Dysbarism

Decompression sickness

There are some reports of spontaneous recovery from decompression sickness (DCS) left untreated.[59]Green RD, Leitch DR. Twenty years of treating decompression sickness. Aviat Space Environ Med. 1987 Apr;58(4):362-6. http://www.ncbi.nlm.nih.gov/pubmed/3579827?tool=bestpractice.com Mild cases (e.g., pruritus or malaise in the absence of other symptoms and signs) may respond to surface oxygen alone. Recompression, however, has an independent beneficial effect on prognosis and is advisable in all other cases. Immediate first aid and prompt recompression for DCS can ameliorate the damaging effects that bubbles exert through tissue distension, ischemia, and secondary inflammation.

Sequelae due to delayed or inadequate initial treatment may respond to daily hyperbaric oxygen therapy (usually shorter, standard “wound healing” treatment tables), which should be continued until all clinical improvement has ceased. In practice, treatment is discontinued when the patient has either experienced complete resolution or there is no sustained improvement after 2 consecutive treatments (a "plateau").[3]US Navy. US Navy diving manual revision 7 with change A entered - chapter 17: diagnosis and treatment of decompression sickness and arterial gas embolism. Washington, DC: US Navy; 2018. https://www.navsea.navy.mil/Home/SUPSALV/00C3-Diving/Diving-Publications The vast majority of patients will require 1 or 2 chamber sessions only, although those with refractory cases (e.g., severe neurological DCI) may require more. The injured diver may continue to slowly improve over months. Physical therapy is indicated.

Pulmonary barotrauma

Pneumothorax may resolve with surface oxygen if mild, or require tube thoracostomy if more serious. Isolated subcutaneous or mediastinal emphysema with no other signs will recover spontaneously.

Otic barotrauma

Middle ear barotrauma generally resolves within 2 weeks if there is no perforation and the patient avoids all further pressure changes. This may be delayed if infection supervenes.

If perforation is present, healing may take up to 2 months. A premature return to diving often results in a further perforation.

The prognosis of inner ear barotrauma is variable, from complete resolution to persistent tinnitus and permanent high-frequency hearing loss. Less commonly, lifelong positional vertigo secondary to vestibular damage may occur. Some require surgical exploration and repair. Symptoms may worsen with further barotrauma, to which the diver is now predisposed, making future diving inadvisable.[60]Elliott EJ, Smart DR. The assessment and management of inner ear barotrauma in divers and recommendations for returning to diving. Diving Hyperb Med. 2014 Dec;44(4):208-22. http://www.ncbi.nlm.nih.gov/pubmed/25596834?tool=bestpractice.com

Sinus barotrauma

Most cases will recover with no treatment and avoidance of pressure changes. Decongestants are advisable along with antibiotics indicated for any worsening of symptoms.

Arterial gas embolism (AGE)

AGE may result in sudden death. If the diver survives, immediate recompression is essential. There seems to be an inverse relationship between time to onset of signs and symptoms and the severity of AGE. Coma/collapse generally present within 30 seconds of surfacing. Fortunately, many patients will improve spontaneously, although neurologic deficits of varying severity may persist. Neurologic symptoms persisting after recompression may continue to gradually improve over months. Physical therapy is advisable.