Discussions of Respiratory Ventilation

[Matt00926]

If you're not using supplemental oxygen, a good oxygen saturation throughout a night of sleep is a pretty good indicator, even if indirect, of adequate ventilation. Both ResMed and Philips Respironics allude to oxygen saturation > 90% all night as being a good indication of adequate ventilation.

If someone was suffering from hypoventilation, you would most likely see sustained desaturations on a pulse oximeter recording (assuming they weren't explained by events like obstructive apneas and/or hypopneas).

You can easily test the utility of a pulse oximeter recording by starting a bi-level machine at low settings of say 8/4. Then record each night and increase the pressure support and watch as your oxygen saturation improves, along with your tidal volume and minute ventilation.

If you are a respiratory patient you should still obviously get your CO2 levels checked on a scheduled basis, but that isn't going to be feasible in the home setting.

[ajack]

@Jessica futher to what you said about o2/co2, I was surprised to read this. We don't know what we don't know and take a lot of stuff for granted.
https://www.amperordirect.com/pc/c-pulse...tions.html
Carbon Monoxide
Carbon monoxide molecules, even in a small amount, can attach to the patient's hemoglobin replacing oxygen molecules. A pulse oximeter cannot distinguish the differences and the reading will show the total saturation level of oxygen and carbon monoxide. If 15% of hemoglobin has carbon monoxide and 80% has oxygen, the reading would be 95%.

Just my fellow forum users opinion, I read some articles and watched a bit of youtube.
I found the forums excellent for apap and apap with central apnea CA, transitioning through unwarranted bpap to ASV or ST etc. Generally people are rightly advised to keep the PS low, because it can otherwise trigger more central apnea CA or clear airways CA.

The problem is when this become part of treating the new ASV owner that can now do both, treat obstructive and central. They now need that pressure support to ventilate the lung during the central apnea. As well as the co2 retaining forum members that have OSB, restrictive/obstructive issues and OHS being treared with BPAP and this view trickles over. New user pressure induced clear airway, also called CA, which normally resolves for most people within 12 weeks. They are seldom associated to a large o2 drop and it is the body waiting for the co2 level to build back up to what they are use to. These forum members have lived with a high percent of co2 crowding out o2. The prescribed pressure support from the BPAP titration can alter co2 levels. Co2 retention is one of the main reasons BPAP is used and can induce short term clear airway CA.

There is a general set of unknowns on treatment using pressure support. We don't know what we don't know. This has lead to a few threads that I found didn't make sense, not that I know any better. The reason PS doesn't scare me is because of my treatment on variable PS. It varies the pressure support for base Ps:5 to normally up to Ps:14 The machine is set to go to the max PS and can use higher PS if it needs it.

This why I think everything on a forum should be run past your competent doctor, he knows the case history for years and has been trained in these procedures.