Predicted body weight relationships for protective ventilation – unisex proposals from pre-term through to adult

Abstract

BackgroundThe lung-protective ventilation bundle has been shown to reduce mortality in adult acute respiratory distress syndrome (ARDS). This concept has expanded to other areas of acute adult ventilation and is recommended for pediatric ventilation. A component of lung-protective ventilation relies on a prediction of lean body weight from height. The predicted body weight (PBW) relationship employed in the ARDS Network trial is considered valid only for adults, with a dedicated formula required for each sex. No agreed PBW formula applies to smaller body sizes. This analysis investigated whether it might be practical to derive a unisex PBW formula spanning all body sizes, while retaining relevance to established adult protective ventilation practice.MethodsHistoric population-based growth charts were adopted as a reference for lean body weight, from pre-term infant through to adult median weight. The traditional ARDSNet PBW formulae acted as the reference for prevailing protective ventilation practice. Error limits for derived PBW models were relative to these references.ResultsThe ARDSNet PBW formulae typically predict weights heavier than the population median, therefore no single relationship could satisfy both references. Four alternate piecewise-linear lean body-weight predictive formulae were presented for consideration, each with different balance between the objectives.ConclusionsThe ‘PBWuf + MBW’ model is proposed as an appropriate compromise between prevailing practice and simplification, while also better representing lean adult body-weight. This model applies the ARDSNet ‘female’ formula to both adult sexes, while providing a tight fit to median body weight at smaller statures down to pre-term. The ‘PBWmf + MBW’ model retains consistency with current practice over the adult range, while adding prediction for small statures.Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-017-0427-1) contains supplementary material, which is available to authorized users.

Ventilation in pediatric anesthesia: A French multicenter prospective observational study (PEDIAVENT)

“…In addition, in pediatric patients, the IBW according to height and according to age is not linear, and the numerous formulae do not provide concordant results in children older than 8 years of age. 25 The fourth is that the current study was not designed to evaluate postoperative complications and morbidity.…”

Evaluating Delivery of Low Tidal Volume Ventilation in Six ICUs Using Electronic Health Record Data*

“…The 50 patients without a height documented were excluded (2%). Patients with a height < 130 cm were excluded because the PBW equation may not apply (15).…”

A Comparative Analysis of Ideal Body Weight Methods for Pediatric Mechanical Ventilation

“…However, calculation of the IBW for the titration of mechanical ventilation settings is not uniformly used. 7 A universal method for determining the IBW in children on mechanical ventilation is elusive. Few studies have assessed the performance and need for IBW methods in a pediatric population.…”

“…Few studies have assessed the performance and need for IBW methods in a pediatric population. 7 Therefore, we sought to compare the actual body weight with 3 commonly used methods for determining IBW in pediatric subjects: the McLaren-Read (a growth chart method), Moore (a growth chart method), and body mass index (BMI) (indexed equation based on height, sex, and age) methods. 8 Further, we aimed to assess the proportion of pediatric subjects who had a clinically important difference between the IBW and actual body weight.…”

“…We decided a priori, that a Ն10% difference between the actual body weight and the IBW would be clinically important. 7 Data were compiled by using MATLAB (V9.1.0.441655, Mathworks, Natick, Massachusetts), and statistical analyses were completed in Excel (V12.0 071130, Microsoft, Redmond, Washington). Prism 6.0 (GraphPad Software, La Jolla, California) was used to graph and derive the equations for the BMI IBW method and to perform the Kruskal-Wallis test.…”