I recently started reading the forum again, and I noticed that the current advice for treating obstructive apnea often includes using a soft cervical collar. The implication is that tucking one's chin down toward one's chest is bad, leads to airway collapse and obstructive apnea events. So I thought, maybe this can help me . . . maybe I could stop using this backpack . . . maybe I could sleep on my back again (my body REALLY prefers this position). So I went out and purchased a cervical collar.
The 1st night, I started off with just the scc, no backpack. When I woke up to use the washroom, I checked the machine's sleep report: after about 4.6 hours, my AHI was almost 9 - about ten or more times the usual. I finished the night with the backpack, and there was only 1 hypopnea during the remainder of the night. Since then I have taken to using a scc along with the backpack, and it seems to help reduce the times I wake up with a dry mouth, so I'm happy with that.
The message I would pass along, is that there are some of us whose Obstructive Apnea is sufficiently positional, that while a cervical collar certainly may prevent chin tucking, this alone may be inadequate to prevent the event clusters that occur when supine. It may be necessary to employ one of the older techniques to avoid supine sleeping.
PAPing in NE Ohio, with a pack of Cairn terriers