By Lambang Buwono Nusantoro Arianto
Chariman: Jesper Johannesen
Opponent: Mika Mäkelä
Opponent: Arne Høst
Children’s asthma is difficult to diagnose due to limited informational output and cooperation when completing lung function measurements. Furthermore, asthma is characterized by different levels of severity and the mildest form is even harder to diagnose with the risk of leaving a large patient group under-diagnosed and under-treated. Asthma is a disease, which involves central and peripheral airways. The peripheral airways are especially important when trying to measure the degree of airway pathology in mild asthma cases.
Multiple Breath Washout (MBW) is a lung function method that has been used for several decades and because of studies with optimized setups, the MBW is in rapid development. The MBW measures peripheral airway pathology by determining the ventilation inhomogeneity occurring when e.g. obstructed airways affect the mixing of gases in the lungs thus prolonging the washout time.
A MBW test is completed solely by using tidal breathing. Compared to traditional lung function tests the MBW is thought to be more adaptive in small children. Furthermore, the MBW has shown to be more sensitive when diagnosing cystic fibrosis and primary ciliary dyskinesia in children. Unfortunately, there are only few studies of MBW within the field of childhood asthma and these studies show ambiguous results.
In 13-year-old children with mild to moderate asthma, the SlopeIII of conductive airways x tidal volume captured from MBW-N2 was significantly different compared to healthy children, whereas lung clearance index (LCI) derived from either MBW-N2 or MBW-SF6 was not significantly different. On the contrary, Scond x VT had low discriminative ability compared to traditional measures of lung function and inflammation.
In comparison, in the case of preschool children with and without asthma, LCI derived from MBW-N2 showed no significant difference and low feasibility with a completion rate of only 25% among three-year-old children.
In conclusion: This thesis, which examines the sensitivity and feasibility of MBW compared to traditional lung function tests when diagnosing asthma in children, does not support the use of MBW in this clinical setting. Adaptation of the MBW equipment must be improved when testing preschool children to achieve a steady uniform breathing pattern, which is necessary in order to complete a successful MBW test.