Central sleep apnea

I have written here several times about the fact that I suffer from sleep apnea and use a CPAP machine to alleviate this. But I have ignored the fact that there are two different types of sleep apnea: obstructive (OSA) and central (CSA). The former is more common; in this form, soft tissues in the back of the throat and elsewhere collapse during the night and block the airway, thus causing an apnea; the pressurised air coming from the machine prevents this collapse. In the latter case, the brain does not send sufficient signals to the body to breathe.

I assumed that I suffer from OSA despite the fact that the data from the CPAP machine clearly shows the opposite. Maybe I convinced myself that I had misread the data stored on the memory chip. Since April, I have suffered about 20 apnea/hour; this suddenly jumped to 35 apnea/hour a few weeks ago! Coincidentally (or not), this jump occurred on the same day that I started taking a certain medicine for pains in my left knee/leg. I needed to take this medicine only for a week, after which the rate dropped down to about 20 apnea/hour. Increasing the pressure in the machine to 8 cmH₂O did not have any effect.

In a visit to my family doctor, following up the 'knee' medicine, I said that the pains had almost completely cleared up; I also mentioned the huge increase in apneic events. She immediately ordered a pulmonary exam, assuming that I am suffering from OSA. We agreed that the machine should be checked.

Today, I had an appointment in the sleep clinic in Jerusalem (which is much less grand than the name might suggest). The technician (not doctor) checked the machine then extracted the data into a much fancier program than mine. He told me that I have CSA and that it would be better to decrease the pressure in the machine (now reduced to 5.5 cmH₂O). I am to see what the readings are like in the next fortnight, then try two weeks at 4.5 cmH₂O then two weeks at 6.5 cmH₂O in order to find the best setting.

Obviously I will return to my doctor with the intention of both updating her and cancelling the pulmonary exam. There aren't many options for dealing with CSA (apart from CPAP) so I don't want to speculate here. What is slightly annoying is that no sleep doctor is at yet involved. It might be that an appointment will be necessary in another month or two.

Edit: I notice that when I bought this CPAP machine three years ago, I was told that I have CSA, but somehow managed to forget this.

[SO: 4262; 5,21,42
MPP: 742; 1,3,6]