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Volume 15 No. 01
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Accepted Papers

Scientific Investigations

Screening for Obstructive Sleep Apnea in Commercial Drivers Using EKG-Derived Respiratory Power Index

M. Melanie Lyons, PhD, ACNP1; Jan F. Kraemer, Dipl-Inform2; Radha Dhingra, MD3; Brendan T. Keenan, MS1; Niels Wessel, PhD2; Martin Glos, PhD4; Thomas Penzel, PhD4; Indira Gurubhagavatula, MD, MPH1,5,6
1Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; 2Department of Physics, Humboldt-Universitat zu Berlin, Berlin, Germany; 3Mahatma Gandhi Medical College and Hospital, Jaipur, India; 4The Centre of Sleep Medicine, Department of Cardiology, Charité Universitätsmedizin, Berlin, Berlin, Germany; 5Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; 6Sleep Disorders Clinic at the Philadelphia CMC VA Medical Center, Philadelphia, Pennsylvania

Study Objectives:

Obstructive sleep apnea (OSA) is common in commercial motor vehicle operators (CMVOs); however, polysomnography (PSG), the gold-standard diagnostic test, is expensive and inconvenient for screening. OSA is associated with changes in heart rate and voltage on electrocardiography (EKG). We evaluated the utility of EKG parameters in identifying CMVOs at greater risk for sleepiness-related crashes (apnea-hypopnea index [AHI] ≥ 30 events/h).


In this prospective study of CMVOs, we performed EKGs with concurrent PSG, and calculated the respiratory power index (RPI) on EKG, a surrogate for AHI calculated from PSG. We evaluated the utility of two-stage predictive models using simple clinical measures (age, body mass index [BMI], neck circumference, Epworth Sleepiness Scale score, and the Multi-Variable Apnea Prediction [MVAP] score) in the first stage, followed by RPI in a subset as the second-stage. We assessed area under the receiver operating characteristic curve (AUC), sensitivity, and negative posttest probability (NPTP) for this two-stage approach and for RPI alone.


The best-performing model used the MVAP, which combines BMI, age, and sex with three OSA symptoms, in the first stage, followed by RPI in the second. The model yielded an estimated (95% confidence interval) AUC of 0.883 (0.767–0.924), sensitivity of 0.917 (0.706–0.962), and NPTP of 0.034 (0.015–0.133). Predictive characteristics were similar using a model with only BMI as the first-stage screen.


A two-stage model that combines BMI or the MVAP score in the first stage, with EKG in the second, had robust discriminatory power to identify severe OSA in CMVOs.


Lyons MM, Kraemer JF, Dhingra R, Keenan BT, Wessel N, Glos M, Penzel T, Gurubhagavatula I. Screening for obstructive sleep apnea in commercial drivers using EKG-derived respiratory power index. J Clin Sleep Med. 2019;15(1):23–32.

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