The accuracy of emergency weight estimation systems in children—a systematic review and meta-analysis

Abstract

The safe and effective administration of fluids and medications during the management of medical emergencies in children depends on an appropriately determined dose, based on body weight. Weight can often not be measured in these circumstances and a convenient, quick and accurate method of weight estimation is required. Most methods in current use are not accurate enough, but the newer length-based, habitus-modified (two-dimensional) systems have shown significantly higher accuracy. This meta-analysis evaluated the accuracy of weight estimation systems in children. Articles were screened for inclusion into two study arms: to determine an appropriate accuracy target for weight estimation systems; and to evaluate the accuracy of existing systems using standard meta-analysis techniques. There was no evidence found to support any specific goal of accuracy. Based on the findings of this study, a proposed minimum accuracy of 70% of estimations within 10% of actual weight (PW10 > 70%), and 95% within 20% of actual weight (PW20 > 95%) should be demonstrated by a weight estimation system before being considered to be accurate. In the meta-analysis, the two-dimensional systems performed best. The Mercy method (PW10 70.9%, PW20 95.3%), the PAWPER tape (PW10 78.0%, PW20 96.6%) and parental estimates (PW10 69.8%, PW20 87.1%) were the most accurate systems investigated, with the Broselow tape (PW10 55.6%, PW20 81.2%) achieving a lesser accuracy. Age-based estimates achieved a very low accuracy. Age- and length-based systems had a substantial difference in over- and underestimation of weight in high-income and low- and middle-income populations. A benchmark for minimum accuracy is recommended for weight estimation studies and a PW10 > 70% with PW20 > 95% is suggested. The Mercy method, the PAWPER tape and parental estimates were the most accurate weight estimation systems followed by length-based and age-based systems. The use of age-based formulas should be abandoned because of their poor accuracy.Electronic supplementary materialThe online version of this article (10.1186/s12245-017-0156-5) contains supplementary material, which is available to authorized users.

A comparison of four weight estimation systems for paediatric resuscitation

“…It has performed better than the Broselow tape in multiple previous studies. 2,4,7 The PAWPER tape did not perform as well in a recent study in a very obese population, however, and failed to achieve the same accuracy as in studies in the rest of the world. 7 As a result, the PAWPER XL tape was developed, which has 7 habitus scores instead of 5 and the length of the tape was extended from 153 cm to 180 cm.…”

Estimación del peso según la edad. Comparación de las fórmulas en una muestra peruana

“…Para asegurar una buena estimación del peso, las ecuaciones deben cumplir idealmente cuatro características 24,25 : ser validadas en muestras de sujetos pediátricos que sean representativos de la población general, de fácil aplicación y rápida obtención, sin requerir métodos de cálculo avanzado con fácil recordación que permita su reproducibilidad, ser lo más cercanas al peso medido para asegurar la exactitud y precisión, estar disponibles para ser usadas en escenarios extra hospitalarios. Si bien el peso de un paciente es una característica que depende de múltiples variables, la estimación basada en la edad es una forma sencilla y útil de utilizar en escenarios especiales como la atención de urgencias o emergencias, atención pre hospitalaria, sistemas de atención ambulatoria (domiciliaria) o en la vía pública así como regiones apartadas 26 .…”

Response

“…We were interested to learn about the PAWPER tape, as it quickly estimates TBW as well as IBW. The authors have demonstrated that an assessment of body habitus significantly improves the accuracy of tape-based systems, 2,3 which are more accurate than age-based formulas alone. 4 We are also very impressed with the development of the PAWPER XL-MAC system, which makes the assessment of body habitus objective by also measuring mid-arm circumference.…”

“…We agree that in patients who are obese, using IBW instead of TBW to calculate tidal volume is correct because lung size does not increase linearly with increasing body habitus. 1,2 The authors' proposed scaling for calculating tidal volume is very similar to how hydrophilic medications should be dosed in children who are of average weight and those who are obese.…”