Table 2.

Associations between Various Risk Factors and Case versus Control Status

Risk Factor	Case (n = 83)	Controls (n = 163)	OR	(95% CI)
Cardiac
History of congestive heart failure (n)	29	13	4.1	(1.68–10.1)
NYHA class 4 congestive heart failure (n)	6	2	13.9	(2.6–74.0)
History of coronary disease (n)	34	29	2.6	(1.23–5.6)
Atrial fibrillation (n)	20	13	2.9	(1.11–7.8)
History bypass surgery (n)	38	11	13.4	(3.2–57.0)
Amiodarone use (n)	12	3	4.0	(0.87–18.6)
Aspirin use (n)	40	41	2.1	(1.04–4.3)
Surgery and ICU
Surgery before transfusion-associated circulatory overload (n)	63	81	3.2	(1.59–6.6)
Duration of surgery (h)	5.1	2.5	1.28	(1.16–1.41)
Cardiac surgery (n)	41	14	10.2	(3.2–32.0)
Vascular surgery (n)	6	5	6.6	(1.17–38.0)
Liver surgery (n)	4	5	7.5	(1.31–43.0)
Mechanical ventilation (n)*	62	79	3.7	(1.83–7.6)
Duration of ventilation (h)*	10.9	4.6	1.02	(1.00–1.03)
Peak airway pressure (mm Hg)†	28.6	25.0	1.1||	(1.01–1.26)
PaO2/FiO2 ratio*	320	390	0.9||	(0.87–0.99)
Volume status
On hemodialysis (n)	14	14	3.3	(1.25–8.4)
Chronic renal disease (n)	15	14	3.2	(0.99–10.4)
Hemorrhagic shock (n)†	7	1	31	(3.1–311)
Other types shock (n)†	25	29	3.6	(1.26–10.2)
Body weight (kg)	74.4	77.5	0.98	(0.96–1.00)
Estimated blood volume (L)‡	3.83	4.25	0.52	(0.33–0.83)
Blood products transfused (units)*	6.3	6.0	1.23	(1.17–1.3)
Fluid balance (L)*§	+4.77	+2.75	1.18	(1.08–1.28)
Fluid balance/hour (L)*§	+0.38	+0.26	3.6	(1.52–8.5)
Central venous pressure* (mm Hg)	13.3	9.7	1.19	(1.04–1.36)
Pulmonary artery diastolic pressure* (mm Hg)	19.9	16.7	1.57	(1.01–2.5)

ICU = intensive care unit; NYHA = New York Heart Association.

Counts (n) are given for binary variables and means for numeric variables, with units as indicated. Odds ratios (ORs) and 95% confidence intervals (CI) adjusted only for center and transfusion intensity.

^*Before onset of edema.

^†Before transfusion.

^‡Nadler formula.

^§Fluid intake minus urine output, in Liters, total and hourly average over previous 24 hours.

^||Odds ratio per 10 units.