No-one who has seen the victim of compressed air illness, gravely ill or unconscious, put back into a chamber and brought back to life by the application of air pressure, will forget the extraordinary efficiency of recompression, or will be backward in applying it to a subsequent case of illness.
—— Robert Davis, 1935
This chapter deals with the definitive management of decompression sickness (DCS). For information on the first aid management of the diving accident victim, see Chapter 48. DCS takes many forms, and although recompression is often the treatment of choice, the optimal treatment varies with circumstance. Consider the following cases:
- Saturation DCS as the diver very slowly approaches the surface.
- The same diver subjected to an extreme excursion from saturation.
- Inner ear DCS after helium breathing.
- A cerebrovascular incident after a short bounce to 50 metres.
- A joint bend developing hours after a long shallow dive.
- A dramatic crisis involving pulmonary, haematological and neurological systems after explosive decompression from saturation or from gross omitted decompression.
- Respiratory symptoms followed by the rapid development of paraplegia.
- Mild joint pain DCS after a shallow dive in a diver who has remained well within the established tables.
These cases cannot be managed optimally by a single regimen, yet the approach to their management is similar.
The guiding principle of treatment for DCS is recompression followed by a slow decompression back to atmospheric pressure, with the patient hopefully devoid of symptoms and signs. Oxygen breathing is used to increase the washout of inert gas and promote bubble resolution. Fluid replacement is recommended because divers are often dehydrated as a consequence of cold water diuresis, seasickness and bubble-induced fluid shifts out of the intravascular compartment. Many adjuvant therapies have been tried, most with little evidence of effect, including antiplatelet agents, corticosteroids, heparin and dextrans, whereas non-steroidal anti-inflammatory drugs (NSAIDs) and lidocaine have shown some promise.
If left untreated, the pain of joint DCS resolves spontaneously, usually within days or weeks. There have been reports of spontaneous resolution of cases of neurological DCS without recompression therapy; however, most patients require treatment or remain symptomatic. It is not known whether untreated DCS increases the likelihood of dysbaric osteonecrosis or subclinical neurological injury.
Care should be taken to avoid circumstances that will aggravate the ‘bubbling’ of DCS. These include excessive movement of the patient, exposure to altitude and the breathing of certain gases (e.g. nitrous oxide anesthesia).