The Science Journal of the American Association for Respiratory Care

2009 OPEN FORUM Abstracts

ASSESSING METHODS FOR ESTIMATING HEIGHT IN RECUMBANT ADULTS

Randall Baker, Susan R. Whiddon, Simmons Catherine, Aleksandr Gulchuk, Verna-Virginia Lehockey; Respiratory Therapy, Medical College of Georgia, Augusta, GA

Introduction: Actual height is used to determine Ideal Body Weight (IBW) for the calculation of the delivered tidal volume in ventilated patients. However, actual and ‘ideal” body weight may differ, and an actual measurement of height may not be available. So, health practitioners must often estimate height in order to calculate IBW. The purpose of this study was to determine a method for accurately and easily estimating height in recumbent patients in order to calculate IBW. Methods: After IRB approval, thirty-six subjects [female=24 and male=12)] were enrolled in the study. Actual height was measured using a stadiometer. Measurements of Demi-Span (DS), Forearm Length (FL), and Knee Height (KH) were made with subjects in both supine and semi-fowler positions. Demi-Span was measured from the subject’s sternal notch to the tip of the middle finger. For FL, the subject’s arm was positioned diagonally across their chest with their fingers extended toward the clavicle, and measurements were made from the point of the elbow to the prominent bone on the wrist. Knee Height was determined by positioning the subject’s ankle at a 90o angle and measuring from the bottom of the foot to the anterior surface of the knee. Estimated height was calculated using the standard, method- and gender-specific formulas or tables. After each measurement, an investigator rated the difficulty in making the measurement as “Least” to “Most” Difficult on an Ease of Use Scale (EUS) ranging from 1 to 3. Results: The DS overestimated height and showed excessive bias with subjects in either the Semi-Fowler [-11.69 cm (females) and -10.36 cm (males)] or Supine positions [-11.70 cm (females) and -10.32 cm (males)]. Furthermore, DS was rated as moderately difficult to obtain (2.13 on the EUS). Knee length not only showed significant gender differences overestimating height by 4.12 cm in females and underestimating height in males by 11.10 cm, but also was rated the hardest to measure on the EUS (2.65). Forearm Length slightly overestimated height in both females and males (3.2 cm and 1.85 cm, respectively), and was the easiest to obtain (1.18 on the EUS). Conclusions: Of the three methods tested, Forearm Length demonstrated the least bias regardless of patient’s position or gender and may be ideal method for estimating height and calculating ideal body weight in the ICU. Sponsored Research - None

You are here: RCJournal.com » Past OPEN FORUM Abstracts » 2009 Abstracts » ASSESSING METHODS FOR ESTIMATING HEIGHT IN RECUMBANT ADULTS