Effect of transfusion on the venous blood lactate level in very low-birthweight infants

In recent years the blood lactate level can be easily and quickly measured with a small amount of blood, and the availability of an arterial blood lactate level has been reported as an indicator of oxygen deficit in adults. To determine whether venous blood lactate level can serve as such a marker for determining the indications for transfusion, blood lactate and hemoglobin level were monitored before and after transfusion. The study subjects consisted of 12 very low-birthweight infants admitted to the neonatal intensive care unit and who had transfusion between June 2005 and June 2007. The data on the blood lactate and hemoglobin were collected retrospectively by referring to the clinical records. A total of 18 transfusions was performed. There was no significant relationship between venous blood lactate and hemoglobin concentration before transfusion. The subjects were classified into two groups according to the lactate level before transfusion: 3.3 mmol/L and < 3.3 mmol/L. In the high-lactate group the lactate decreased significantly after transfusion (P < 0.01) and it continued to decrease thereafter. In the low-lactate group, however, the lactate remained unchanged. Venous blood lactate measurements may offer some additional information regarding the optimal time for performing a transfusion. To the authors' knowledge this is the first report to study the changes in lactate levels using venous blood sampling in red blood cell transfusion in very low-birthweight infants.