Short- and long-term effects of nocturnal oxygen therapy on sleep apnea in chronic heart failure.

Abstract

This paper studies the short- and long-term effects of nocturnal oxygen therapy (NOT) on sleep apnea in chronic heart failure (CHF). We enrolled 51 adults in New York Heart Association (NYHA) heart failure functional classes II or III, ≤45% left ventricular ejection fraction (LVEF), in a randomized, open, single-center study. Nocturnal cardiorespiratory polygraphy showed sleep apnea [apnea-hypopnea index (AHI) ≥15 events/h] in 33 patients, of whom 19 were randomly assigned to NOT, 3.0l/min, and 14 to no NOT. The NOT group underwent follow-up polygraphy at 24h and 6months, and the no NOT group a single follow-up polygraphy at 6months. No significant difference was observed between baseline and 6months in the no NOT group. In the NOT group, AHI decreased from 36.8 ± 2.6 events/h at baseline to 20.8 ± 3.0 at 24h and to 18.3 ± 2.4 at 6months (both P < 0.0001 vs. baseline), due to central AHI changes from 23.3 ± 2.8 events/h at baseline to 8.3 ± 1.6 at 24h and to 6.1 ± 1.4 at 6months (both P < 0.0001 vs. baseline). Oxygen desaturation index (ODI) decreased from 33.0 ± 5.2 events/h at baseline to 7.5 ± 0.5 at 24h and 9.3 ± 2.6 at 6months (both P < 0.0001 vs. baseline). NOT had no significant effect on obstructive and mixed AHI, quality of life (QOL), NYHA class, and LVEF up to 6months of follow-up. NOT decreased central AHI and ODI significantly within 24h and up to 6months in CHF patients with sleep apnea, without significantly modifying obstructive and mixed AHI, QOL, and ventricular function.