Effect of acute hemorrhage on transcutaneous, subcutaneous, intramuscular, and arterial oxygen tensions.

Although transcutaneous PO2 is a close approximation of arterial PO2 in most neonates, infants in shock often show lower transcutaneous than arterial PO2 values. For a better understanding of this discrepancy, we investigated the effect of acute hemorrhage on transcutaneous, tissue, and arterial PO2 in rabbits. With progressive hemorrhage, transcutaneous and tissue PO2 values declined steeply while arterial PO2 values did not. We speculate that the progressive decrement in transcutaneous and tissue PO2 value with hemorrhage is produced by diminished peripheral blood flow. Rather than representing a failure of the transcutaneous PO2 monitoring method, we speculate that transcutaneous hypoxia with shock may be a clinically valuable danger signal.