Figure 1. Right ventricular hypertrophy and strain in a 1-month old neonate with hypoplastic left heart syndrome: Negative QRS in Lead I, dominant R in leads V1 and V2, and dominant S wave in leads V5 and V6. This can be a normal finding in a newborn as neonates have right ventricular dominance – a normal ekg does not exclude CHD.[1]
Figure 2. Left Ventricular Hypertrophy and Left Axis Deviation in a 6-week-old infant with a Ventricular Septal Defect: increased S in V1 and R in V6 and isoelectric V6 respectively.[2]
Chest X-Ray Findings:
Based on both the type of defect and its severity, the chest X-ray may have characteristic findings. For example, cardiomegaly, consolidations, and pulmonary congestion can be seen in truncus arteriosus; tetralogy of Fallot has a classic “boot shaped” cardiac silhouette; transposition of the great arteries has an “egg on a string” cardiac shape; and the heart takes on a “snowman” appearance in total anomalous pulmonary venous return (Figure 3).[1, 2, 5,7,8]
Figure 3. A) “Egg on a string.” Anterior-posterior chest X-ray with increased pulmonary blood flow and egg on a string-shaped heart seen in Transposition of the Great Arteries.[9] B) “Boot shaped“ heart: Anterior-posterior chest X-ray with decreased pulmonary vascularity, a normal heart size with a “boot shape” as seen in tetralogy of Fallot.[10]
Point-of-Care Ultrasonography:
Ultrasonography will allow the physician to determine the number of cardiac chambers, the direction of blood flow, and whether B-lines are present (Figure 4).
Figure 4. A) Parasternal long axis of tetralogy of Fallot showing a ventricular septal defect and overlying aorta. B) Apical 4-Chamber view in Tricuspid Atresia. C) Apical 4-Chamber view in Ebstein’s Anomaly showing the displaced tricuspid valve with regurgitation.[11]
Management:
Neonates with significant CHD will need corrective or palliative cardiac surgery for definitive management. Our goal is to provide cardiopulmonary support and stabilize the neonate until they can be safely transferred to a hospital equipped with pediatric cardiac surgery.
After administering supplemental oxygen, the treatment goal is to increase the pulmonary blood flow in right-sided ductal-dependent defects, increase the systemic blood flow in left-sided ductal-dependent defects, and allow for adequate mixing of the pulmonary and systemic circulation in mixing lesions. This will increase the percentage of oxygenated blood delivered to the tissues, increasing perfusion and decreasing cyanosis, end-organ damage, and hypoxemia.
The mainstay of initial treatment is administering prostaglandin E-1 (PGE1) infusions. PGE1 is a potent vasodilator of the ductus arteriosus (DA) and will prevent functional closure of the DA until definitive treatment is underway. Given that 60-80% of endogenous PGE1 is broken down by neonatal lung enzymes, exogenous PGE1 (alprostadil) can offset this loss and should be administered when suspecting cyanotic CHD.[13] The starting rate of alprostadil infusion is 0.05 to 0.1 mcg/kg/min and it should be titrated down to the lowest dose required to increase oxygenation and reduce cyanosis. The maximum maintenance dose of PGE1 is 0.4 mcg/kg/min.[1,14,15] Prostaglandin E-1 is known to cause dose-dependent apnea, hypotension, and fever.[16] Therefore, consider intubation based on factors such as respiratory status, recurrent apnea, and transit time to a hospital with pediatric cardiac surgery.[1,15-17]
Also, always remember to administer appropriate antibiotics early on until an infectious etiology is ruled out.
Tet Spells:
Tet spells are periods of cyanosis witnessed during periods of newborn stress such as crying or agitation in patients with Tetralogy of Fallot. During these periods of stress, a cycle of catecholamine surge and infundibular spasms causes decreased pulmonary blood flow to worsen hypoxemia.[9,22] Tet spells can be the first sign in a patient with Tetralogy of Fallot, and depending on the extent of the cardiac defects, these spells may occur even after one month of life. Initial treatment for these Tet spells in known Tetralogy of Fallot include:
1) Positioning maneuvers (knee to chest) to increase venous return and increase systemic vascular resistance to decrease right-to-left shunting.
