Weight estimation among multi-racial/ethnic infants and children aged 0-5·9 years in the USA: simple tools for a critical measure
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Published on: August 19, 2020
Yeyi Zhu1,2,3, Ladia M Hernandez3, Yongquan Dong3
1Kaiser Permanente Northern California Division of Research, 2000Broadway, Oakland, CA94612, USA.
Insights
New models using ulna length and forearm measurements accurately estimate paediatric weight in emergencies. These portable methods offer improved precision over existing formulas for children under six.
Area of Science:
- Paediatric medicine
- Anthropometry
- Biostatistics
Background:
- Accurate paediatric weight estimation is critical in resource-limited settings and during resuscitation.
- Existing methods, such as Advanced Paediatric Life Support (APLS), Theron, and Traub-Johnson formulas, have limitations in precision.
Purpose of the Study:
- To develop and validate new paediatric weight estimation models using ulna length and forearm measurements.
- To compare the accuracy of these novel models against established weight estimation formulas.
Main Methods:
- A cross-sectional analysis of anthropometric measurements was conducted.
- Four weight estimation models were developed based on ulna length, forearm width, and circumference in a training set (n=1016).
- Model performance was assessed for bias, precision, and accuracy in a validation set (n=457).
Main Results:
- The developed models demonstrated high predictive precision (R²=0.91-0.97).
- Mean percentage errors were significantly lower for the new models (0.1-0.7%) compared to APLS, Theron, and Traub-Johnson formulas (-1.7% to 9.2%).
- The new models achieved higher accuracy, with 95-99% of estimations within 20% of actual weight.
Conclusions:
- Ulna length and forearm measurements provide valid and reliable surrogate measures for paediatric weight estimation in children under six.
- These portable and precise methods offer an improvement over existing age- or length-based estimation techniques.
- Further validation in physically impaired or non-ambulatory children is recommended.
Objective:
In resource-constrained facilities or during resuscitation, immediate paediatric weight estimation remains a fundamental challenge. We aimed to develop and validate weight estimation models based on ulna length and forearm width and circumference measured by simple and portable tools; and to compare them against previous methods (advanced paediatric life support (APLS), Theron and Traub-Johnson formulas).
Design:
Cross-sectional analysis of anthropometric measurements. Four ulna- and forearm-based weight estimation models were developed in the training set (n 1016). Assessment of bias, precision and accuracy was examined in the validation set (n 457).
Setting:
National Children's Study-Formative Research in Anthropometry (2011-2012).
Subjects:
Multi-racial/ethnic infants and children aged <6 years (n 1473).
Results:
Developed Models 1-4 had high predictive precision (R 2=0·91-0·97). Mean percentage errors between predicted and measured weight were significantly smaller across the developed models (0·1-0·7 %) v. the APLS, Theron and Traub-Johnson formulas (-1·7, 9·2 and -4·9 %, respectively). Root-mean-squared percentage error was overall smaller among Models 1-4 v. the three existing methods (range=7·5-8·7 v. 9·8-13·3 %). Further, Models 1-4 were within 10 and 20 % of actual weight in 72-87 and 95-99 % of the weight estimations, respectively, which outperformed any of the three existing methods.
Conclusions:
Ulna length, forearm width and forearm circumference by simple and portable tools could serve as valid and reliable surrogate measures of weight among infants and children aged <6 years with improved precision over the existing age- or length-based methods. Further validation of these models in physically impaired or non-ambulatory children is warranted.
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