Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 37-13: Dysbarism & Decompression Sickness + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis ++ Symptoms temporally related to recent altitude or pressure changes (eg, scuba diving) Early recognition and prompt treatment are extremely important Patient must also be assessed for hypothermia, hypoglycemia, concurrent injuries, and medical conditions Consultation with a specialist in diving medicine or in hyperbaric oxygen therapy is indicated +++ General Considerations ++ Dysbarism and decompression illness result from altitude changes and the environmental pressure effects on gases in the body during underwater descent and ascent, particularly when scuba diving is followed closely by travel to high altitudes (ie, air travel or mountain hiking) Dysbarism results from barotrauma when gas compression or expansion occurs in parts of the body that are noncompressible or have limited compliance Pulmonary overinflation syndrome One of the most serious and potentially fatal results of barotrauma Due to an inappropriately rapid ascent causing alveoli rupture and air bubbles extravasation into tissue planes or even the cerebral circulation Lung barotrauma can result in Pneumomediastinum Pneumothorax Rupture of the pulmonary vein causing arterial gas embolism Overpressurization of the bowels may occur, resulting in Gastric rupture Bowel obstruction or perforation Pneumoperitoneum Less serious conditions include Mask squeeze Ear squeeze Sinus squeeze Headache Tooth squeeze Decompression illness occurs when the ascent is too rapid and gas bubbles form Symptoms depend on the size and number of gas bubbles released (notably nitrogen) Location (eg, coronary, pulmonary, spinal or cerebral blood vessels, joints, soft tissue) of released gas bubbles also determines symptoms The appearance of symptoms depends on Dive details (depth, duration, number of dives, and interval surface time between dives, water conditions) Degree of physical exertion Age, weight, and physical condition of the diver Rate of ascent The length of time between the low altitude (scuba dive) and high altitude (air travel or ground ascent) Predisposing factors for decompression illness Obesity Injury Hypoxia Lung or cardiac disease, especially right to left cardiac shunt (ie, patent foramen ovale) Dehydration Panic attacks Other comorbidities Alcohol and medication effects Decompression illness also occurs in persons who take hot showers after cold dives Delayed decompression illness May be caused by the cavitation effects of gas trapped in the body, which is described as "vacuum phenomenon" in radiological studies Clinical cases have been reported following post-dive exercise Possible contraindications to diving Asthma Pneumothorax Reduced pulmonary function Lung cysts Thoracic trauma Cardiovascular disease History of bowel obstruction Recent brain or eye surgery Seizures Diabetes and hypoglycemic episodes Definite contraindications to diving Perforated tympanic membrane Active upper respiratory infection + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs ++ Symptom onset may be immediate, within minutes or hours (in the majority), or up to 36 hours later Symptoms are highly variable Pain in the joints ("the bends") Skin pruritus or burning ("skin bends") Cardiac symptoms (acute coronary syndrome, conduction abnormalities) Focal neurologic dysfunction or "dissociation" symptoms that do not follow typical distribution neuro-anatomy patterns Labyrinthine decompression illness ("the staggers," central vertigo) Pulmonary decompression illness ("the chokes," inspiratory pain, cough, and respiratory distress) Arterial gas embolism (cerebral, pulmonary) Barotrauma of the lungs, ear, and sinus Coma Death + Diagnosis Download Section PDF Listen +++ ++ CT can detect the vacuum phenomenon of trapped gas MRI is the most accurate neuroimaging to detect these lesions in brain and spinal cord lesions + Treatment Download Section PDF Listen +++ +++ Medications ++ Nonsteroidal anti-inflammatory drugs, acetaminophen, or aspirin may be given for pain control if no other contraindications Opioids should be used only very cautiously to avoid obscuring the patient's response to recompression +++ Therapeutic Procedures ++ Administer continuous 100% oxygen to all patients Hyperbaric oxygen therapy for recompression (see When to Refer) Complete alleviation of decompression symptoms is possible with treatment given up to 2 weeks post onset + Outcome Download Section PDF Listen +++ +++ Prevention ++ Preventive measures include Diver education Pre-dive medical screening and dive planning Strict adherence to dive course, timing and depths Slow and controlled ascent Proper control of buoyancy Conservative recommendation is to avoid high altitudes (air travel or ground [hiking] ascent) for at least 24 hours after surfacing from the dive, especially following multiple dives +++ Complications ++ Hemiparesis Neurologic dysfunction Osteonecrosis +++ When to Refer ++ Rapid transportation to a hyperbaric treatment facility for recompression is imperative The Divers Alert Network, which is associated with Duke University, provides assistance in the management of diving-related conditions Website: www.diversalertnetwork.org + References Download Section PDF Listen +++ + +Gore MD et al. Is it safe to SCUBA dive with asthma? Expert Rev Respir Med. 2019 Sep 11:1–9. [PubMed: 31509025] + +Koopsen R et al. Persistent foramen ovale closure in divers with a history of decompression sickness. Neth Heart J. 2018 Nov;26(11):535–9. [PubMed: 30178210] + +Mallen JR et al. SCUBA medicine for otolaryngologists: Part II. Diagnostic, treatment, and dive fitness recommendations. Laryngoscope. 2020 Jan;130(1):59–64. [PubMed: 30776095] + +Mitchell SJ et al. Consensus guideline: pre-hospital management of decompression illness: expert review of key principles and controversies. Undersea Hyperb Med. 2018 May–Jun;45(3):273–86. [PubMed: 30028914] + +Pollock NW et al. Updates in decompression illness. Emerg Med Clin North Am. 2017 May;35(2):301–19. [PubMed: 28411929]