Comparing the usability of paediatric weight estimation methods: a simulation study

Objective: Estimating weight is essential in order to prepare appropriate sized equipment and doses of resuscitation drugs in cases where children are critically ill or injured. Many methods exist with varying degrees of complexity and accuracy. The most recent version of the Advanced Paediatric Life Support (APLS) course has changed their teaching from an age-based calculation method to the use of a reference table. We aimed to evaluate the potential implications of this change.

Method: Using a bespoke online simulation platform we assessed the ability of acute paediatric staff to apply different methods of weight estimation. Comparing the time taken, rate and magnitude of errors were made using the APLS single and triple age-based formulae, Best Guess and reference table methods. To add urgency and an element of cognitive stress, a time-based competitive component was included.

Results: 57 participants performed a total of 2240 estimates of weight. The reference table was the fastest (25 (22-28) vs 35 (31-38) to 48 (43-51) s) and most preferred, but errors were made using all methods. There was no significant difference in the percentage accuracy between methods (93%-97%) but the magnitude of errors made was significantly smaller using the three APLS formulae 10% (6.5-21) compared with reference table (69% (34-133)) mainly from month/year table confusion.

Conclusion: In this exploratory study under psychological stress none of the methods of weight estimation were free from error. Reference tables were the fastest method and also had the largest errors and should be designed to minimise the risk of picking errors.