Hello doctor,
I feel that I am a complicated case and I am trying to figure out the best way to titrate my oxygen treatment. I have late-stage cystic fibrosis, and I am experiencing a few months of exacerbation that has led to me needing oxygen full time. A few weeks ago I began, for the first time, to titrate my oxygen (O2) saturation vigilantly to between 90-95%, to combat Co2 retention. Previously, even when sick and using O2 full time, I had not retained carbon dioxide (Co2). But on my recent emergency room (ER) visit when I was in pulmonary distress (very short of breath) my pCo2 was 65. I was advised to titrate it. I had been advised before, but I had not always done so rigorously, because frankly it just felt uncomfortable. This time I stuck to it, however, because I was very nervous about increased Co2 retention. My pCo2 has wavered around, from 65-62-57-62-58, in about three weeks. The thing that has significantly changed, however, is that I am no longer sensitive to low oxygen saturation. My breathing is much more shallow, and I can sit comfortably at 90% and not even feel bad. It is scary because I can also be walking around and desaturating to 85% without even feeling it. I used to be able to know my oxygen saturation just by feel and how short of breath I was. My breathing, as I said, is very shallow even as I desaturate. It is only when I exercise to a certain point, at high levels of O2, that I am able to inhale and exhale involuntarily and deeply. I have some different issues that make me wonder if the protocol for titrating oxygen at low saturations for Co2 retention is the right treatment for me, and I am going in circles trying to figure it out. My doctors do not seem too concerned about my Co2 retention in general, given my late-stage CF and that I am about to be listed for a transplant, but I always want to figure out what is the best thing to be doing. I have a right to left pulmonary shunt. It is demonstrated when I lie down. My O2 saturation actually rises while lying down, and rises higher if I lie on my left side vs right. So I believe that this would be a component in that venous blood is being recycled into arterial blood but I do not have a grasp of how that could effect Co2 retention (only that it can lower my O2 saturation). Secondly, I am very anemic. My hemoglobin has dropped from 9-7 g/dL in the recent three weeks. I have always been anemic, but I have become even more so in the past three weeks, despite having been sick with exacerbations for months. The last three weeks have been different. (For example, I am also experiencing low magnesium for the first time, and we keep supplementing, but I cannot get my levels up). Lastly, my lungs have improved and infection has cleared somewhat, but I have not been able to come closer at all to being off oxygen. I know I do need to accept that maybe this is not a reality. But regardless, my O2 needs are lower, yet as soon as I exercise or move around even a little, they drop rapidly. Before three weeks, it was much less extreme. Now, I can sit resting on 1 liter and have a saturation of 97, yet as soon as I get up and move for 15 seconds, it drops quickly to the 80's. There are all these components, lungs (shot), anemia (no red blood cells to carry), and pulmonary shunt (diversion of oxygenated blood), that I am trying to piece together to figure out if titrating my oxygen to lower numbers is actually helping me or hurting me?