Table 2.

Perfusion of the left lung.

Variable	Group	TLVsupine		OLVsupine		OLVsemilateral		OLVlateral		OLVprone		Sequence P =	Group P =	Position P =	ME P =
Center of perfusion left-right axis [% from left]	Normo	30.7 ± 5.0	p	28.8 ± 3.6	se, l, p	31.6 ± 2.6	p	31.1 ± 4.2	p	32.8 ± 2.6		0.614	0.695	≤ 0.001	0.368
	Hypo	28.5 ± 4.9		29.0 ± 3.3		29.9 ± 3.5		30.8 ± 3.1		33.4 ± 2.7
Center of perfusion dorsal-ventral axis [% from dorsal]	Normo Hypo	27.5 ± 3.6 27.5 ± 4.4		28.9 ± 3.0 28.3 ± 3.9	sl, l, p	27.1 ± 3.1 27.7 ± 4.1		27.3 ± 2.9 27.5 ± 3.3		27.5 ± 3.0 27.7 ± 3.8		0.673	0.948	0.025	0.627
Center of perfusion caudal-cranial axis [% from caudal]	Normo Hypo	45.4 ± 6.0 42.9 ± 3.7	sl	46.0 ± 5.2 44.2 ± 4.1		46.8 ± 4.6 46.1 ± 4.5		46.1 ± 4.7 45.0 ± 4.0		45.2 ± 3.1 45.3 ± 3.5		0127	0.462	0.048	0.444
CV of relative perfusion %	Normo	157.9 ± 19.1	sl, l, p	154.4 ± 11.2		151.4 ± 15.9		147.2 ± 10.3		139.4 ± 10.4	s, se	0.026	0.075	≤ 0.001	0.104
	Hypo	180.0 ± 24.3		153.4 ± 14.7		152.9 ± 14.9		145.4 ± 8.4		143.8 ± 8.0

Mean ± SD; Normo, normovolemia group; Hypo, hypovolemia group; TLV, two-lung ventilation; OLV, one-lung ventilation; CV, coefficient of variation; ME, mixed effects position × group. Significance was accepted at P < 0.05. The differences between the two groups, respective body positions, and the sequences of interventions were compared using a linear mixed-effects model with repeated measures, with TLVsupine, OLVsupine, OLVsemilateral, OLVlateral, and OLVprone as within-subject factors and with group and sequence as fixed between subject-factors. The significance of the within-subject factors was corrected for sphericity according to Greenhouse–Geisser. Pairwise post-hoc multiple comparisons were performed according to least significant difference (LSD) when appropriate. s P < 0.05 vs. OLVsupine, se P < 0.05 vs. OLVsemilateral, l P < 0.05 vs. OLVlateral, and p P < 0.05 vs. OLVprone.