Curriculum · Pediatric / Nutrition & Growth / EPI / Routine Child Examination
Hyperoxia test in the cyanotic newborn
What it is
The hyperoxia test is used in a newborn who is blue, to tell a cyanotic heart lesion from the other causes of cyanosis. A PaO2 that stays below 70 mmHg and is unchanged is the reading that points to the heart.
How it presents
Cyanosis is there within the first half hour of life and does not lift over the next few minutes: bluish discoloration of the skin, mucus membranes and tongue. Much of the rest of the newborn check can be normal, which is what makes the picture easy to miss. Respiratory rate can be normal, heart rate normal at around 120 beats/min, mean blood pressure around 61 mmHg, and there may be no systolic murmur at all, while SaO2 on room air sits at 85%.