Nocturnal oxygen therapy in patients with chronic heart failure and sleep apnea: a systematic review.

Chronic heart failure (CHF) is a public health problem which affects >2% of the adult population, with high morbidity, mortality, and financial cost. Sleep apnea, prevalent in >50% of patients with CHF, can aggravate vital prognosis due to worsening of heart failure. It is considered that a decrease in the apnea-hypopnea load may improve outcomes for those patients. Nocturnal non invasive ventilation can be proposed to treat sleep apnea in this situation, there being few alternatives. The present review concerns the use of nocturnal oxygen therapy (NOT) in patients suffering from both CHF and sleep apnea. The interest of NOT in this situation lies in its ability to reduce the central apnea-hypopnea index and to improve nocturnal oximetry disorders related to sleep apnea. Impact on cardiac contractility, patient tolerance, side effects, and costs of NOT are also approached as well as the underlying mechanisms of NOT. In addition, the results of the SERVE-HF trial have shown an increased death rate in patients with CHF and central sleep apnea and who were treated with adaptive servo-ventilation versus control patients. This may lead to renewed interest in NOT in those patients.