T h e ne w e ngl a nd jou r na l o f m e dicine n engl j med 369;23 nejm.org december 5, 2013

No abstract

No abstract

No abstract

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2015 and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/annualupdate2015. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.