Prognostic factors associated with hospital survival in comatose survivors of cardiac arrest

Table 1 Demographics, cardiac arrest details and management of included patients

Variable	All patients n = 582
Patient
Age (yr) - mean (SD) (n = 581)	63 (16)
Gender (male) - n (%) (n = 579)	361 (62)
Cardiac arrest
Time to ROSC (min) - mean (SD) (n = 571)	23 (15)
Presenting rhythm (shockable) - n (%) (n = 582)	286 (49)
Location of arrest (OHCA) - n (%) (n = 582)	408 (70)
Apache 2 score - mean (SD) (n = 427)	28 (8.4)
Apache 3 score - mean (SD) (n = 427)	78 (37.8)
Management
Cooled - n (%) (n = 582)	295 (51)
Target temperature (°C) - median (IQR) (n = 290)	33 (33-33)
Time to temp1 (h) - mean (SD) (n = 288)	2.1 (3.0)
Time at temp2 (h) - median (IQR) (n = 290)	24 (12-24)
Outcome
Survived to hospital discharge - n (%) (n = 582)	206 (35)
ICU LOS (d) - median (IQR) (n = 582)	3 (1-5)
Hospital LOS (d) - median (IQR) (n = 581)	5 (2-14)

¹Time to temp = time taken to reach target temperature (hours);

²Time at temp = time at target temperature (hours). LOS: Length of stay (days); ROSC: Return of spontaneous circulation (minutes); OHCA: Out of hospital cardiac arrest; IQR: Interquartile range.

Table 2 Comparison of survivors and non-survivors

Variable	Died n = 376 (65%)	Survived n = 206 (35%)	P value
Patient
Age (yr) - mean (SD) (n = 581)	64 (17)	63 (15)	0.28
Gender (male) - n (%) (n = 579)	218 (58)	143 (70)	0.006
Cardiac arrest
Time to ROSC (min) - mean (SD) (n = 571)	26 (14.5)	18 (14.3)	< 0.001
Presenting rhythm (shockable) - n (%) (n = 582)	134 (36)	152 (72)	< 0.001
Location of arrest (OHCA) - n (%) (n = 582)	269 (72)	139 (67)	0.3
Apache 2 score - mean (SD) (n = 427)	30 (7.6)	24 (8.5)	< 0.001
Apache 3 score - mean (SD) (n = 427)	79 (37.9)	77 (37.8)	0.5
Management
Cooled - n (%) (n = 582)	178 (47)	117 (57)	0.03
Target temperature (°C) - median ( IQR) (n = 290)	33 (33-33)	33 (33-33)	0.44
Time to temp1 (h) - mean (SD) (n = 288)	1.8 (2.9)	2.5 (3.1)	0.04
Time at temp2 (h) - median (IQR) (n = 290)	24 (12-24)	24 (12-24)	0.84
Outcome
ICU LOS (d) - median (IQR) (n = 582)	2 (1- 4)	4 (2-7)	< 0.001
Hospital LOS (d) - median (IQR) (n = 581)	3 (1-6)	15 (8-27)	< 0.001

¹Time to temp = time taken to reach target temperature (hours);

²Time at temp = time at target temperature (hours). LOS: Length of stay (days); ROSC: Return of spontaneous circulation (minutes); OHCA: Out of hospital cardiac arrest; IQR: Interquartile range.

Table 3 Comparison of patients before and after 2002

Variable	1993-2002 n = 257 (44%)	2003-2012 n = 325 (56%)	P value
Patient
Age (yr) - mean (SD) (n = 581)	65 (15)	62 (16)	0.04
Gender (male) - n (%) (n = 579)	161 (63)	200 (62)	0.73
Cardiac arrest
Time to ROSC (min) - mean (SD) (n = 571)	21 (14)	24 (15)	0.02
Presenting rhythm (shockable) - n (%) (n = 582)	151 (59)	135 (42)	< 0.001
Location of arrest (OHCA) - n (%) (n = 582)	165 (64)	243 (75)	0.006
Apache 2 score - mean (SD) (n = 427)	26 (8.3)	29 (8.3)	0.007
Apache 3 score - mean (SD) (n = 427)	75 (35.9)	79 (38.2)	0.23
Management
Cooled - n (%) (n = 582)	73 (28)	222 (68)	< 0.001
Target temperature (°C) - median (IQR) (n = 290)	33 (33-33)	33 (33-33)	0.62
Time to temp1 (h) - mean (SD) (n = 288)	1.3 (2.2)	2.4 (3.2)	0.04
Time at temp2 (h) - median (IQR) (n = 290)	12 (12-24)	24 (12-24)	0.56
Outcome
Survived to hospital discharge - n (%) (n = 582)	99 (38)	107 (33)	0.16
ICU LOS (d) - median (IQR) (n = 582)	2 (1-4)	3 (1-6)	0.008
Hospital LOS (d) - median (IQR) (n = 581)	6 (2-15)	4 (2-13)	0.18

¹Time to temp = time taken to reach target temperature (hours);

²Time at temp = time at target temperature (hours). LOS: Length of stay (days); ROSC: Return of spontaneous circulation (minutes); OHCA: Out of hospital cardiac arrest; IQR: Interquartile range.

Table 4 Final model of logistic regression analysis

Variables	B	SE	Wald	df	Sig.	OR	95%CI
							Lower	Upper
ROSC	-0.048	0.009	27.588	1	0.000	0.953	0.937	0.971
Shockable rhythm	1.860	0.248	56.222	1	0.000	6.422	3.949	10.441
APACHE II	-0.001	0.003	0.156	1	0.693	0.999	0.993	1.005
Therapeutic hypothermia	0.088	0.248	0.126	1	0.722	1.092	0.672	1.775
Gender	-0.456	0.247	3.388	1	0.066	0.634	0.390	1.030
Constant	-0.210	0.410	0.263	1	0.608	0.810

ROSC: Time to return of spontaneous circulation.