Rationale: Continuous positive airway pressure (CPAP) is the current treatment for patients with symptomatic obstructive sleep apnea (OSA). Its use for all subjects with sleep-disordered breathing, regardless of daytime symptoms, is unclear. Objectives: This multicenter controlled trial assesses the effects of 1 year of CPAP treatment on blood pressure (BP) in nonsymptomatic, hypertensive patients with OSA. Methods: We evaluated 359 patients with OSA. Inclusion criteria consisted of an apnea–hypopnea index (AHI) greater than 19 hour−1, an Epworth Sleepiness Scale score less than 11, and one of the following: under antihypertensive treatment or systolic blood pressure greater than 140 or diastolic blood pressure greater than 90 mm Hg. Patients were randomized to CPAP (n = 178) or to conservative treatment (n = 181). BP was evaluated at baseline and at 3, 6, and 12 months of follow-up. Measurements and Main Results: Mean (SD) values were as follows: age, 56 ± 10 years; body mass index (BMI), 32 ± 5 kg · m−2; AHI, 45 ± 20 hour−1; and Epworth Sleepiness Scale score, 7 ± 3. After adjusting for follow-up time, baseline blood pressure values, AHI, time with arterial oxygen saturation less than 90%, and BMI, together with the change in BMI at follow-up, CPAP treatment decreased systolic blood pressure by 1.89 mm Hg (95% confidence interval: −3.90, 0.11 mm Hg; P = 0.0654), and diastolic blood pressure by 2.19 mm Hg (95% confidence interval: −3.46, −0.93 mm Hg; P = 0.0008). The most significant reduction in BP was in patients who used CPAP for more than 5.6 hours per night. CPAP compliance was related to AHI and the decrease in Epworth Sleepiness Scale score. Conclusions: In nonsleepy hypertensive patients with OSA, CPAP treatment for 1 year is associated with a small decrease in BP. This effect is evident only in patients who use CPAP for more than 5.6 hours per night. Clinical trial registered with www.clinicaltrials.gov (NCT00127348).

The aim of the present study was to assess the impact of nasal continuous positive airway pressure (nCPAP) in ischaemic stroke patients followed for 2 yrs.Stroke patients with an apnoea–hypopnoea index ≥20 events·h⁻¹were randomised to early nCPAP (n = 71; 3–6 days after stroke onset) or conventional treatment (n = 69). The Barthel Index, Canadian Scale, Rankin Scale and Short Form-36 were measured at baseline, and at 1, 3, 12 and 24 months.The percentage of patients with neurological improvement 1 month after stroke was significantly higher in the nCPAP group (Rankin scale 90.9versus56.3% (p<0.01); Canadian scale 88.2versus72.7% (p<0.05)). The mean time until the appearance of cardiovascular events was longer in the nCPAP group (14.9versus7.9 months; p = 0.044), although cardiovascular event-free survival after 24 months was similar in both groups. The cardiovascular mortality rate was 0% in the nCPAP group and 4.3% in the control group (p = 0.161).Early use of nCPAP seems to accelerate neurological recovery and to delay the appearance of cardiovascular events, although an improvement in patients’ survival or quality of life was not shown.

Objective To assess the effect of continuous positive airway pressure (CPAP) on 24 hour ambulatory blood pressure monitoring values in a large number of patients with untreated systemic hypertension of new onset and obstructive sleep apnoea. Design Multicentre, double blind, randomised, placebo controlled trial. Setting Eleven general hospitals in Spain between 2004 and 2007. Participants 340 patients recently diagnosed as having systemic hypertension by a general practitioner (systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or both) and an apnoea-hypopnoea index per hour of sleep of >15 events/hour. Intervention Patients were assigned to CPAP (n=169) or sham CPAP (n=171) for three months. Main outcome measurements Net changes in the different 24 hour ambulatory blood pressure monitoring values from baseline to three months of optimal or sham CPAP. Results 277 (81%) of the 340 patients randomised were men; the patients had a mean age of 52.4 (SD 10.5) years, a body mass index of 31.9 (5.7), an Epworth sleepiness scale score of 10.1 (4.3), an apnoea-hypopnoea index of 43.5 (24.5). No differences between groups were seen at baseline. Compared with placebo and analysed by intention to treat, the mean 24 hour ambulatory blood pressure of the CPAP group decreased by 1.5 (95% confidence interval: 0.4 to 2.7) mm Hg (P=0.01). The mean 24 hour ambulatory blood pressure monitoring measures decreased by 2.1 mm Hg (0.4 to 3.7) mm Hg (P=0.01) for systolic pressure and 1.3 (0.2 to 2.3) mm Hg (P=0.02) for diastolic blood pressure. Mean nocturnal blood pressure decreased by 2.1 (0.5 to 3.6) mm Hg (P=0.01). Conclusions CPAP produced a statistically significant reduction in blood pressure in patients with systemic hypertension and obstructive sleep apnoea. This reduction is small and did not achieve the 3 mm Hg drop in mean 24 hour ambulatory blood pressure that the trial was powered to detect. Consequently, these results may have uncertain clinical relevance. However, taking into account the prevalence of hypertension and the likelihood of comorbidities, the decrease in blood pressure, although minimal, may be beneficial. Trial registration Clinical trials NCT00202527.

