Estimating weight in patients of all-ages: a prospective study in Rwanda

ABSTRACT Introduction Weight estimation of both adult and paediatric patients is often necessary in emergency or low-resource settings when it is not possible to weigh the patient. There are many methods for paediatric weight estimation, but no standard methods for adults. PAWPER and Mercy tapes are used in children, but have not been assessed in adults. The primary aim of this study was to assess weight estimation methods in patients of all ages. Methods Patients were prospectively recruited from emergency and out-patient departments. Subjects (or guardians) were asked to estimate weight. Investigators collected weight, height, mid-arm circumference (MAC) and humeral-length data. In all subjects, estimates of weight were calculated from height and MAC (PAWPER tapes), MAC and humeral-length (Mercy tape). In children, Broselow tape and age-based formulae were also used. Primary outcome measures were proportions of estimates within 10%, 20% and 30% of actual weight (p10, p20, p30). Results 947 subjects were recruited: 307 children, 309 adolescents and 331 adults. For p20, the best methods were: in children, guardian estimate (90.2%) and PAWPER XL-MAC (89.3%); in adolescents, PAWPER XL-MAC (91.3%) and guardian estimate (90.9%); in adults, subject estimate (98.5%) and PAWPER XL-MAC (83.7%). Conclusion This is the first prospective study of weight estimation methods in Rwanda, and the first adult study of PAWPER and Mercy tapes. In children, age-based rules performed poorly. In patients of all ages, the PAWPER XL-MAC and guardian/subject estimates of weight were the most reliable and we would recommend their use in this setting.