My son just had this this last winter, he was about 22 months also. Is she nursing? Ds had already weaned at this point, so we didn't let him drink any milk (makes phlegm MUCH worse), pushed clear water (no juice, can also make phlegm worse), had him sleep in a semi-sitting position, rubbed and actively patted his back (to break up mucus in the lungs, etc to help his cough be more productive) but ulitimatly I had to take him to the e.r., he was just laboring so hard to breath, his airway was so swollen and enflamed from all that coughing, etc. They had him breath in some epinephren (sp?) and immediatly he was breathing clearer. He also had a very high fever (almost 105) and they gave him both acetomenophin and ibuprophen to bring it down, make him more comfortable, and reduce the swelling in his airway. He did much better from there on out.
Ugh, I sure feel for you!! Hang in there!! I hope she doesn't get to the point where she needs to go to the e.r...but if her breathing gets real labored and you are worried, please don't hesitate to take her! I was so relieved as my sweet baby sat on my lap, breathing in the epenephrin, and seeing him being able to breath again. And then once the meds kicked in he was laughing and giggling again. I knew I had made the right choice to bring him in!!