Excessive daytime sleepiness (EDS) is not invariably present in patients with obstructive sleep apnoea syndrome (OSAS). The aim of the present study was to investigate polysomnographic determinants of EDS in patients with OSAS.EDS was assessed using the Epworth Sleepiness Scale (ESS) and the multiple sleep latency test (MSLT). Patients showed EDS whenever the ESS score was >10 and the MSLT score <5 min. Absence of EDS was defined as having an ESS score of 10 min.In total, 23 male patients with EDS (mean±sdESS and MSLT score 17±3 and 4±1 min, respectively) and 17 without EDS (ESS and MSLT score 5±2 and 16±3 min, respectively), were studied. Both groups exhibited a similar apnoea/hypopnoea index (62±18versus60±20 events·h⁻¹). Patients with EDS exhibited shorter sleep latency (11±16versus18±18 min) and greater sleep efficiency (90±7versus82±13%) than those without EDS. Patients with EDS showed lower oxygenation (lowest arterial oxygen saturation 69±12versus79±8%; mean arterial oxygen saturation 87±6versus90±5%). Sleep stage distribution and arousal index did not differ between the groups.Patients with obstructive sleep apnoea syndrome and excessive daytime sleepiness are characterised by shorter sleep latency, increased sleep efficiency and worse nocturnal oxygenation than those without excessive daytime sleepiness. Nocturnal hypoxaemia can be a major determinant of excessive daytime sleepiness in patients with obstructive sleep apnoea syndrome.

The episodes of hypoxia/re-oxygenation associated with the respiratory disturbances observed in patients with obstructive sleep apnoea syndrome (OSAS) may induce the generation of oxygen free radicals. Indeed, several studies suggest that OSAS is associated with oxidative stress. The present study tested the hypothesis that patients with OSAS have an alteration in antioxidant defences.The plasma levels of total antioxidant status (TAS), glutathione peroxidase (GPX), γ-glutamyltransferase (GGT), vitamins A, E, B₁₂and folate, and homocysteine were determined in 47 patients with OSAS and 37 healthy subjects. Of these, 27 patients who used continuous positive airway pressure (CPAP) for >4 h·night⁻¹were re-examined 12 months later.Patients with OSAS had lower TAS (1.4±0.16versus1.50±0.10 mmol·L⁻¹), vitamin A (64±19versus74±17 μg·dL⁻¹) and vitamin E levels (1,525±499versus1,774±503 μg·dL⁻¹), and increased values of GGT (42±22versus32±16 U·L⁻¹) than controls. There was no difference between groups in GPX, homocysteine, vitamin B₁₂and folate plasma levels. CPAP treatment normalised the levels of TAS (1.50±0.13 mmol·L⁻¹) and the activity of GGT (30±14 U·L⁻¹) without any influence on vitamins levels.In conclusion, the results indicate that patients with obstructive sleep apnoea syndrome have a decreased antioxidant capacity that is partially reversed by continuous positive airway pressure treatment.

Background: Previous studies have presented contradictory data concerning obstructive sleep apnoea syndrome (OSAS), lipid oxidation and nitric oxide (NO) bioavailability. This study was undertaken to (1) compare the concentration of 8-isoprostane and total nitrate and nitrite (NOx) in plasma of middle-aged men with OSAS and no other known co-morbidity and healthy controls of the same age, gender and body mass index; and (2) test the hypothesis that nasal continuous positive airway pressure (CPAP) therapy attenuates oxidative stress and nitrate deficiency. Methods: A prospective, randomised, placebo controlled, double-blind, crossover study was performed in 31 consecutive middle-aged men with newly diagnosed OSAS and 15 healthy control subjects. Patients with OSAS were randomised to receive sham CPAP or effective CPAP for 12 weeks. Blood pressure, urinary catecholamine levels and plasma 8-isoprostane and NOx concentrations were obtained before and after both treatment modalities. Results: Patients with OSAS had significantly higher 8-isoprostane levels (median (IQR) 42.5 (29.2–78.2) vs 20.0 (12.5–52.5) pg/ml, p = 0.041, Mann-Whitney test) and lower NOx levels (264 (165–650) vs 590 (251–1465) μmol/l, p = 0.022) than healthy subjects. Body mass index, blood pressure and urinary catecholamines were unchanged by CPAP therapy, but 8-isoprostane concentrations decreased (38.5 (24.2–58.7) pg/ml at baseline vs 22.5 (16.2–35.3) pg/ml on CPAP, p = 0.0001) and NOx levels increased (280 (177–707) vs 1373 (981–1517) μmol/l, p = 0.0001) after CPAP. Conclusions: OSAS is associated with an increase in oxidative stress and a decrease in NOx that is normalised by CPAP therapy.