TABLE 1.

Summary demographic and washout data for control and cystic fibrosis subjects who completed repeat wash-out measurements with both an open circuit wash-in and a modified closed circuit wash-in

	Healthy volunteers	Cystic fibrosis	p-value for healthy volunteers versus cystic fibrosis
Subjects n	12	19
Age years	34.2±10.4	30.2±6.2	0.2
Males/females n/n	1/11	13/6	0.002
FEV1 z-score	−0.5±1.0	−2.3±1.3	0.0006
FVC z-score	−0.1±1.2	−1.2±1.2	0.03
FEV1 % predicted	−94.7±12.5	71.9±15.9	0.0005
FEV1/FVC	0.80±0.07	0.69±0.09	0.003
LCI open	6.5±0.5	10.9±2.6	<0.0001
LCI closed	6.4±0.5	10.8±2.2	<0.0001
p-value for open versus closed	0.2	0.2
FRC open L	2.32±0.70	2.66±0.81	0.2
FRC closed L	2.34±0.67	2.75±0.80	0.2
p-value for open versus closed	0.6	0.1

Data are presented as mean±sd unless otherwise stated. FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; LCI: lung clearance index; FRC: functional residual capacity.