Decompression Illness: Causes and Treatments

Decompression illness (DCI) is a term that encompasses various medical conditions arising from the reduction in ambient pressure surrounding a person, usually after scuba diving. These conditions are chiefly associated with the formation of gas bubbles in the blood or tissues due to rapid decompression. 

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Causes of Decompression Illness

Decompression illness occurs when dissolved gases, primarily nitrogen, come out of solution and form bubbles in the body. This phenomenon is often a result of a diver ascending too rapidly and not allowing sufficient time for the inert gases absorbed under pressure to be safely expelled from the body through respiration.

The Role of Nitrogen in Decompression Illness

While diving, increased pressure allows for more nitrogen to dissolve into the body’s tissues. If ascent occurs too quickly, the rapid decrease in pressure can lead to nitrogen coming out of solution too rapidly, forming bubbles in the bloodstream and tissues. This is akin to the fizz that forms in a soda bottle when opened quickly. These bubbles can cause a range of physiological disturbances, leading to decompression sickness, also known as "the bends".

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Types of Decompression Illness

Decompression illness is broadly classified into two types: Decompression Sickness (DCS) and Arterial Gas Embolism (AGE).

Decompression Sickness (DCS)

DCS, commonly referred to as "the bends", manifests when nitrogen bubbles form in tissues and blood. This can occur in various parts of the body, leading to joint and limb pain, dizziness, fatigue, and in severe cases, neurological symptoms.

Arterial Gas Embolism (AGE)

AGE occurs when gas bubbles enter the arterial system, which can happen if a diver holds their breath during ascent, causing lung over-expansion and the release of gas bubbles into the bloodstream. This can lead to serious complications such as stroke-like symptoms, unconsciousness, or even death.

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Symptoms of Decompression Illness

Symptoms of decompression illness can vary widely depending on the severity and location of the bubbles. Common symptoms include:

It is crucial for divers to recognize these symptoms early, as timely treatment is essential to prevent long-term damage or fatality.

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Diagnosing Decompression Illness

Diagnosis of decompression illness is typically based on the patient’s symptoms and history of recent diving activity. A thorough physical examination is conducted, focusing on neurological function and respiratory status. In some cases, imaging studies such as MRI may be used to assess the extent of injury, particularly in severe cases with neurological involvement.

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Treatment for Decompression Illness

The primary treatment for decompression illness is hyperbaric oxygen therapy. This involves placing the patient in a hyperbaric chamber where they breathe 100% oxygen at increased atmospheric pressure. This treatment helps reduce the size of nitrogen bubbles and facilitates their elimination from the body.

Hyperbaric Oxygen Therapy

Hyperbaric oxygen therapy is effective because it increases the amount of oxygen in the blood, promoting healing and reducing edema in affected tissues. The increased pressure helps to dissolve nitrogen bubbles, alleviating symptoms and preventing further complications.

Supportive Care and Monitoring

In addition to hyperbaric therapy, supportive care is vital. Patients should be monitored for respiratory and cardiovascular stability, and pain management should be addressed. Hydration is also important, as it helps in the natural elimination of nitrogen through urination.

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Preventive Measures Against Decompression Illness

Preventing decompression illness is paramount for divers. The following strategies are recommended:

Adhering to Safe Diving Practices

Divers should follow established dive tables or dive computers to manage ascent rates and decompression stops. Avoiding excessive exertion during and after dives is also advisable, as it can increase the risk of bubble formation.

Pre-dive Planning and Education

Comprehensive pre-dive planning, including understanding dive profiles and limits, is essential. Divers should be educated on the risks of nitrogen narcosis and the importance of slow ascents and safety stops.

Fitness and Health Considerations

Maintaining physical fitness and addressing any underlying health issues can reduce the risk of DCI. Divers should avoid diving with a cold or congestion, as this can impede the equalization of pressure in air spaces.