Original ArticleSleep in ventilatory failure in restrictive thoracic disorders. Effects of treatment with non invasive ventilation
Introduction
Over the past 20 years, non-invasive positive pressure ventilation (NIV) has been increasingly used in the treatment of chronic hypercapnic ventilatory failure [1], [2]. In patients with restrictive thoracic diseases of either skeletal or neuromuscular origin, long term NIV improves or normalizes nocturnal and diurnal blood gases, alleviates dyspnea, improves performance in activities of daily living as well as health related quality of life [1], [2], [3].
Although NIV is generally applied at night, few studies have addressed the issue of the influence of NIV on sleep in adults [4], [5], [6], [7]. Data on sleep quality and sleep architecture in subjects with hypercapnic respiratory failure are also scarce. This is all the more surprising since there is a known reciprocal influence of non invasive ventilation and sleep. Sleep modifies the response to non invasive ventilation seen in awake humans, whereas non invasive ventilation may either improve or impair sleep quality [8], [9], [10], [11], [12].
When long-term ventilation seems warranted in patients with ventilatory failure secondary to restrictive disorders, we usually perform complete sleep recordings both before and immediately after implementation of NIV, thus allowing an assessment not only of the impact of NIV on diurnal blood gases but also a comparative evaluation of changes in sleep induced by NIV. This report details results obtained in a large cohort of patients included over a period of 20 years.
Section snippets
Patients and methods
This study is a retrospective analysis of all patients with ventilatory failure due to predominantly restrictive disorders submitted to NIV in preparation for long-term home ventilation and assessed between 1987 and 2008 at the Sleep laboratory of Saint-Luc University Hospital (Belgium). During this period, full night polysomnographies were systematically performed in patients with ventilatory failure when NIV was required—before introducing NIV—unless the severity of the clinical situation
Statistical analysis
Paired t-tests were performed for comparison of all continuous variables recorded before and after initiating NIV. A p value below 0.05 was used as threshold value for statistical significance.
The study protocol was approved by the Ethics Committee for Medical Research of Saint-Luc University Hospital (Belgium). The study protocol was registered at http://www.clinicaltrials.gov NCT009915364.
Patients
Ninety-five files were reviewed. Thirty-five were excluded (four patients ventilated by tracheostomy, three who did not tolerate NIV, eight for whom polysomnography prior to NIV had been performed in another hospital and 20 patients with incomplete recordings). Data were thus collected for sixty patients [male: 52% (n = 31); female: 48% (n = 29)]. None of these patients had sleep apnea, except four out of the six patients with Obesity–Hypoventilation Syndrome, who had a mean apnea–hypopnea index of
Discussion
This report summarizes the clinical and polysomnographic changes induced by nocturnal NIV in 60 patients with chronic hypercapnic ventilatory failure due to predominantly restrictive disorders. It is, to our knowledge, the largest study providing data on sleep studies before and shortly after implementing NIV. Baseline studies show that respiratory failure exerts a profound deleterious effect on sleep, with a decrease in sleep length, prolonged sleep latency, a high number of movement arousals,
Conflict of Interest
The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: doi: 10.1016/j.sleep.2010.09.008.
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