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

PURPOSE

This paper studies the short- and long-term effects of nocturnal oxygen therapy (NOT) on sleep apnea in chronic heart failure (CHF).

METHODS

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, 3.0 l/min, and 14 to no NOT. The NOT group underwent follow-up polygraphy at 24 h and 6 months, and the no NOT group a single follow-up polygraphy at 6 months.

RESULTS

No significant difference was observed between baseline and 6 months 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 24 h and to 18.3 ± 2.4 at 6 months (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 24 h and to 6.1 ± 1.4 at 6 months (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 24 h and 9.3 ± 2.6 at 6 months (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 6 months of follow-up.

CONCLUSIONS

NOT decreased central AHI and ODI significantly within 24 h and up to 6 months in CHF patients with sleep apnea, without significantly modifying obstructive and mixed AHI, QOL, and ventricular function.