Article of the Month - Nov 2020

The Hypertensive Neonate

Seminars in Neonatal and Fetal Medicine, 2020; 25: 101138. doi: 10.1016/j.siny.2020.101138

Joseph Flynn

Reviewed by John D Mahan

Background:

As hypertension (HTN) continues to be an increasingly recognized issue in neonates, particularly those in NICUs and those with kidney problems, clear recognition of the data on normal and abnormal blood pressure (BP) and factors that contribute to increased risk for HTN in this population becomes even more important.  The incidence of ~ 1% for HTN in neonates continues to increase with our advances in care for sick neonates.  The common causes of neonatal HTN and best approaches to evaluation and treatment are presented in this review.

What was the purpose of the review?

To summarize the state-of-the-art information on neonatal BP measurement, definitions for HTN and best approaches to evaluation and treatment of HTN in neonates.

What were the key areas of the review?

Normal BP values and influences; criteria for diagnosis of neonatal HTN; incidence of neonatal HTN; differential diagnosis of neonatal HTN; clinical presentation of neonatal HTN; techniques for measurement of BP and detection of neonatal HTN; treatment of neonatal HTN, including acute severe neonatal HT; and outcomes.

What were the key findings and/or contributions of the review?

The most relevant and useful charts for normal BP in neonates are presented (adapted from Zabow and Dionne’s publications) for use by all clinicians caring for neonates. The 2017 AAP Clinical Practice Guidelines on Childhood HTN recommendations for criteria for diagnosis of neonatal HTN (utilize Dionne, Table1 in this article) are presented, with the important guideline that neonates with BP values >95th percentile be monitored closely while those with BP >99th percentile deserve investigation and ultimately treatment.  The incidence of HTN in NICU patients of 1-1.4% and the striking evidence of even greater incidence of HTN diagnosed after discharge from the NICU are presented. A detailed Table is presented with demonstration of with 54 (!) different etiologies for neonatal HTN to consider. 

The best techniques for BP measurement and appropriate evaluation of neonates with elevated BP measurements are presented.  The techniques for proper BP measurement should be posted in every NICU bay for all to see, and review regularly!  The differentiation of routine studies (7) and additional studies for differential diagnosis in neonatal HTN is a valuable Table.  The approach to treatment of neonatal HTN is well presented, with endorsement of isradipine as the best initial therapy (because of its quick onset and short duration of action) and when to consider agents form other anti-hypertensive categories for neonates with HTN.  The Table that presents recommended doses for selected anti-hypertensives in this age group, and identification of agents with oral and oral suspension options should prove useful to all clinicians treating these patients.

What are the implications?

Neonatal BP is determined by multiple factors, including birth weight, gestational age and post-menstrual age; other perinatal factors and maternal health conditions such as pre-eclampsia also play important roles.  Concurrent conditions, such as BPD/chronic lung disease, kidney disorders, UAC placement, and select medications are risk factors for neonatal HTN.  Accurate measurement of BP is key; a careful diagnostic strategy aids in the evaluation for causes of neonatal HTN in any individual patient.  Treatment options are less diverse than those available to treatment of HTN in children and adults but are quite effective in this population.  Flynn ends with a nice series of practice points and research directions in this field. 

Limitations:

None – this is the best review on neonatal HTN in the literature and a must read for all clinicians caring for neonates with BP concerns.  Thank you, Dr. Flynn.