I don't know that these are peer reviewed journals, yet the best place to find research is by going to AARC.org, RT Magazine, Advance for rt. The AARC times is, I think, one of the best magazines in RT, as well as chest, although the later is more research and analysis than what I think you're looking for.
I think the main emphasis of respiratory therapy right now is meeting criteria for reimbursement, reducing costs, and improving patient outcomes. The Keysone committee of is a big success and even the Obama administration is encouraging other states to adapt a similar program. Since the program was adapted, pneumonia admission rates have decreasing in Michigan, deaths in the CCU have decreased, etc.
Another area of big change is oxygenation of neonates. Where it used to be recommended to give 100% oxygen to newborns, it's now recommended to give 21-40% due to studies showing giving newborns too much oxygen was linked to cancer later in life, among other consequences.