Hyperbaric oxygen therapy is the definitive treatment for decompression sickness
Hyperbaric oxygen therapy is the definitive treatment for decompression sickness
Understanding decompression sickness and why HBOT is the only definitive treatment
Decompression sickness (DCS) occurs when dissolved nitrogen — absorbed into the blood and tissues under elevated pressure during a dive — comes out of solution as bubbles when a diver ascends too quickly. These gas bubbles can form throughout the body, blocking blood flow, distending tissue and triggering an inflammatory cascade that causes the characteristic symptoms of "the bends."
DCS is classified by the systems affected. Type I DCS involves musculoskeletal symptoms — the deep, aching joint pain traditionally associated with the bends — along with skin mottling and lymphatic obstruction. Type II DCS is more serious, involving neurological, pulmonary or cardiovascular manifestations: spinal cord injury, stroke-like symptoms, inner ear damage, or pulmonary arterial gas embolism (known as "the chokes"). Type II DCS is a neurological emergency with potentially permanent consequences if not treated immediately.
HBOT is the only definitive treatment for DCS. By returning the patient to elevated pressure, HBOT physically compresses gas bubbles back into solution, restoring blood flow and tissue perfusion. Breathing 100% oxygen simultaneously accelerates the washout of dissolved nitrogen from tissues and reduces the inflammatory response triggered by bubble formation. Treatment must begin as rapidly as possible — delays significantly worsen outcomes, particularly in Type II DCS.
Important note about treatment at Bay Area Hyperbarics: DCS is the single most famous and well-recognized HBOT indication, yet in 28 years of practice at Bay Area Hyperbarics, we have seen only one case. This reflects the geography of DCS: most patients are divers who become symptomatic near the ocean — at Monterey Bay, the Bay Area coastline, or coastal sites in Santa Cruz and Watsonville — and they require treatment within hours of symptom onset. Hospital-based hyperbaric facilities located closer to these dive sites are better positioned to provide immediate emergency recompression for most DCS patients. We refer severe or acute DCS cases to appropriate hospital-based hyperbaric centers near the site of injury. If you or someone you know has experienced DCS symptoms, call 911 and contact the nearest hospital with a hyperbaric unit immediately — do not delay treatment while traveling to Los Gatos.
Deep, aching joint pain — most commonly in the shoulders, elbows, hips and knees (Type I)
Skin mottling, rash or itching (cutaneous DCS)
Neurological symptoms — weakness, numbness, tingling, paralysis, bladder dysfunction (Type II)
Inner ear symptoms — vertigo, tinnitus, hearing loss (inner ear DCS)
Respiratory symptoms — chest pain, shortness of breath, "the chokes" (pulmonary DCS)
Loss of consciousness, stroke-like symptoms or cardiovascular collapse in severe cases
How HBOT eliminates decompression bubbles and restores tissue health
DCS is caused by gas bubbles forming in blood and tissue. HBOT is the only treatment that physically eliminates those bubbles while simultaneously treating the ischemia and inflammation they cause.
Physically compresses gas bubbles back into solution
Accelerates nitrogen washout from tissues
Restores oxygen delivery to ischemic tissue
Reduces neurological inflammation and edema
Prevents permanent neurological injury
Treats pulmonary and cardiovascular complications
For Providers
Clinical evidence for HBOT in decompression sickness
HBOT for decompression sickness is a Medicare-approved indication and one of the most thoroughly established applications in all of hyperbaric medicine, with an evidence base built over more than a century of diving medicine research and practice.
Foundational mechanism: Boyle's Law underpins the physics of DCS treatment — increasing ambient pressure reduces the volume of gas bubbles, physically returning dissolved nitrogen back into solution in blood and tissue. Breathing 100% oxygen simultaneously accelerates nitrogen washout by creating a steep inert gas gradient between tissues and the breathing gas, and reduces the ischemia and inflammation that bubble formation triggers.
