RT Journal Article SR Electronic T1 BET 4 JF Emergency Medicine Journal JO Emerg Med J FD BMJ Publishing Group Ltd and the British Association for Accident & Emergency Medicine SP 954 OP 955 DO 10.1136/emj.2010.104943 VO 27 IS 12 YR 2010 UL http://emj.bmj.com/content/27/12/954.abstract AB