Study of the changes in respiratory function in self-contained underwater breathing apparatus divers

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 charac- terised 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: MEF25 (p = 0.06), MEF50 (p = 0.04), and MEF75 (p = 0.01), as well as for the ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FEV1/FVC; p = 0.001) and MEF25–75/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.

Eustachian tube function test as a predictor of middle ear barotrauma

Background: Most of the cases of middle ear barotrauma in divers are due to the impassability of the Eustachian tube. The aim of our study is to compare the results of tympanometry and Valsalva part of Eustachian Tube Function test (ЕТF-test) with the ability of divers to compensate for the change in ambient pressure in a hyperbaric chamber. Material and methods: The study included 35 professional divers undergoing annual medical examination. For all subjects is measured first intratympanal pressure at rest, then after the maneuver of Valsalva with impedancemeter. Then a barofunction test (BFT) was performed to assess the diving fitness and the passability of the Eustachian tubes. It consists of divers compressing and decompressing in a hyperbaric chamber to a pressure of 2.2 ATA for 1 minute. Based on results from previous studies we are using a 20 DaPa cutoff point on the ETF test to predict Eustachian tube passability and a successful barofunction test. Results: In the current study 24 divers have ETF test results higher than 20 DaPa. 3 divers have ETF test values lower than 20 DaPa in both ears, but none of them displayed difficulties in the BFT. 8 divers have ETF values lower than 20 DaPa in one ear and higher than 20 DaPa in the other. 7 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 function sufficient for diving activities. Values of 20 DaPa and less are not a definite predictor of the BFT 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

Abstracts Of The Proceedings And The Posters From The Third Scientific Session Of The Medical College Of Varna

October 2-3, 201