Multiple breath washout becoming feasible for the assessment of lung function in infants and young children with cystic fibrosis in a clinical setting.

tained with commercially available equipment in infants and young children in a center that had no prior expertise in this technique. As assessment of lung function by spirometry is not feasible in the first years of life, MBW is an attractive alternative approach because it does not require forced expiratory maneuvers and can be performed in spontaneously breathing children, either awake or sleeping, from the first months of life. To explore the feasibility of MBW in the clinical setting, the authors studied children below the age of 4 years with CF and a control group without lung disease during a routine visit. After an initial learning curve, they report highly acceptable success rates of ∼ 90% of MBW studies with at least one successful washout and 75% with two successful washouts. These results support that MBW measurements with commercially available equipment are feasible for monitoring of lung function during routine clinical workup in this young age group. Furthermore, the results confirm that MBW measurements are a sensitive tool to detect differences in the lung clearance index between the CF and control groups with relatively small group size and to identify individual CF patients with early abnormalities in lung function. To our knowledge, this is the first study demonstrating the feasibility of MBW in the clinical setting in small chilChronic obstructive lung disease has still the greatest impact on morbidity and mortality of patients with cystic fibrosis (CF). A series of recent studies in infants with CF who were diagnosed early by newborn screening demonstrated that CF lung disease starts already in the first months of life, mostly without any respiratory symptoms [1–3] . Therefore, sensitive noninvasive outcome measures are needed to detect early alterations and monitor lung disease in non-cooperative infants and young children with CF. The multiple breath washout (MBW) technique has been shown to be sensitive in the detection of alterations in the small airways [4–6] , i.e. the airway region where CF lung disease is thought to originate. The most widely used parameter determined by MBW is the lung clearance index that reflects the number of lung turnovers necessary to clear a tracer gas from the lung and thus the severity of ventilation inhomogeneity. MBW has already been used for the assessment of lung function in older and cooperative children with CF in the clinical setting. However, MBW measurements in infants and young uncooperative children have so far only been performed at a limited number of specialized centers and with specialized equipment. In the current issue of Respiration , Stahl et al. [7] report data on the feasibility of MBW measurements obPublished online: March 19, 2014