Background: The objective was to investigate the respiratory function of professional divers by conducting spirometry and to compare the data obtained with those of non-divers. Materials and methods: This study involved 52 military divers who carried out dives at small and medium depths using a self-contained underwater breathing apparatus (SCUBA) with open-circuit regulators attached to a mouthpiece. The control group consisted of 48 persons from deck commands with similar physiological characteristics and lifestyle that were not divers and had never been under increased pressure. Results: It was found that, compared with non-divers, the spirometry parameters of the divers are characterised by higher values of forced vital capacity (FVC) of the lungs (p = 0.02), but significantly lower values of the mid-expiratory flow (MEF) parameters: MEF 25 (p = 0.06), MEF 50 (p = 0.04), and MEF 75 (p = 0.01), as well as for the ratio of forced expiratory volume in 1 second (FEV 1) to forced vital capacity (FEV 1 /FVC; p = 0.001) and MEF 25-75 /FVC ratio (p < 0.001). Conclusions: Hyperoxia, gas decompression bubbles, hypothermia, mouth-breathing dry, cold, compressed air, and other factors accompanying the diving activity are capable of initiating damage to the airways, which is reflected in characteristic changes in spirometry. The pattern of these changes is consistent with small airway obstruction and they could be related mostly to diving activities.

Background: Most cases of middle ear barotraumas in divers are due to impassability of the Eustachian tube, and typically occur during diving or during compression and decompression in a hyperbaric chamber. The aim of our study is to compare the results of tympanometry and Valsalva part of Eustachian tube function test (ETF-test) with the ability of divers to compensate for the change in ambient pressure in a hyperbaric chamber and to evaluate the tests as predictors of middle ear barotraumas. Materials and methods: The study included 35 professional divers undergoing annual medical examination. Using tympanometer we measured the intratympanic pressure at rest, and after the manoeuvre of Valsalva. Then all subjects underwent a barofunction test (BFT) to assess their diving fitness and the passability of the Eustachian tubes. In a typical BFT divers are compressing and decompressing to a pressure of 2.2 ATA for 1 min in a hyperbaric chamber. Based on results from previous studies we are using a 20 daPa cut-off point on the ETF test to predict Eustachian tube passability and a successful BFT. Results: In the current study 24 divers received ETF test results higher than 20 daPa; 3 divers had ETF test values lower than 20 daPa in both ears, but none of them displayed difficulties in the BFT; 8 divers had ETF values lower than 20 daPa in one ear and higher than 20 daPa in the other; 7 divers of the last group displayed difficulties with the BFT in the ear with poor ETF result. Conclusions: We consider that the ETF test can be used to assess diving fitness as a screening method before performing a BFT, as values above 20 daPa guarantee Eustachian tube passability sufficient for diving activities. Values of 20 daPa and less are not a definite predictor for the barofunction results. The results of the ETF test can also be used in the usual work of an otorhinolaryngologist to evaluate Eustachian function in cases of unilateral disease of middle ear.