U.S. Navy Treatment Tables: The U.S. Navy developed the standardized recompression protocols — particularly Treatment Table 6 (TT6) — that remain the gold standard for DCS management worldwide. TT6 involves recompression to 60 feet of seawater equivalent (2.8 ATA) while breathing 100% oxygen in a structured cycle, typically lasting approximately 4 hours 45 minutes per session. These tables were developed through systematic empirical research from the 1930s through the 1960s and have been validated across thousands of clinical cases. [Moon RE, Gorman DF. Decompression sickness. Physiology and medicine of diving. 2003.]
Outcome data: Vann et al. and colleagues have documented that early treatment with HBOT results in complete or near-complete resolution in the majority of Type I DCS cases, and substantially improves outcomes in Type II DCS including spinal cord involvement. Delays in treatment correlate directly with worse neurological outcomes. [Vann RD et al. Decompression illness. Lancet. 2011;377(9760):153–164. PMID: 21215883]
Inner ear DCS: Inner ear DCS, involving vestibular and cochlear structures, is a recognized subtype requiring prompt HBOT. Edema and hemorrhage in labyrinthine structures respond poorly to delayed treatment. Early HBOT is associated with significantly better vestibular and hearing recovery. [Klingmann C et al. Undersea Hyperb Med. 2012;39(4):847–852. PMID: 22905503]
UHMS and DAN: Both the Undersea and Hyperbaric Medical Society (UHMS) and Divers Alert Network (DAN) recognize HBOT as the definitive treatment for all forms of DCS. DAN operates a 24-hour diving emergency hotline (+1-919-684-9111) that provides immediate expert guidance for DCS emergencies worldwide.
HBOT protocol for decompression sickness
DCS treatment follows standardized U.S. Navy recompression protocols. Because of the emergency nature of DCS and the importance of geographic proximity to treatment, most patients should be directed to the nearest hospital-based hyperbaric facility. We are available to assist with coordination and triage.
Emergency assessment and immediate transfer coordination
DCS is a time-critical emergency. If you suspect DCS, the first priority is reaching the nearest hospital-based hyperbaric facility as quickly as possible. We can assist with triage, provide guidance on emergency oxygen administration during transport, and help coordinate transfer to the appropriate facility. In the Bay Area and along the central California coast, hospital-based hyperbaric centers near common dive sites — including facilities in Monterey, San Francisco and the Watsonville/Santa Cruz area — are best positioned for immediate DCS care.
Recompression with 100% oxygen using Navy Treatment Tables
The standard DCS protocol — U.S. Navy Treatment Table 6 — involves recompression to 2.8 ATA (approximately 60 feet of seawater equivalent) while breathing 100% oxygen in a structured 20/5 minute cycle over approximately 4 hours 45 minutes. Neurological DCS may require longer or extended tables. Most patients require one to three treatment sessions, though residual neurological deficits may require additional courses.
Monitoring and adjunctive care
Rehydration, neurological monitoring and rest are standard adjuncts to HBOT recompression. Patients with residual symptoms following standard recompression may benefit from additional HBOT sessions targeting neurological recovery. We coordinate follow-up HBOT for patients with residual DCS deficits once the acute emergency has been managed at a hospital-based facility.
Frequently Asked Questions
Answers to the questions divers and families most commonly ask about decompression sickness and HBOT treatment.
DCS occurs when a diver breathes compressed gas at depth — typically air or nitrox — causing nitrogen to dissolve into the blood and tissues at elevated concentrations. If the diver ascends too quickly, ambient pressure drops faster than the body can safely eliminate the dissolved nitrogen, and bubbles form in blood and tissues. These bubbles mechanically obstruct blood flow and trigger an inflammatory cascade, causing DCS symptoms ranging from joint pain to neurological emergencies.
Questions about DCS or HBOT? We can help
For acute decompression sickness, please go immediately to the nearest emergency room and call DAN at +1-919-684-9111. For questions about HBOT for DCS, residual diving injury, or to coordinate care following emergency recompression, call Bay Area Hyperbarics.