2) Reducing the catecholamine surge by first calming the patient. Second-line is to administer either morphine (0.05 to 0.2 mg/kg) or intranasal fentanyl or midazolam to decrease agitation and provide fluid bolus to increase preload.[23]
3) If the above is unsuccessful, propranolol IV (0.2 mg/kg) can be used to decrease infundibular spasms, phenylephrine (2 to 10 mcg/kg/min) to increase systemic vascular resistance, and/or ketamine to decrease agitation and to increase systemic vascular resistance.[5,23]
Back to the Case:
The 1-week-old neonate’s oxygen minimally improved to 77% on supplemental oxygen 2 L/min via nasal cannula. He was subsequently placed on high-flow nasal cannula at 2 L/kg/min.[24,25] Pulses were normal in all 4 extremities. Auscultation revealed clear lungs bilaterally and a holosystolic murmur at the left lower sternal border indicating a ventricular septal defect. The modified hyperoxia test did not show an improvement in oxygen saturation. The patient was given vancomycin and cefepime for presumed sepsis. An ECG demonstrated left ventricular dominance and left axis deviation. POCUS revealed an atretic tricuspid valve. The chest x-ray showed decreased pulmonary vascular markings with a prominent right heart border. The team diagnosed tricuspid atresia, started alprostadil at 0.05 mcg/kg/min, and transferred the patient to a center for palliative cardiac surgery.
Take Home Points:
1) Cyanotic congenital heart defects typically present around one to four weeks of life with fatigue, poor weight gain, and cyanosis.
2) Central or differential cyanosis is always abnormal.
3) Minimal response to oxygen with the hyperoxia or modified hyperoxia test suggests a cardiac etiology of cyanosis.
4) Alprostadil (PGE1) keeps the DA patent. The infusion starting rate is 0.05 to 0.1 mcg/kg/min with a maximum maintenance rate of 0.4 mcg/kg/min. As there are dose-dependent side effects, titrate down to the lowest dose required to maintain clinical improvement.
5) Give appropriate antibiotics until sepsis is ruled out.
References
1) Judge P, Meckler Mshs G. Congenital Heart Disease In Pediatric Patients: Recognizing The Undiagnosed And Managing Complications In The Emergency Department. Pediatr Emerg Med Pract. 2016 May;13(5):1-28; quiz 27-8. Epub 2016 May 1. PMID: 27096879
2) Strobel AM, Lu le N. The Critically Ill Infant with Congenital Heart Disease. Emerg Med Clin North Am. 2015 Aug;33(3):501-18. doi: 10.1016/j.emc.2015.04.002. PMID: 26226862.
3) Pahal P, Goyal A. Central and Peripheral Cyanosis. [Updated 2021 Oct 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK559167/
4) Ossa Galvis MM, Bhakta RT, Tarmahomed A, et al. Cyanotic Heart Disease. [Updated 2022 Jun 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK500001/
5) King L, Young KD. Congenital Heart Disease. In: Tenenbein M, Macias CG, Sharieff GQ, Yamamoto LG, Schafermeyer R. eds. Strange and Schafermeyer’s Pediatric Emergency Medicine, 5e. McGraw Hill; 2019.
6) Popenko, N. and Mitra, A. (2019) A blue baby comes into your Ed, EMRA. Available at: https://www.emra.org/emresident/article/blue-baby/ (Accessed: 07 June 2023).
7) Buttner, R. and Burns, E. (2021) Normal paediatric ECG, Life in the Fast Lane • LITFL. Available at: https://litfl.com/normal-paediatric-ecg/ (Accessed: 03 June 2023).
8) O’Connor M1, McDaniel N, Brady WJ. The pediatric electrocardiogram part III: Congenital heart disease and other cardiac syndromes. Am J Emerg Med. 2008 May;26(4):497-503. PMID: 18410822.
9) Transposition of the great arteries: Pediatric radiology reference article: Pediatric imaging: @pedsimaging (2022) Pediatric Imaging. Available at: https://pediatricimaging.org/diseases/transposition-of-the-great-arteries/ (Accessed: 07 June 2023).
10) Tetralogy of Fallot: Pediatric Radiology Reference Article: Pediatric Imaging: @pedsimaging (2022) Pediatric Imaging. Available at: https://pediatricimaging.org/diseases/tetralogy-of-fallot/ (Accessed: 07 June 2023).
