Pulmonary Barotrauma: Prevention (Dive Training/Medical Selection)

Attempts to prevent PBT, or reduce its incidence, have centered on standards of fitness for divers and modification of training and diving techniques.

Dive training

Entry level recreational divers are taught that the most important rule in scuba diving is to breathe normally at all times and never hold your breath. Considerable effort goes into instilling this mantra. In addition, dangerous diving practices to be avoided include skip breathing, buddy breathing at depth and during ascent, ditch and recovery training, and emergency free ascent training when there are no experienced medical staff and full recompression facilities on site. In recent years major dive training agencies have abandoned free ascent training from bottom to surface, and instead simulate it in a horizontal orientation.

Medical selection

Predisposing disease includes previous spontaneous pneumothorax, asthma, sarcoidosis, cysts, tumors, pleural adhesions, intrapulmonary fibrosis, infection, previous penetrating chest wounds and inflammation. These disorders may result in local compliance changes or airway obstructions. Some (spontaneous pneumothorax and known gas trapping lesions in particular) merit automatic exclusion from diving, whereas others (e.g. ‘asthma’) imply an increase in the magnitude of risk that is very context sensitive, and determinations about diving are made for each case based on its own merits. Pleurodesis for spontaneous pneumothorax may protect from pneumothorax but does not mitigate the risk of other barotraumatic injuries arising from the same predisposing lesions that led to the pneumothorax.

Medical standards are dealt with in Chapters 53 and 54 and involve the exclusion of candidates with significant pulmonary disorders as described earlier. Diver evaluation may involve the performance of respiratory function tests and a pre-diving chest x-ray study. In most cases, a single full-plate chest x-ray film is acceptable. However, some groups insist upon inspiratory and expiratory x-ray studies to demonstrate air trapping in the latter view. If there is a high index of suspicion for gas trapping, more sophisticated lung function tests are indicated. High-resolution or spiral CT scans of the lungs are useful in demonstrating emphysematous cyst and pleural thickening but also frequently reveal lung changes whose significance is uncertain.