Chest

Chest

Volume 116, Issue 6, December 1999, Pages 1545-1549
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Clinical Investigations
Sleep & Breathing
Effect of Continuous Positive Airway Pressure vs Placebo Continuous Positive Airway Pressure on Sleep Quality in Obstructive Sleep Apnea

https://doi.org/10.1378/chest.116.6.1545Get rights and content

Study objectives

Continuous positive airway pressure (CPAP) therapy has become the treatment of choice for obstructive sleep apnea (OSA). However, the efficacy of CPAP therapy has not been evaluated against a suitable control. We investigated the effectiveness of CPAP therapy in improving sleep quality in patients with OSA. We hypothesized that CPAP improves sleep quality.

Patients

Forty-eight CPAP-naive OSA patients were evaluated. None were receiving antihypertensive medications, and none had major medical illnesses.

Design

Patients were randomized to receive either CPAP or placebo CPAP (CPAP at an ineffective pressure) for 7 days in a double-blind fashion. Forty-one patients completed the protocol. Sleep quality variables, arousals, sleep arterial oxygen saturation (Sao2), and respiratory disturbance index (RDI) were assessed at baseline, after 1 day of treatment, and after 7 days of treatment. Repeated measures analysis of variance was used to evaluate the effects of treatment, time, and the interaction of the two.

Results

As expected, CPAP lowered RDI and number of arousals, and increased Sao2 over time (p = 0.001). Contrary to expectations, both CPAP and placebo CPAP had comparable effects on sleep quality as assessed by sleep architecture, sleep efficiency, total sleep time, and wake after sleep onset time.

Conclusions

This study confirms the effectiveness of CPAP in lowering the number of arousals and the RDI, and in raising Sao2. However, our data suggest that short-term CPAP is no different than placebo in improving sleep architecture. Further evaluation of the effectiveness of CPAP using a suitable placebo CPAP in prospective randomized studies is needed

Section snippets

Subjects

All subjects gave informed consent to the protocol, which was approved by the University of California San Diego Institutional Review Board. Forty-eight CPAP-naive OSA patients were studied at the University of California San Diego Clinical Research Center. Subjects responded to public service advertisements, were referred from community physicians, or were referred by previous subjects. Subjects ranged in age from 30 to 65 years, and their weight was between 1.0 and 1.7 times the ideal body

Results

Table 1 provides the subjects’ characteristics. Of the 48 subjects admitted for testing, 1 was removed from the analysis due to breach of randomization due to severe OSA and severe hypoxemia when using placebo CPAP. A second patient was removed from the analysis due to inability to sleep with the CPAP equipment. Five subjects were not included in the analysis because their RDI on overnight PSG was < 20. The final sample included 41 subjects with an RDI ≥ 20. The subjects were predominantly

Discussion

A wide range of beneficial physiologic, psychological, and cognitive changes in the OSA patient have been attributed to the effects of treatment with nasal CPAP.678 Nasal CPAP was primarily designed to reverse by means of a pneumatic splint the experience of a repetitive collapse of the upper airway by the OSA patient.1415 Thus, it has been well documented that CPAP is effective in abolishing the resultant apneas, hypopneas, and associated hypoxia and sleep fragmentation.45 What is not clear is

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    • Cited by (0)

    This research was supported in part by National Institutes of Healthgrants HL44915, AG02711, AG08415, and RR00827.

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    Copyright © 1999 The American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.