(1395) There's an App for That! iPhone Measure App Versus Tape Measure for Supine Height in ICU Patients

Introduction: ICU patients are at risk of developing ventilator induced lung injury. Lung protective ventilation that emphasizes low tidal volume (Vt) can minimize risk. Vt is calculated with predicted body weight by height. The gold standard of measuring standing height is impractical in ICU patients. Providing a measuring tape to clinicians improves compliance with lung protective ventilation. The use of measuring tapes can be limited by their cumbersome nature. Use of an iPhone app to measure patient height may improve compliance due to its ease of use. In this study, we assess the validity of the iPhone Measure app compared to standard tape measure for assessing supine height in critically ill patients.

Methods: Our study assessed the agreement between two quantitative methods of height measurement in ICU patients. 32 patients were measured four times, twice each with both the iPhone app and tape measure. Measurements were rounded to the nearest inch. Researchers measured each patient once and were blinded to other researcher’s measurements. In a separate session, the same researchers measured five simulated patients, twice with the iPhone app and twice with a tape measure to determine intra-rater reliability.

Results: The iPhone measure app was a highly similar and reliable tool when compared to the tape measure. The average difference between iPhone measure app and tape measure was 2.85 inches (95% CI [1.77,3.93]). This correlates to a range of tidal volumes at 6 ml/kg of 324 ml vs 354 ml, or a 30 ml difference. The intraclass coefficient (ICC) with two-way random effects model was used to assess the precision of different researchers measuring the height of the same patient. This showed almost perfect agreement (individual CA-ICC of 0.98 [95% CI 0.94-0.99], average CA-ICC of 0.99 [95% CI 0.99-1.00]). The concurrent validity of the iPhone measure app compared to tape measure was evaluated using Pearson’s Correlation. This showed near excellent concurrent validity (0.873 [p < 0.001]).

Conclusions: The iPhone measure app provides clinically reliable measurements that are comparable to those taken by tape measures. The iPhone measure app can offer a convenient and reliable alternative for measuring patient height in clinical settings, potentially saving time and mitigating risks in ventilated patients.