Objectives Several cross-sectional studies have described a decrease in the
expiratory flow rates of divers. The objective of this study was to determ
ine whether the combined application of high-resolution computed tomography
(HRCT) and lung function testing supports the reported development of smal
l airway obstruction in divers.
Methods Thirty-two navy divers, 27 commercial divers, and 48 referents matc
hed for age and smoking history underwent pulmonary function testing and HR
CT of the lungs supplemented by a Limited number of expiratory scans. The c
ommercial divers were older and dived longer than the navy divers. Multivar
iate regression analysis was used to assess the relevant correlations of ag
e, height, pack-years of cigarette smoking, and indices of diving exposure
with lung function parameters.
Results The inspiratory vital capacity and forced vital capacity (FVC) were
greater, while the FEV% [(100 x FEV1.0)FVC] and maximum expiratory flow (M
EF) at 25% (MEF25) of the FVC were lower for the navy divers than for the r
eferents. The lung volumes and expiratory airflow pattern did not differ be
tween the commercial divers and the corresponding referents. The forced exp
iratory volume in 1 second (FEV1.0), FEV%, MEF75, and MEF25 correlated nega
tively with the years of diving experience. This association was independen
t of age, height, and pack-years of cigarette smoking. For the majority of
the divers and referents the expiratory HRCT revealed minor lobular air tra
pping without any difference between the groups. The HRCT did not show rele
vant morphologic abnormalities of small or large airways.
Conclusions The data confirm that diving may affect pulmonary function. How
ever, there is no radiologic evidence for the development of small airway d
isease in these 2 subgroups of divers.