesia in the prone position were rolled supine before completing the surgical procedure. Recovery time before discharge for patients treated on an ambulatory basis was significantly shorter for those patients undergoing intravenous sedation plus local anesthesia (79 +/- 34 minutes, n = 174) than for patients undergoing regional anesthesia (161 +/- 63 minutes, n = 45; P < 0.001, t-test).

Conclusion: Intravenous sedation plus local anesthesia in the prone position is safe and effective for anorectal surgery and offers potential cost savings by decreasing recovery room time for outpatient procedures.