The effect of beta-blocker premedication on the surgical field during endoscopic sinus surgery.

Abstract

A number of previous studies have tried to assess the effects of hypotension on the surgical field during endoscopic sinus surgery. These studies have been limited by inadequate sample sizes, lack of a control group, and limited data collection. The aim of the present study was to determine whether the routine use of beta-blockers as a pre-medication could improve the operative field in endoscopic sinus surgery. A prospective, randomized, double-blinded, placebo-controlled trial. Eighty patients undergoing endoscopic sinus surgery who fit the inclusion and exclusion criteria were randomly assigned to receive either a beta-blocker, Metoprolol (group 1), or a placebo tablet (group 2) 30 minutes before surgery. A standard anesthetic protocol was followed. At the commencement of surgery and at regular 15-minute intervals the surgical field, blood loss, heart rate, blood pressure, and isoflurane concentration were assessed. There was a significant difference in overall mean heart rate between the placebo and beta-blocker groups (P <.0001). In the entire group, surgical grade correlated with heart rate (r = 0.36, P <.05) but not with mean arterial blood pressure. Mean surgical grade was similar between the placebo and beta-blocker groups, but early in the study a significantly better surgical field was recorded in the beta-blocker group (P <.001). Surgical grade was significantly better in those with a mean heart rate of less than 60 beats per minute (P <.02). Although "optimum" conditions were present in the patients receiving beta-blocker, the authors thought that the grading system was not discriminating enough to demonstrate a significant difference between the groups. The crucial finding in the study was the correlation between heart rate and surgical grade in the entire group. During endoscopic sinus surgery surgery, anesthetic manipulations should be directed at maintaining a low heart rate.