Ep 2: The Case of Baby Boy Blue Part 2: Cardio Approach to the Cyanotic Newborn

Learning Objectives

By the end of this episode, NICU Grads will be able to:
1. Discuss postnatal evaluation of congenital heart disease outside of the delivery room
2. Construct initial NICU management for patients suspected for congenital

Guest Speaker
Gregory Kitley Yurasek, MD FAAP
Pediatric cardiac intensive care specialist
PubMed

Cyanosis: Cardiac Evaluation

• Central cyanosis and hypoxemia in the absence of respiratory distress—> Consider cardiac etiology
• Cyanosis may be seen in several types of congenital heart disease (CHD)
  • Right sided heart obstructive lesions
    • Tricuspid valve atresia 
    • Tricuspid valve stenosis
    • Ebstein’s anomaly of the tricuspid valve
    • Pulmonary valve atresia 
    • Critical pulmonary valve stenosis 
    • Tetralogy of Fallot  (TOF)
  • Left sided heart obstructive lesions
    • Hypoplastic left heart syndrome 
    • Interrupted aortic arch/coarctation of the aorta
    • Critical aortic stenosis
  • Mixing lesions
    • Truncus arteriosus 
    • Transposition of the great arteries (TGA)
    • Total anomalous pulmonary venous return  (TAPVR)
• Differential cyanosis/O2 differential
  • Refers to the appearance of cyanosis in both lower extremities with pink right upper extremity
  • Pre- and postductal difference of more than 20 torr in PaO2 or at least 5% difference in oxygen saturation 
  • Occurs when there is PDA with pulmonary hypertension and/or left-heart abnormalities (aortic arch hypoplasia, interrupted aortic arch, critical coarctation, and critical aortic stenosis) 
    • Deoxygenated blood in the PA –> PDA –> Descending aorta –> Sending blue blood to lower extremities –> Cyanotic lower extremities with lower postductal saturations
    • Oxygenated blood from LV –> Ascending aorta –> Sending red blood to upper extremities –> Pink upper extremities with higher preductal saturations
• Reverse differential cyanosis
  • Refers to the appearance of cyanosis in both upper extremities with a pink lower extremities
  • DDX:
    • TGA
      • Deoxygenated blood from the RV –> Ascending aorta –> Sending blue blood to upper extremities –> Cyanotic upper extremities with lower preductal saturations
      • Oxygenated blood from the pulmonary circulation –> LA –> LV–> PA–> PDA –> Descending aorta –> Sending red blood to lower extremities–> Pink lower extremities with higher postductal saturations
    • Supracardiac TAPVR
      • Oxygenated blood from pulmonary veins drain into SVC –> RA –> Preferentially travels through the tricuspid valve –> RV –> PA –> PDA –> Descending aorta –> Sending red blood to lower extremities –> Pink lower extremities with higher postductal saturations
      • Deoxygenated blood returning to heart –> Preferentially travels through the PFO –> LA–> LV–> Ascending aorta –> Sending blue blood to upper extremities –> Cyanotic upper  extremities with lower preductal saturations
• Delivery Room Cardiac Evaluation of Cyanosis
  • 100% oxygen
  • Decide to admit to NICU
  • Obtain access 
• NICU Cardiac Evaluation of Cyanosis 
  • Tier 1: 
    • Cardiac exam
      • BP, HR, O2 saturation, FiO2, heart sounds, murmur, pulses, perfusion
    • Arterial blood gas
      • It is important to get gas to confirm arterial hypoxemia and assess ventilation
    • Hyperoxia test
      • Used to differentiate cardiac from noncardiac causes of neonatal cyanosis
      • The test is performed by measuring the PaO₂ in the right radial artery (preductal) on room air and again after 10 minutes of supplementation with 100% oxygen 
      • An ↑ PaO₂ should be seen if heart is normal
      • No significant ↑ in PaO₂  is abnormal and suggestive of CHD

References: Dasgupta S, Bhargva V, Huff M, Jiwani AK, Aly AM. Evaluation of the cyanotic newborn: part I—a Neonatologist’s Perspective. Neoreviews. 2016;17(10):e598 LP-e604. doi:10.1542/neo.17-10-e598.

