Association between hemoglobin levels and clinical outcomes in adult patients after in-hospital cardiac arrest: a retrospective cohort study.

In addition to cardiac output, oxygen delivery is determined by the amount of oxygen carried by hemoglobin, which is estimated by the product of hemoglobin level and peripheral hemoglobin oxygen saturation (SpO2). Optimal hemoglobin concentration for post-cardiac arrest syndrome (PCAS) has not yet been investigated thoroughly. We conducted a retrospective observational study in a single medical center. We included adult patients between 2006 and 2012 who experienced in-hospital cardiac arrest, and achieved sustained return of spontaneous circulation (ROSC). We used multivariable logistic regression analysis to identify factors associated with favorable neurological status at hospital discharge, defined as a score of 1 or 2 on the Cerebral Performance Category scale. Minimum hemoglobin concentration and SpO2 during the initial 24 h after ROSC were used for analysis. Anemia was defined by the World Health Organization criteria as a hemoglobin concentration <12 g/dL in women and <13 g/dL in men. Of the 426 patients included in our analysis, 387 patients (90.8 %) met the criteria for anemia. The mean minimum hemoglobin concentration among all the patients was 9.2 g/dL. The product of hemoglobin × SpO2 was correlated with a favorable neurological outcome (odds ratio 1.003, 95 % confidence interval 1.002-1.004). According to recommended SpO2 by resuscitation guidelines (94-98 %), we calculated the corresponding range of minimum required hemoglobin concentration to be 8.6-9.0 g/dL for a favorable neurological outcome. Anemia common among PCAS patients. Neurological outcome in PCAS might be correlated with hemoglobin concentration following resuscitation.