Pulse oximetry: an alternative method for the assessment of oxygenation in newborn infants.

Continuous monitoring of oxygenation in sick newborns is vitally important. However, transcutaneous PO2 measurements have a number of limitations. Therefore, we report the use of the pulse oximeter for arterial oxygen saturation (SaO2) determination in 26 infants (birth weights 725 to 4,000 g, gestational ages 24 to 40 weeks, and postnatal ages one to 49 days). Fetal hemoglobin determinations were made on all infants and were repeated following transfusion. SaO2 readings from the pulse oximeter were compared with the SaO2 measured in vitro on simultaneously obtained arterial blood samples. The linear regression equation for 177 paired measurements was: y = 0.7x + 27.2; r = .9. However, the differences between measured SaO2 and the pulse oximeter SaO2 were significantly greater in samples with greater than 50% fetal hemoglobin when compared with samples with less than 25% fetal hemoglobin (P less than .001). The pulse oximeter was easy to use, recorded trends in oxygenation instantaneously, and was not associated with skin injury. We conclude that pulse oximetry is a reliable technique for the continuous, noninvasive monitoring of oxygenation in newborn infants.