216 - Comparison of Different Methods for Pediatric Weight Estimation

Poster Number: 216
Publication Number: 216.1842

Background: Accurate weight estimation is essential for appropriate drug dosing and equipment selection for critically ill children in settings where weight ascertainment may be impractical. This may be of greater importance in children with medical complexity, who are particularly at higher risk for adverse drug events. Several methods have been published, but there is no consensus on the best method to guide physicians in pediatric weight estimation.

Objective: To evaluate and compare the accuracy of different methods of weight estimation in children with and without medical complexity.

Design/Methods: We performed a retrospective single-center cross-sectional study of children ( < 18 years) seen in either an emergency department (ED) or ambulatory clinic from January 1, 2013 to December 31, 2022 at a tertiary academic pediatric health system. We randomly selected a single encounter for patients with multiple encounters. We compared the performance of ten different methods of weight estimation (Table 1) using the metrics of mean average error (MAE), root mean square error (RMSE), and agreement within 10% and 20% of measured weight. We performed a separate analysis to compare subsets of patients with and without medical complexity.

Results: We included 361,755 children, with a median age of 8.2 years (IQR 2.5-14.2 years) of whom 51.5% were male. 59,283 (16.4%) patients were seen in the ED. Length was measured in 21,330 (36.0%) patients in the ED and 293,410 (97%) patients in the clinic. The Broselow tape was the most accurate method with 53.8% estimates within 10% of the measured weight and the lowest MAE (2.3 kg) and RMSE (4.2 kg; Table 2). The Antevy method provided the most accurate weights among age-based approaches. Weight estimations became less accurate in older children for all methods (Figure 1). Medical complexity was identified in 14.1% of patients. Among children with medical complexity, the Broselow tape consistently outperformed age-based formulae with 51.3% estimates within 10% of the measured weight, MAE of 2.3 kg, and RMSE of 4.6 kg.

Conclusion(s): Because of different age criteria within the formulae, direct comparisons of pediatric weight estimation methods are difficult to make. Despite this limitation, the Broselow tape predicts weight most accurately and remains the most accurate in children with medical complexity.