Table 1.

Constant phase parameters

PEEP (cm H2O)	WT	DiNOS	Sftpd−/−
Rn, cm
H20·ml−1·s−1
0	0.532 ± 0.033	0.630 ± 0.024	0.565 ± 0.053
1	0.543 ± 0.074	0.585 ± 0.028	0.592 ± 0.049
3	0.488 ± 0.050	0.583 ± 0.031	0.519 ± 0.031
6	0.430 ± 0.046	0.490 ± 0.016	0.462 ± 0.026
9	0.344 ± 0.026	0.398 ± 0.011	0.400 ± 0.022
H, cm H20/ml
0	44.4 ± 3.2	54.9 ± 1.9*	46.6 ± 4.9 §
1	53.9 ± 3.2	61.9 ± 1.8*	57.3 ± 3.3
3	52.0 ± 2.3	57.3 ± 1.5*	52.1 ± 4.8
6	47.8 ± 2.3	52.1 ± 1.4*	48.2 ± 5.3
9	46.4 ± 3.1	52.9 ± 1.6*	45.7 ± 5.5
G, cm H20/ml
0	7.42 ± 0.67	9.43 ± 0.26*	8.00 ± 0.74 §
1	7.28 ± 0.61	9.38 ± 0.26*	7.62 ± 0.68 §
3	7.36 ± 0.52	8.99 ± 0.29*	7.35 ± 0.79 §
6	7.72 ± 0.47	9.07 ± 0.27*	7.35 ± 0.78 §
9	8.64 ± 0.49	9.85 ± 0.28*	7.68 ± 0.87 §
η (Dimensionless)
0	0.166 ± 0.005	0.172 ± 0.003	0.175 ± 0.016
1	0.136 ± 0.010	0.152 ± 0.003*	0.132 ± 0.006 §
3	0.142 ± 0.008	0.157 ± 0.003*	0.141 ± 0.007 §
6	0.162 ± 0.008	0.174 ± 0.003*	0.153 ± 0.007 §
9	0.187 ± 0.004	0.186 ± 0.002	0.169 ± 0.004 §

Means ± SD of n = 6 independent measurements are shown. PEEP, positive end-expiratory pressure; WT, wild type; DiNOS, NOS2 double knockout; Sftpd^−/−, surfactant protein D deficient; Rn, Newtonian resistance; H, tissue elastance; G, tissue dampening; η, ratio of G and H. Constant-phase model was fitted to forced oscillation perturbation-derived impedance spectra to calculate Rn, H, and η. Measurements were performed during different PEEP ventilations.

^*P < 0.05 DiNOS vs. WT;

^§P < 0.05 Sftpd^−/− vs. DiNOS mice.