Table 3.

Relationship Between Center Volume and Odds of Mechanical Ventilation After Cardiac Surgery

Center Volume	Unadjusted		Adjusted
	OR (95% CI)	P Value	OR (95% CI)	P Value
Volume as a continuous variablea	1.20 (1.12–1.29)	<0.001	0.68 (0.59–0.80)	<0.001
Volume as a categorical variable
<175	1.26 (1.14–1.39)	<0.001	2.68 (2.15–3.35)	<0.001
175–275	1.78 (1.60–1.98)	<0.001	1.31 (1.12–1.52)	<0.001
≥275	Ref		Ref
STS‐EACTS risk categories 1–3
Volume as a continuous variablea	1.08 (0.99–1.18)	0.067	0.65 (0.54–0.78)	<0.001
Volume as a categorical variable
<175	1.57 (1.40–1.76)	<0.001	3.12 (2.40–4.06)	<0.001
175–275	2.18 (1.92–2.47)	<0.001	1.43 (1.19–1.71)	<0.001
≥275	Ref		Ref
STS‐EACTS risk categories 4–5
Volume as a continuous variablea	1.32 (1.09–1.61)	0.005	0.93 (0.68–1.28)	0.66
Volume as a categorical variable
<175	0.90 (0.70–1.15)	0.41	1.35 (0.86–2.14)	0.19
175–275	1.16 (0.90–1.49)	0.26	0.89 (0.65–1.22)	0.46
≥275	Ref		Ref

Abbreviations: CI, confidence interval; OR, odds ratio; Ref, reference; STS‐EACTS, Society of Thoracic Surgeons–European Association for Cardiothoracic Surgery.

^aVolume as a continuous variable depicts comparison of high center volume vs low center volume.