Using initial serum lactate level in the emergency department to predict the sustained return of spontaneous circulation in nontraumatic out-ofhospital cardiac arrest patients

Figures & data

Table 1 Demographic and baseline characteristics of study patients

Variables	All patients (n=207)	Survival to hospital discharge (n=85)	Nonsurvivors (n=122)	P-value
Age, year, median (IQR)	66 (53–79)	69 (55–79)	66 (52–78)	0.416
Sex, n (%)				0.467
Male	141 (68.1)	55 (64.7)	86 (70.5)
Female	66 (31.9)	30 (35.3)	36 (29.5)
Comorbidities, n (%)				0.009
Yes	151 (72.9)	69 (81.2)	82 (67.2)
No	13 (6.3)	7 (8.2)	6 (4.9)
Unknown	43 (20.8)	9 (10.6)	34 (27.9)
Metabolic syndrome	91 (60.3)	37 (53.6)	54 (65.9)	0.173
Cardiovascular disease	46 (30.5)	24 (34.8)	22 (26.8)	0.379
Noncardiovascular disease	100 (66.2)	48 (69.6)	52 (63.4)	0.533
Locations of cardiac arrest, n (%)				<0.001
Home	152 (73.4)	51 (60)	101 (82.8)
Public area	55 (26.6)	34 (40)	21 (17.2)
Collapse witnesses				<0.001
Unwitnessed	131 (63.3)	41 (48.2)	90 (73.8)
Witness	76 (36.7)	44 (51.8)	32 (26.2)
CPR team, n (%)				1.000
Bystander	29 (14)	12 (14.1)	17 (13.9)
No bystander cPR	178 (86)	73 (85.9)	105 (86.1)
Initial cardiac rhythm, n (%)				0.243
Nonshockable rhythm	183 (88.4)	72 (84.7)	111 (91)
Shockable rhythm	24 (11.6)	13 (15.3)	11 (9)
Initial lactate value recorded, mean ± SD	12.4±4.9	12±4.8	12.6±5	0.381

Note: Data are presented as n (%) unless indicated otherwise.

Abbreviations: CPR, cardiopulmonary resuscitation; IQR, interquartile range.

Figure 1 The study flow diagram.

Note: The result of CPR was sustained ROSC.
Abbreviations: CPR, cardiopulmonary resuscitation; ROSC, return of spontaneous circulation.

Table 2 Serum lactate level and outcome

Outcome	N (%)	Lactate level Mean ± SD	P-value
rosc			0.381
rosc	85 (41)	12.0±4.8
Non-ROSC	122 (59)	12.6±5.0
24-hour mortality			0.031
Survivor	52 (25.1)	11.1 ±4.2
Nonsurvivor	155 (74.9)	12.8±5.1
48-hour mortality			0.049
Survivor	48 (23.2)	11.2±4.3
Nonsurvivor	159 (76.8)	12.7±5.1
Neurological outcome			0.553
CPC 1-2	6 (54.5)	11.2±4.6
CPC 3-5	5 (45.5)	9.7±3.1

Abbreviations: CPC, cerebral performance category; ROSC, return of spontaneous circulation.

Table 3 Best cut-off point of serum lactate level and prediction of outcome

Outcome	Cut-off point serum lactate level (mmol/L)	Sensitivity (%)	Specificity (%)	AUC	OR 95% CI	P-value
ROSC	6.2	80	32	0.54	0.97 (0.97, 1.03)	0.378
24-hour in mortality	9.1	63	54	0.60	0.93 (0.87, 0.99)	0.028
48-hour in mortality	9.4	57	61	0.59	0.93 (0.87, 1.00)	0.046

Note: Association of initial lactate value with sustained ROSC.

Abbreviations: AUC, area under the curve; CI, confidence interval; OR, odds ratio; ROSC, return of spontaneous circulation.

Table 4 Multivariate analysis of risk factors association with ROSC using unadjusted and adjusted logistic regression

Characteristic	Unadjusted analysis			Adjusted analysis
	OR	95% CI	P-value	OR	95% CI	P-value
Age, year	1.007	(0.99, 1.02)	0.413
Sex					-
Male	1
Female	1.3	(0.72, 2.35)	0.381		-
Comorbidity
Yes	1			1
No	1.39	(0.44, 4.32)		1.71	(0.51, 5.71)
Unknown	0.31	(0.14, 0.70)	0.007	0.34	(0.15, 0.79)	0.014
Locations of cardiac arrest
At home	1			1
Public area	3.21	(1.69, 6.08)	<0.001	2.4	(1.2, 4.79)	0.013
Collapse witnessed
Unwitnessed	1			1
Witnessed	3.02	(1.68, 5.42)	0.011	2.39	(1.26, 4.52)	0.008
CPR team
Bystander	1
No bystander CPR	0.98	(0.44, 2.19)	0.97		-
Initial cardiac rhythm
Nonshockable rhythm	1
Shockable rhythm	1.82	(0.77, 4.29)	0.277		-
Initial lactate value recorded, mean	0.97	(0.92, 1.03)	0.378
Initial lactate level
≥6.2 mmol/L	1			1
<6.2 mmol/L	0.67	(0.26, 1.77)	0.423	0.62	(0.22, 1.77)	0.374

Abbreviations: CI, confidence interval; CPR, cardiopulmonary resuscitation; OR, odds ratio; ROSC, return of spontaneous circulation.

Table 5 Sustained ROSC prediction score developed by the coefficient of logistic regression model

Variable	Coefficient	Coefficient 4	Score
Comorbidity
Yes	Ref		0
No	0.53	2.12	2
Unknown	-1.07	-4.20	-4
Location of cardiac arrest
Home	Ref		0
Public area	0.87	3.48	3.5
Unwitnessed collapse	Ref		0
Witnessed collapse	0.87	3.48	3.5
Serum lactate level
(mmol/L)
≥6.2	Ref		0
<6.2	0.47	1.88	2

Note: Coefficients from multivariable logistic regression; Ref: reference category.

Abbreviation: ROSC, return of spontaneous circulation.

Figure 2 ROC curve of cut off point score for predicted sustained ROSC.

Abbreviations: AUC, area under the curve; ROC, receiver operating characteristic; ROSC, return of spontaneous circulation.