Changes in pulmonary function in hyperbaric chamber inside attendants: a case-control study.

BACKGROUND: Inside attendants (IAs) [are] exposed to high pressure during hyperbaric oxygen (HBO2) therapy. The aim of this study was to evaluate the alterations of pulmonary functions in IAs over time. METHODS: IAs in our hyperbaric center constituted the IA group (n=11). A sex- and age-matched control group (n=15) was constituted from hospital staff who had not dived or been exposed to hyperbaric environments before. We measured the respiratory function of all subjects at two time points: 1) at the start of the study; and 2) 12 months after the first measurement. The following parameters were recorded: forced vital capacity (FVC), forced expiratory volume in one second (FEV1), rate of FEV1 to FVC (FEV1/FVC%), forced expiratory flow at 25% to 75% vital capacity (FEF25-75%), forced expiratory flow at 50% vital capacity (FEF50%), forced expiratory flow at 25% vital capacity (FEF25%). RESULTS: Both groups were similar in terms of age, sex, smoking and body mass index. We found that FEV1, FEV1/FVC%, FEF25-75% and FEF50% significantly reduced in both groups after 12 months (p⟨0.05). However, the rate of change in all parameters was similar in both groups (p⟩0.05). In the IA group, the total number of exposures within the 12 months was positively correlated with the rate of reduction in FEF25% (r=0.788, p=0.004). CONCLUSION: Working as an IA does not deteriorate pulmonary function in the short term. However, there is a need for long-term follow-up studies.