08-06-2019, 05:17 AM
RE: Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea
Thanks, RayBee and Sleepless -- I appreciate your posts.
Obviously, that SERV-HF study was for patients with diagnosed heart failure. I also noticed in the study that the outcomes were worse in patients with the worst heart failure (lowest ejection fraction). So I don't mean to automatically suggest that the study should raise concerns for those without heart failure.
At the same time, I did notice that the ASV patients had what we would normally think of as improvement in their situations -- better oxygenation, much lower AHIs and AIs, and even less daytime sleepiness -- yet had worse survival with somewhat greater overall mortality and cardiac mortality specifically. (At the same time, I don't believe they had actual improvements in "Qualify of Life," notwithstanding the reduced sleepiness.) So that gave me pause, and I wondered if it's possible that some of the same lessons might apply to those who don't have heart failure: that improvement in oxygenation and AHI and sleepiness don't necessarily translate into better long-term outcomes.
As far as the actual pressure ranges, I understand your (RayBee's) point and did click on the thumbnail you attached showing the 25 cm maximum (though also noting Sheepless' comments about what might happen in actuality). I guess my point was less about the exact numerical pressure than a concern that ASV, by raising intrathoracic (intra-chest) pressure during inspiration, reverses an aspect of the normal physiology (lower pressure during inspiration, higher during expiration), which could also alter some of the normal changes of cardiac output that happen during the respiratory cycle (inspiration + respiration).
As you can tell, I'm both detail oriented and a worrier (not an easy combination, I can assure you, to live with) who is always seeing the limitations of our our current knowledge and feeling the need to get to the bottom of things. The problem is, it's often just not possible to know, given the current state of knowledge, what the best path really is.
Once again, I much appreciate the support and helpful comments and suggestions I've been receiving here.
Obviously, that SERV-HF study was for patients with diagnosed heart failure. I also noticed in the study that the outcomes were worse in patients with the worst heart failure (lowest ejection fraction). So I don't mean to automatically suggest that the study should raise concerns for those without heart failure.
At the same time, I did notice that the ASV patients had what we would normally think of as improvement in their situations -- better oxygenation, much lower AHIs and AIs, and even less daytime sleepiness -- yet had worse survival with somewhat greater overall mortality and cardiac mortality specifically. (At the same time, I don't believe they had actual improvements in "Qualify of Life," notwithstanding the reduced sleepiness.) So that gave me pause, and I wondered if it's possible that some of the same lessons might apply to those who don't have heart failure: that improvement in oxygenation and AHI and sleepiness don't necessarily translate into better long-term outcomes.
As far as the actual pressure ranges, I understand your (RayBee's) point and did click on the thumbnail you attached showing the 25 cm maximum (though also noting Sheepless' comments about what might happen in actuality). I guess my point was less about the exact numerical pressure than a concern that ASV, by raising intrathoracic (intra-chest) pressure during inspiration, reverses an aspect of the normal physiology (lower pressure during inspiration, higher during expiration), which could also alter some of the normal changes of cardiac output that happen during the respiratory cycle (inspiration + respiration).
As you can tell, I'm both detail oriented and a worrier (not an easy combination, I can assure you, to live with) who is always seeing the limitations of our our current knowledge and feeling the need to get to the bottom of things. The problem is, it's often just not possible to know, given the current state of knowledge, what the best path really is.
Once again, I much appreciate the support and helpful comments and suggestions I've been receiving here.
