Presentation:

• Central: buccal mucosa, under the tongue (serious)
• Peripheral: lips, fingernails (+ capillary reflex, > 2s = abnormal) (benign)
• Chronic: associated with Clubbing - Shamroth’s window

Etiology

• Cardiac Causes (Do not respond to Hyperoxia Test (<150/>250))
• Pulmonary Causes (respond to Hyperoxia Test (<150/>250))

Pathogenesis

• Directly related to the amount of de-oxyHb in blood
  • Anemia (↓Hb) → less likely to be cyanotic
  • Polycythemia vera → more likely to be cyanotic

Diagnosis

Pre-to-postductal SpO2 (Δ <3%, > 95%)

• Routine CCHD Screaning at 36 hr of life
• < 90%, or Δ >3% + 95=90% → Investigate more

Hyperoxia Test (<150/>250)

• PAO2 < 150 = !Cyanotic CHD
• PAO2 > 250 = Other Causes

Complications