Abstract
Cheyne-Stokes respiration (CSR) is common in patients with congestive heart failure (CHF) and is associated with significant nocturnal O2 desaturation, arousals and sympathetic activation. Nocturnal O2 reduces CSR by only about 50%. More complete suppression of CSR may be achieved by adding CO2 to O2. This study therefore aimed to evaluate the effects of nocturnal O2 plus CO2 on CSR, sleep and sympathetic activation. Nine patients with CHF (age 59+/-5 yrs; left ventricular ejection fraction 17.8+/-1.2% (mean+/-SEM) were studied in a cross-over, single-blind, placebo-controlled trial. After an accommodation night the patients were randomly assigned to one night each of O2 plus CO2 as well as air applied by nasal prongs. Nocturnal O2 plus CO2 reduced the duration of CSR as percentage of total sleep time (48.0+/-10 versus 7.4+/-2.0%; p=0.008) and increased arterial oxygen saturation (Sa,O2) as well as mean transcutaneous carbon dioxide tension (Ptc,CO2) (5.2+/-0.3 kPa (39+/-2 mmHg) versus 5.7+/-0.3 kPa (43+/-2 mmHg) p=0.011). Sleep did not improve and arousals were not reduced. Plasma noradrenaline was higher on the treatment night (486+/-116 versus 669+/-163 ng x L(-1); p=0.035). In conclusion, nocturnal O2 plus CO2 improves Cheyne-Stokes respiration in patients with congestive heart failure but has adverse effects on the sequel of Cheyne-Stokes respiration, namely sympathetic activation.
