How much does a patient weigh? In emergency medicine, finding the answer isn't always so simple

Self-estimates are, for now, the most-accurate means of discerning a patient’s total body weight during an emergency, according to a new review.However, patient self-estimates aren’t always obtainable and more comprehensive research on weight estimation for adults in emergency clinical settings is needed, according to a review and meta-analysis of existing studies on the accuracy of weight estimation methods.While the need for weight estimation in children during emergency care is “well understood,” the same need for adults is “less well appreciated,” according to a study published in the American Journal of Emergency Medicine.Weight estimation during emergency care is critical for “drug dose calculations, fluid volume calculations, mechanical ventilation settings, and other weight-based interventions,” according to the study.“In order to ensure the efficacy of the drug therapy, while avoiding harm from overdose, the weight estimation should be as accurate as possible,” the authors wrote.The review found that patient self-estimation has shown to be “generally very accurate” and “should be regarded as the best method of weight estimation at this time.”However, the authors noted important limitations to self-estimation, citing retrospective studies on weight estimation during emergency care. These studies showed that a significant number of patients (as high as 70% to 85% in some studies) were unable to estimate their weight as they may have been either “confused or unresponsive.”Self-estimations were also “substantially less accurate during actual emergency care than during elective care,” the review stated.The authors also wrote that self-estimations were “generally accurate in normal weight individuals” but “significantly less accurate in obese and underweight patients.” However, they noted elsewhere in the review that “weight estimation accuracy was the worst at extremes of weight status, irrespective of the method.”Other weight estimation methods include family-member estimates, healthcare provider estimates, automatic and high-tech systems, pediatric methods applied to adults, and single-variable as well as multivariate anthropometric formulas.Family-member estimates haven’t been studied enough for clinicians to have a clear view of how reliable they tend to be or to understand their limitations, according to the review. Weight estimation using 3-D cameras “showed extraordinary promise” but needs to be studied further.The Lorenz formula, an anthropometric formula that was designed for dose calculations for thrombolysis in stroke patients, showed “acceptable accuracy, but questions remain about its suitability for use during emergency care,” the authors wrote.Healthcare provider estimates, unmodified pediatric systems and other anthropometric formulas “did not show an acceptable level of consistency or accuracy” and “should not be used for weight estimation for clinical purposes.”Alternative methods of weight estimation need to be made available and additional research is “urgently needed” in order to ensure patient safety during emergency care, the authors concluded.The authors conducted a systematic review of a total of 95 studies conducted between January 1986 and April 2022. Of the 95 studies, 42 were included in a meta-analysis.

How much does a patient weigh? In emergency medicine, finding the answer isn't always so simple

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