Background and purpose: Subarachnoid hemorrhage (SAH) is known to result in elevated systemic oxygen consumption (Vo(2)) and increases in high-sensitivity C-reactive protein (hsCRP), although the relationship among hsCRP, Vo(2), and delayed cerebral ischemia (DCI) after SAH remains unknown. We hypothesized that hsCRP is directly associated with Vo(2) and that elevated Vo(2) is a predictor of DCI after SAH.
Methods: Prospective serial assessments of Vo(2) and hsCRP over 4 prespecified time periods during the first 14 days after bleed in consecutive SAH patients admitted to a single academic medical center for a 2-year period.
Results: One hundred ten SAH patients met study criteria (mean age, 55±16 years; 62% women), with a median admission Hunt Hess grade of 3 (interquartile range, 2-4). In multivariate generalized estimating equation model of the first 14 days after bleed, Vo(2) was associated with younger age (P=0.01), male gender (P=0.01), and hsCRP levels (P=0.03). Twenty-four (22%) patients had DCI develop, with a median onset on day 7 after bleed (interquartile range, 5-11). The mean Vo(2) (291±65 mL/min versus 226±55 mL/min; P=0.003) was higher in DCI patients. In a multivariable Cox proportional hazards model, younger age (hazard ratio, 1.2 per 5 years; 95% CI, 1.1-1.3), a higher modified Fisher scale score (hazard ratio, 3.4 per 1-point increase; 95% CI, 1.7-6.9), and higher Vo(2) (HR, 1.2 per 50-mL/min increase; 95% CI, 1.1-1.3) were predictive of DCI.
Conclusions: Systemic oxygen consumption is associated with hsCRP levels in the first 14 days after SAH and is an independent predictor of DCI.