Height Prediction from Ulna Length of Critically Ill Patients.

Background: Ulna length (UL) has been used in mathematical formulas to predict the body height of healthy and sick individuals. However, the evaluation of its use with patients admitted to intensive care units (ICU) is scarce. The objective of this study was to develop a mathematical equation to estimate critically ill patients' height using the UL measure and to evaluate its agreement with measured standing height. Methods: This cross-sectional study was performed at the ICU of a tertiary hospital in Brazil. A total of 100 patients aged >= 18 years who had their body height measured before ICU admission were enrolled. The equation was developed through multiple linear regression, and its agreement was assessed through paired Student's t test and Bland-Altman plot. Results: The following formula was obtained: height in cm = 153.492 - (7.97 x sex [sex: male = 1, female = 2]) + (0.974 x UL [in cm]). The difference between means of measured height (MH) and height estimated from UL was not significant (166.26 +/- 8.75 cm and 166.30 +/- 5.29 cm, respectively, P = .96), and a significant correlation (r = 0.624, P < .001) was detected. In the Bland-Altman analysis, UL was in agreement with MH; however, there was a significant bias (P < .001) suggesting that it may be disproportional and dependent on the average's height value. Conclusion: The mathematical equation for height estimation using UL developed in this study matched the MH of critically ill patients. However, we suggest more studies for its validation.