In vivo oxygen dissociation curve for whole fetal blood: fitting the Adair equation and blood gas nomogram

Abstract

Oxygen tension, oxygen saturation of haemoglobin, plasma pH and carbon dioxide tension were analysed from 436 blood samples of the umbilical arteries and umbilical vein and 33 blood samples obtained by puncture of the arteria radialis of newborn babies younger than one day. A computer was used to fit the data to the Adair equation, and to calculate the pH- and Pco, -shift of the oxygen dissociation curve. The results were translated into a Po₂-So₂-pH-Pco₂-nomogram.

Key Words:

• carbon dioxide
• fetal blood oxygen affinity in vivo
• hydrogen ion concentration
• oxygen
• oxygen saturation
• P₅₀
• umbilical cord blood