TABLE 2

Change in lung clearance index (LCI) and functional residual capacity (FRC) following modelled pre-capillary expiratory leaks

Size % VTHealthy individualsCystic fibrosis patients
LCI % change (95% CI)FRC % change (95% CI)LCI % change (95% CI)FRC % change (95% CI)
Continuous
 Start10−0.46 (−1.12–0.19)−10.71 (−11.14– −10.28)#−0.20 (−0.45–0.05)−11.10 (−11.68– −10.52)#
20−1.06 (−2.56–0.44)−21.38 (−22.03– −20.73)#−0.42 (−0.97–0.13)−22.16 (−23.23– −21.09)#
50−4.51 (−11.03–2.01)−53.39 (−54.72– −52.06)#−1.75 (−4.17–0.67)−55.34 (−58.05– −52.64)#
 After one-quarter10−4.80 (−5.16– −4.45)#−4.09 (−4.85– −3.34)#−5.17 (−5.52– −4.82)#−3.72 (−4.36– −3.09)#
20−10.07 (−10.77– −9.36)#−8.20 (−9.49– −6.90)#−10.73 (−11.5– −9.97)#−7.51 (−8.78– −6.24)#
50−28.92 (−31.51– −26.32)#−20.31 (−23.25– −17.38)#−30.44 (−33.15– −27.73)#−18.48 (−21.57– −15.40)#
 After one-half10−4.41 (−4.70– −4.12)#−1.48 (−1.75– −1.22)#−4.35 (−4.99– −3.72)#−1.67 (−1.93– −1.40)#
20−8.81 (−9.28– −8.34)#−3.08 (−3.66– −2.50)#−8.82 (−10.07– −7.56)#−3.30 (−3.54– −3.06)#
50−23.43 (−25.04– −21.82)#−7.27 (−7.88– −6.67)#−23.17 (−26.40– −19.95)#−8.19 (−8.90– −7.49)#
 After three-quarters10−2.33 (−2.61– −2.04)#−0.51 (−0.79– −0.24)#−2.46 (−3.00– −1.93)#−0.73 (−0.92– −0.53)#
20−6.64 (−11.7– −1.57)#−0.99 (−1.30– −0.68)#−4.93 (−5.99– −3.87)#−1.42 (−1.60– −1.24)#
50−12.34 (−13.64– −11.05)#−2.42 (−2.85– −2.00)#−12.55 (−15.23– −9.86)#−3.50 (−4.36– −2.64)#
Isolated
 Start104.72 (−0.10–9.54)−4.35 (−8.54– −0.15)#2.65 (2.36–2.95)−3.27 (−4.21– −2.34)#
205.28 (1.96–8.60)#−5.60 (−6.52– −4.68)#9.08 (−1.21–19.37)−9.14 (−17.74– −0.55)#
5012.88 (7.41–18.36)#−13.95 (−16.38– −11.51)#15.50 (13.4–17.59)−16.23 (−19.36– −13.1)#
 After one-quarter101.09 (−1.25–3.44)−0.97 (−1.61– −0.33)#−1.60 (−6.13–2.93)−0.73 (−1.41– −0.04)#
201.36 (−1.03–3.75)−1.90 (−3.03– −0.78)#0.08 (−0.27–0.43)−1.42 (−2.46– −0.38)#
505.77 (−2.93–14.47)−7.87 (−14.38– −1.37)#0.25 (−0.67–1.18)−3.50 (−5.67– −1.33)#
 After one-half100.79 (−1.36–2.94)−0.48 (−0.93– −0.04)#−1.43 (−4.14–1.29)−0.31 (−0.86–0.25)
200.27 (−1.76–2.30)−0.90 (−1.36– −0.45)#−0.82 (−1.36– −0.29)−0.56 (−1.31–0.19)
50−1.13 (−3.01–0.75)−1.67 (−2.43– −0.90)#−2.03 (−3.37– −0.69)−1.40 (−2.65– −0.14)#
 After three-quarters100.29 (−1.90–2.48)−0.25 (−0.38– −0.12)#−0.47 (−1.03–0.10)−0.31 (−0.86–0.25)
20−0.38 (−2.68–1.91)−0.18 (−1.03–0.67)−1.13 (−1.89– −0.38)−0.35 (−0.79–0.08)
50−1.57 (−3.25–0.10)−1.04 (−1.70– −0.37)#−2.80 (−4.68– −0.93)−0.83 (−1.34– −0.33)#

VT: tidal volume. Changes due to modelled pre-capillary expiratory leaks of different duration (continuous and isolated over two breaths), stage of washout (start, after one-quarter, one-half and three-quarters of the washout) and size (10, 20 and 50% VT) through breath-by-breath modification of breath tables from nitrogen multiple-breath washout measurements from five healthy individuals (baseline LCI 6.99 lung turnovers; FRC 2.30 L) and five patients with cystic fibrosis (baseline LCI 11.12 lung turnovers; FRC 1.47 L). #: p<0.05.