Oxygen desat and CO2 oversat under cpap

[feeling_better]

Under cpap therapy, is o2 desat related to additional co2 at all, or how is related?

I know there are many other conditions that could change o2 saturation under cpap. My question is specific to the interplay betweeen co2 and o2 levels. Suppose, because of whatever conditions (such as the particular mask has higher dead space or lower than normal out port flow), the CO2 wash out under one mask is less than that of another mask. Does that make the O2 desat change? I know they measure O2 desat at the titration. Do they measure co2 levels at all at the titration?

[Snoredog]

you need to research Respiratory Physiology & Neurobiology and the human respiratory drive, many of the sites that explain that this time of the year are subscription access, but there are books on it. While the paper below doesn't explain it very well, it does talk about the apneoeic threshold which you may find interesting.

http://ep.physoc.org/cgi/content/full/90/1/13
Crossing the apnoeic threshold: causes and consequences

This brief review addresses the characteristics, lability and the mechanisms underlying the hypocapnic-induced apnoeic threshold which is unmasked during NREM sleep. The role of carotid chemoreceptors as fast, sensitive detectors of dynamic changes in CO2 is emphasized and placed in historical context of the long-held debate over central vs. peripheral contributions to CO2 sensing and to apnoea. Finally, evidence is presented which points to a significant role for unstable, central respiratory motor output as a significant contributor to upper airway narrowing and obstruction during sleep.

[feeling_better]

While the paper below doesn't explain it very well, it does talk about the apneoeic threshold which you may find interesting.
http://ep.physoc.org/cgi/content/full/90/1/13
Crossing the apnoeic threshold: causes and consequences

Snoredog, thank you very much for posting the url to that every interesting papper!

[Snoredog]

those on the SV machine might be interested in this paper:

Transient hypocapnia is required to cause these apnoeas and small amounts of inspired CO2 will eliminate central apnoeas and periodic breathing in sleep (Berssenbrugge et al. 1983; Xie et al. 1997).

related link:
http://ep.physoc.org/cgi/content/full/90/1/13#B4

But if small amounts of CO2 are inspired and they eliminate central apnea, same can happen if you retain more CO2 with proper use of mask and machine settings to control your breathing.

[feeling_better]

those on the SV machine might be interested in this paper:

Transient hypocapnia is required to cause these apnoeas and small amounts of inspired CO2 will eliminate central apnoeas and periodic breathing in sleep (Berssenbrugge et al. 1983; Xie et al. 1997).

related link:
http://ep.physoc.org/cgi/content/full/90/1/13#B4

But if small amounts of CO2 are inspired and they eliminate central apnea, same can happen if you retain more CO2 with proper use of mask and machine settings to control your breathing.

I am not an SV machine. But I have already observed the reduction of my HI, with slight CO2 retention increase. BTW, I may be a candidate for SV, and my doc and I have discussed the possibility of another titration.

[Lee2263]

those on the SV machine might be interested in this paper:

Transient hypocapnia is required to cause these apnoeas and small amounts of inspired CO2 will eliminate central apnoeas and periodic breathing in sleep (Berssenbrugge et al. 1983; Xie et al. 1997).

related link:
http://ep.physoc.org/cgi/content/full/90/1/13#B4

But if small amounts of CO2 are inspired and they eliminate central apnea, same can happen if you retain more CO2 with proper use of mask and machine settings to control your breathing.

I am not an SV machine. But I have already observed the reduction of my HI, with slight CO2 retention increase. BTW, I may be a candidate for SV, and my doc and I have discussed the possibility of another titration.

What is SV?

[feeling_better]

What is SV?

Servo Ventilator machines.