Current techniques for measuring oxygenation in newborn infants with r
espiratory insufficiency are reviewed, as well as the consequences of
variable and high fetal hemoglobin (HbF) fractions on both the measure
ment of sO2 and FCOHb and the application of Siggaard-Andersen's oxyge
n status algorithm to newborn infants. A procedure involving tonometry
of blood is described for measuring FHbF in newborn infants' blood.