Hyperbaric oxygen chambers represent the most fundamental and effective treatment for decompression sickness (commonly known as “the bends”). Their core principle adheres to the laws of gas physics and physiology, employing a scientific process of “pressurization, stabilization, and gradual decompression” to eliminate abnormal gas bubbles within the body and restore normal tissue function.

Step 1: Pressurization—Forcing Bubbles Back
When divers ascend too rapidly, inert gases dissolved in the blood and tissues (primarily nitrogen) escape due to sudden pressure reduction, forming microscopic bubbles. These bubbles obstruct blood vessels and compress nerves, triggering symptoms such as severe joint pain, skin itching, dizziness, numbness, and even paralysis.
The first step in hyperbaric oxygen chamber therapy is rapidly elevating chamber pressure to a level exceeding the depth at which symptoms occurred (typically 2.0 to 2.8 ATA or higher, determined by symptom severity and diving profile). According to Boyle’s Law (at constant temperature, gas volume is inversely proportional to pressure), increasing environmental pressure immediately compresses existing bubbles within the body, significantly reducing their size. This alleviates mechanical compression on blood vessels and nerves, rapidly relieving acute pain and neurological symptoms.

Step 2: Stable Pressure Oxygenation—Accelerating Bubble Dissolution and Expulsion
At the target pressure, the patient breathes high-concentration oxygen (typically 100%) via a mask for a sustained period. This phase plays a critical role:

Oxygen Displaces Nitrogen: According to Henry’s Law, the solubility of a gas in a liquid is proportional to its partial pressure. Inhaling high partial pressure oxygen significantly increases blood oxygen partial pressure while creating a substantial nitrogen partial pressure gradient. This drives nitrogen diffusion from bubbles and surrounding tissues into the bloodstream, while oxygen is metabolized by tissues. This process accelerates nitrogen dissolution and elimination within bubbles.

Correcting Hypoxia and Edema: Hyperbaric oxygen dramatically increases the physical solubility of oxygen in plasma, enabling direct oxygen delivery to hypoxic tissues without relying on hemoglobin. This rapidly corrects tissue ischemia and hypoxia caused by bubble embolism while reducing vascular leakage and edema.

Step 3: Slow Decompression—Safely and Thoroughly “Guiding” Gas Out
This is critical to treatment success. After bubbles are largely dissolved and symptoms sufficiently alleviated, chamber pressure is reduced at an extremely slow, controlled rate following a strictly defined decompression profile. This process mimics the “staged decompression” required in diving, allowing ample time for residual dissolved inert gases in the body to be gradually transported via the bloodstream to the lungs and safely exhaled. This prevents the reformation of harmful bubbles during decompression.

In summary, hyperbaric oxygen chamber therapy for decompression sickness is a systematic physical treatment process: it first addresses symptoms by compressing small bubbles, then accelerates bubble dissolution and improves tissue oxygenation through steady-pressure oxygenation to address the root cause, and finally ensures safe gas expulsion and prevents recurrence through meticulously controlled, gradual decompression. Conducted under strict monitoring, this therapy directly targets the core pathology of decompression sickness, offering a curative treatment.