Hyperbaric Oxygen Therapy for Decompression Sickness (“The Bends”)
Decompression Sickness (DCS) is a critical medical emergency. Immediate recompression in a Clinical Hyperbaric Chamber is the only definitive treatment for resolving intravascular bubbles and restoring neurological function.
Intro: The Gold Standard for Diving and Pressure Injuries
Decompression Sickness (DCS), commonly known as “the bends,” is the foundation upon which modern hyperbaric medicine was built. Whether occurring in a professional diver in the Great Lakes, a recreational diver on vacation, or a high-altitude pilot, DCS is a complex systemic syndrome caused by the evolution of inert gas bubbles in the blood and body tissues.
Hyperbaric Oxygen Therapy (HBOT) is not merely an adjunctive treatment for Decompression Sickness; it is the primary, life-saving clinical mandate. At TorontoHyperbaric.ca, we represent the highest standard of diving medicine in Ontario, providing the clinical infrastructure and emergency recompression expertise required to manage these traumatic events with the highest medical precision.
1. What is Decompression Sickness?
To understand DCS, one must understand the fundamental relationship between gas, liquid, and pressure.
The Physics of Henry’s Law: Gas Saturation
According to Henry’s Law, the amount of gas that dissolves into a liquid is proportional to the partial pressure of that gas. When a diver descends and the ambient pressure increases, nitrogen from the air they breathe is forced to dissolve into their blood and tissues (saturation).
The Evolution of Bubbles: Desaturation and Ascent
As a diver ascends, the ambient pressure decreases, and the nitrogen must leave the tissues (desaturation). If the ascent is too rapid, the nitrogen cannot stay dissolved and instead forms bubbles—much like the bubbles that form when you quickly open a carbonated beverage. These bubbles can physically obstruct blood flow, damage the lining of the blood vessels, and trigger a massive inflammatory response.
2. Categorizing “The Bends”: Type I vs. Type II DCS
Clinical management of DCS is determined by the severity and location of the bubbles.
Type I DCS (Pain-Only)
Type I is generally less severe but still requires urgent recompression to prevent progression.
- Musculoskeletal Pain: Often felt in the shoulders, elbows, or knees (hence the term “the bends”).
- Skin Manifestations: Itching (pruritus) or localized rashes.
- Lymphatic Involvement: Localized swelling and tenderness.
Type II DCS (Neurological & Cardiovascular)
Type II DCS is a life-threatening emergency that involves vital organ systems.
- Neurological: Numbness, tingling, paralysis, or “the staggers” (vestibular DCS).
- Pulmonary (The Chokes): Severe shortness of breath, chest pain, and cough.
- Cardiovascular: Hypovolemic shock due to fluid leaking from damaged vessels.
3. The Recompression Mechanism: Resolving the Bubbles
The primary therapeutic effect of HBOT in treating DCS is governed by two physiological laws:
Boyle’s Law: Immediate Volume Reduction
The first goal of treatment is to physically reduce the size of the bubble. Under recompression (typically to 2.8 ATA or higher), the bubble’s volume is instantly reduced. For example, at 2.8 atmospheres, an air bubble is compressed to less than 40% of its original size. This can allow a previously “stuck” bubble to enter the smaller micro-circulation where it can be dissolved.
Creating the Oxygen Washout Gradient
While the patient is under pressure, they breathe 100% molecular oxygen. This creates a massive partial pressure gradient between the nitrogen in the bubble and the nitrogen-free blood surrounding it. This causes the nitrogen to rapidly diffuse out of the bubble and into the blood plasma, where it is transported to the lungs and exhaled. This “washout” leads to the total dissolution of the bubbles.
4. The Clinical Gold Standard: US Navy Recompression Table 6
In Ontario, the standard of care for Decompression Sickness is the US Navy Recompression Table 6.
Step 1: Initial Descent to 60 Feet
The session begins with a rapid descent to a depth of 60 feet (2.8 ATA). This depth is specifically chosen to provide a balance between maximum bubble compression and a safe concentration of oxygen.
Step 2: Oxygen Breathing Cycles & Air Breaks
The patient breathes 100% molecular oxygen through a specialized mask or hood in 20-minute cycles. These are followed by 5-minute “air breaks” to minimize the risk of oxygen toxicity.
Step 3: Gradual Decompression
The session involves a slow, controlled ascent back to the surface, lasting approximately 4 hours and 45 minutes in total. If symptoms are severe or slow to resolve, the table can be extended with additional time at the 60-foot or 30-foot levels.
5. Emergency Protocols for Ontario Divers
Ontario’s Great Lakes are world-renowned for wreck diving, but the colder water and extreme depths present unique risks for DCS.
Immediate Oxygen First-Aid
If you or a dive buddy shows symptoms of DCS, the first and most critical step is 100% Surface Oxygen. This should be administered immediately via a non-rebreather mask to begin the nitrogen washout process while you are in transit.
Regional Referral Paths in the GTA
For diving accidents occurring near Toronto, North York, or Scarborough, treating emergency physicians must coordinate with the Divers Alert Network (DAN) and regional clinical hubs for emergency recompression. Our centralized hub at 525 Markham Rd provides the specialized medical-grade infrastructure and expert technicians necessary for both acute recompression and long-term neurological follow-up for the diving community.
6. Summary: The Definitive Response to Pressure Injury
Decompression Sickness is a condition of trapped gas. High-pressure recompression is the only physiological method to physically reduce the bubbles and restore cellular function.
At TorontoHyperbaric.ca, we provide the clinical clarity, emergency recompression expertise, and specialized support required by Ontario’s diving community to manage “the bends” with the highest standard of medical precision.
To discuss clinical next steps, contact our team or review the physician referral portal.