RESUMO
OBJECTIVE: To evaluate the effects of preoperative sub-Tenon's capsule injection of ropivacaine on intraoperative hemodynamics, postoperative pain, nausea, and recovery in patients undergoing scleral buckling surgery under general anesthesia (GA). DESIGN: Randomized double-masked controlled clinical trial. PARTICIPANTS: Ninety-eight patients with primary rhegmatogenous retinal detachment undergoing scleral buckling surgery under GA. METHODS: Random allocation to either preoperative sub-Tenon's capsule injection of 3 ml of 0.75% ropivacaine or sub-Tenon's capsule injection of 3 ml of saline (controls) immediately before a scleral buckling procedure under GA. Intraoperative monitoring of hemodynamic parameters, need of analgesia with sevoflurane and alfentanil, time in the recovery unit, measurements of pain and nausea on the visual analog scale (VAS) up to 12 hours postoperatively, and consumption of analgesics and antiemetics was recorded. MAIN OUTCOME MEASURES: Intraoperative systolic blood pressure (BP); bradycardia; minimum alveolar concentration (MAC) of sevoflurane; maximum postoperative VAS scores of pain and nausea; time in recovery unit; and total need of alfentanil, ketobemidone, dextropropoxyphene, and dixyrazine. RESULTS: Ninety-seven patients were analyzed (48 in the ropivacaine group and 49 controls). A significantly lower intraoperative systolic BP (104+/-6 vs. 112+/-7 mmHg; P = 0.004), less need of sevoflurane (1.33+/-0.19 vs. 1.56+/-0.23; P = 0.03), and shorter time in the recovery unit (67+/-9 vs. 76+/-16 minutes; P = 0.01) were observed in the ropivacaine group. Maximum VAS pain scores were 50+/-21 in the control group and 36+/-25 in the ropivacaine group (P = 0.05), with a significantly lower consumption of opioids (ketobemidone) in the ropivacaine group (3.6+/-3.5 vs. 1.3+/-2.0 mg). No significant difference was observed regarding nausea or need of dixyrazine or dextropropoxyphene postoperatively. CONCLUSIONS: Preoperative sub-Tenon's capsule injection of ropivacaine in scleral buckling surgery under GA lowers the intraoperative systolic BP, reduces the amount of inhalable sevoflurane needed, and enhances postoperative vigilance through reduction of pain and need of opioids.
