Estimating children's weight in a Rwandan emergency centre

Introduction: Most drugs, fluids and ventilator settings depend on the weight of a paediatric patient. However, knowledge of the weight is often unavailable as the urgency of the situation may impede measurement. The most common methods for paediatric weight estimation are based on height or age. This study aimed to compare the accuracy of various weight estimation methods and to derive a dedicated age-based tool within a Rwandan setting. Methods: This was a retrospective study using age, weight and height data from randomly selected charts of Rwandan children, aged between one and ten years, who attended the paediatric emergency centre, Centre Hospitalier Universitaire de Kigali, Rwanda. Weights were estimated using four versions of the Broselow Tape and several age-based formulae. Linear regression was used to derive a new age-based weight estimation formula, the Rwanda Rule. Weight estimations were then compared with actual weight using Bland-Altman analysis, and the proportions of estimates within 10 and 20% of actual weight. Results: There were 327 children included in the study. The derived Rwanda Rule was: weight (kg) = [1.7 × age (years)] + 8. This formula and the original Advanced Paediatric Life Support formula (weight = [2 × age] + 8) performed similarly. Both were better than other age-based formulae (69% of estimates within 20% of actual weight). All editions of the Broselow Tape performed better than age-based rules. The 1998 version performed best with 84.8% of estimates within 20% of actual weight. Discussion: This study is the first to compare paediatric weight estimation methods in Rwanda. Locally, and until we have evidence from further research that other methods are superior, we would advise use of the 1998 Broselow Tape in children aged one to ten years old. Where the Broselow Tape is not available, the original Advanced Paediatric Life Support formula should be used.