• • Chest x-ray
    • May or may not be normal
    • Heart size and shape 
      • Dextrocardia 
      • Enlarged heart size —> Suggestive of CHD > 60% of the chest 
      • Boot shaped heart –> Consider TOF
      • Egg shaped heart –> Consider TGA
      • Snowman shaped heart –> Consider TAPVR
    • Pulmonary vascular markings
      • Decreased markings –> Consider cardiac etiologies that ↓ pulmonary blood flow 
      • Asymmetric markings –> Consider cardiac etiologies that ↑ pulmonary blood flow
    • Site of the aortic arch 
      • Left sided arch is normal
      • Right sided arch abnormal 
• Tier 2:  
  • EKG
    • Usually nonspecific in most CCHDs and has a limited value
    • Helpful in 2 congenital heart diseases (CHDs)
      • Atrioventricular septal defect 
        • Left superior axis due to inferior and posterior displacement of the AV node
        • Right ventricular hypertrophy
      • Tricuspid atresia
        • Left superior axis due to inferior and posterior displacement of the AV node
        • Diminished right ventricular forces
  • ECHO
    • Cardiac function?
    • Are there four chambers of the heart?
    • Septum intact? ASD? VSD?
    • PDA?
    • Outflow tracts?
  • Consult cardiology
• Medical Management
  • Obtain central access
  • To consider starting oxygen in certain cardiac lesions
    • It is a natural pulmonary vasodilator –> increases pulmonary blood flow
  • Support respiratory support & minimize metabolic demand
    • To consider intubation
    • To consider sedation
• Consider starting PGE 
  • Prostaglandin should be started prior to an ECHO 
  • Indications:
    • Restriction of pulmonary blood flow
    • Poor arterio-venous admixture
    • Ductal dependent systemic blood flow
  • MOA:
    • Maintains ductus patency/reopen a closed duct by directly acting on vascular smooth muscle
  • Dosing:
    • Metabolized rapidly infusion must be continuous
    • Initial dose: 0.05-0.1mcg/kg/min 
    • Can titrate lower to 0.01 and still see effect
  • Route
    • Prefer to be given via central line
    • Can be given via PIV in emergency
  • Adverse effects
    • Apnea
• Transfer to a referral center

BP = Blood pressure
HR = Heart rate
BAS = Balloon atrial septostomy
LA = Left atrium
LV = Left ventricle
PA = Pulmonary artery
PDA = Patent ductus arterious
RA = Right atrium
RV = Right ventricle
SVC = Superior vein cava
TAPVR = Total anomalous pulmonary venous return
TGA = Transposition of the great arteries
TOF= Tetralogy of Fallot 

References: 

1. Dasgupta S, Bhargava V, Huff M, Jiwani AK, Aly AM. Evaluation of the cyanotic newborn: part I—a Neonatologist’s Perspective. Neoreviews. 2016;17(10):e598 LP-e604. doi:10.1542/neo.17-10-e598.
2. Dasgupta S, Bhargava V, Huff M, Jiwani AK, Aly AM. Evaluation of the cyanotic newborn: part 2—a cardiologist’s perspective. NeoReviews. 2016;17(10):e605-e620. doi: 10.1542/neo.17-10-e605.
3. Hua N, Yieh L, Dukhovny D, Armsby L. Important considerations in the management of newborns with cyanosis. Neoreviews. 2017;18(4):e258-e264. doi: 10.1542/neo.18-4-e258.
4. Martin TC. Reverse differential cyanosis: a treatable newborn cardiac emergency. NeoReviews. 2011;12(5):e270-e273. doi: 10.1542/neo.12-5-e270.
5. Yap SH, Anania N, Alboliras ET, Lilien LD. Reversed differential cyanosis in the newborn: a clinical finding in the supracardiac total anomalous pulmonary venous connection. Pediatr Cardiol. 2009;30:359-362. doi: 10.1007/s00246-008-9314-0
6. Sims ME. Legal Briefs: Should This Neonate with Transposition of the Great Arteries Have Survived? Neoreviews. 2017;18(11):e674 LP-e676. doi:10.1542/neo.18-11-e674
7. Richard J. Martin, Avroy A. Fanaroff, Michele C. Walsh. (2015). Fanaroff and Martin’s neonatal-perinatal medicine : diseases of the fetus and infant. Philadelphia, PA: Elsevier/Saunders.
8. Brodsky, Dara, and Camilia Martin. Brodsky and Martin’s Neonatology Review Series. 3rd ed., Lulu, 2020.
9. Brodsky, Dara. Neonatology Review: Q&A. 3rd ed., Lulu, 2016.
10. Chess, Patricia. Avery’s Neonatology Board Review: Certification and Clinical Refresher. 1 ed., Elsevier, 2019.
11. Polin, Richard A., and Mervin C. Yoder. Workbook in Practical Neonatology. 5th ed., Saunders, 2014.

Credits

• Written and Produced by: Neena Jube-Desai MD, MBA FAAP
• Cover Art and Infographic by: Neena Jube-Desai MD, MBA FAAP
• Host: Neena Jube-Desai MD, MBA FAAP
• Editor: Neena Jube-Desai MD, MBA FAAP
• Guest: Gregory Kitley Yurasek, MD FAAP