Background and Objectives: Secondary cerebral vasospasm (CV) with subsequent delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH) remains an unpredictable pathology. The aim of this retrospective study was to investigate the association between inflammatory parameters, white blood cell (WBC) count, and C-reactive protein plasma levels (CRP) and the occurrence of secondary CV in patients with aSAH. Materials and Methods: The medical records of 201 Intensive Care Unit patients in Riga East University Hospital with aSAH were retrospectively reviewed in a 24-month period. WBC count and CRP values were observed at admission to the hospital and on the third day. According to the inclusion criteria, 117 (48 males) participants were enrolled for further analysis, with average age of 56 ± 15 years (mean ± SD). In total, secondary CV was diagnosed in 21.4% of cases, and DCI in 22.4% of cases. The patients were classified into three groups: SAH-CV group (n = 25), SAH-DCI group (n = 12), and SAH or control group (n = 80), for comparative analysis. Results: We found that SAH-CV patients demonstrated notably higher inflammatory parameters compared to controls: WBC 13.2 ± 3.3 × 10⁹/L vs. 11.2 ± 3.7 × 10⁹/L; p = 0.01 and CRP median 9.3 mg/L vs. 1.9 mg/L; p < 0.001, respectively. We found that the odds of developing CV increased by 5% for each CRP increase of 1 mg/L at admission (OR, 1.05; CI, 1.014–1.087; p = 0.006). Concomitantly, the odds increased by 16% for every rise in WBC count of 1 × 10⁹/L (OR, 1.16; CI, 1.02–1.32; p = 0.02). WBC count was associated with the occurrence of CV with 96% sensitivity and 40% specificity, with a cut off level of 10.015 × 10⁹/L and AUC 0.683; p = 0.006. CRP displayed 54% sensitivity and 90% specificity with a cut off value of 8.9 mg/L and AUC 0.751; p < 0.001. Moreover, higher values of inflammatory parameters at admission correlated with a longer stay in ICU (r = 0.3, p = 0.002 for WBC count and r = 0.305, p = 0.002 for CRP values), and poor outcome (death) was significantly associated with higher CRP values at admission and on the third day (16.1. vs. 2.2. and 57.4. vs. 11.1, p < 0.001, respectively). Higher mortality was detected in SAH-CV patients (32%) compared to controls (6.3%; p < 0.001). Conclusions: Inflammatory parameters such as WBC count and CRP values at admission might be helpful to predict the development of secondary CV.

Background/Objectives: Delayed cerebral ischemia (DCI) represents a major cause of morbidity and mortality after aneurysmal subarachnoid haemorrhage (aSAH). Early identification of developing cerebral ischemia is essential for timely prevention of DCI. Near-infrared spectroscopy (NIRS) provides continuous, non-invasive bedside monitoring of regional cerebral oxygen saturation (rSO₂); however, its clinical value in patients with aSAH has not yet been fully established. The primary objective of this study was to investigate whether NIRS-detected rSO₂ desaturation can serve as an early indicator of cerebral vasospasm (CV) and predict the occurrence of DCI. Secondary objectives were to examine the associations between rSO₂ changes and other cerebral deterioration events, length of intensive care unit stay, functional outcome, and in-hospital mortality. Methods: This prospective, single-centre study included 30 patients with aSAH admitted to the intensive care unit (ICU) of Riga East University Hospital between January 2019 and January 2023. Bilateral frontal near-infrared spectroscopy (NIRS) monitoring (Covidien INVOS™ 5100C-PB) was initiated within 72 h after ictus and continued for up to 7 days. Cerebral desaturation was defined as a >20% reduction from baseline (BL) or an absolute regional cerebral oxygen saturation (rSO₂) value < 50% lasting ≥30 min. CV and DCI were diagnosed according to established clinical and radiological criteria. Receiver operating characteristic (ROC) analysis was performed to evaluate the sensitivity and specificity of rSO₂ thresholds for the detection of CV, DCI, and other cerebral deterioration events. Results: CV occurred in 10 patients (33%); however, only four cases were detected during the NIRS monitoring period. NIRS demonstrated very high sensitivity (97.5%) but extremely low specificity (6%) for the early detection of CV. In contrast, diagnostic accuracy for DCI was high. An absolute rSO₂ cut-off value of 52% yielded a sensitivity of 97.5% and a specificity of 95%, whereas a decrease of ≥26% from baseline (BL) demonstrated a sensitivity of 98% and a specificity of 93%. Significant rSO₂ reductions were also observed during aneurysm re-rupture, hydrocephalus, cerebral edema, and postoperative ischemia; however, the sensitivity of NIRS for detecting these events was negligible. Patients with ≥20% desaturation tended to have longer ICU stays, and lower mean rSO₂ values as well as greater desaturation were associated with poorer functional outcomes as assessed by the modified Rankin Scale. Patients who died exhibited more pronounced rSO₂ decreases and less recovery compared with survivors. Conclusions: In this cohort, NIRS demonstrated limited specificity for the early detection of CV but showed strong associations with DCI and neurological outcome. NIRS may be useful as a non-invasive adjunct to multimodal neuromonitoring rather than as a stand-alone diagnostic tool for cerebral vasospasm. Larger, prospective studies incorporating standardized imaging protocols and optimized rSO₂ thresholds are required to more clearly define the role of NIRS in the management of aSAH.