Involuntary Sniff or Arousal: what triggers CAs and periodic breathing?

[PeterFD]

For over a year now, I have been aware that I often have several sudden involuntary deep inhalations during the day, which I call “sniffs” for want of a better word. They are quite different from yawns and hiccups. When I first noticed them, I thought that I must have been breathing too shallowly, and that a sniff was a reaction to it.

Sometime later, I was diagnosed with sleep apnea and started using a CPAP machine. I then met Oscar and his helpful volunteers and began reviewing my night’s data each morning. When I looked at the air flow rate, I could see the sniffs that I recalled having while still awake as inhalation spikes, but there was no obvious shallow breathing before them. There were more of these sniff spikes when I was asleep and they were often followed by a CA which I think of as a “central apnea”, but which ResMed calls a “clear airway”. 

I am also prone to periodic breathing, in which (using engineering speak!) the air flow rate “carrier wave” is amplitude modulated by a damped sine wave having a period of about one minute (i.e. 1/60 Hz). A sniff induced CA is often followed by such periodic breathing. A few times, when it also contains several apneas, such breathing is flagged as Cheyne-Stokes Respiration (CSR).

In the thread “Very high amounts of periodic breathing / CSR ?”, Jay51 said,

“In general, large spikes in the Flow Rate graph can be arousals.”

I have tried to recognize the difference in the shape of my air flow rate graphs between sleeping and waking and it seems to me that the sniff and resulting CA might cause an arousal, but the sniff itself is not an arousal. Am I wrong?

Does anyone know what might be causing my sniffs?

[Jay51]

Since it is happening during the day as well as during sleep, their might possibly be a neurological or pulmonary reason for this as well.  Have any of your Dr.'s said anything about this? 

Other members may have suggestions as well as to what may be causing this.

[PeterFD]

I am booked in for a lung function examination next month.

[Jay51]

Great.  It may not hurt to take some OSCAR charts to your visit to see if Pulmonologist wants to look at them. 

I am grateful my Pulmonologist also has his own sleep lab, etc.  Even more grateful that he has patiently listened to everything I have said and carefully looked over all of my OSCAR's and ventilator reports as well.  

On a side note, my ENT also had some experience with sleep apnea treatment.   When my PCP referred me to these specialists and my hospital person who does the consultations set these up, for me personally, it was a good move getting a Dr. with some experience in sleep medicine.  Not a Sleep Dr. per se, but real Dr.'s with more experience than Dr.'s than no experience with sleep apnea treatment.  

I have an excellent PCP as well (who knew to do this instinctively).