Table 1 Demographic factors and baseline characteristics of the enrolled patients

rSO₂, median (25^th, 75^th percentiles), % ^b

19 (15, 47)

61 (43, 65)

15 (15, 36)

Hemoglobin, mean (SD), g/dl ^b

12.1 (2.3)

13.9 (2.1)

11.7 (2.2)

Oxy-Hb, median (25^th, 75^th percentiles) ^b

2.3 (1.7, 5.2)

8.3 (5.5, 9.7)

2.2 (1.7, 3.9)

Age, mean (SD), years ^b

68 (16)

59 (14)

69 (15)

Male sex, n (%)^a

330 (66.7)

58 (77.3)

272 (64.8)

Location of cardiac arrest, n (%)^b

Home

261 (52.7)

27 (36.0)

234 (55.7)

Nursing home/Assisted living

48 (9.7)

4 (5.3)

44 (10.5)

Public building

43 (8.7)

14 (18.7)

29 (6.9)

Street

47 (9.5)

12 (16.0)

35 (8.3)

Others

96 (19.4)

18 (24.0)

78 (18.6)

Bystander–witness status, n (%)^b

344 (69.5)

67 (89.3)

277 (66.0)

Type of bystander witness status, n (%)^b

No witness

151 (30.5)

8 (10.7)

143 (34.0)

Family member

177 (35.8)

27 (36.0)

150 (35.7)

EMS

45 (9.1)

8 (10.7)

37 (8.8)

Others

122 (24.6)

32 (42.7)

90 (21.4)

CPR initiated by bystander, n (%)^b

199 (40.2)

47 (62.7)

152 (36.2)

Presumed cardiac etiology, n (%)^b

291 (58.8)

64 (85.3)

227 (54.0)

Initial shockable rhythm, n (%)^b

121 (24.4)

43 (57.3)

78 (18.6)

Pre-hospital procedures by EMS personnel, n (%)

Advanced airway device^a

278 (56.2)

25 (33.3)

253 (60.2)

Use of epinephrine^a

155 (31.3)

13 (17.3)

142 (33.8)

Defibrillation^b

146 (29.5)

50 (66.7)

96 (22.9)

Time from EMS call to hospital arrival, mean (SD), min^b

34.7 (14.5)

30.3 (16.2)

35.5 (14.0)

Achievement of ROSC prior to hospital arrival, n (%)^b

119 (24.0)

55 (73.3)

64 (15.2)

Treatment given after hospital arrival, n (%)

Coronary angiography^b

137 (27.7)

53 (70.7)

84 (20.0)

Primary percutaneous coronary intervention^b

57 (11.5)

20 (26.7)

37 (8.8)

Therapeutic hypothermia^b

187 (37.8)

56 (74.7)

131 (31.2)