Why spike in pressure?

Does anyone know why the pressure would spike like this? I had just gotten up, reconnected the tube and turned it back on. I had also turned on my right side. The pressure started going up even with no apneas recorded. (hope the image comes through).

http://imgur.com/0dUMCAd

Take a look at your flow limitations graph, and snoring graph. These are two things the resmed machines look at when determining how much pressure you need.

stienman wrote:Take a look at your flow limitations graph, and snoring graph. These are two things the resmed machines look at when determining how much pressure you need.

I agree. But, that's what will cause ALL APAPs to increase pressures........not just ResMed machines.


Den

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Flow and sore graphs. What does Flow indicate?

http://imgur.com/etYRjtz

Nin6 wrote:Flow and sore graphs. What does Flow indicate?

http://imgur.com/etYRjtz

Clearly shows increases in flow limitations.
A "flow limitation" is a partial reduction or change in the shape of the air flow. Think of it as a partial hypopnea.
The machines are programmed (algorithms) to believe that the flow limitations or snores may precede apneas, so that's why they are triggers to increase pressure to prevent the apneas from occurring. Lots of other things can cause flow limitations (like nasal congestion or nasal structural problems) and some apneas may not have them as preceding events.


Den

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It would be interesting to see the whole night and not just 30 minutes. Maybe the reason you see no events is because of the pressure increase. It's possible that the 11 is closer to the pressure you need. 5.4 minimum is quite low. Every time you turn off the machine you re- start the ramp which starts low and builds the pressure.

This is the whole night. During the fast spike I was awake the entire time. The second large upswing I was asleep.

http://imgur.com/a/s8hAm

Nin6 wrote:This is the whole night. During the fast spike I was awake the entire time. The second large upswing I was asleep.

http://imgur.com/a/s8hAm

The fast spike when you were awake was caused by your machine misinterpreting your (normal) wake breathing pattern as a flow-limited sleep breathing pattern, and so it increased the pressure rather dramatically because the Resmeds are programed to respond rather aggressively to flow limitations. Remember: The machine has no way to tell when you are awake or when you are asleep. It assumes that if you are using the machine, then you must be asleep.

The second large upswing when you were asleep was caused by real flow limitations in your sleep breathing. Flow limitations during sleep breathing can indicate the airway is at high risk of collapsing. So the machine responds by increasing the air pressure to make it harder for the airway to collapse.

Could the flow limitation be caused by the hose being twisted or having a sharp bend in it? When I sleep on my right side, it isn't hanging from the headboard and may have gotten kinked.

Nin6 wrote:Could the flow limitation be caused by the hose being twisted or having a sharp bend in it? When I sleep on my right side, it isn't hanging from the headboard and may have gotten kinked.

no. flow limitations are a specific kind breathing, normally a flattening of the intake of breath. if you zoom in enough to see the individual breaths, you can see flattened inhalation bumps when the flow limit graph is spiking up.

Fascinating! Thanks all for the help.