2.

使用机械通气与未使用机械通气患者单因素分析结果

The univariate analysis of risk factors between mechanical ventilation group and without mechanical ventilation group

Variable	Mechanical ventilation (n=62)	Non-mechanical ventilation (n=50)	P
Abbreviations as in Table 1.
Age/years, x±s	50±16	49±12	0.716
Gender, n			0.578
Male	44	38
Female	18	12
ISS, median (P25, P75)	34 (26, 41)	22 (18, 29)	< 0.001
GCS, median (P25, P75)	11 (3, 15)	15 (13, 15)	< 0.001
AIS, median (P25, P75)
Head and neck	4 (2, 6)	3 (1, 4)	0.083
Thorax	6 (3, 8)	4 (1, 5)	0.010
Abdomen	2 (0, 4)	0 (0, 2)	0.001
Extremities and pelvis	2 (0, 4)	1 (0, 2)	0.087
Rib fracture, n (%)	5 (1, 8)	0 (0, 5)	0.009
Volume of pulmonary contusion≥20%, n (%)	28 (45.2)	8 (16.0)	0.040
Hydrothorax, n (%)	46 (74.2)	22 (44.0)	0.008
Pneumothorax, n (%)	22 (35.4)	12 (24.0)	0.558
Lactic acid/(mmol/L)，median (P25, P75)	3.5 (1.5, 5.2)	0.9 (1.2, 2.1)	0.001
Base excess/(mmol/L)，median (P25, P75)	-5.2 (-3.75, -7.55)	-1.28 (-3.57, 0.87)	< 0.001
Length of hospital stay/d, median (P25, P75)	20 (15, 31)	15 (9, 22)	< 0.001