Measurement of ventilation and cardiac related impedance changes with electrical impedance tomography

Table 1 Phase angle α and slopes for perfused lung quadrants in comparison to ROI_Heart while filtered around the heart rate.

		Phase angle α (degrees)				Slope of linear regression fit
		Ant-R	Ant-L	Post-R	Post-L	Ant-R	Ant-L	Post-R	Post-L
Breath hold period unfiltered	Mean	181	152	180	153	-0.75	-0.53	-0.98	-0.44
	CI	40	55	41	54	0.58	0.23	0.98	0.31
Breath hold period filtered	Mean	159	152	159	157	-0.53	-0.45	-0.58	-0.36
	CI	11	13	11	10	0.15	0.20	0.16	0.15
Spontaneous breathing filtered	Mean	167	159	172	168	-0.50	-0.49	-0.50	-0.37
	CI	7	11	8	7	0.09	0.16	0.10	0.12

All lung quadrants had phase angles close to 180 degrees and negative slopes indicating reversed ΔZ behaviour. Neither filtering of the impedance signal nor respiration impacted on the slopes (P = ns, two-way-ANOVA). Ant L/R, anterior left/right; CI, confidence interval; Post L/R, posterior left/right.

ISSN: 1364-8535