I'm caring for my bedridden mother, 75, she's got end stage heart failure, COPD, a host of other stuff. Recently, we took her off of diuretics because her blood pressure couldn't maintain. Now, it is hard to keep her o2 saturation in the 88-92 range. The nurses hotline said not to raise up the o2 to 5 liters (co2 retention, etc.), but lately if we move her around, it sinks to the low 80s. Everything is fine when she sleeps, but the slightest little things bring the o2 down. Her machine doesn't go past 5l, so occasionally I'll attach a tank and go to 5 just to get her back to a comfortable level, then go back down slowly to 3. Have you guys ever dealt with something like this? I appreciate any reply in advance.