Three broad classifications of acute respiratory failure etiologies based on regional ventilation and perfusion by electrical impedance tomography: a hypothesis-generating study

Annals of Intensive Care

Table 2 Comparisons of EIT-related parameters in four groups

Variables	Control group n = 15	PED group n = 14	DLD group n = 21	FLD group n = 58	ANOVA-P value (Kruskal–Wallis test)
UR-ventilation (%)	31 ± 7	25 (16, 37)	29 (24, 34)	36 (23, 44)	0.088
UL-ventilation (%)	29 ± 9	24 (15, 33)	23 (19, 29)	28 (19, 39)^b	0.206
LR-ventilation (%)	22 ± 10	23 (19, 31)	23 (19, 29)	18 (10, 26)	0.041
LL-ventilation (%)	17 ± 6	28 (19, 30)	22 (16, 25)	18 (8, 25)^b	0.010
UR-perfusion (%)	24 (19, 30)	20 (9, 34)	23 ± 6	26 ± 11	0.271
UL-perfusion (%)	27 ± 5	22 (17, 27)	26 (21, 30)	27 (21, 33)	0.200
LR-perfusion (%)	22 (21, 27)	18 (8, 30)	25 (21, 29)	21 (15, 27)	0.147
LL-perfusion (%)	22 (21, 30)	37 (26, 42)	22 (19, 27)	22 (17, 29)^b	0.015
UR-V/Q (%)	1.3 (1.1, 1.5)	1.3 (0.9, 1.7)	1.2 (1.0, 1.5)	1.2 (1, 1.7)	0.978
UL-V/Q (%)	1.1 (0.8, 1.3)	0.9 (0.5, 1.8)	1.0 (0.7, 1.2)	1.1 (0.8, 1.3)	0.795
LR-V/Q (%)	0.9 (0.7, 1.1)	1.5 (1.0, 2.6)	1.1 (0.9, 1.2)	0.8 (0.6, 1.1)^b	0.09
LL-V/Q (%)	0.6 (0.7, 0.8)	0.8 (0.6, 1.0)	0.7 (0.7, 1.1)	0.7 (0.4, 1.0)	0.250
VQ Match_%	72 (65, 80)	51 (36, 58)^a	66 (62, 75)^b	63 (47, 73)^a	< 0.0001
DeadSpace_%	12 (7, 17)	40 (30, 54)^a	18 (14, 27)^b	14 (8, 23)^b	< 0.0001
Shunt_%	12 (8, 19)	9 (5, 12)	13 (5, 20)	20 (8, 33)^b	0.015
Defect_V score	0 (0, 1)	1 (0, 1)	0 (0, 0.5)	2 (1, 3)^{a, b, c}	< 0.0001
Defect_Q score	0 (0, 0)	1 (1, 2)^a	0 (0, 0)^b	0 (0, 1)^{a, b, c}	< 0.0001
Defect_V+Q score	0 (0, 1)	2.5 (2, 4)^a	0 (0, 1)^b	3 (1, 4)^{a, c}	< 0.0001

The control group was postoperative ICU patients without acute respiratory failure; PED group: patients with pulmonary embolism-related disease; DLD group: patients with diffuse lung involvement disease; FLD group: patients with focal lung involvement disease. Normally distributed results are presented as mean ± SD, whereas non-normally distributed results are presented as median (25th, 75th percentile)
UR: upper right; UL: upper left; LR: lower right; LL: lower left; V/Q (%): relative regional ventilation/corresponding regional perfusion, both in percentage
^aP < 0.05 vs. control group (adjusted with the Bonferroni correction for multiple test)
^bP < 0.05 vs. PED group (adjusted with the Bonferroni correction for multiple test)
^cP < 0.05 vs. DLD group (adjusted with the Bonferroni correction for multiple test)