Table 1.

Prospective randomized studies on the effect of restrictive versus liberal hemoglobin transfusion triggers

	Study population	Leukoreduction	Storage duration (median), days	RBC transfusion before enrollment
Hébert et al. 1999 [21]	general ICU	no	unknown	2.5 U/patient (restrictive)
	(n = 838)			2.3 U/patient (liberal)
Hajjar et al. 2010 [22]	cardiac surgery	no	3	none
	(n = 502)
Carson et al. 2011 [23]	hip fracture	90%	22	1.8 U/transfused patient (restrictive)
	(n = 2,016)			1.8 U/transfused patient (liberal)
Villanueva et al. 2013 [25]	upper GI bleeding	100%	15	none
	(n = 912)
Walsh et al. 2013 [26]	mechanical ventilation	no	21	71% with a median of 3 U/patient (restrictive)
	(n = 100)			67% with a median of 2 U/patient (liberal)
Robertson et al. 2014 [27]	traumatic brain injury	100%	unknown	none
	(n = 200)
Holst et al. 2014 [28]	septic shock	100%	unknown	10% with a median of 2 U/transfused patient (restrictive)
	(n = 998)			12% with a median of 2 U/transfused patient (liberal)

ICU = Intensive care unit; U= unit; GI = gastrointestinal.