Chest
Volume 99, Issue 4, April 1991, Pages 855-860
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Clinical Investigations
The Effect of Nightly Nasal CPAP Treatment on Underlying Obstructive Sleep Apnea and Pharyngeal Size

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Nasal continuous positive airway pressure (CPAP) is an effective treatment for obstructive sleep apnea (OSA). It is usually prescribed for nightly use; however, recent studies show that patients often do not wear the appliance consistently. Previous studies have also suggested that nasal CPAP may improve a patient's underlying OSA even when the mask is not in place. We investigated 12 men with OSA to see if nasal CPAP used nightly for six weeks would improve their underlying sleep-disordered breathing. We also studied pharyngeal volumes measured using magnetic resonance imaging and a computer-controlled digitizing pad. Patients with more severe OSA had improvement after six weeks; however, they still demonstrated significant OSA. Patients with less severe OSA did not have significant change. We were unable to show a significant difference in any patient's awake pharyngeal volumes. We conclude that patients with OSA should be encouraged to wear their nasal CPAP machines regularly.

Section snippets

Subjects

A total of 12 patients were enrolled in this study, all male. All of the patients had symptoms of daytime hypersomnolence and loud snoring. Patients were enrolled after they had undergone a full night of polysomnography at our VA sleep laboratory. The presence of OSA was defined by an apnea-hypopnea index (apneas plus hypopneas/hours of total sleep time) of more than five events per hour with accompanying oxygen desaturation to less than 85 percent. In addition, all patients demonstrated marked

Subjects

Twelve male patients were studied, and all had symptoms consistent with the sleep apnea syndrome. Their mean age (±SD) was 52.75 ± 10.57 years (range = 40 to 70 years), their mean height was 178.79 ± 8.25 cm (range = 167.7 to 193 cm), their mean weight was 108.29 ± 16.38 kg (range = 85.3 to 143.3 kg) giving them a mean body index (MBI) of 33.71 ± 6.44 kg/sq m (range = 25.41 to 43.18 kg/sq m). Two patients experienced mild weight loss during the study, one went from 112.5 kg to 108.0 kg, and the

Discussion

Over the past decade nasal CPAP has been shown to be an extremely effective form of therapy for OSA.1, 2, 4, 5, 12, 13 It has obviated the need for tracheostomy in a large number of patients and has been shown to improve daytime arterial blood gas values14 as well as possibly improve mortality.15 Nasal CPAP, however, is not without problems. The majority of patients tolerate nasal CPAP well.16 Conversely, some patients are unable or unwilling to use the appliance for a variety of reasons: chest

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Supported by a grant from the American Lung Association of Florida.

Manuscript received July 3; revision accepted September 24.

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