Objective: To determine the effect of single-shot interscalene brachial plexus (ISBP) block on intracranial pressure (ICP) by evaluating the extravascular volume effect of the medicine on the internal jugular vein (IJV).
Study design: Interventional study.
Place and duration of study: Department of Anaesthesiology and Reanimation, Sivas Cumhuriyet University, Sivas, Turkey, from January to June 2022.
Methodology: Thirty-four patients were included in this prospective clinical study. All patients had single-shot ISBP block with 25 ml of local anaesthetic. Optic nerve sheath diameter (ONSD), maximum (Dmax) and minimum (Dmin) diameters of IJV and IJV collapsibility index (IJV-CI) were recorded before the block (basal), 20 minutes, and 60 minutes after the block.
Results: Twenty-nine patients had higher ONSD values at 60th minute compared to their basal values. There were negative correlations between the changes of ONSD and IJVCI (r=0.616, p<0.001) and ONSD and Dmax (r=0.581, p<0.001) in time period between basal and 20th minute. There were negative correlations between the changes of ONSD and IJVCI (r=0.518, p=0.002), ONSD and Dmax (r=0.664, p<0.001) in time period between basal and 60th minute.
Conclusion: Single-shot ISBP block with 25 ml of local anaesthetic may be a factor that increases ICP. Repeated intraoperative ONSD measurements are recommended in patients operated with ISBP block.
Key words: Interscalene Brachial Plexus Block, Intracranial pressure, Optic nerve sheath diameter, Internal jugular vein collapsibility index.