Short Attention Span Summary
Broselow tape for adults
Ever have a sick patient and need the weight but can’t weigh them? In kids, you can pull out the Broselow tape or use other formulas. But what about adults? This clever formula was derived from a large dataset and validated using mid-arm circumference (MAC). It performed poorly in kids but was not too bad in adolescents and adults. 90% of patient weight estimates using the formula fell within 20% of the measured weight.
The formula is: weight (kg) = 4 × MAC (in cm) – 50.
A great way to estimate the weight of an adolescent or adult is this formula: Weight (kg) = 4 x MAC (cm) – 50. My MAC is 30cm, which should make me 70kg. Would that this were true…alas.
Emerg Med J. 2016 Dec 19. pii: emermed-2015-205623. doi: 10.1136/emermed-2015-205623. [Epub ahead of print]
1Emergency Department, Centre Hospitalier Universitaire de Kigali, Kigali, Rwanda.
2Accident and Emergency Medicine Academic Unit, Chinese University of Hong Kong, Shatin, Hong Kong.
3Emergency Department, University Hospital of Wales, Cardiff, UK.
Many drug and fluid regimens in emergency medicine are weight dependent in adults, but no standard adult weight estimation tools exist. Paediatric weight is often estimated in emergency situations using methods based on age or height when direct measurement is not possible, and recently, methods based on mid-arm circumference (MAC) have also been developed. The aim of this study was to derive and validate an accurate MAC-based method for weight estimation for use in all age groups.
Data were obtained from the US National Health and Nutrition Examination Survey (NHANES). MAC-based methods of weight estimation were derived in 8498 subjects (5595 adults aged 16-80 years, 2903 children aged 1-15.9 years) from the NHANES 2011-2012 dataset, using linear regression. NHANES 2009-2010 was used for validation in 9022 subjects (6049 adults aged 16-79 years, 2973 children aged 1-15.9 years).
A simplified method of MAC-based weight estimation was derived from linear regression equation: weight in kg=4×MAC (in cm)-50. On validation, results in children aged 1-10.9 years were poor. In adults and children aged 11-15.9 years, over 60%, 90% and 98% of estimates fell, respectively, within 10%, 20% and 30% of actual weights when using the simplified formula.
In this description of a method for estimating weight in adults, we have derived and validated a simplified formula that is at least as precise in adults and adolescents as commonly used paediatric weight estimation tools in children.
Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
PMID: 27993936 [PubMed – as supplied by publisher]