Date	Event	Description
16 December 2021	New search has been performed	The review has been updated to 16 November 2020. Two new review authors joined the team: Marialena Trivella in November 2020, and Jane Dennis in July 2021.
16 December 2021	New citation required and conclusions have changed	Update of 2016 review; 17 new trials are included. We added six‐month (long‐term) mortality as an outcome and clarified the outcome "blood transfusion as a measure of implementation".
13 November 2017	New search has been performed	We updated the search ‐ the review was published elsewhere.
27 May 2016	New citation required and conclusions have changed	The conclusions of the review changed; the search date is now 27 May 2016.
26 May 2016	New search has been performed	We made the following changes • We added 16 new trials • We used 30‐day mortality as the primary outcome because mortality is a more clinically relevant outcome and the number of participants enrolled in the trials provided sufficient power to examine this outcome • We added sensitivity analyses to evaluate heterogeneity for transfusion outcomes between trials • We made changes to the author line
20 December 2011	New citation required and conclusions have changed	We updated searches to February 2011. We included data from two new trials and amended the results accordingly. We identified one trial through the updated search; the other was previously included as an ongoing trial, and the results became available recently. We updated the Background section of the review. The overall conclusions of the review remain similar, but we have extended the clinical specialties for which the results can be generalised. As part of this update, we replaced the assessment of methodological quality used in earlier versions of this review with an assessment of risk of bias. This amendment is in accordance with a change in Cochrane's methodological guidance. The authors of the review have changed.
1 February 2011	New search has been performed	We updated the search for studies to February 2011.
9 September 2008	Amended	We converted the review to new review format.
17 November 2004	New search has been performed	We conducted an updated search for new trials in November 2004. We identified no new trials eligible for inclusion.