Decompression Sickness

Decompression Sickness

Decompression Sickness (DCS), also known as the bends, is a condition arising from dissolved gases coming out of solution into bubbles inside the body due to a rapid decrease in pressure. It is most commonly associated with divers who ascend too quickly, but it can also occur in aviators and astronauts.

Pathophysiology

DCS occurs when inert gases, primarily nitrogen, that are dissolved in body tissues and blood under high pressure form bubbles as the pressure decreases. These bubbles can cause mechanical and biochemical effects, leading to a variety of symptoms.

Bubble Formation

During a dive, the body absorbs nitrogen from the breathing gas. If the diver ascends too quickly, the reduction in pressure causes the nitrogen to come out of solution and form bubbles. These bubbles can obstruct blood vessels, compress nerves, and trigger inflammatory responses.

Symptoms

The symptoms of DCS can vary widely depending on the location and size of the bubbles. Common symptoms include:

• Joint and muscle pain (the "bends")
• Dizziness and vertigo
• Fatigue
• Difficulty breathing
• Skin rashes
• Neurological symptoms such as confusion or paralysis

Diagnosis

Diagnosis of DCS is primarily clinical, based on the history of recent pressure changes and the presence of characteristic symptoms. Imaging studies, such as MRI, can be used to assess the extent of neurological involvement.

Treatment

The primary treatment for DCS is hyperbaric oxygen therapy. This involves placing the patient in a hyperbaric chamber where they breathe 100% oxygen at increased pressure. This helps to reduce bubble size and improve oxygen delivery to tissues.

First Aid

Immediate first aid for suspected DCS includes:

• Administering 100% oxygen
• Keeping the patient lying flat
• Hydration
• Rapid transport to a medical facility with hyperbaric capabilities

Prevention

Preventing DCS involves careful planning and adherence to safe diving practices:

• Ascend slowly and perform safety stops
• Use dive tables or dive computers to monitor nitrogen levels
• Avoid flying or ascending to high altitudes soon after diving

Related Conditions

DCS is related to other conditions caused by pressure changes, such as arterial gas embolism and barotrauma.

See Also

• Scuba diving
• Hyperbaric medicine
• Nitrogen narcosis

References

• Edmonds, C., Lowry, C., Pennefather, J., & Walker, R. (2015). Diving and Subaquatic Medicine. CRC Press.
• Vann, R. D., Butler, F. K., Mitchell, S. J., & Moon, R. E. (2011). Decompression illness. The Lancet, 377(9760), 153-164.