The association between anemia and neurological outcome in hypoxic ischemic brain injury after cardiac arrest.

Abstract

To examine the relationship between daily mean hemoglobin concentration and neurological outcome in hypoxic ischemic brain injury (HIBI) following cardiac arrest. We conducted a single center retrospective observational study using a database of HIBI patients between March 2009 and December 2014. We included all adults admitted to the intensive care unit following an in-hospital or out-of-hospital cardiac arrest. The primary outcome was neurological outcome measured by the Cerebral Performance Category (CPC) at hospital discharge. Multivariable logistic regression was used to analyze the association of mean hemoglobin concentration over 48h and 7 days after the onset of HIBI and discharge CPC. Favorable and unfavorable neurological outcome was dichotomized for a discharge CPC 1-2 vs 3-5, respectively. 118 patients were included in the analysis. Patients with a favorable neurological outcome had higher mean 7-day hemoglobin (115g/L vs 107g/L; p=0.05) compared to those with unfavorable outcome. Multivariate logistic regression controlling for age, time to return of spontaneous circulation and blood transfusion demonstrated that lower mean 48-h hemoglobin concentration was associated with unfavorable outcome (OR 0.69 per 10 unit change in Hgb, 95% CI 0.54-0.88, p<0.01). A repeated analysis using mean Hgb for the first 7 days yielded similar results for unfavorable outcome (OR 0.75 per 10 unit change in Hgb, 95% CI 0.57-0.97, p=0.03). Lower mean hemoglobin concentration in the first 48h and 7 days following HIBI is associated with a higher odds of unfavorable outcome at hospital discharge. Further study to examine this association is warranted.