Medical Aspects of Diving—part 3

Embolic Inner Ear Decompression Illness: Correlation With a Right‐to‐Left Shunt

“…There is currently a discrepancy between the treatment recommended in standard textbooks of diving medicine 5,7,36 for cases of inner ear dysfunction and that actually practiced by many clinical hyperbaric units which routinely treat inner ear dysfunction with HBOT even in cases in which IEB cannot be excluded. This is contrary to classic advice which warns that HBOT may result in additional damage in IEB cases as a result of air being forced into the inner ear during attempts to equalize middle ear pressure during the compression phase of HBOT.…”

“…Several mechanisms have been suggested for the pathophysiology and susceptibility of the inner ear to DCI. 7 There are many reports about the coincidence of right‐to‐left shunts and diving accidents, 8–12 but apart from a case report from our working group, 13 no reports have been published to date that link a right‐to‐left shunt with the incidence of IEDCI. We present 11 cases in 9 divers with IEDCI and a right‐to‐left shunt of high hemodynamic relevance, thereby favoring paradoxical inert gas embolism to be the probable pathological mechanism in IEDCI.…”

Isolated pulmonary oedema associated with SCUBA diving

“…Consistent with other reported cases, 5–13 the cause of the pulmonary oedema was not definitively determined in this case. Postulated mechanisms include: DCI, 2,3 pulmonary barotrauma, 4 salt water aspiration syndrome, 5,14 Pseudomonas contamination of equipment, 6 pulmonary oedema of immersion or cold, 7,8,10,11,15 exercise‐induced pulmonary oedema 16–18 and overhydration. 16,17 …”

“…Pulmonary barotrauma may occur at shallow depths, 22,23 usually in the last metres of ascent where the pressure and thus volume changes in the lung are greatest, as predicted by Boyle’s Law. Although alveolar rupture producing dyspnoea, cough and haemoptysis is a manifestation of pulmonary barotrauma, 2,3 pulmonary oedema occurring without other features, such as pneumothorax, 4 subcutaneous or mediastinal emphysema, 4,22 cerebral arterial gas embolism (CAGE) 4,23,24 or cardiovascular signs, including those of coronary artery gas embolism, 25 has not been documented in the literature and is considered to be an unlikely explanation.…”

“…Decompression illness (DCI) is a relatively frequent complication of compressed gas diving and prevention is achieved by limiting time and depth exposures. 1 Pulmonary oedema may be seen in severe decompression illness 2,3 as well as in pulmonary barotrauma; 4 however, isolated pulmonary oedema is reported relatively infrequently. 5–13 …”