Influence of donor blood temperature on metabolic and hormonal changes during exchange transfusion.

Measurements of plasma glucose, free fatty acid, glycerol, insulin, growth hormone, and glucagon were made during exchange transfusions performed with blood heated to 36·5 to 38·5 °C or cooled to 10 to 13 °C. Term, normally grown infants suffering from rhesus incompatibility were studied. 10 received warm transfusions and 9 cold transfusions. Cold transfusions caused a progressive fall in rectal, umbilical vein, and skin temperature, whereas warm transfusions caused little change in body temperature. Infants receiving cold transfusions had a greater net positive balance of glucose and a smaller net negative balance of free fatty acids than those receiving warm transfusions. Other metabolic and hormonal responses to exchange transfusion were similar in the two groups. It was concluded that while exchange transfusion performed with cold blood did cause thermal stress to the infant, the metabolic consequences were slight and were mitigated by the glucose in the donor blood. There was no evidence that insulin, growth hormone, or glucagon played a part in the response of the newborn infant to cold.