Chest

Chest

Volume 131, Issue 1, January 2007, Pages 156-163
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Original Research: Noninvasive Mechanical Ventilation
Effects of Nocturnal Noninvasive Mechanical Ventilation on Heart Rate Variability of Patients With Advanced COPD

https://doi.org/10.1378/chest.06-1423Get rights and content

Abstract

Background:Cardiovascular comorbidities have a negative impact on the health status and prognosis of patients with COPD. We determined whether nocturnal noninvasive (positive) mechanical ventilation (NIMV) can improve heart rate variability (HRV), decrease circulating natriuretic peptide levels, and improve functional performance of patients with very advanced COPD.

Methods:A randomized, double-blind, parallel controlled trial was conducted in 23 participants with stable but advanced COPD. Participants received standard medical therapy plus nocturnal NIMV or standard medical therapy plus sham NIMV for 3 months.

Results:After 3 months of NIMV therapy, the 24-h triangular interpolation of N-N intervals increased from 322 to 473 ms (p = 0.034), the 24-h HRV index (HRVI) increased from 21.8 to 29.9 ms (p = 0.035), nocturnal HRVI increased from 6.1 to 8.0 ms (p = 0.026), and the SD of the average N-N interval increased from 37 to 41 ms (p = 0.020). None of these indexes changed significantly in the control group. Additionally, compared with the control group, the pro-atrial natriuretic peptide levels declined significantly in the NIMV group (p = 0.013).

Conclusions:NIMV applied nocturnally over 3 months may improve HRV, reduce circulating natriuretic peptide levels, and enhance the functional performance of patients with advanced but stable COPD. While not definitive due to small sample size, these data suggest that nocturnal NIMV may reduce the impact of cardiac comorbidities in COPD patients.

Section snippets

Subjects

We recruited study participants from specialists' clinics at the University of Alberta Hospital. To qualify for the study, patients had to meet the following entry criteria: (1) clinical diagnosis of COPD; (2) age ≥ 40 years old; (3) ≥ 10-pack-year history of cigarette smoking; (4) FEV1/FVC ratio < 70% and postbronchodilator FEV1< 70% of predicted. Patients were excluded if they had the following conditions: (1) coexisting medical conditions that made survival for at least 6 months unlikely;

Results

There were 23 subjects who were enrolled in the study, but 2 subjects refused any nocturnal therapy following randomization and were excluded from the main analysis. There were no significant differences in any of the other parameters measured at baseline between the NIMV and control groups except for baseline FEV1, which was significantly higher in the group that received NIMV (p = 0.045). The mean IPAP delivered was 15.5 ± 4.2 cm H2O for the NIMV group (p < 0.001 compared to control group).

Discussion

The principal finding of this study was that nocturnal NIMV for 3 months increased some indexes of HRV at nighttime and reduced circulating natriuretic peptide levels in patients with advanced but stable COPD. These data suggest that nocturnal NIMV may be able to improve certain cardiac end points in COPD. However, due to the small sample size and lack of other cardiac performance data, these findings must be interpreted cautiously.

There have been several randomized controlled trials that have

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    • This project is supported by Canadian Institutes of Health Research (clinical trials), the Institute of Health Economics, and the University of Alberta Hospital Foundation.

    Dr. Sin is a Senior Scholar with the Michael Smith Foundation for Health Research and is supported by a Canadian Research Chair and a Michael Smith Health Foundation and St. Paul's Hospital Foundation Professorship in COPD.

    The authors have no conflicts of interest to disclose.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestjournal.org/misc/reprints.shtml).

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    Copyright © 2007 The American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.