Subtenon block combined with general anesthesia for vitreoretinal surgery improves postoperative analgesia in adult: a randomized controlled trial.

Study Objective: To evaluate the effects of subtenon block (SB) as an adjunct to general anesthesia on intraoperative oculocardiac reflex (OCR), postoperative pain, and postoperative nausea and vomiting (PONV) for vitreoretinal surgery.

Design: Prospective, randomized, double-blinded clinical trial.

Setting: Operating room, postanesthesia care unit, and ward at a university-affiliated hospital.

Patients: Eighty patients aged 40 to 65 years of American Society of Anesthesiologists I to II requesting general anesthesia for vitreoretinal surgery. Intervention and Measurements Patients were randomly assigned to 1 of 2 groups receiving either SB with mixture of 4 mL of 2% lidocaine and 0.5% bupivacaine (50:50) in group SB or subtenon injection of saline in group C after induction of anesthesia and before surgery in a double-blind manner. The time to first postoperative analgesic dose, incidence of intraoperative OCR, postoperative pain scores, perioperative analgesic requirements, number of patients requiring rescue analgesics during the 24-hour study period, incidence of PONV, and possible complications were recorded.

Results: Time to first postoperative analgesia was significantly longer in group SB (P= .002). Pain scores at the first 6 hours postoperatively were significantly lower in group SB (P= .002). Intraoperative and postoperative analgesic requirements were significantly reduced in group SB (P= .015). The incidence of OCR and PONV also significantly decreased in this group (P= .001 and P= .011, respectively).

Conclusion: Use of SB combined with general anesthesia in patients undergoing vitreoretinal surgery reduces postoperative analgesic requirements and complications such as intraoperative OCR and PONV.