Effect of erroneous body-weight estimation on outcome of thrombolyzed stroke patients

The accuracy of total body weight estimation in adults - A systematic review and meta-analysis

BACKGROUND

Weight estimation is required in adult patients when weight-based medication must be administered during emergency care, as measuring weight is often impossible. Inaccurate estimations may lead to inaccurate drug doses, which may cause patient harm. Little is known about the relative accuracy of different methods of weight estimation that could be used during resuscitative care. The aim of this study was to evaluate the performance and suitability of existing weight estimation methods for use in adult emergency care.

METHODS

A systematic literature search was performed for suitable articles that studied the accuracy of weight estimation systems in adults. The study characteristics, the quality of the studies, the weight estimation methods evaluated, the accuracy data, and any information on the ease-of-use of the method were extracted and evaluated.

RESULTS

A total of 95 studies were included, in which 27 different methods of total body weight estimation were described, with 42 studies included in the meta-analysis. The most accurate methods, determined from the pooled estimates of accuracy (the percentage of estimates within 10% of true weight, with 95% confidence intervals) were 3-D camera estimates (88.8% (85.8 to 91.8%)), patient self-estimates (88.7% (87.7 to 89.7%)), the Lorenz method (77.5% (76.4 to 78.6%)) and family estimates (75.0% (71.5 to 78.6%)). However, no method was without significant potential limitations to use during emergency care.

CONCLUSION

Patient self-estimations of weight were generally very accurate and should be the method of choice during emergency care, when possible. However, since alternative estimation methods must be available when confused, or otherwise incapacitated, patients are unable to provide an estimate, alternative strategies of weight estimation should also be available.

Development and validation of a length- and habitus-based method of total body weight estimation in adults

BACKGROUND

Erroneous weight estimation during the management of emergency presentations in adults may contribute to patient harm and poor outcomes. Patients can often not be weighed during emergencies and a weight estimation is required to facilitate weight-based therapies. Many existing methods of weight estimation are either unacceptably inaccurate or very difficult to use during the provision of emergency care.

METHODS

The weight estimation system developed in this study was based on and modified from the PAWPER XL-MAC method, a pediatric weight estimation system that uses recumbent length and mid-arm circumference (MAC) to predict total body weight. This model was validated in the 2015-2018 National Health and Nutrition Examination Survey (NHANES) datasets. The primary outcome measure was to achieve >95% of estimations within 20% of measured weight (P20 > 95%).

RESULTS

The modified PAWPER XL-MAC model achieved a P20 of 96.0% and a P10 of 71.3% in the validation dataset (N = 11,520). This accuracy (P20 > 95%) was maintained in both sexes, all ages, all ethnic groups, all lengths and in all habitus-types, except for the subgroup of severely obese individuals.

CONCLUSIONS

The modified PAWPER XL-MAC model proved to be a very accurate method of weight estimation. It is more accurate than most other published reports of existing methods of weight estimation, except for patients' own estimations. It therefore could have a role in facilitating emergency drug dose calculations, if prospective studies bear out the accuracy found in this study.

Comparison of adult weight estimation methods for use during emergency medical care

OBJECTIVE

Many emergency drug and fluid doses are weight dependent in adults, but in resuscitation and low-resource settings it can be impractical or impossible to weigh a patient. It is especially important to obtain accurate weight estimation for dose calculations for emergency drugs with narrow therapeutic ranges. Several weight estimation methods have been proposed for use in adults, but none is widely established. The aim of this study was to compare the accuracy of adult weight estimation methods.

METHODS

Demographic and body measurement data were obtained from the US National Health and Nutrition Examination Survey (NHANES), and 7 previously published weight estimation methods were used to estimate the weight for each individual. The primary outcomes were the proportions of estimates within 10% and 20% of actual weight (P10, P20). An acceptable accuracy was predetermined to be P10 = 70% and P20 = 95%.

RESULTS

The data set included 5158 adults (51.2% women) with sufficient data to calculate all weight estimation methods. The Lorenz method performed best (P10 = 86.8%, P20 = 99.4%) and met the standard of acceptability across sex and body mass index subgroups. The Mercy and PAWPER XL-MAC methods performed acceptably in non-obese adults.

CONCLUSION

The ideal weight estimation method should be accurate, rapid, simple, and feasible. This study has demonstrated the accuracy of 7 methods. The Lorenz method performed best but is complex and likely to be difficult to apply in resuscitation settings. Other simpler and quicker methods are at least as accurate as the best methods widely used in children, and there is potential for further calibrating these for use in adults before validation in real-world studies.