Timed Breathes

[thebestdog]

I just got four hours sleep last night for the first time in years. Normally I wake up every 90 minutes. But I just got a new machine- Dreamstation vpap because I suspected I might have central apnea. I set a backup rate of 7 breathes per minute and it seems to have worked. 

After two hours  I was getting a period of 90 seconds when the machine switched to timed breathes. But for the rest of the night breathing was spontaneous. 

But something doesn't look correct in the OSCAR chart. The flow rate during the 90 seconds is almost a flat line- was I really breathing during that time? I was attached to a pulse oximeter which indicates normal oxygen levels. I'm not sure if this is an error or a glitch in how the flow is being reported in OSCAR. I'm attaching a screen shot showing the flow, tidal volume and minute ventilation. Given that minute ventilation and tidal volume appear normal why is the flow zero? 

Thank if you have the time to look at this and give me your opinion.
   

[Jay51]

Great question.  I can't answer it, but I have used a lot of ventilators and have experimented with many different numerical back up rates.  Normal rate during sleep is approximately 12 -  20 breaths per minute, but can vary.  My RT likes 15 for me.  I have gotten used to about 12-15 or so.   7 seems a little low.  

If you want to (and this is up to you), you can try very slowly raising that back up rate by 1 say every week or 2.  And watch your OSCAR numbers.  At some point, the back up rate will become uncomfortable and unnatural.  When you you find that point, maybe back off a point or 2 and balance that against your OSCAR charts therapy performance (evaluate both comfort and therapy).

[thebestdog]

Do your timed breathes look similar to your spontaneous one?

7 is a bit low I admit and thanks for the suggestion to increase it sounds like a good idea so will try it out. I've only switched to ASV this week after being on cpap for six years and literally woke up every 90 minutes without exception. It's encouraging at this stage to be able to stay asleep for four hours after only a few nights experimenting with pressures. I'm finding now my pressures are ipap 13cm and epap 10 which stay constant most of the time.

[SarcasticDave94]

Future OSCAR charts should include the left panel data, minus the calendar.

With a backup breath rate at 7, it almost won't assist with timed breath which might be helpful during a Central Apnea.