Pressure pulse - what is the purpose

[Cpapian]

Hello, I am a relatively new user to APAP, and mostly lurking, trying to absorb all the information that I can to help me get the best sleep possible.

I was looking at my sleepyhead data from last night.  I exported the data to excel so I could better see the correlation of the data.

What I noticed is that of 18 press pulses, half of them occurred during sleeping/waking.  The remaining pulses often preceeded on obstructive event.

I have been gradually upping my settings so now they are 9.5 - 15.

Most of the time the machine hangs out at 9.5 and never got to 15 once, bit is sending these presure pulses at 14.

So I am trying to understand what the machine is trying to accomplish with these high pules.

Any thoughts?

[Sleepster]

What I noticed is that of 18 press pulses, half of them occurred during sleeping/waking.

What do you mean by sleeping/waking?

So I am trying to understand what the machine is trying to accomplish with these high pules.

A pressure pulse appears on the pressure graph as an oscillation.

The machine wants to respond to obstructive apneas with a pressure increase, but not respond to central apneas. It uses uses pressure pulses to determine the difference.

[Cpapian]

Sleeping/waking that drowsy time moving between the two states.    Last night it took me about 20 minutes to fall asleep.  During that time there were 4 pressure pulses.  Same for the waking state.  But I was breathing pretty normally.

[Sleepster]

Sleeping/waking that drowsy time moving between the two states.    Last night it took me about 20 minutes to fall asleep.  During that time there were 4 pressure pulses.  Same for the waking state.  But I was breathing pretty normally.

The pressure pulses should be occurring during apneas. Check to see if you had 4 apneas during that 20-minute period, and if they were obstructive or central. Also, what are you seeing that you're identifying as a pressure pulse?

[SideSleeper]

My PR machine use pressure pulses to try and start my breathing during a CA--sometimes at other periods of ragged breathing. They show as a vertical line at the top pf the Flow Rate chart. They don't seem to raise the pressure any--the ones I had last night were at periods of my near max pressure level. I'm using APAP at 11 min, 13 max.

[Cpapian]

Oh okay, I think I get it. I was probably not breathing enough to satisfy the machine so it sent a pulse to wake up my breathing.

I was using data from sleepyhead, the pressure pulses were those identified by the software but I exported to excel.

Thanks for your help sleepster.

[Sleeprider]

A pressure pulse is a quick puff of air that is used to differentiate between an obstructive, or central apnea event. It is only emitted during an apnea.

The Philips Respironics Auto CPAPs and BiPAPs are programmed to "test" a higher pressure of 1.5 cm, and this occurs every 20 minutes or so for 1-1/2 minutes. The machine slowly ramps up pressure, and if improved respiratory volume is not detected, the pressure drops back to baseline. This is characteristic behavior of Philips machines and it looks awful, but is probably inconsequential to most people. I have not seen documentation on why the pressure is increased, or what criteria must be met to maintain the higher pressure. This has been characterized as "hunt and peck" pressure, or a sawtooth pressure. My opinion is that it is ineffective compared to Resmed which is more aggressive in increasing pressure on many respiratory parameters, but YMMV.

[Sleepster]

My PR machine use pressure pulses to try and start my breathing during a CA--sometimes at other periods of ragged breathing.

No, your PRS1 Model 560 doesn't have the capability of initiating breathing to treat central sleep apnea. Machines that do that are called ASV.

Oh okay, I think I get it.  I was probably not breathing enough to satisfy the machine  so it sent a pulse to wake up my breathing.

No. See above.

I was using data from sleepyhead, the pressure pulses were those identified by the software

They are used to distinguish between a CA and a OA. (The machine needs to know the difference so it will know how to respond. It will raise the pressure in response to an OA, but do nothing in response to a CA.)

OA is obstructive apnea. A failure to breathe because of an obstructive apnea.
CA is central apnea. A failure to breathe because of a lack of a central nervous system signal.

Most people with sleep apnea have the affliction known as obstructive sleep apnea, but will still have a few central apnea, although not enough to be clinically diagnosed with the affliction known as central sleep apnea.

[SideSleeper]

In my post I said the pressure post "tries" to start breathing, not that it does. It doesn't, but the CA usually stops at the time of the pressure pulse,

[OpalRose]

As Sleepster has described above, an APAP has no capability to "try" to start breathing.  
Only an ASV machine can do that.

If the APAP's algorithm sends out a pressure pulse, it is probing the airway to determine one of two things:  Obstructive or Clear Airway.

If Obstructive, (which means the airway is blocked, usually collapse of the airway) the APAP will attempt to raise the pressure to help "splint" open the airway.

If Clear Airway, (meaning the airway is "not" blocked, it is open....but the brain fails to send a signal to breathe), then the APAP will "not" respond, as an APAP machine will "not" treat Clear Airways.

NOTE:  Some Clear Airway events are normal for most of us, and nothing to worry about.  If you were to experience a sharp increase in Clear Airway events for an extended period of time, then you may want to bring this concern up to your doctor.