title: Ambulatory blood pressure on and off continuous positive airway pressure therapy for the sleep apnea/hypopnea syndrome: effects in "non-dippers".
abstract: Ambulatory blood pressure (BP) monitoring was performed in 13 patients with the sleep apnea/ hypopnea syndrome (SAHS) during a randomized, placebo controlled crossover trial of the effects of continuous positive airway pressure (CPAP) therapy. BP was monitored at half-hourly intervals for a 24-hour period both on CPAP and on an oral placebo, each given for a minimum of 3 weeks. Objective effective CPAP use averaged 4.3 hours per night. Weight and anti-hypertensive medications remained stable over the study period. Systolic, diastolic and mean arterial BP for 24-hour, daytime and nighttime periods were not significantly different on placebo compared to CPAP. Those patients with no significant overnight fall in BP on placebo ("non-dippers") showed a significant improvement in daytime mean arterial BP on CPAP (98 +/- 4 mm Hg) compared to placebo (102 +/- 4 mm Hg; p = 0.01). These findings, in a well-controlled trial, suggest that BP is not reduced by CPAP in a heterogeneous group of SAHS patients, but it may be selectively improved in those patients most at risk for cardiovascular morbidity and mortality.
authors.affiliation: Department of Medicine, University of Edinburgh, U.K.
authors.forename: H M
authors.initials: HM
authors.lastname: Engleman
authors.forename: K
authors.initials: K
authors.lastname: Gough
authors.forename: S E
authors.initials: SE
authors.lastname: Martin
authors.forename: R N
authors.initials: RN
authors.lastname: Kingshott
authors.forename: P L
authors.initials: PL
authors.lastname: Padfield
authors.forename: N J
authors.initials: NJ
authors.lastname: Douglas
mesh_terms: D000328:Adult; D001794:Blood Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010919:Placebos; D011175:Positive-Pressure Respiration; D012891:Sleep Apnea Syndromes / Q000628:therapy*
chemical_list: D010919:Placebos