Not every research question can be answered by a randomized controlled trial. Often they are not feasible or ethical and out of necessity other study designs are utilized. I like this clever little study investigating whether one can use an intraosseous line for induction of anaesthesia.
Where else would you conduct this study other than Afghanistan? This was a prospective observational study of previously healthy young patients (mostly soldiers) who had just suffered severe trauma. Upon presentation to a British combat hospital, 34 patients underwent RSI using an IO line.
These patients were quite sick with a median injury severity score of 25. As expected, the predominant mechanism of injury was blast.
First pass intubation success rate was 97% (95% CI 81%-100%) with mostly great visualization of the cords.
One could reasonably argue that this study has some limitations. The numbers were small. Mostly young previously healthy soldiers would make external validity an issue. Perhaps they were looking at the wrong primary outcomes and they should have focused on time to intubation and/or relaxation.
But given the big picture, I think they put in a decent effort. Research on resuscitation is always challenging and getting numbers is hard. How many IO lines have you put in? Most health care practitioners would have other priorities when caring for a very sick patient (who has just been blown up) rather than focusing attention on ticking boxes on a study form. In the end, I think their outcome measures were quite pragmatic.
Sure, this study is not definitive evidence but I think it is enough to suggest the efficacy of the IO route for rapid sequence induction.
Barnard EBG, Moy, RJ, Kehoe AD, et al. Rapid sequence induction of anaesthesia via the intraosseous route: a prospective observational study. Emerg Med J. 2014 Jun 24. pii: emermed-2014-203740. doi: 10.1136/emermed-2014-203740. [Epub ahead of print]