11) Siassi B, Ebrahimi M, Acherman RJ. Suspecting Congenital Heart Disease*. In: Siassi B, Noori S, Acherman RJ, Wong PC. eds. Practical Neonatal Echocardiography. McGraw Hill; 2018. Accessed March 03, 2023.
12) Blood circulation in the fetus and newborn (2014) Children’s Hospital of Philadelphia. Available at: https://www.chop.edu/conditions-diseases/blood-circulation-fetus-and-newborn#:~:text=About%20two%20thirds%20of%20the,continues%20on%20to%20the%20lungs.
13) Akkinapally S, Hundalani SG, Kulkarni M, Fernandes CJ, Cabrera AG, Shivanna B, Pammi M. Prostaglandin E1 for maintaining ductal patency in neonates with ductal-dependent cardiac lesions. Cochrane Database Syst Rev. 2018 Feb 27;2(2):CD011417. doi: 10.1002/14651858.CD011417.pub2. PMID: 29486048
14) Hew MR, Gerriets V. Prostaglandin E1. [Updated 2022 May 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.
15) Huang, F.-K., Lin, C.-C., Huang, T.-C., Weng, K.-P., Liu, P.-Y., Chen, Y.-Y., … Hsieh, K.-S. (2013). Reappraisal of the Prostaglandin E1 Dose for Early Newborns with Patent Ductus Arteriosus-Dependent Pulmonary Circulation. Pediatrics & Neonatology, 54(2), 102–106. doi:10.1016/j.pedneo.2012.10.007
16) Haughey BS, Elliott MR, Wiggin JY, Conaway MR, White SC, Swanson JR, Dean PN. Standardizing Prostaglandin Initiation in Prenatally Diagnosed Ductal-Dependent Neonates; A Quality Initiative. Pediatr Cardiol. 2022 Dec 20. doi: 10.1007/s00246-022-03075-9. Epub ahead of print. PMID: 36538050.
17) Costello, J. M., & Almodovar, M. C. (2007). Emergency Care for Infants and Children with Acute Cardiac Disease. Clinical Pediatric Emergency Medicine, 8(3), 145–155. doi:10.1016/j.cpem.2007.06.005
18) Vari, D., Xiao, W., Behere, S., Spurrier, E., Tsuda, T., & Baffa, J. M. (2020). Low-dose prostaglandin E1 is safe and effective for critical congenital heart disease: is it time to revisit the dosing guidelines? Cardiology in the Young, 1–8. doi:10.1017/s1047951120003297
19) Allen KA. Premedication for neonatal intubation: which medications are recommended and why. Adv Neonatal Care. 2012 Apr;12(2):107-11. doi: 10.1097/ANC.0b013e31824c1583. PMID: 22469965; PMCID: PMC3319658.
20) Nasr NF, Al-Jindi PC, Nasr IF. Rapid Sequence Intubation. In: Reichman EF. eds. Reichman’s Emergency Medicine Procedures, 3e. McGraw Hill; 2018. https://accessemergencymedicine-mhmedical-com.newproxy.downstate.edu/content.aspx?bookid=2498§ionid=201305594
21) George H Meakin, MD FRCA, Neuromuscular blocking drugs in infants and children, Continuing Education in Anaesthesia Critical Care & Pain, Volume 7, Issue 5, October 2007, Pages 143–147, https://doi.org/10.1093/bjaceaccp/mkm032
22) Diaz-Frias J, Guillaume M. Tetralogy of Fallot. [Updated 2022 Jan 18]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK513288/
23) Yue EL, Meckler GD. Congenital and Acquired Pediatric Heart Disease. In: Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. McGraw Hill; 2020.
24) Kwon JW. High-flow nasal cannula oxygen therapy in children: a clinical review. Clin Exp Pediatr. 2020 Jan;63(1):3-7. doi: 10.3345/kjp.2019.00626. Epub 2019 Oct 28. PMID: 31999912; PMCID: PMC7027347.
25) Milési C, Boubal M, Jacquot A, Baleine J, Durand S, Odena MP, Cambonie G. High-flow nasal cannula: recommendations for daily practice in pediatrics. Ann Intensive Care. 2014 Sep 30;4:29. doi: 10.1186/s13613-014-0029-5. PMID: 25593745
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