Nocturnal Oxygen Needs and Central Sleep Apnea in Patients With Chronic Heart Failure.

Oximetry recordings will be performed using a Pulse Oximeter. Two O2 titration sessions will be conducted at home in random order one week apart. One will consist of a stepwise night-to-night increase in O2 flow for up to 4 nights with supplemental O2, each at flow rates of 1L/min, 2L/min, 3L/min and 4L/min, respectively. During the other titration session, an automatic O2 delivery system will be used for 4 consecutive nights with O2 flow allowed to vary from 0 to 4 L/min with a 95 ± 2% SpO2 target. At the end of the titration periods, oxygen concentrators will be set at the lowest flow rate (1L/min to 4L/min) that maintained oxyhemoglobin saturation to \> 90% (Tsat90%) for ≥ 98% of the estimated sleep period and reduced the oxygen desaturation index 3% (ODI3) to \< 5/hour according to conventional O2 titration. If these targets are not reached, the lowest flow rate will be selected that minimizes the ODI3. These procedures will be repeated at week 5 and 11.