I have been using my CPAP for 2 years now and find that sometimes it causes gas to build up in my stomach and I have to take it off as I feel like I'm suffocating. My O2 level was 94 without oxyen and I'm wondering if the CPAP is in fact, causing the air to go into my stomach, which bloats and then I have trouble taking a deep breath. I also have a hiatal hernia. I feel like I'm falling apart. I walk 2 miles a day (using my oxygen at 1L and feel great during the day. It's at night that all this happens. I don't use oxygen unless I'm walking. This only happened a few times. But I swear the stomach bloating is being caused by the CPAP. My doctor has my Resmed on 4 which he said was low. Anyone else have this problem? Any suggestions on this? I'm a side sleeper and use the nose pillows for the CPAP. Thanks