Chest
Volume 98, Issue 2, August 1990, Pages 325-330
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Treatment of Obstructive Sleep Apnea: A Preliminary Report Comparing Nasal CPAP to Nasal Oxygen in Patients with Mild OSA

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Nasal CPAP is presently accepted as first-line therapy for obstructive sleep apnea, but a significant minority of patients do not tolerate nasal CPAP. The purpose of this study was to compare the benefits of nasal CPAP, nasal oxygen (O2), and placebo (air) using patients as their own controls. We studied eight men, aged 33 to 72 (mean 57 years), who had mild obstructive sleep apnea. To be eligible for study, patients had to have an apnea plus hypopnea index ≥5, plus one or more of the following: blood pressure >150705 mm Hg, multiple sleep latency test mean score ≤10 minutes, or significant nocturnal cardiac ectopy. After a baseline study, patients received a month each of nocturnal O2 at 4 LPM and air at 4 LPM, presented in random order. The third month of treatment consisted of nasal CPAP (range 2.5 to 12.5 cm H2O). Patients underwent evaluation at baseline and after each month of treatment. It was concluded that oxygen was more effective in improving oxygenation and hypopneas than is nasal CPAP. However, oxygen did not reduce apneas or improve daytime hypersomnolence as well as nasal CPAP in patients with mild OSA. Oxygen might be considered as an alternate form of treatment for patients who are not hypersomnolent, or as an adjunct to nasal CPAP.

Section snippets

Subjects

Subjects were recruited from patients studied in the Sleep Apnea Laboratory at the University of Kentucky College of Medicine, either through routine clinical referral or as part of an ongoing study of sleep disordered breathing in the elderly.11

We defined an apnea as total cessation of airflow at the nose and mouth lasting for at least 10 seconds as indicated by both a thermistor and a CO2 meter. We defined hypopnea as a reduction in the amplitude of the thermistor signal by at least 50

RESULTS

Patient characteristics are reported in Table 1. These patients are typical of those commonly encountered in clinical practice of sleep apnea: the majority are overweight and they are all men. In every patient, apneas were predominantly obstructive.

Results of treatment of sleep disordered breathing and oxygen saturation are reported in Table 2. In general, nasal CPAP was more effective in reducing SDB events, but oxygen was more effective in improving oxygen saturation. Repeated measures

DISCUSSION

To our knowledge, this is the first study to compare the effects of nasal CPAP and nasal oxygen treatment on the major sequelae of mild obstructive sleep apnea. The main findings of our study were that oxygen does not reduce the total number of sleep disordered breathing events compared to baseline or placebo, although CPAP certainly does. However, oxygen does improve nocturnal oxygenation as does CPAP. With the exception of reduced number of arousals noted with CPAP, neither form of treatment

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    Supported by the Sanders Brown Center on Aging, University of Kentucky NIA P 50AG-05144 (Alzheimer’s Disease Research Center) and by NIH General Clinical Research Center grant M01RR026202. We acknowledge the support of the University of Kentucky Major Research Instrument Bond Program in the purchase of equipment used in this study.

    †Supported by a Preventive Pulmonary Academic Award from the National Institutes of Health.

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