TABLE 23.

Group O red blood cell (RBC) units in inventory and group O suppled considered critically low stratified by annual inpatient surgical operations, 2015 and 2017

	Group O RBC units on shelf, average weekday		Group O+ RBC units at which supply considered critically low
Annual inpatient surgical operations	2017 mean (S.D.)	2015 mean (S.D.)	2017 mean (S.D.)	2015 mean (S.D.)
100–999 surgeries per year	12.9 (8.0)	13.3 (8.1)	5.7 (4.3)	5.7 (4.2)
1000–1399 surgeries per year	23.5 (15.3)	22.7 (12.5)	10.8 (8.0)	10.1 (6.7)
1400–2399 surgeries per year	28.8 (15.7)	29.8 (20.2)	13.7 (11.6)	13.7 (10.1)
2400–4999 surgeries per year	45.5 (26.3)	45.7 (32.0)	21.1 (16.1)	20.4 (14.7)
5000–7999 surgeries per year	71.4 (40.1)	70.7 (41.3)	31.9 (21.2)	30.6 (24.6)
>8000 surgeries per year	145.6 (101.9)	135.3 (106.2)	63.4 (52.8)	61.2 (49.8)