Table 1.

Patient characteristics and EEG findings with respect to 28-day survival

Variable	All patients (n = 118)	28-day survivors (n = 56)	28-day non-survivors (n = 62)	p value
At ICU admission
Age, years	58 [48; 66]	54 [40; 61]	61 [51; 68]	< 0.001
Male gender	80 (67.8%)	36 (64.3%)	44 (71%)	0.554
BMI	25.3 [23.1; 30.2]	25.1 [23.3; 30.7]	26 [22.7; 29.7]	0.757
Pre-hospital Rankin score	1 [0; 2]	2 [0; 2]	1 [0; 2]	0.518
Charlson score	2 [0; 3]	1 [0; 2.5]	2 [1; 3]	0.075
SAPS II	57 [43; 74.5]	54 [35; 68]	60 [44.75; 78]	0.08
Pre-ECMO cardiac arrest	35 (29.7%)	15 (26.8%)	20 (32.3%)	0.55
SOFA score at ICU admission	11 [8; 13]	10 [8; 13]	11 [9; 14]	0.211
SOFA score at time of ECMO cannulation	12 [10; 15]	12 [9; 13.5]	13 [11; 15]	0.05
At time of EEG recording
Temperature, °C	36.7 [36.2; 37]	36.8 [36.2; 37.2]	36.7 [36.2; 37]	0.359
Catecholamine infusion	107 (90.7%)	53 (94.6%)	54 (87.1%)	0.211
Neuromuscular blockade	25 (21.2%)	13 (23.2%)	12 (19.4%)	0.656
Sedation	106 (89.8%)	50 (89.3%)	56 (90.3%)	0.999
Midazolam, mg/h	5 [2; 5]	4 [0; 6]	5 [2.75; 5]	0.846
Morphine, mg/h	4 [0; 5]	4 [0; 5]	4 [0; 5]	0.474
stdEEG findings
Reactivity	109 (92.4%)	54 (96.4%)	55 (88.7%)	0.167
Continuity	88 (74.6%)	49 (87.5%)	39 (62.9%)	0.002
Background rhythm (Hz)	6 [6; 7]	7 [6; 8]	6 [6; 7]	0.003
Synek score	2 [2; 5]	2 [1; 2]	2 [2; 5]	< 0.001
4-frontEEG
Reactivity	106 (89.8%)	53 (94.6%)	53 (85.5%)	0.131
Continuity	88 (74.6%)	50 (89.3%)	38 (61.3%)	< 0.001
Background rhythm (Hz)	7 [5; 8]	7 [6; 8]	6 [5; 7]	0.012
Synek score	2 [2; 5]	2 [1; 2]	3 [2; 5]	< 0.001

The Synek score ranges from 1 to 5, with higher scores indicating more severe encephalopathy

Data are presented as median (interquartile range) or numbers (percentages)

ICU: intensive care unit; BMI: body mass index; SAPS: Simplified Acute Physiology Score; SOFA: Sequential Organ Failure Assessment; EEG: electroencephalography; _stdEEG: 21-electrode montage; _4-frontEEG: 4-electrode montage