Establishment of a prediction model for prehospital return of spontaneous circulation in out-of-hospital patients with cardiac arrest

Table 1 Characteristics of the patients with out-of-hospital cardiac arrest

Features	Patients			P value
	Total (n = 2685)	ROSC failure (n = 2529)	ROSC (n = 156)
Gender				0.730
Female	668 (24.9)	631 (25.0)	37 (23.7)
Male	2017 (75.1)	1898 (75.0)	119 (76.3)
Age	56.18 ± 17.98	56.63 ± 17.96	49.01 ± 16.82	< 0.001
Season				0.570
Spring	636 (23.7)	599 (23.7)	37 (23.7)
Summer	625 (23.3)	582 (23.0)	43 (27.6)
Autumn	666 (24.8)	632 (25.0)	34 (21.8)
Winter	758 (28.2)	716 (28.3)	42 (26.9)
Time (min)				0.029
08-16	953 (35.5)	888 (35.1)	65 (41.7)
16-24	1049 (39.1)	984 (38.9)	65 (41.7)
00-08	683 (25.4)	657 (26.0)	26 (16.7)
Bystander CPR				< 0.001
No	2246 (83.6)	2135 (84.4)	111 (71.2)
Yes	439 (16.4)	394 (15.6)	45 (28.8)
Initial rhythm				< 0.001
VF/VT	293 (10.9)	232 (9.2)	61 (39.1)
Asystole/PEA	2358 (87.8)	2278 (90.1)	80 (51.3)
Ag ECG (slow ventricular escape, bradycardia)	34 (1.3)	19 (0.8)	15 (9.6)
Duration of CPR	35 (15.0)	38 (18.0)	10 (16.0)	< 0.001
ETI				< 0.001
No	2194 (81.7)	2104 (83.2)	90 (57.7)
Yes	491 (18.3)	425 (16.8)	66 (42.3)
DF				< 0.001
No	2000 (74.5)	1914 (75.7)	86 (55.1)
Yes	685 (25.5)	615 (24.3)	70 (44.9)
Epinephrine dose	3 (3.0)	3 (3.0)	3 (2.0)	< 0.001
Atropine				0.243
No	2081 (77.5)	1966 (77.7)	130 (83.3)
Yes	604 (22.5)	563 (22.3)	26 (16.7)
Lidocaine or amiodarone				< 0.001
No	2556 (95.2)	2426 (95.9)	135 (86.5)
Yes	129 (4.8)	103 (4.1)	21 (13.5)
Etiology				0.019
Cardiac	1430 (53.3)	1327 (52.5)	103 (66.0)
Trauma	122 (4.5)	116 (4.6)	6 (3.8)
Toxicosis or asphyxia	45 (1.7)	44 (1.7)	1 (0.6)
Brain and nervous	64 (2.4)	60 (2.4)	4 (2.6)
Unknow and other	1024 (38.1)	982 (38.8)	42 (26.9)

VF: Ventricular fibrillation; VT: Ventricular tachycardia; PEA: Pulseless electrical activity; Ag ECG: Agonal electrocardiogram; CPR: Cardiopulmonary resuscitation; ETI: Endotracheal intubation; DF: Defibrillation.