Figure 4From: Long-term gas exchange characteristics as markers of deterioration in patients with cystic fibrosis Crosstab comparison of initial z -scores of FEV 1 (mean during age range of 5 to 8 years) and oxygenation under 4 different conditions: ( i ) decreased airway patency (FEV 1 < -2SDS) and normocarbia (PaCO 2 > = 34 mmHg), ( ii ) normal airway patency and normocarbia, ( iii ) decreased airway patency and hypocarbia, and ( iv ) normal airway patency and hypocarbia.Back to article page