INTRAOCULAR PRESSURE AND SAFETY OF VITRECTOMY WITH VITREOUS GAS REPLACEMENT USING LOW-CONCENTRATION NITROUS OXIDE GAS ANESTHESIA.

Purpose: The aim of this study is to evaluate the efficacy and safety of vitrectomy with vitreous gas replacement using low-concentration nitrous oxide (N 2 O) gas anesthesia, focusing on intraocular pressure (IOP) changes, pain, anxiety, and safety outcomes.

Methods: This retrospective study analyzed 133 patients undergoing fluid-air exchange without use of SF6 or C3F8, at Saneikai Tsukazaki Hospital, Japan, from April 2019 to March 2022. Participants were divided into two groups: those receiving low-concentration nitrous oxide gas anesthesia (N 2 O group) and those receiving local anesthesia with room air inhalation (air group). IOP, pain, anxiety levels, and intraoperative complications were assessed.

Results: No significant differences were found in IOP changes postoperatively between the N 2 O and air groups. The N 2 O group reported significantly lower pain scores and had lower intraoperative systolic blood pressure and heart rate changes compared with the air group. No significant intraoperative or postoperative complications were observed in either group.

Conclusion: Vitrectomy with fluid-air exchange using low-concentration nitrous oxide gas anesthesia is safe, does not increase IOP, and may offer benefits in reducing intraoperative pain and stabilizing vital signs compared with traditional local anesthesia methods. This approach could be considered a viable option for vitreous surgery requiring fluid-air exchange.