APPROACH TO CYANOTIC NEWBORN

CYANOSIS: Cyanosis in the newborn is Defined as an arterial saturation less than 90% and a pO2 less than 60 torr.

• It is visible if the deoxygenated hemoglobin content is greater than 3 gm per 100ml
• It is the absolute concentration of the deoxygenated hemoglobin than determines cynosis and not the percentage.

CONCENTRATION OF DEOXYGENATED hemoglobin HAS 3 IMPLICATIONS:

• A polcytehmic baby exhibit cyanosis readily whereas it is difficult to diagnose cyanosis in a severely anaemic infatnt unless the oxygen saturation falls much below 90%.
• As the Foetal Hemoglobin has higer oxygen affinity, The new born baby manifests cyanosis when the oxygen content of the blood has fallen much below that expected of an older child.Therefore, a cyanotic newborn should recive immediate attention.
• Peripheral cyanosis is seen when Deoxyhemoglobin increasis due to dluggish peripheral ciculation although the oxygen content of the arterial blodd is normal.

It could be the presenting sign of cardiac conditions such as Hypoplasic left heart Syndrome.