Effect of remote ischemic preconditioning on cerebral oxygen saturation in aneurysmal subarachnoid hemorrhage: Secondary analysis of a randomized controlled trial.

Remote ischemic preconditioning (RIPC) can ameliorate cerebral vasospasm and delayed cerebral ischemia and improve neurological outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH). Monitoring of regional cerebral oxygen saturation (rScO2) during the critical phase after aSAH can help detect ischemia and assess the effect of RIPC intervention. We investigated the effect of RIPC on rScO2 in patients with aSAH. Our study was a single-center, prospective, parallel-group, randomized pilot trial. After approval by institutional ethics committee, consenting patients (n = 25) with aSAH presenting within 72 h of ictus and scheduled for surgical clipping of cerebral aneurysm were randomized 1:1 to true RIPC (inflation of upper extremity blood pressure cuff thrice to 30 mmHg above systolic blood pressure for 5 min) or sham RIPC (inflation of blood pressure cuff thrice to 30 mmHg for 5 min). In this secondary analysis, our outcome measures assessed by a blinded observer were incidence of cerebral oxygen desaturation (COD) during 7-10 days after ictus and Glasgow outcome scale extended (GOSE) at discharge. The incidence of COD (decrease in rScO2 > 20% from baseline) was lower in the RIPC group (15.4% versus 33.3%); p = 0.378. The absence of ipsilateral COD resulted in a higher mean GOSE (estimate 1.15, p = 0.015). The RIPC group had a higher mean GOSE compared to sham group (estimate 0.8, p = 0.027). This pilot trial demonstrated that RIPC has the potential to prevent COD in patients with aSAH. Larger trials with cerebral oxygenation as the primary outcome are needed to confirm our findings.