Diving and pulmonary physiology: Surfactant binding protein, lung fluid and cardiopulmonary test changes in professional divers.

Alteration of breathing pattern ranging from an increase of respiratory rate to overt hyperventilation during and after SCUBA diving is frequently reported and is associated with intrathoracic fluid overload. This study was undertaken to assess breathing efficiency after diving and the association with damage of alveolar cells. Ventilation efficiency (VE/VCO) during maximal cardiopulmonary exercise test (CPET) before and 2h after a standard protocol dive has been analyzed in twelve professional males divers (39.5±10.5years). Furthermore, within 30min from surfacing, subjects underwent blood sample for surfactant derived proteins (SPs) determination, while thoracic ultrasound was performed at 30, 60, 90 and 120min. Dive consisted in a single quick descend to 18m of sea water, a 47min bottom stay and a direct ascent to the surface. CPET showed a preserved exercise performance with an increase of VE/VCO after diving (21.4±2.9 vs. 22.9±3.3, p<0.05). Mature SP-B increased while other SPs were unchanged. Ultrasound lung comets (ULC) were high in the first post-dive evaluation with a significant, but not complete, progressive reduction at 120min after surfacing. In conclusion we showed that, after a single dive, lung fluid increased with an increase of ventilation inefficiency and of the mature form of SP-B.