Association of central sleep apnea and nocturnal CO 2 exhalation volume under oxygen inhalation in patients with chronic heart failure

Abstract

We investigated impacts of O 2 on sleep apnea and nocturnal CO 2 exhalation volume in stable/severe CHF.Subjects were 7 patients with stable CHF (LVEF = 23.2 ± 7.6%, NYHA class = III). Nocturnal SaO 2 and sleep data were analyzed using PSG, with single breath CO 2 exhalation volume(SBCO 2) using a monitoring device.1. All of the patients had central sleep apnea (CSA). 2. SaO 24%ODI decreased with O 2 inhalation (7.9 ± 3.8 vs. 0.6 ± 0.5 times/hour, p < 0.01). 3. AHI was reduced with O 2 (19.7 ± 2.3 vs. 2.4 ± ;3.6 times/hour, p < 0.01). 4. SBCO 2 during sleep were: in room air, 44.0 ± 4.8ml during regular respiration and 119 ± 9.8ml at onset of CSA; in O 2, 90.8 ± 4.0ml during regular respiration. An increased level of the SBCO2 was attained with O 2.In CHF with CSA, a low level of SBCO 2 was observed. It was suggested that O 2 improved this low value and suppressed CSA.