DD2 is coming down with a cold (again!) and has started coughing in her sleep. She is not congested in her chest, and is not coughing anything up, and she is able to breathe without diffculty, but the coughing is pretty constant. She has a bout of it every 5 minutes or so, and sometimes to the point where I think she will throw up. I have given her ibuprofen in case it is giving her a sore throat or sore head, or whatever.
DD1 did this on occasion when she was younger too, and it was exhausting for both of us! I would sleep in her bed with her to comfort her when the coughing woke her up, and to get a bowl if it looked like she really was going to throw up, etc, and seriously we were up every 5-10 minutes! I took her to the hospital for it once, and they said there was nothing they could do. Cough medicines are useless - we tried a number of different types with no effect, and the doctor told me, too, that they are pretty much useless.
So now I am at a loss. Does anyone have a suggestion on how to settle this cough down? We really could use our sleep here - we've had a long winter of coughs, colds, teething, ear infections, etc. Help!

Oh, and she is two years old, by the way.