How to Avoid Rapid Ascents and Arterial Gas Embolism

Decompression illness (DCI) is a term used to describe two conditions: decompression sickness (DCS) and arterial gas embolism (AGE). AGE is one of the most serious medical emergencies a diver may experience. It can occur following a rapid ascent without adequate exhalation and is one of the reasons for the golden rule of scuba: never hold your breath.

As a diver ascends, air in the lungs expands. If the diver fails to exhale sufficiently, the expanding air may rupture lung tissue (pulmonary barotrauma) and release gas bubbles into the arteries (arterial gas embolism) or elsewhere in the body. These bubbles can restrict blood flow and cause damage in the brain and other body tissues.

AGE Recognition and Treatment

The signs and symptoms of AGE typically occur within 15 minutes of surfacing and may include:

• Loss of consciousness
• Confusion
• Convulsions
• Bloody froth from the mouth or nose
• Weakness or paralysis in the extremities

An arterial gas embolism is extremely serious, and a diver with suspected AGE requires immediate medical treatment. If you observe symptoms of AGE, contact emergency medical services and provide the diver with emergency oxygen.

Avoiding Rapid Ascents

The best way to avoid AGE and other pressure-related injuries is to ascend slowly every time you dive. Use your dive computer or depth gauge to monitor your ascent rate and conduct a slow, controlled ascent. The U.S. Navy uses an ascent rate of 30 feet per minute rule.

Rapid ascents can be prevented by using a well-maintained BCD (and drysuit, if applicable) and remembering to vent air periodically during ascent. Divers should also routinely refresh their emergency skills, such as what to do with a stuck inflator.

Proper weight distribution is also important, as one diver learned when her weight belt fell off unexpectedly. In an emergency, a diver experiencing a rapid ascent can flare out their arms and legs to create drag or try to swim away from the surface.

Be Prepared

There are instances of AGE occurring after an otherwise normal, safe ascent due to medical factors such as asthma, infections, cysts, tumors, scar tissue from surgery or obstructive lung disease. The cost of emergency medical transportation averages US$20,000 — an unforeseen expense no diver wants to pay out of pocket.

Many health insurance plans won’t cover hyperbaric treatments and or emergency transportation. Learn more about DAN’s low cost, flexible dive accident coverage plans and be prepared.