Demographic and diagnostic characteristics of patients with primary ciliary dyskinesia.

$Median (range) nNO = 26 (4 to 190); †Chronic PSA = chronic infection with Pseudomonas Aeruginosa, defined as more than 50% of positive airway cultures the previous year; *Intermittent PSA = intermittent infection with P. Aeruginosa, defined as least one positive culture in the last year; §Chronic AX = chronic infection with Achromobacter xylosoxidans, defined as more than 50% of positive airway cultures the previous year.