How ironic Carrie, I was just reading about this yesterday online and maybe perhaps can answer your question from a "medical" standpoint.
From what I read. In the studies on patients, giving two groups, one regular saline, one the hypertonic saline, it seemed as tho, the hypertonic saline did have better results, but, not without symptoms. The symptoms were increased coughing, chest tightness, irritation in the airways.
Now being that a 2 yr old cannot exibit and speak of their symptoms, the physicians and care team would be hesitant to use this type of therapy.
So, with all that and said....it might be a good idea to try this when they are ready to introduce it to your child. Try not to be upset, from what I read, there is other methods of treatment that might be as good or better with less symptoms at your 2 yr olds age and can tell you when he/she is having a reaction or complications to the treatment that is given.
One example...my twin boys are 10 yrs old. They have minimal lung damage. The lung transplant specialist coordinator which is their regular pulmonary doctor says that they need to be started on a treatment to "deter" further changes in their lungs. His choice of treatment is: Pulmozyme, which costs $1,666.00 without insurance. Now, if he thought that hypertonic saline was the way to go, he would have chosen a cheaper, less en-expensive way of handling their progression of the disease. I hope I have made some sense of this for you.
Never give up hope! we will soon get there!.