CARDIOVASCULAR AND METABOLIC RESPONSE TO RED-BLOOD-CELL TRANSFUSION IN CRITICALLY ILL VOLUME-RESUSCITATED NONSURGICAL PATIENTS

We examined the cardiovascular and metabolic response to RBC transfusion in patients with circulatory shock after volume resuscitation. Data were analyzed from 36 transfusions in 32 patients who were undergoing continuous hemodynamic monitoring. Transfusions were administered for moderate to severe anemia, mean Hgb 83 g/dl. The diagnosis were sepsis (19/36), cardiogenic shock (14/36), connective tissue disease (2/36), and severe hypocalcemia (1/36). Benefit from transfusion was defined as an improvement in tissue oxygen utilization (increased oxygen consumption [V̇O2] or decreased lactate), a decrease in myocardial V̇O2 (MAP x HR), or a decrease in myocardial work (left ventricular work index). Mean transfusion volume was 577 ml over 4.5 h. Hgb and oxygen delivery (ḊO2) increased by 27% and 28%, respectively, while pulmonary artery wedge pressure and cardiac index were unchanged. No significant change was noted in V̇O2, or lactate, after augmentation or red cell mass. An increase occurred in myocardial work indices and MAP x HR. No changes were identified when subgroups were analyzed based on diagnosis, pretransfusion Hgb, lactate, or V̇O2 levels. We conclude that selective increase in ḊO2 by augmentation of RBC mass and oxygen-carrying capacity did not improve the shock state in these volume-resuscitated patients, regardless of the etiology of the shock.