Capillary Po2 in neonates

Capillary samples were obtained from warmed heel punctures of 30 full-term, healthy neonates 3 to 23 hours after birth (3 samples between 3-4 hours, 15 samples between 5-12 hours, and 12 samples between 12-23 hours). The blood was processed promptly, observing usual precautions, using London-Astrup equipment. Corrections were made to 37°C,assuming a rectal temperature of 36°C.After ternperatune correction, oxygen saturation was calculated from pH using Nelson's oxygen dissociation curve and Helleger's and Schruefer's pH corrections.