Original Contribution
Can ED staff accurately estimate the weight of adult patients?

Presented at the Society for Academic Emergency Medicine 2005 Annual Meeting, New York, May 25, 2005.
https://doi.org/10.1016/j.ajem.2006.08.010Get rights and content

Abstract

Purpose

The purpose of the study was to determine the accuracy of adult weight estimates by emergency department personnel.

Basic procedures

This was a prospective, nonrandomized, observational study in a university tertiary referral center. All patient care staff and all adult patients were eligible. Patients were weighed at the bedside, then staff were asked individually for estimates. Data were analyzed using SPSS general linear modeling procedures (SPSS, Chicago, IL) to obtain a generalized analysis of variance.

Main findings

Eighty-seven staff provided 957 estimates on 241 patients. Providers were within 5% of true weight on 33% of estimates (95% confidence interval [CI], 28-38). In our a priori subgroups, a significant difference was noted only for body mass index (BMI); percentages of correct estimates were 16% (95% CI, 0-33; n = 33) for BMI < 18.5; 38% (95% CI, 33-43; n = 654) for 18.5 ≤ BMI ≤ 30; and 23% (95% CI, 17-30; n = 270) for BMI > 30 (P < .001).

Principal conclusions

Emergency department personnel provided accurate weights in only 33% of estimates. Estimates became significantly less accurate in underweight and obese patients (defined by BMI).

Introduction

Estimation of the weight of pediatric patients has been well studied, including several descriptions of visual estimation rules and various devices based on length or other quickly measurable parameters [1], [2], [3], [4], [5], [6], [7]. However, adult weight estimation has not been studied nearly as well. A few articles in the last decade have examined the accuracy of adult weight estimates made in the prehospital or operative setting [8], [9], [10], [11]. Recent articles have begun to address this issue in the emergency department (ED) setting [12], [13], [14], [15], [16]. However, there is still limited understanding of the effect of body mass index (BMI) on the resultant estimate; in other words, is an adult who is unusually heavy or light for his or her size more likely to have his or her weight inaccurately estimated? In addition, previous studies have suffered from an insufficient sample size.

We sought to address these issues in a large, prospective, observational trial.

Section snippets

Study design

This was a prospective, observational cohort study of adults presenting to our ED over a 7-month period. Our Institutional Review Board approved the study as an exempt protocol before patient enrollment. Because of the low-risk nature of the weight estimations, the Institutional Review Board waived informed consent in lieu of providing study information sheets and obtaining verbal consent to be weighed.

Study setting and population

This study took place in the ED of a suburban university tertiary referral center with an

Results

A total of 96 staff members and 250 patients were enrolled; 975 total estimates were obtained. To control for both staff and patient, our data analysis required that we exclude analyses with only 1 associated estimate. Accordingly, 9 staff members were excluded from analysis. Nine patients were also excluded; 2 of these patients had 2 estimates each before the staff exclusion. Our final data set therefore consisted of 87 staff members, 241 patients, and 957 estimates.

The mean estimate was 98%

Discussion

Providers were within 5% of measured weight on 33% of overall estimates and within 10% of measured weight on 63% of overall estimates. Only the BMI proved to be a statistically significant factor in contributing to error of measurement.

To place our results in more clinical terms, we looked at 2 clinical scenarios. First, we searched for instances where an incorrect weight estimate would have sent a dangerously heavy patient to the computed tomographic scanner or, conversely, would have

Acknowledgment

The authors acknowledge the UC Irvine Emergency Medicine Research Associates Program students for their assistance in patient and staff enrollment.

References (18)

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