Journal Article

Effect of Continuous Positive Airway Pressure and Placebo Treatment on Sympathetic Nervous Activity in Patients With Obstructive Sleep Apnea

Mills, Paul J., Ziegler, Michael G., Loredo, Jose S., Ancoli-Israel, Sonia, Dimsdale, Joel E.

2001

Overview

We studied the effect of continuous positive airway pressure (CPAP) treatment on sympathetic nervous activity in 38 patients with obstructive sleep apnea. Randomized, placebo-controlled trial. Patients underwent polysomnography on three occasions in a clinical research center, and had BP monitored over 24 h at home. All of the patients had sleep apnea with a respiratory disturbance index (RDI) > 15. The patients were randomized blindly to CPAP or placebo (CPAP at ineffective pressure) treatment. Prior to therapy, the number of apneas and the severity of nocturnal hypoxia correlated significantly with daytime urinary norepinephrine (NE) levels, but not nighttime urinary NE levels. CPAP treatment lowered daytime BP from 99 ± 2 mm Hg to 95 ± 3 mm Hg (mean ± SEM) and nighttime BP from 93 ± 3 mm Hg to 88 ± 3 mm Hg. Placebo CPAP treatment decreased both day and night mean BP only 2 mm Hg. CPAP, but not placebo, treatment lowered daytime plasma NE levels by 23%, daytime urine NE levels by 36%, daytime heart rate by 2.6 beats/min, and increased lymphocyteβ 2-adrenergic receptor sensitivity (all p < 0.05). The effect of CPAP treatment on nighttime urine NE levels and heart rate did not differ from placebo treatment. There was a suggestion of an effect of placebo CPAP treatment on nighttime measures, but not on daytime measures. We conclude that daytime sympathetic nervous activation is greater with more severe sleep apnea. CPAP treatment diminished the daytime sympathetic activation; the potential nighttime effect of CPAP treatment was obscured by a small placebo effect.

• Publisher: Elsevier Inc,American College of Chest Physicians
• Subject: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy / Biological and medical sciences / Continuous positive airway pressure / Emergency and intensive respiratory care / Female / heart rate / Heart Rate - physiology / Humans / Intensive care medicine / Male / Medical sciences / Middle Aged / norepinephrine / Norepinephrine - urine / Polysomnography / Positive-Pressure Respiration / pulse / Receptors, Adrenergic, beta / Sleep Apnea Syndromes - physiopathology / Sleep Apnea Syndromes - therapy / Sympathetic Nervous System - physiopathology / β-adrenergic receptors