4. Number of red cell transfusions and number of red cell units.

Study	Intervention	Number of participants in each arm	Number of red cell transfusions/participant	Comparison statistics	P value	Number of red cell units transfused/participant	Comparison statistics	P value
Short‐term follow‐up (up to 30 days)
Diedrich 2005	< 10 x 109/L	79	Median 4; range 0 to 26	Not reported	Not significant	Not reported	Not reported	Not reported
	< 30 x 109/L	87	Median 4; range 0 to 31			Not reported	Not reported
Heckman 1997	≤ 10 x 109/L	37	Mean 12.2 ± SD 6.9*	MD 1.50, 95% CI ‐1.22 to 4.22*	Not reported	Not reported	Not reported	Not reported
	≤ 20 x 109/L	41	Mean 10.7 ± SD 5.1*			Not reported	Not reported
Rebulla 1997	< 10 x 109/L	135	Mean 9.57 ± SD 5.18	MD 0.50, 95% CI ‐0.70 to 1.70*	Not reported	Not reported	Not reported	Not reported
	< 20 x 109/L	120	Mean 9.07 ± SD 4.58			Not reported	Not reported

*unpublished data provided by the author. The paper provided medians and ranges median 11 (8 to 14) for the standard‐trigger arm and median 10 (6 to 14) for the higher‐trigger arm (P = 0.41).

CI = confidence interval

MD = mean difference

SD = standard deviation