Article of the Month - Sep 2020

Method of blood pressure measurement in neonates and infants: a systematic review and analysis

J Pediatrics. 2020 Jun;221:23-31.e5. doi: 10.1016/j.jpeds.2020.02.072

Janis M Dionne, Stephen A Bremner, Simin K Baygani, Beau Batton, Ebru Ergenekon, Varsha Bhatt-Mehta, Eugene Dempsey, Martin Kluckow, Luana Pesco Koplowitz, Dina Apele-Freimane, Hiroko Iwami, Agnes Klein, Mark Turner, Heike Rabe, International Neonatal Consortium

Reviewed by Lochie (Lawrence) Milner

Summary

Accurate blood pressure measurements in neonates are fraught with challenges which is influenced by several factors including technique, cuff size and location of measurement. Since hypertension is being seen more frequently in neonates, especially in those with RDS /CLD, the accuracy of neonatal blood pressure measurements is important for therapeutic guidance and potentially preventing long term cardiovascular complications.

This study entitled: ”Method of blood pressure measurement in neonates and infants :a systematic review and analysis by Dionne et al, appeared in J Pediatrics, June 2020 sheds some light on some of these issues highlighting important aspects and pitfalls in evaluating blood pressures of premature babies (LBW + VLBW) in the NICU. Helpful recommendations are offered by the authors which are thought provoking with important implications.

1)The purpose of the study was to evaluate the accuracy of different methodologies of neonatal blood pressure measurements especially in terms of optimal cuff size using oscillometric methods as well as location with the understanding that direct intra- arterial measurement is considered the most accurate and “gold standard”

2) Study Design: The study is a meta- analysis/review based on a literature search concerning blood pressures in neonates until 3 months of age with appropriate studies selected for analysis. In particular forest plots of Bland - Altman analyses are utilized for comparisons of blood pressure techniques the results of which are of interest

3) The samples appearing in most of these studies are essentially quite heterogenous in terms of post conceptual age and size of the babies studied, which is a limiting factor.

4) Results: In this paper, the issues regarding cuff size and optimal location for neonatal BP checks are well covered with practical measures offered based on analyses of the relevant studies despite the heterogeneity of the study groups and also with the knowledge that recent normative values for this population have not been fully established.

  1. The optimal cuff size suggested is using a cuff with width to arm circumference ratio of 0.5
     
  2. The recommended site is the right upper arm
     
  3. When comparing intra-arterial vs oscillometric (indirect) methodologies for BP measurements, using Forest plots for the Bland Altman analyses, they demonstrated good correlation but poor agreement, with the mean BP’s being the most reliable measure. However systolic BP’s are reportedlyhigher with the oscillometric measurements which may problematic as indications for antihypertensive therapy is generally governed by the level of systolic and diastolic readings and not by the mean BP. Oscillometric measurements tend to be unreliable when the mean BP’s are low (<30 ).

Implications

Some of the recommendations by the authors include improving device technology to allow more accurate non-invasive BP measures. Balancing the need for accurate BP monitoring with the risk of intra-arterial devices continues to be an important aspect of neonatal BP management.

However, I wonder if there may be any value looking at external Doppler BP’s as a surrogate for intra-arterial BP (some places use this in the clinic to get accurate systolic BP’s in infants) to see how this compares to oscillometric values in the neonatal population.

Further blood pressure studies within this population group will hopefully improve the accuracy of blood pressure interpretation.