INTRODUCTION
Congenital lung malformations (CLM) are rare and a heterogeneus group of
disorders including abnormal and dysfunctional pulmonary parenchyma and
airways. Congenital lung malformations are a large spectrum of disorders
such as congenital pulmonary airway malformation (CPAM), congenital
lobar emphysema (CLE), bronchogenic cyst (BC), bronchopulmonary
sequestration (BPS)1. Surgical resection is the
definitive treatment for these lesions with a controversy of elective
surgery or conservative treatment in the management of asymptomatic
patients and standard surgical treatment method is
lobectomy2-4. After resection of abnormal congenital
lesion, lung volume and function may be expected to improve.
Small peripheral airways are defined as conducting airways and gas
exchange bronchioli and alveolar ducts with luminal diameter less than 2
mm. Despite representing large amount of total lung volume,
peripheral airways contribute little to overall airway resistance.
Therefore peripheral airways can not be evaluated by spirometry which
assesses large airways’ flow and resistance5. Changes
and impairment in peripheral small airway structure with pathological
processes, affects the distribution of ventilation among different
parallel lung units and cause ventilation
inhomogeneity6,7.
Lung Clearance Index (LCI) is a lung function test derived from multiple
breath washout technique. It is defined as dividing cumulative expired
volume calculated by assessment of the number of respiratory turnovers
required to clear saturated inert gas from the lungs, into functional
residual capacity. It exhibits ventilation distribution and reflects
peripheral airway status7. As LCI is feasible for
young children measurements are performed during tidal breathing without
require forced expiratory maneuvers8-10.
In early stages of chronic progressive lung diseases without increased
general airway resistance, LCI may be much more specific than spirometry
to demonstrate periferic airway involvement7,8.
Data on long-term lung function in children with postoperative CLMs is
rare and in the published articles spirometry is the most preferred
method11-13. Although surgical resection of the
affected part may facilitate the compensatory growth of the remaining
lung, it may cause inhomogeneity of ventilation distribution. Depending
on this fact, LCI may be more appropriate to evaluate peripherical
airway function.
The primary objective of this study is to evaluate the long term lung
function of patients who had lobectomy for CLM. As a secondary
objective, diagnostic accuracy of LCI and spirometry was compared in
patients and healthy controls.