RE: Need Advice about Central Apneas
(07-03-2016, 03:08 PM)justMongo Wrote: Sometimes increased PS will increase CA because it permits CO2 washout. CO2 being a primary trigger for breathing while sleeping. PS is helpful for people who have resistance upon exhale: such as COPD. Also, PS gives exhale relief when using large Inhalation pressure (like me.)
I'd leave the PS at 3. But narrow the 4 to 25 cm-H2O pressure window.
If it were me, I'd set minEPAP to 6 -- which is your 95 percentile for 02JUL2016; and maxIPAP to 12. You only went to 10 last night, so that gives the machine 2 cm of headroom. That should take care of the HA and OA. The CA will bear watching.
I agree with Mongo. I think raising Min EPAP to 6 is warranted.
Notice how the first two CAs in the zoomed-in period on July 2 were preceded by sudden arrowhead-shaped recovery breathing (which clearly indicates something obstructive also going on), which likely washed out too much CO2, leading to the CAs. And many of the CAs in other zoomed-in periods appear to be preceded by less obvious sudden recovery breathing.
Sudden recovery breaths indicate an obstructive arousal to a more shallow state of sleep in response to obstructive apnea, obstructive hypopnea, Flow Limitation or other partial restriction of the airway. The sudden increase in the amplitude of the Flow waveform represents a sudden increase in breathing effort which, if we remain asleep, is typically followed by a steady reduction in amplitude, forming an overall arrowhead shape in the amplitude. When recovery breathing is not flagged as an event, it means these were probably respiratory effort related arousals which did not quite meet the criteria to be scored as RERA, or perhaps our machine simply does not detect/report RERA at all.
Higher Min EPAP would tend to help reduce the obstructive component of the problem, which may be triggering most of the CAs.
Regarding Pressure Support, I think that increasing PS would likely worsen the number of CAs.
Adjusting Min EPAP to 6 could be done in two steps of 1 cmH2O each, waiting at least a week between changes. (Raising the Min EPAP, like raising the Min Pressure in an APAP machine, is partly a comfort choice, but it is important that it not be adjusted too low.) After at least a week can decide what next.
If at least a week after raising Min EPAP the average number of CAs is still higher than 2 or 3 per hr, I would probably suggest lowering PS to 2 and retaining the higher Min EPAP.
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