Relationship between transcutaneous and arterial oxygen tension in sick neonates during mild hyperoxemia

The effect of mild hyperoxemia on the relationship between transcutaneous (PtcO2) and arterial PO2 (PaO2) was determined in a group of 68 neonates with cardiopulmonary disease. In contrast to the relationship during normoxemia which did not differ from the line of identify, PtcO2 underestimated PaO2 by 17 +/- 9 torr (p less than 0.001) at PaO2 values ranging from 100-140 torr. Considerable caution, therefore, must be exercised in exclusively employing PtcO2 monitoring in neonates whose PaO2 is to be maintained near 100 torr.