Prediction of protective lung tidal volume using the ulna length in Egyptian adults

Abstract

Background Ventilation with low tidal volume (VT) is advised for critically ill patients to protect against ventilator-induced lung injury and provide better clinical outcomes. Previous studies showed poor compliance with using height to predict VT. Ulna length has been used successfully to predict protective low VT. Our study aims to evaluate the ability of ulna length measurement to predict accurate protective lung VT in Egyptian people in reference to their standing height. Methods This study included healthy adult volunteers aged greater than or equal to 18 years. The height of each patient was measured while standing upright against a wall. Then, the left ulna was measured with a measuring tape from the olecranon to the mid-point of the styloid process. From ulna length, height was estimated, and protective lung VT was calculated using predicted body weight (PBW). Results Total 102 participants were enrolled in this study. The agreement between the calculated VT from standing height and ulna length was analyzed with Bland Altman analysis and showed a bias of (-5.7) ml, and limits of agreements (±1.96 SD) −91 ml to 76 ml in females; when the calculated VT of ulna length was compared with predicted body weight from height, the predicted mean VT was 6.2 ml/kg (95% confidence interval CI 4.5-7.8 ml/kg). In males, using ulna length, the predicted mean VT was 6.1 ml/kg (95% CI 4.8-7.4 ml/kg). Conclusion Ulna length can be used to predict protective lung VT in Egyptian people compared with their standing height.