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A smartphone application to determine body length for body weight estimation in children: a prospective clinical
Oliver Wetzel1, Alexander R Schmidt2, Michelle Seiler3
1Institute of Anaesthesiology, University and University Hospital Zurich, Raemistrasse 100, 8091, Zurich, Switzerland.
Insights
A smartphone app accurately measures children's body length, showing excellent agreement with real measurements. This technology aids in reliable weight estimations, outperforming manual methods in some cases.
Area of Science:
- Pediatric Medicine
- Medical Technology
- Biometrics
Background:
- Accurate anthropometric measurements are crucial for pediatric care.
- Traditional methods for measuring children's length can be challenging, especially in clinical settings.
- Smartphone technology offers potential for novel, accessible measurement tools.
Purpose of the Study:
- To assess the feasibility and accuracy of a smartphone application for measuring children's body length.
- To evaluate weight estimations derived from app-measured lengths.
- To compare app-based measurements and weight estimates with traditional methods and clinician assessments.
Main Methods:
- A prospective clinical trial involving 627 children aged 0-<13 years.
- Validation of length measurements using the "Optisizer" smartphone application against real patient lengths.
- Correlation of ordinal length categories derived from app and real measurements.
- Comparison of weight estimations by physicians, nurses, parents, and the app.
Main Results:
- The smartphone application demonstrated a minimal bias (-0.1%) in length measurement compared to real lengths.
- Ordinal length categories derived from the app showed excellent agreement (kappa = 0.83) with those based on real lengths.
- Physicians, nurses, and parents tended to underestimate children's weight, while app-based categories showed slight overestimation. Parental weight estimation showed the lowest absolute difference.
Conclusions:
- Smartphone-based length measurement for children is accurate and feasible, showing good agreement with real patient lengths.
- The app effectively categorizes children's length, correlating well with categories based on direct measurements.
- While app-based weight estimations align with known limitations, parental estimation proved most precise in this study.
Abstract:
The aim of this study was to test the feasibility and accuracy of a smartphone application to measure the body length of children using the integrated camera and to evaluate the subsequent weight estimates. A prospective clinical trial of children aged 0-<13 years admitted to the emergency department of the University Children's Hospital Zurich. The primary outcome was to validate the length measurement by the smartphone application «Optisizer». The secondary outcome was to correlate the virtually calculated ordinal categories based on the length measured by the app to the categories based on the real length. The third and independent outcome was the comparison of the different weight estimations by physicians, nurses, parents and the app. For all 627 children, the Bland Altman analysis showed a bias of -0.1% (95% CI -0.3-0.2%) comparing real length and length measured by the app. Ordinal categories of real length were in excellent agreement with categories virtually calculated based upon app length (kappa = 0.83, 95% CI 0.79-0.86). Children's real weight was underestimated by physicians (-3.3, 95% CI -4.4 to -2.2%, p < 0.001), nurses (-2.6, 95% CI -3.8 to -1.5%, p < 0.001) and parents (-1.3, 95% CI -1.9 to -0.6%, p < 0.001) but overestimated by categories based upon app length (1.6, 95% CI 0.3-2.8%, p = 0.02) and categories based upon real length (2.3, 95% CI 1.1-3.5%, p < 0.001). Absolute weight differences were lowest, if estimated by the parents (5.4, 95% CI 4.9-5.9%, p < 0.001). This study showed the accuracy of length measurement of children by a smartphone application: body length determined by the smartphone application is in good agreement with the real patient length. Ordinal length categories derived from app-measured length are in excellent agreement with the ordinal length categories based upon the real patient length. The body weight estimations based upon length corresponded to known data and limitations. Precision of body weight estimations by paediatric physicians and nurses were comparable and not different to length based estimations. In this non-emergency setting, parental weight estimation was significantly better than all other means of estimation (paediatric physicians and nurses, length based estimations) in terms of precision and absolute difference.
