Arterial Gas Embolism (AGE)

Embolism in medical terms is a condition which describes objects called emboli, in this case they are gas bubbles, formed in a human body which enter the circulatory system.

Emboli (gas bubbles) can block arterial or venous blood flow. Another harming effect of AGE includes platelets clumping. This leads to the obstruction of blood vessel walls and leaking of fluids into surrounding tissues. The resulting swelling further reduces tissue blood flow.

A condition associated with this serious problem often referred to as either Arterial Gas Embolism (AGE) or Air Gas Embolism. Play the short video below to visualize AGE formation...

Gas bubbles (emboli) leading to AGE can be formed in the body by several possible reasons, some of them are listed below:

• During rapid ascent in divers in divers after breathing compressed gas at depth
• During normal ascent in divers with lung pathology, e.g. asthma, bullous disease, etc...
• Pulmonary Barotrauma as a result of blast injury in or out of water
• Chest tube placement
• Bronchoscopy
• Penetrating chest trauma
• Mechanical ventilation
• Accidental intravenous air injection

AGE - Possible Outcomes

Compromised blood circulation promoted by AGE ("the bends") results in poor oxygen delivery to the affected body areas. Possible outcomes of AGE may be permanent with severe impact on the quality of life and be disastrous.

AGE can result in irreversible physical disabilities and in severe cases be fatal. The damage can affect vital organs like brain (cerebral embolism), heart or lungs, can impair the vision, paralyze the limbs and lead to a total disability.

Symptoms of AGE

• Extreme fatigue
• Dizziness
• Joint pain
• Hearing loss
• Numbness
• Tingling
• Skin rash
• Paralysis
• Weakness of arms or legs

AGE Treatment

Hyperbaric Oxygen Therapy remains the definitive treatment of choice for AGE. A review of numerous cases of cerebral embolism and AGE reveals superior outcomes with the use of Hyperbaric Oxygen Therapy comparing to non-recompression treatment. Only Hyperbaric Oxygen Therapy if applied in time can immediately restore cellular oxygenation levels correcting blood flow in deprived sites and tissue swelling.

The rationale behind the AGE treatment is that increased pressure inside Hyperbaric Chamber reduces bubbles size and forces the gas inside the bubbles back into a physical solution, the blood and plasma. Higher oxygen levels create a large diffusion gradient for inert gas to leave bubbles and thus restoring normal blood flow. With restored blood flow, poorly oxygenated tissues start receiving more oxygen, and local edema gradually subsides. Hyperbaric Oxygen Therapy reduces ischemic-reperfusion injury.

Usually AGE is treated according to US Navy Treatment Table 6A applying the pressure of 6ATA. If after initial recompression the symptoms of AGE still present, another deeper recompression may be required.

During decompression in Hyperbaric Chamber in cases when AGE was caused by Pulmonary Barotrauma, a complication may occur with coexisting Pneumothorax which can develop into Tension Pneumothorax. Such patients should be closely monitored during Hyperbaric Treatment. For patients treated in a Monoplace Hyperbaric Chamber a chest tube insertion before the Hyperbaric Oxygen Treatment can be considered. In cases of AGE with co-existing Pneumomediastinum no specific therapy is generally required and the condition is usually corrected by Hyperbaric Oxygen Treatment.

An injured diver is helped from a Royal Navy Sea King Helicopter on arrival at Millport on the Island of Cumbrae for treatment at the Hyperbaric Chamber at the islands University Marine Biology Station.

Photo courtesy of "Sea Pigeon"