Rapid Review·Cardiovascular
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HY Approach
T1Must knowApproach to Neonatal Cyanosis
Focus on
Is the blue baby a lung problem or a heart problem? The hyperoxia test answers it: saturation that climbs on 100% oxygen means lung; saturation that stays low means a right-to-left cardiac shunt — start prostaglandin E1 and get an echo. Acrocyanosis of the hands and feet in a pink baby is normal. Timing sorts the cardiac causes: hours (TGA), days (duct closure), months (tetralogy).
Key takeaways
Central vs peripheral, and the causes
Central cyanosis
lips, tongue, trunk; it means hypoxemia and needs evaluation now.Acrocyanosis
hands, feet and perioral skin in a pink, comfortable newborn; common in healthy infants immediately after birth, may persist 24 to 48 hours, and needs nothing.Cardiac causes (right-to-left shunt or mixing)
Transposition of the Great Arteries, Tetralogy of Fallot, Tricuspid Atresia, Total Anomalous Pulmonary Venous Return, Truncus Arteriosus, Ebstein Anomaly, Hypoplastic Left Heart Syndrome and critical Coarctation of Aorta (cyanosis plus shock).Pulmonary causes
respiratory distress syndrome, transient tachypnea, meconium aspiration, pneumonia, pneumothorax, diaphragmatic hernia, choanal atresia.- Persistent Pulmonary Hypertension of the Newborn: a structurally normal heart shunting through the duct and foramen.
Other causes
sepsis, hypoglycemia, apnea from maternal drugs or asphyxia, polycythemia, methemoglobinemia (chocolate-brown blood, normal arterial oxygen tension, no response to oxygen).Heart vs lung at the bedside
cardiac is cyanosis without much respiratory distress (comfortably blue), a murmur or single S2, weak or unequal pulses, no improvement with oxygen.- Pulmonary: grunting, retractions, nasal flaring, crackles, improvement with oxygen.
The pathway
Stabilize
airway, breathing, glucose, temperature.Tests
follow the Neonatal cyanosis pathway: pre- and postductal saturations (right hand versus foot), chest radiograph, electrocardiogram, blood gas, cultures.Hyperoxia test
arterial oxygen tension after 10 minutes of 100 percent oxygen.Echocardiography
defines the anatomy.Reading the hyperoxia test
saturation and tension rise (over 250 mm Hg): pulmonary disease.- Tension stays low (under 100 to 150) with continued cyanosis: a fixed right-to-left cardiac shunt (or severe pulmonary hypertension), so start prostaglandin E1 and get an echocardiogram.
Reading the saturation gradient
a preductal saturation higher than postductal means right-to-left ductal shunting (persistent pulmonary hypertension, critical coarctation).- Reverse differential cyanosis (postductal higher) is transposition with pulmonary hypertension.
Normal tension but blue
a methemoglobin level.The duct-dependent lesions
The list
coarctation of the aorta, D-transposition, hypoplastic left heart, total anomalous pulmonary venous connection, tricuspid atresia (and pulmonary atresia, severe tetralogy).| Lesion | Timing of cyanosis | Examination | Chest film | Key first step |
|---|---|---|---|---|
| Transposition of the great arteries | First hours | Single loud S2, no murmur (unless a ventricular septal defect) | Egg on a string, narrow mediastinum | Prostaglandin E1, balloon atrial septostomy, arterial switch |
| Tricuspid atresia | First days | Holosystolic murmur, single S2 | Oligemic lungs; left axis deviation on the newborn electrocardiogram | Prostaglandin E1, then staged surgery |
| Total anomalous pulmonary venous return | First days to weeks | Right-ventricular heave, right heart failure | Snowman; pulmonary edema if obstructed | Surgical repair |
| Truncus arteriosus | First weeks, with heart failure | Bounding pulses, harsh murmur, single S2 | Increased vascularity, right arch, absent thymus | Surgical repair |
| Tetralogy of Fallot | Weeks to months (spells at 2 to 4 months) | Harsh ejection murmur at the left upper sternal border, single S2 | Boot-shaped heart, decreased vascularity | Knee-chest, oxygen, morphine, fluids, beta blocker; repair |
| Ebstein anomaly | Variable | Tricuspid regurgitation murmur, pre-excitation | Massive cardiomegaly | Supportive, repair |
| Hypoplastic left heart syndrome | Days 3 to 14, with shock as the duct closes | Single S2, no murmur, weak pulses | Cardiomegaly, pulmonary edema | Prostaglandin E1, staged palliation |
| Persistent pulmonary hypertension | First 24 hours, with respiratory distress | Prominent S2; meconium, post-term | Clear, or the underlying lung disease | Oxygen, ventilation, inhaled nitric oxide, extracorporeal support |
Management
Cardiac cyanosis or shock in a newborn
intravenous prostaglandin E1 (alprostadil) immediately, before the echocardiogram.Inadequate mixing (transposition)
balloon atrial septostomy.Pulmonary causes
oxygen, ventilation, surfactant, antibiotics, a chest tube, surgery for a hernia.Persistent pulmonary hypertension
oxygen, gentle ventilation, inhaled nitric oxide, extracorporeal support if refractory.Methemoglobinemia
methylene blue.A comfortably blue newborn with little respiratory distress has an arterial oxygen tension of 45 mm Hg that stays at 60 after 10 minutes of 100 percent oxygen. What does this mean, and what is started before the echocardiogram, with which side effect to watch?
A failed hyperoxia test: a fixed right-to-left cardiac shunt. Start intravenous prostaglandin E1 (alprostadil) before the echo, and be ready to intubate for apnea.
How it's tested
A term newborn is blue at 6 hours with a saturation of 75% that does not rise on 100% oxygen; comfortable breathing, single S2, no murmur: cardiac right-to-left shunt — most likely transposition; start PGE1, echocardiogram, balloon septostomy.
Blue hands and feet, pink lips and tongue, saturation 97%, in a 12-hour-old: acrocyanosis — normal; reassure.
Cyanosis with grunting and retractions in a preterm infant that improves to 98% on oxygen; ground-glass lungs: respiratory distress syndrome — surfactant and CPAP, not a cardiac lesion.
Post-term infant delivered through meconium, cyanotic within hours, preductal saturation 94% and postductal 82%, structurally normal heart on echo: persistent pulmonary hypertension of the newborn — oxygen, ventilation, inhaled nitric oxide.
Cyanosis unresponsive to oxygen with a normal PaO2 and chocolate-colored blood: methemoglobinemia — methylene blue.
Well newborn discharged home, collapses grey and mottled on day 8 with no femoral pulses: duct-dependent systemic lesion (critical coarctation or HLHS) — PGE1 before anything else.
Go deeper
Related Step 2 pages: Approach to Congenital Heart Disease, Fetal Circulation & Transition at Birth, Transposition of the Great Arteries, Tetralogy of Fallot, Persistent Pulmonary Hypertension of the Newborn, Hypoplastic Left Heart Syndrome, Coarctation of Aorta
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