Prevalence of acute respiratory symptoms in breath-hold divers

After repetitive deep dives, breath-hold divers are often affected by a syndrome characterized by typical symptoms such as cough, sensation of chest constriction, blood-striated expectorate (hemoptysis) and, rarely, an overt acute pulmonary edema syndrome, often together with various degrees of dyspnea. The aim of this work is an epidemiological investigation to evaluate the prevalence of acute respiratory symptoms (ARS) in breath-hold divers (BHDs) in practicing breath-hold diving.

A retrospective investigation has been performed using specific questionnaires completed by a selected sample of free-divers (212 breath-hold diving instructors--194 male, 18 female; mean age 34 +/- 6.91 years); affiliated with Apnea Academy, (International School for Education and Research of Free-Diving). We also investigated possible risk factors for post-dive acute respiratory symptoms. Furthermore, the authors report that a severe case of acute pulmonary edema occurred to a healthy and experienced breath-hold diving instructor. We reported detailed CT scan and follow-up CT scans three days later, with another scan reported 10 days later as well.

A total of 56 subjects (26.4%) reported previous events such as cough, thoracic constraint, hemoptysis, associated with various degrees of dyspnea as confirmation of pulmonary involvement. Forty-five of them (82%) reported signs of true hemoptysis and a high degrees of dyspnea. A CT scan revealed the presence of patchy bilateral lung opacities at the level of superior and parahilar zones; follow-up CT scans three days later and 10 days later are also reported.

Our data show that this is a common condition among experienced BHDs. In our opinion, this is particularly interesting for the free-diving community.