Noninvasive estimation of arterial oxygenation in newborn infants.

Two noninvasive methods of estimating arterial oxygenation were compared in a group of 48 infants ranging in birth weight from 870 to 4,000 gm, with diagnoses including apnea of prematurity, hyaline membrane disease, meconium aspiration, and congenital heart disease. Both transcutaneous oxygen measurements and ear oximetry gave reasonably accurate estimations of arterial oxygen levels within commonly used clinical ranges (PO2 50 to 70 mm Hg, arterial saturation 90 to 98%). Infants with shock demonstrated a wide range of values for transcutaneous oxygen levels, suggesting that this method has limited usefulness in this situation. Ear oximetry had limited ability to distinguish high, but safe, levels of arterial oxygen from excessively elevated levels. While neither method can be recommended for replacement of arterial oxygen sampling, both methods may be useful in a clinical setting if care is exercised in interpretation of the results and if the values obtained are checked against those from arterial blood.