Make your Best Guess: an updated method for paediatric weight estimation in emergencies

For children requiring weight-based resuscitative measures, it is often difficult to obtain an accurate weight. In these cases, it is common practice to estimate the weight based on age. As the average weight of Australian children has increased over the last two decades, the widely used advanced paediatric life support (APLS) method might systematically underestimate weight in paediatric patients.

To devise a simple age-based method for estimating weight that is more accurate than the APLS method.

A retrospective observational study of all patients (aged 0-14 years) presenting to a tertiary paediatric ED over a 3 year period was performed. Presentations were divided into infants (<12 months), preschool-aged (1-4 years) and school-aged children (5-14 years). Weight measurements performed at triage were recorded and regression analysis performed to produce equations describing the relationship between weight and age for each group.

There were 70,181 presentations suitable for inclusion in the present study. Mean weight for age (+/-2 SD) is presented in tabular form. Three simplified linear equations were derived to calculate mean weight for age. For Infants < 12 months: Weight (kg) = (age in months + 9)/2 For Children aged 1-5 years: Weight (kg) = 2 x (age in years + 5) For Children aged 5-14 years: Weight (kg) = 4 x age in years.

The present study devised an age-based method for paediatric weight estimation which should more accurately predict weight than the widely used APLS formula.