Table 2. Summary statistics: numeric variables.

Variable		Normal ventilation (n=1,540)			Prolonged ventilation (n=77)
Name	Units	Mean	Median	S.D.	Mean	Median	S.D.
Pre-operative
Age	years	30.29	27.00	13.95	39.50	41.00	21.28
Height	cm	156.69	158.00	15.83	161.10	160.00	90.99
Weight	kg	48.94	48.00	14.83	55.90	52.50	16.62
Body mass index		19.61	18.39	4.61	21.63	19.53	6.88
Hemoglobin	mg/dL	12.09	12.00	1.82	10.85	10.50	1.95
Serum creatinine	mg/dL	0.90	0.80	0.74	1.12	1.00	0.28
Ejection fraction	%	58.89	60.00	8.77	55.10	60.00	13.92
LVIDD	mm	49.57	48.00	17.62	52.30	50.00	11.16
LVIDS	mm	34.54	33.50	10.84	36.70	37.00	7.69
Parsonnet score		5.99	6.00	4.79	14.20	8.80	16.42
Log-EuroScore		3.13	3.13	1.99	5.59	3.30	5.40
Operative
Bypass time	min	86.87	81.50	33.62	119.40	101.50	41.75
Cross clamp time	min	61.35	58.00	28.95	68.20	70.50	37.38
Post-operative
Ventilation time	hours	5.36	4.00	4.01	143.40	91.00	147.37
ICU stay	hours	36.84	30.00	22.31	227.00	120.00	250.04
Inotropic support	hours	15.38	6.00	24.13	141.90	107.00	124.57
Chest drainage	mL	642.35	500.00	485.33	1121.00	905.00	767.22