Using ulnar length to estimate height in undifferentiated adult emergency department patients

The dose of critical medicines or ventilator settings should not be a guessing game. Yet in the emergency setting, dosing that relies on ideal body weight (IBW) is difficult logistically in a helicopter or a busy trauma bay and often relies on a simple visual estimate to determine the patient’s height, and thus IBW. There have been previous studies showing a relationship between the length of a patient’s ulna and their height, but these were mostly in the pediatric pulmonology literature. We measured patients’ ulna length and height in a convenience sample of undifferentiated adult Emergency Department patients in order to make a linear regression with best-fit line equation for this population. After easily measuring the patient’s arm, the emergency provider can then plug the length into our equation to calculate height and then IBW. Our whole cohort equation is y = 3.5852x + 74.908, with a correlation coefficient of 0.7109 and an R 2 value of 0.5054. This study suggests that with one quick and easy measurement life-saving medicine doses and ventilator settings can more accurately be determined.