Sleep
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Comparative Study
Effect of nasal continuous positive airway pressure during sleep on 24-hour blood pressure in obstructive sleep apnea.
Ambulatory blood pressure (BP) was measured noninvasively (Oxford Medilog ABP) at 15-minute intervals for 24 hours before and after 8 weeks of treatment with nasal continuous positive airway pressure (nCPAP) in 19 men with obstructive sleep apnea (OSA). We included both normotensive and hypertensive patients, but hypertensives were studied after withdrawal of antihypertensive drugs. Ambulatory BP before and after treatment was compared using patients as their own controls. ⋯ The mean blood pressure fell in both normotensive and hypertensive patients. Patients who were inadequately treated with nCPAP had no reduction in mean 24-hour BP. Effective treatment of sleep apnea with nCPAP was associated with a significant fall in both systolic and diastolic BP independent of changes in body weight or alcohol consumption, suggesting that sleep apnea was an independent factor contributing to elevated nighttime and daytime BP in these patients.
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We investigated the way in which nasal continuous positive airway pressure (CPAP) affects the circadian profiles of blood pressure (BP) and heart rate (HR) in obstructive sleep apnea syndrome (OSAS) patients. Nine patients with OSAS, confirmed by nocturnal polysomnography, were studied with ambulatory blood pressure monitoring (Colin ABPM-630) during two 48-hour periods, before and during nasal CPAP treatment, at the Stanford University Sleep Disorders Clinic. During each 48-hour monitoring period, blood pressure measurements were taken by the ambulatory device every 30 minutes. ⋯ Average BP (systolic/diastolic) and HR during the 48-hour periods decreased significantly from 148.6/88.2 mm Hg to 138.7/81.4 mm Hg, and from 77.9 beats per minute (bpm) to 67.2 bpm in hypertensives during CPAP treatment (p = 0.04), but there were no significant changes observed in normotensives. Average BP, during the day and at night, decreased from 152.3/91.8 mm Hg to 141.2/85.1 mm Hg and from 133.9/76.8 mm Hg to 125.9/73.7 mm Hg, respectively, in the hypertensives during CPAP, but such changes were not observed in normotensives. Average HR during the day and at night decreased significantly from 85.2 bpm to 72.6 bpm and from 69.8 bpm to 56.5 bpm in the hypertensives (p = 0.04), but not in normotensives.(ABSTRACT TRUNCATED AT 250 WORDS)