Slight pressure change, dramatic results

I've been using BiPAP for almost two years. I recently went to a new doctor and he said it was time for another sleep-over, so I did it. My old pressures were 18/15. This time they recommended 17/13 so I started that a couple of weeks ago. What a change!

Flow Limitations: Before the pressure change there were a lot of spikes, during most of the night. After, just a few scattered hits.

I:E Ratio: After, much better balanced.

Minute Ventilation: Before, dense, wide variations spread out from 10 to 30 L/min. After, mostly confined to a narrow band from 10 to 15.

Respiratory Rate: This was the BIG surprise. Before, it was all over the lot, from 20 to frequently over 60, with wide and dense graph. After, it was mostly 16 to 22, with 5 or 6 groups up to 35 breaths/minute. None higher than 40.

AHI: I've been running below 3, mostly below 2, with 1.73 average for the last 6 months. After the pressure change, I've been below 1.0.

Both I and the doctor were surprised such a slight lowering of the pressures would have such a dramatic effect.

The only down side is my Residual Daytime Sleepiness (RDS) is still there. A French study says about 6% of those who have successful CPAP usage still have RDS. Guess I'm in that 6%. Maybe over time that will improve because of the pressure change.

Good to hear that recent changes are working out for you. I'm guessing after this long, you've already assessed things like medication side effects and other medical conditions as culprits in your residual daytime sleepiness? No problems with jumpy legs? If all else has been said and done to no avail, has narcolepsy been ruled out?

wardmiller, I question that such a small change in pressure could actually lead to such change in treatment. Were there any other variables? Would you be able to provide 30 or 60 days data of before and after the change?

Such as this:



In that French multicenter study that you mentioned, the prevalence of residual excessive sleepiness (RES) in CPAP treated patients actually was 12%. But after excluding associated restless leg syndrome, major depressive disorder, and narcolepsy as confounding causes, the final prevalence dropped to 6%. But being younger than 55 years was associated with a two -folds risk of suffering from that RES. You at an age of 86 is not even close to that age of 55.

Link to the French study:

http://erj.ersjournals.com/content/33/5/1062.full.pdf

Prevalence of residual excessive sleepiness in CPAP-treated sleep apnoea patients: the
French multicentre study.

By: J-L. Pe´pin*,#, V. Viot-Blanc",+, P. Escourrou1, J-L. Racineuxe, M. Sapene**, P. Le´vy*,#,
B. Dervaux##, X. Lenne## and A. Mallart""

No problem with jumpy legs -- while I'm awake. But the video they took at the sleep-over says I had occasional leg movement, something I'm not aware of. I sleep with my knees together because I have a severe back problem (spinal stenosis) and that keeps my hips and spine straight.

"I question that such a small change in pressure could actually lead to such a change..." So do I and the doctor. But I have very complete data records and they show, for example Respiration Rate has frequently been above 60 since Day One. Since the change, it is much lower on average (around 25) and never above 40. Nothing else has changed -- meds, daily routine, sleep routine, diet. Because of my back, I have been working out at the gym 7 days a week for the past 3.5 years, about 1h 15m each morning. That has not changed.

The only change is I get up to urinate more often that I did before the change. Before, I would get up about once every week or every two weeks. Since the change, I get up about 1 hour before my normal rising time maybe every other day, every third day, then go back to bed and immediately to sleep, getting up at my usual time (I don't use an alarm clock).

You mentioned "such a small change". As I was making the change on the machine I noticed they have provisions for changing just tenths of inches, so in the whole scheme of things, changing from 18/15 to 17/13 may be more than a small change.