To delineate the reference range and variability of electrical impedance tomography (EIT) lung ventilation parameters among healthy volunteers.

Seventy-five volunteers were enrolled, and their EIT data were analyzed. Various EIT-based parameters were computed, including ventilation distribution in regions of interest (ROIs) of layers from ventral to dorsal (ROI 1, ROI 2, ROI 3, ROI 4) or quadrants (ROI_{upper left}, ROI_{upper right}, ROI_{lower left}, ROI_{lower right}), center of ventilation (CoV), anterior-posterior ventilation ratio (A/P ratio), global inhomogeneity index (GI), standard deviation of regional ventilation delay (RVDSD) and amplitude of pendelluft (AP). The 95% reference interval for normally distributed parameters were determined by mean ± 1.96 standard deviations, while the 2.5th and 97.5th percentiles were employed for non-normally distributed parameters.

The established reference ranges for the parameters were as follows: ROI 1: 5.52-16.42, ROI 2: 31.20-50.56, ROI 3: 28.40-52.78, ROI 4: 3.45-11.77, ROI_{upper left}: 15.13-36.21, ROI _{upper right}: 18.56-33.34, ROI _{lower left}: 15.56-30.30, ROI_{lower right}: 16.52-34.36, ROI _left: 47.38-49.82, ROI_right: 50.18-52.59, CoV: 43.16-53.24, A/P ratio: 35.66-60.74, GI: 0.27-0.45, RVD_SD: 2.30-8.66, A_P: 0.21-4.93. CoV had low dispersion with coefficient of variation (CV) of 0.05, while ROI 1 (CV =0.25), ROI 4 (CV =0.28), RVD_SD (CV =0.30), A/P ratio (CV=0.28) and A_P (CV=3.68) had high dispersion. GI (R=0.33, P=0.00), RVD_SD (R=0.31, P=0.00), A_P (R=0.44, P=0.00) showed a significant positive correlation with age. ROI 1 (R=0.23, P=0.04), ROI _{upper right} (R=0.23, P=0.04), RVD_SD (R=0.25, P=0.03), A_P (R=0.25, P=0.03) were significantly positively correlated with BMI. CoV (P<0.01) and ROI 3+4 (P<0.05) in female subjects were remarkably higher than those in male subjects, and male A/P ratio was significantly higher than that in female subjects (P<0.05).

While CoV demonstrated relative stability, variations were observed in regional ventilation distribution, GI and AP within the population. Gender and BMI emerged as influential factors in interpreting EIT ventilation parameters, necessitating consideration in clinical applications.