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Validation and human factor analysis study of an infant weight estimation device
Susan M Abdel-Rahman1,2, Ian M Paul3, Paula Delmore4
1Children's Mercy, University of Missouri Kansas City-School of Medicine, Kansas City, MO, USA. srahman@cmh.edu.
Insights
A new infant weight estimation device, using head and chest circumference, accurately predicts infant weight when scales are unavailable. Human factors testing shows the device is easy to use and reliable for medical settings.
Area of Science:
- Medical device development
- Pediatric medicine
- Human factors engineering
Background:
- Accurate infant weight measurement is crucial for medical management but scales are not always accessible.
- A validated method using chest circumference (CC) and head circumference (HC) for infant weight estimation was previously developed.
- This study evaluated a device implementing this method for its human factors (HF) and predictive accuracy.
Purpose of the Study:
- To assess the human factors experience with a novel infant weight estimation device.
- To determine the predictive performance of the device in estimating infant weight.
- To validate the device's utility in clinical settings where traditional scales are impractical.
Main Methods:
- A prospective, multi-center, observational, masked study involving 486 infants (0-90 days).
- Fifteen raters used both calibrated scales and masked versions of the device for infant measurements.
- Human factors aspects, including task evaluation and rater confidence, were assessed alongside predictive performance metrics (Mean Error, Mean Percentage Error).
Main Results:
- The device demonstrated high correlation with actual infant weight (r=0.97).
- Predicted weights were within 10% (86%) and 15% (99%) of actual weights, with low Mean Error (-69 ± 257g) and Mean Percentage Error (-1.3 ± 6.9%).
- Human factors errors were minimal (0.1-0.8%), and raters reported high confidence in device use.
Conclusions:
- The infant weight estimation device is statistically equivalent to the established method and provides weight approximations within acceptable variance.
- Human factors data indicate the device is user-friendly and suitable for clinical application.
- This device offers a practical solution for estimating infant weight when calibrated scales are unavailable or inconvenient.
Background:
Weight is critical for the medical management of infants; however, scales can be unavailable or inaccessible in some practice settings. We recently developed and validated a robust infant weight estimation method based on chest circumference (CC) and head circumference (HC). This study was designed to determine the human factors (HF) experience with, and predictive performance of, an infant weight estimation device that implements this method.
Methods:
Prospective, multi-center, observational, masked study of 486 preterm and term infants (0-90 days) assessed by 15 raters. Raters measured the infant using calibrated scales/measures and masked versions of the device. Raters also evaluated critical tasks associated with device use. Mean error (ME) and mean percentage error (MPE) were used to assess predictive performance.
Result:
Among 486 infants enrolled (36.8 ± 4.0 weeks gestational age, 31.5 ± 28.6 days postnatal age), predicted weight correlated highly with actual weight (r = 0.97, ME: - 69 ± 257 g, MPE: - 1.3 ± 6.9%). Predicted weight was within 10 and 15% of actual weight in 86 and 99%, of infants. HF errors were low, 0.1-0.8% depending on task. In all cases raters were confident or very confident in their measurements.
Conclusion:
The device was statistically equivalent to the method on which it was based and approximated weight with acceptable variance from the true weight. HF data suggest the device is easy to use. This device can be used to estimate weight in infants when calibrated scales are impractical or unavailable.
