Brief Article
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Cardiol. Apr 26, 2012; 4(4): 121-127
Published online Apr 26, 2012. doi: 10.4330/wjc.v4.i4.121
Continuous respiratory monitoring for sleep apnea screening by ambulatory hemodynamic monitor
Roger Dillier, Markus Baumann, Mabelle Young, Susanne Erne, Bernhard Schwizer, Michel Zuber, Paul Erne
Roger Dillier, Mabelle Young, Susanne Erne, Michel Zuber, Paul Erne, Division of Cardiology, Luzerner Kantonsspital, 6000 Lucerne 16, Switzerland
Markus Baumann, Bernhard Schwizer, Division of Pneumology, Center of Sleep Disorders, Luzerner Kantonsspital, 6000 Lucerne 16, Switzerland
Author contributions: Dillier R and Young M registered the patients and collected the acoustic cardiography data; Baumann M and Schwizer B carried out the polysomnography studies; Erne S performed data entry and quality control; Zuber M and Erne P designed the study and were involved in the analysis and interpretation of the data; Dillier R and Zuber M wrote the manuscript.
Supported by An equipment grant from Inovise Medical, Inc., Beaverton OR, United States, for clinical data collection
Correspondence to: Paul Erne, MD, FESC, Professor, Head of Cardiology, Luzerner Kantonsspital, Luzern, 6000 Lucerne 16, Switzerland. paul.erne@luks.ch
Telephone: +41-41-2055208 Fax: +41-41-2052234
Received: January 21, 2012
Revised: March 26, 2012
Accepted: April 2, 2012
Published online: April 26, 2012
Abstract

AIM: To validate the sleep-disordered breathing components of a portable electrocardiography and hemodynamic monitor to be used for sleep apnea screening.

METHODS: Sleep-disordered breathing (SDB) is associated with cardiovascular disease. Patients with existing cardiovascular disease may have unrecognized SDB or may develop SDB while under the care of a cardiologist. A screening device for SDB, easy to use and appealing to cardiologists, would assist in referral of appropriate patients for full polysomnography (PSG). A cardiac and respiratory monitor (CPAM) was attached to patients undergoing PSG and an apnea/hypopnea index (AHI) generated. The CPAM device produced respiration rate, snoring rate, individual apnea/hypopnea events and an SDB severity score (SDBSS). In addition to AHI, an expert over-reader annotated individual breaths, snores and SDB breathing events to which the automated algorithms were compared.

RESULTS: The test set consisted of data from 85 patients (age: 50.5 ± 12.4 years). Of these, 57 had a positive PSG defined as AHI ≥ 5.0 (mean: 30.0 ± 29.8, negative group mean: 1.5 ± 1.2). The sensitivity and specificity of the SDBSS compared to AHI was 57.9% and 89.3%, respectively. The correlation of snoring rate by CPAM compared to the expert over-reader was r = 0.58 (mean error: 1.52 snores/min), while the automated respiration rate had a correlation of r = 0.90 (mean error: 0.70 breaths/min).

CONCLUSION: This performance assessment shows that CPAM can be a useful portable monitor for screening and follow-up of subjects for SDB.

Keywords: Portable monitor, Sleep-disordered breathing, Polysomnography, Sleep apnea, Hemodynamic monitor