Effects of environmental warming on blood components dispensed in syringes for neonatal transfusions

We examined the quality of blood components dispensed in syringes for transfusion into neonates, including the effects on quality of environmental conditions to which blood is exposed when it is transfused into neonates nursed in warm-air incubators or under radiant warmers. Syringes of blood placed in incubators rapidly warmed to 36 degrees C. Blood placed under radiant warmers operated at full power was heated rapidly to temperatures approaching 45 degrees C, and all blood components exhibited evidence of falling pH and cellular damage after 6 hours exposure to radiant energy. Erythrocyte damage was suggested by an increase in plasma hemoglobin, potassium, and lactic dehydrogenase. Platelets lost the ability to recover from hypotonic shock. Granulocytes exhibited a marked defect in the ability to produce superoxide anion after stimulation. The excessive warming and functional abnormalities exhibited by all blood components exposed to infrared energy were abrogated when syringes were shielded by covering them with aluminum foil. The clinical importance of these experimental findings remains to be established. Meanwhile, it would seem prudent either to shield syringes of blood placed under radiant warmers by covering them with aluminum foil or to limit the volume of a single transfusion to a quantity that can be infused within a relatively brief period.