Paediatrics: management of Cyanosis

2021-03-10 12:00 AM

Bedside diagnosis of methaemoglobinaemia: place a drop of blood on a piece of filter paper.


Cyanosis: management


Blood tests

  • FBC with differential.
  • Blood cultures.
  • Glucose.
  • Bedside diagnosis of methaemoglobinaemia: place a drop of blood on a piece of filter paper. After 30s exposure to air, normal blood turns red, while blood taken from a patient with methaemoglobinaemia remains chocolate brown.


  • Lumbar puncture as indicated.
  • Urinary culture.

Arterial blood gas

In the older child, a single measurement is needed. In the neonate, assess the change in PaO2 in response to FiO2 100% for 5–10min.

Chest X-ray

In the neonate, the lung fields should be assessed for signs of increased vascularity, pulmonary congestion, or oligaemia. Characteristic radiographic findings are:

  • Egg on a string: transposition of the great arteries.
  • Boot-shaped heart: tetralogy of Fallot, pulmonary atresia,ventriculoseptal defect.
  • Snowman sign: supracardiac total anomalous pulmonary venous drainage.
  • Wall-to-wall heart: Ebstein’s anomaly.


Characteristic findings include:

  • Superior left axis: tricuspid atresia; endocardial cushion defect; primatial septal defect.
  • Left axis deviation: pulmonary atresia ± atrial atresia.
  • Marked right atrial hypertrophy: Ebstein’s anomaly.


Assessment of specific cardiac lesions.


Standard cardiorespiratory monitoring.


Therapies for specific cardiac, respiratory, and poisoning conditions are discussed elsewhere