Here's how I think of it. Back in college, I had classes in the Humanities building (funny place for an Spanish/English major, right?). Anyway, it was an older building with kinda narrow halls. Top that off with an auditorium for those massive classes right in a corner. Let's just say, even for a 100 pound freshman girl, getting through those hallways during class changes was a challenge. Even getting INTO the hallway could be difficult.
So imagine if you are the blood and blood vessels that are supposed to travel through the lungs. Except the lungs are full, full way up with air (narrow hallways crammed with other students). It's really hard to move that blood through, causing the blood vessels to be cramped, the heart to work harder, and sometimes the blood decides to escape through the VSD, the hole between the lower chambers in the heart rather than go to the trouble of trying to get to the lungs to pick up that oxygen. Anyone ever been tempted to just use that Emergency Exit door??
So when the doctor lowered the tidal volume of his ventilator (think "tidal waves" in the ocean, the breath that's pushed into the lungs) and let him set the rate of his breathing, it cleared those "hallways" out pretty good. The big question was, is he strong enough after over three years of not having to breathe, to be able to start back up and do it all on his own, all the time?
And it looks like the answer is, YES! It's kinda weird to hear him when he's asleep. I've gotten so used to 30 breaths per minute, that rhythm, that it's a bit disconcerting to hear 17-22 breaths, and some are really deep, long ones. But apparently, that's what he needs. Sometimes he doesn't breathe quite deeply enough and the ventilator complains, but it's becoming less and less often, and it's usually an every other, or every third breath when he's already breathing relatively fast. So no biggie. (Part of me wonders if the vent is confusing rocking movement with breathing motions.)
We went in to get some lab work done on Saturday, just to check things, and almost every one of his numbers was perfect. The only one that was off (bicarbs, produced by his kidneys) was only slightly off. Plus, he's started using less oxygen on a regular basis. Again, a sign that the blood is not taking the easy route, the emergency exit through the VSD because it's just too crowded in those hallways. What a blessing, what a tremendous answer to prayer.