Height estimation in intensive care: A comparative study

Accurate height and weight measurements are essential in critical care to guide various aspects of patient management, including medication dosing, ventilator settings and the calculation of physiological parameters. However, there is no consensus on the optimal method for estimating height in the intensive care unit (ICU).

The aim of this study was to determine the accuracy of various methods of height estimation in the critical care setting, including a smartphone measurement application.

This cross-sectional study was performed in the intensive care unit at Sunshine Coast University Hospital. Participants were adult volunteers recruited from intensive care staff or outpatient waiting areas. Height was measured using four different methods. Direct measurements using paper tape or the Measure™ (Apple Inc, USA) iPhone app, and an indirect measurement derived from ulna length, were compared with the gold-standard stadiometric height measurement.

Seventy-seven participants were included in the analysis. The paper tape and iPhone methods demonstrated excellent agreement with stadiometric height, with strong correlations on Bland-Altman analysis and Deming regression (R² = 0.89 and 0.91, respectively). By contrast, predictions made using ulna length were less accurate (R² = 0.59). The Barbosa ulna model demonstrated moderate accuracy in estimating height (R² = 0.73) but showed reduced accuracy across different sexes and age groups in our population. Population-specific equations were derived, increasing the accuracy of tape, iPhone, and ulna-based methods (R² = 0.91, 0.93, and 0.72 respectively), demonstrating their potential applicability for predicting height from ulna length.

Paper tape and iPhone methods provided the most accurate height estimations. However, population-specific ulna equations offer a practical alternative when direct measurement is not feasible in real-world critical care settings.