Evaluation of the cyanotic newborn: Part I- A neonatologist’s perspective

Cyanosis is a commonly observed symptom in the newborn; however, its recognition and prompt management in a timely manner might be challenging in some instances. The presence of fetal hemoglobin and the concentration of hemoglobin in the blood have implications in the assessment of severity of cyanosis. Methodical evaluation and testing are essential in the diagnosis and treatment of the underlying condition. Pulse oximetry screening for critical congenital heart disease is important for detecting unsuspected life-threatening cardiac conditions. This 2-part article discusses the evaluation of cyanosis in the newborn period. Cyanosis, derived from the Greek word meaning “dark blue,” is defined as a dusky to bluish hue in the patient. (1) Although oxygenated hemoglobin is bright red, reduced hemoglobin is bluish to purple in color. Cyanosis is dependent on the absolute concentration of reduced hemoglobin and is usually visible when its concentration exceeds 3 to 5 g/dL (30-50 g/L) in the blood.