Date	Event	Description
5 February 2016	New citation required and conclusions have changed	We reran the search to June 2015. We included five new RCTs in this updated review (Han 2012; Hua 2013; Jain 2010; Levy 2011; Svoboda 2012). We updated all existing analyses, tables and figures for the newly included studies and for the new features of RevMan 5.3. Shortly before submission of the current update, we identified other studies that might be suitable for inclusion. These studies are listed under Studies awaiting classification
5 February 2016	New search has been performed	We included a network meta‐analysis A new author, Nathan Pace, joined the review team. Gunnar Gamper took the lead for this update
5 April 2011	New search has been performed	In this updated systematic review we reorganized all analyses and present new analyses for all comparisons and sensitivity analyses, 'Risk of bias' tables, and a 'Summary of findings' table.
5 April 2011	New citation required and conclusions have changed	This review is an update of the previous Cochrane systematic review (Müllner 2004) that included eight RCTs and excluded nine studies. In the previous version we searched the databases until November 2003. In this updated version we reran the searches to March 2010. This updated version contains 15 new RCTs (Albanese 2005: Annane 2007; Choong 2009; De Backer 2010; Lauzier 2006; Luckner 2006; Mathur 2007; Morelli 2008a; Morelli 2008b; Morelli 2009; Myburgh 2008; Patel 2010; Russell 2008; Seguin 2006; Yildizdas 2008;) and two new excluded studies (Sperry 2008; Schmoelz 2006) and three new ongoing studies (Cohn 2007a; Fernandez 2006; Lienhart 2007). These new studies changed the conclusion of our review, in particular for the comparison of norepinephrine versus dopamine. Change in authors: Bernhard Urbanek (co‐author Müllner 2004) has left the review team. A new author (Jasmin Arrich) has joined the review team of this updated version.
7 August 2008	Amended	Minor edit to text
1 August 2008	Amended	Converted to new review format.