Table 2 Effects of continuous positive airway pressure (CPAP) on blood pressure (BP) and urinary catecholamines, oxidative stress and nitrate and nitrite concentrations in patients with obstructive sleep apnoea syndrome
BaselineSham CPAPTherapeutic CPAP
Weight (kg)88.8 (14.5)88.6 (15.2)88.4 (15.8)
Daytime ambulatory BP (mm Hg)
    Systolic126 (10)126 (12)127 (9)
    Diastolic79 (6)77 (6)78 (5)
Nighttime ambulatory BP (mm Hg)
    Systolic118 (12)117 (12)117 (17)
    Diastolic70 (8)70 (6)69 (9)
Norepinephrine (μg/g)
    Diurnal32.9 (26.6–47.5)32.2 (25.3–41.8)32.8 (21.1–37.5)
    Nocturnal20.6 (15.4–32.7)16.4 (13.9–27.5)19.8 (14.8–29.4)
Epinephrine (μg/g)
    Diurnal7.0 (3.9–11.5)7.2 (4.7–11.2)7.3 (4.9–10.5)
    Nocturnal6.2 (3.9–11.3)4.6 (3.7–7.5)5.4 (3.7–10.9)
8-isoprostane (pg/ml)38.5 (24.2–58.7)42.1 (34.7–50.1)22.5 (16.2–35.3)†‡
NOx (μmol/l)280 (177–707)494 (292–940)1373 (981–1517)†‡
  • Values are mean (SD) or median (interquartile range) depending on the distribution.

  • †p<0.001 vs baseline; ‡p<0.001 vs sham CPAP.

  • NOx, total nitrate and nitrite concentration in plasma.