Analysis of the tcPO2 response to blood interruption in infants and adults.

The transcutaneous PO2 (tcPO2) response to blood interruption (BIS test) was measured in 6 healthy adults and 28 infants, including premature infants. The response was similar in both infants and adults with a time lag at the beginning of blood interruption, a subsequent linear decrease, a time lag at the end of blood interruption, and an exponential recovery to the final steady state. The linear decrease of tcPO2 in the BIS test had a correlation coefficient of more than 0.98 in all subjects and indicated the cutaneous oxygen consumption rate independent of the oxygen pressure. There was a significant difference in oxygen consumption according to birth weight in the infants (< 2 kg, 2-3 kg, and > 3 kg). The recovery time constant for infants was 13 seconds which was about 1.4 times faster than that for adults, and it increased significantly along with a higher birth weight. The time lag at blood interruption was longer than that at blood recovery. The time lag for infants was significantly shorter than that for adults, and in infants there was a significant difference between the group with a birth weight < 2 kg and the others (p < 0.005). All of the parameters of the BIS test suggested the physiological immaturity of premature infants.