Is hemoglobin level alone a reliable predictor of outcome in the severely anemic surgical patient?

The relationship between outcome and hemoglobin (Hgb), oxygen extraction ratio (ER), history of cardiac, renal, pulmonary, and/or hepatic disease, diabetes, malignancy, sepsis, hypertension, and active bleeding was analyzed in 47 patients with severe anemia (Hgb less than 7.0 gm/dl, mean = 4.6 +/- .2 gm/dl) to evaluate the effect of Hgb on survival and to look for other predictors of outcome. All patients had refused blood transfusion on religious grounds and were participants in a randomized, controlled study of the blood substitute Fluosol DA-20 per cent. Patients were analyzed as a group and after stratifying by Hgb into four levels: (Hgb less than 3.0 gm/dl, N = 7; Hgb less than 3.5 gm/dl, N = 12; Hgb less than 4.0 gm/dl, N = 17; Hgb less than 4.5 gm/dl, N = 23) and by ER into two levels of less than 50 per cent and greater than 50 per cent. Only Hgb, ER, sepsis and active bleeding were predictors of outcome, with sepsis being the only significant, independent predictor of outcome at all levels (P less than .01). Active bleeding was a predictor for levels of Hgb below 4.0 gm/dl. Hgb level alone was a significant predictor only at levels below 3 gm/dl (P less than .05). Extraction ratio interacted with Hgb only below 3 gm/dl (P less than .05). Multiple independent factors influence outcome in the severely anemic patient, the strongest being sepsis and active bleeding. Prevention of sepsis and early intervention to stop bleeding should improve survival in the patient who refuses transfusion.