Listen here to a shortcut to the answers for these clinical questions:

Ultrarapid intravenous rehydration in children who are dehydrated from viral gastroenteritis: does it work?

http://adc.bmj.com/content/99/9/878.1.full

Humidified heated high flow nasal cannula versus nasal continuous positive airway pressure for providing respiratory support following extubation in preterm newborns

http://adc.bmj.com/content/99/9/880.full

After that, you might want to read about studies which compare some therapy to "standard care":

http://blogs.bmj.com/adc/2014/07/09/compared-to-standard-care/