Application of Near-Infrared Spectroscopy for the Detection of Delayed Cerebral Ischemia in Poor-Grade Subarachnoid Hemorrhage

The objective of this study was to investigate the clinical feasibility of near-infrared spectroscopy (NIRS) for the detection of delayed cerebral ischemia (DCI) in patients with poor-grade subarachnoid hemorrhage (SAH) treated with coil embolization.

Cerebral regional oxygen saturation (rSO₂) was continuously monitored via two-channel NIRS for 14 days following SAH. The rSO₂ levels according to DCI were analyzed by using the Mann–Whitney U-test. A receiver operating characteristic curve was generated on the basis of changes in rSO₂ by using the rSO₂ level on day 1 as a reference value to determine the optimal cutoff value for identifying DCI.

Twenty-four patients with poor-grade SAH were included (DCI, n = 8 [33.3%]; non-DCI, n = 16 [66.7%]). The rSO₂ levels of patients with DCI were significantly lowered from 6 to 9 days compared with those in without DCI. The rSO₂ level was 62.55% (58.30–63.40%) on day 6 in patients with DCI versus 65.40% (60.90–68.70%) in those without DCI. By day 7, it was 60.40% (58.10–61.90%) in patients with DCI versus 64.25% (62.50–67.10%) those without DCI. By day 8, it was 58.90% (56.50–63.10%) in patients with DCI versus 66.05% (59.90–69.20%) in those without DCI, and by day 9, it was 60.85% (58.40–65.20%) in patients with DCI versus 65.80% (62.70–68.30%) in those without DCI. A decline of greater than 14.5% in the rSO₂ rate yielded a sensitivity of 92.86% (95% confidence interval: 66.1–99.8%) and a specificity of 88.24% (95% confidence interval: 72.5–96.7%) for identifying DCI. A decrease by more than 14.7% of the rSO₂ level indicates a sensitivity of 85.7% and a specificity of 85.7% for identifying DCI.

Near-infrared spectroscopy shows some promising results for the detection of DCI in patients with poor-grade SAH. Further studies involving a large cohort of the SAH population are required to confirm our results.