Basaran B, et al. - This inquiry was set up to determine the impact of interscalene block (ISB) on intraocular pressure (IOP) and/or ocular perfusion pressure (OPP). In study participants ie, patients scheduled for ambulatory shoulder surgery under regional anesthesia with a single-shot ISB, it was noted that ISB decreased IOP in the blocked side. Data also indicated that in elderly patients at high risk for developing glaucoma, ISB could be considered as a safe regional technique of choice.

Methods

• Researchers recruited 30 patients scheduled for ambulatory shoulder surgery under regional anesthesia with a single-shot ISB (15 mL 0.5% bupivacaine and 15 mL 2% lidocaine).
• They measured IOP and OPP in both eyes, mean arterial pressure (MAP), heart rate (HR) and end-tidal CO₂(ETCO₂) before ISB and 5, 10, 20, 30 and 60 min after ISB in the beach-chair position.

Results

• Findings demonstrated that the baseline IOP and OPP were similar in the blocked and unblocked sides (IOP 17.60 ± 1.69 and 17.40 ± 1.96 respectively p=0.432; OPP 49.80 ± 8.20 and 50 ± 8.07 respectively p=0.432).
• Researchers also observed that in comparison to the baseline values (p < 0.001), the IOP in the blocked side significantly decreased between 10th to 60th min following ISB.
• Furthermore, a significant increase was seen in the OPP in the blocked side from 10th to 60th min (p < 0.001) whereas, no significant changes were evident in IOP and OPP throughout the measurement period in the unblocked side.