Late effect of nocturnal mist tent therapy related to the severity of airway obstruction in children with cystic fibrosis.

To evaluate the long-term effect of nocturnal mist tent therapy on the 
progression of airway obstruction in children with cystic fibrosis (CF) of 
varying severity, two matched groups each consisting of 24 children with 
CF were studied during 18 months on mist tent therapy and 
18 months of therapy. The progression in airway obstruction was measured 
by change in serial measurements of maximal midexpiratory flow (MMEF), from 
which a regression equation of MMEF against time was obtained for 
each individual. Changes in MMEF value with or without therapy were 
compared in patients matched for severity of disease as indicated by 
initial MMEF values. For the group as a whole no differences 
were found in the progression of the airway obstruction whether the 
patients received mist tent therapy or not. This therapy failed to 
benefit any of the groups of children with CF who had 
early, moderate, or advanced airway obstruction as judged from their initial 
MMEF value. It is concluded that nocturnal mist tent therapy neither 
decreases airway obstruction nor prevents its progression in children with CF. 
