Influence of compressed air diving on pulmonary alveocapillary membrane and right ventricular systolic function

Promjena obrazaca disanja u obliku porasta respiratorne brzine do pretjerane hiperventilacije često se pojavljuje tijekom i nakon SCUBA ronjenja. Povezana je s preopterećenjem pluća intersticijskom i alveolarnom tekućinom. Također je poznata pojavnost cirkulirajućih venskih plinskih mjehurića (VPM) u ronilaca i njihov utjecaj na plućnu funkciju, porast plućnog arterijskog tlaka (PAT-a) i hemodinamiku desne klijetke (DK). Ova studija je provedena radi procjene učinkovitosti disanja nakon ronjenja i utvrđivanja povezanosti promjena disanja s oštećenjem alveokapilarne membrane. Drugi cilj našeg istraživanja bio je procijeniti moguće učinke zarona na funkciju DK-a pomoću dvodimenzionalne (2D) "Speckle tracking" ehokardiografije kao nove slikovne metode. Ispitivanje je provedeno na 12 profesionalnih muških ronilaca (39,5 ± 10,5 godina), a ronjenje se sastojalo od jednog brzog urona u morsku vodu do 18 metara dubine, trajanja 47 minuta i izravnog uspona na površinu. Analizirana je učinkovitost ventilacije (VE/VCO2) tijekom maksimalnog spiroergometrijskog testa prije i dva sata nakon standardnog protokola ronjenja. Nadalje, u razdoblju 30 minuta od izrona, ispitanici su podvrgnuti uzimanju uzoraka krvi za određivanje proteina surfaktanta (SPs). U razdobljima 30, 60, 90 i 120 minuta od izrona, učinjen je ultrazvuk pluća zbog detektiranja ultrazvučnih kometa (UK). U istim intervalima rađen je i ultrazvuk srca zbog detekcije VPM-a, procjene srednjeg plućnog arterijskog tlaka (sPAT) i procjene sistoličke funkcije srca s fokusom na DK-a. Ehokardiografski je praćen novi pokazatelj sistoličke funkcije DK-a, odnosno, mjerena je dvodimenzionalna longitudinalna deformacija slobodne stijenke DK (2D GLS) uz uobičajene ehokardiografske pokazatelje sistoličke funkcije DK-a: amplituda sistoličkog pomaka trikuspidalnog prstena (TAPSE), vršna sistolička brzina lateralnog trikuspidalnog prstena (RV S`) i promjena frakcije površine (FAC). Spiroergometrijsko testiranje je pokazalo očuvanu funkcionalnu sposobnost i učinak vježbanja, ali s povećanjem VE/VCO2, tj. smanjenjem učinkovitosti disanja nakon ronjenja (21,4 ± 2,9 prema 22,9 ± 3,3, p < 0,05). Zreli SP-B se povećao za 13 % dok su ostali SP-i bili nepromijenjeni. Ultrazvučne plućne komete (UK) i VPM bili su značajno prisutni u prvoj evaluaciji nakon ronjenja sa značajnom, progresivnom, ali ne i potpunom, redukcijom nakon 120 min. po izronu. Srednji plućni arterijski tlak (sPAT) povećao se nakon ronjenja sa 13,3 mmHg na maksimalno 23,5 mmHg (p = 0,002), što ukazuje na porast opterećenja DK-a nakon ronjenja. Utvrđen je porast sistoličke funkcije lateralne stijenke zida DK-a, tj. 2D GLS s početnih -24,26 % na -28,44 % (p = 0,003) i to u sva tri segmenta uz porast 26 % (bazalno), 15,4 % (medijalno) i 16,3 % (apikalno), a što su potvrdili i standardni pokazatelji sistoličke funkcije DK: TAPSE (11,6 %), RV FAC (19,2 %), RV S' (12,7 %). Ispitivanjem smo pokazali da se nakon jednog zarona nakupila intersticijska i alveolarna tekućina u plućima sa smanjenom učinkovitosti ventilacije. Selektivan porast samo zrelog oblika SP-B moguće predstavlja funkcionalno oštećenje alveokapilarne membrane. Naši rezultati su pokazali da uz značajni porast VPM-a u srcu i UK-a u plućima raste PAT i opterećenje DK-a, na koje srce odgovara porastom sistoličke funkcije i longitudinalne deformacije DK-a kao mogućim kompenzatornim mehanizmom.Changing breathing patterns in the form of increased respiratory rate to excessive hyperventilation often occurs during and after SCUBA diving and is associated with overloading the lung with interstitial and alveolar fluid. Also known is the occurrence of circulating venous gas embolism (VGE) in diver and their effect on pulmonary function, pulmonary arterial pressure (PAP) and hemodynamics of the right ventricle (RV). This study was conducted to assess the effectiveness of breathing after diving and to establish the association of respiratory changes with damage to the alveolocapillary membrane. Another aim of our study was to evaluate the potential effects of dive on RV function using two-dimensional (2D) "Speckle tracking" echocardiography as new image method. The survey was carried out on 12 professional male divers (39,5 ± 10,5 years), and diving consisted of one fast dive in sea water up to 18 meters deep, 47 minutes duration and direct rises to the surface. Ventilation efficiency (VE/VCO2) was analyzed during the maximum spiroergometric test two and a half hours after the standard diving protocol. Furthermore, within 30 minutes of the ascend, subjects were subjected to blood samples for surfactant protein (SPs) determination. In the 30, 60, 90 and 120 minutes after ascend, ultrasonography was performed for the detection of ultrasound lung comets (ULC). At the same intervals, cardiac ultrasound was performed for VGE detection, mean pulmonary arterial pressure (m PAP) measurement and heart systolic estimation with RV focus. Echocardiographic measurements were performed of a new indicator of the systolic function of the RV, two-dimensional longitudinal deformation of the free wall RV (2D GLS) with the usual echocardiographic indicators of the systolic function of the RV: systolic shift of tricuspid ring (TAPSE), peak systolic velocity of the lateral tricuspid ring (RV S') and fractional area change (FAC). Spiroergometric testing has shown conserved functional ability and exercise effect but with increased VE/VCO2 and decreased breathing efficiency after diving (21.4 ± 2.9 vs. 22.9 ± 3.3, p < 0.05). The mature SP-B increased 13 % while the other SPs were unchanged. The ultrasound long comets (ULC) and VGE were significantly present in the first evaluation after diving with a significant, progressive but not complete reduction after 120 min. The mean pulmonary arterial pressure (mPAP) increased after diving from 13.3 mmHg to a maximum of 23.5 mmHg (p = 0.002), indicating an increase in RV load after diving. The increase of the systolic function of the RV lateral wall, 2D GLS from the initial -24.26 % to -28.44 % (p = 0.003), was established in all three segments with an increase of 26 % (basal), 15.4 % ( medial) and 16.3 % (apical), as confirmed by standard echocardiographic indicators: TAPSE (11.6 %), RV FAC (19.2 %), RV S' (12.7 %). In conclusion, we showed that after one dive there was an accumulation of interstitial and alveolar fluid in the lungs with reduced ventilation efficiency. Selective growth of only one form of SP-B indicates possible functional damage of the alveo-capillary membrane. Our results showed that with significant increases in VGE in the heart and the UK in the lungs increase PAP and the load of RV, with increased systolic function and longitudinal deformation of RV as possible compensatory mechanism