Gas Embolism in Scuba Diving

Gas embolism, a critical and potentially life-threatening condition, occurs when gas bubbles enter the bloodstream and block blood vessels. In scuba diving, gas embolisms are often the result of rapid ascents, poor breathing techniques, or equipment malfunction. To ensure the safety of divers and prevent the occurrence of gas embolisms, it is essential to understand the causes, symptoms, and management strategies for this condition.

Causes of Gas Embolism in Scuba Diving

  1. Decompression Sickness (DCS)

Decompression sickness, also known as the bends, is a primary cause of gas embolism in scuba diving. DCS occurs when divers ascend too quickly, causing dissolved inert gases (mainly nitrogen) in the body to come out of solution and form bubbles in tissues and blood vessels. These bubbles can then obstruct blood flow, leading to a gas embolism.

  1. Pulmonary Barotrauma

Pulmonary barotrauma, or lung overexpansion injury, is another common cause of gas embolism in scuba diving. This occurs when a diver holds their breath during ascent, causing the air in their lungs to expand due to decreasing pressure. The expanding air can rupture lung tissues, allowing air to enter the bloodstream and form gas bubbles, leading to an arterial gas embolism (AGE).

  1. Equipment Malfunction

Faulty or poorly maintained scuba diving equipment can also contribute to the development of a gas embolism. For example, a malfunctioning regulator may deliver air at an excessive pressure, causing lung overexpansion and increasing the risk of AGE.

Symptoms and Diagnosis

The symptoms of a gas embolism can range from mild to severe and may vary depending on the location and size of the gas bubble. Common symptoms include:

  1. Chest pain
  2. Shortness of breath
  3. Dizziness or vertigo
  4. Visual disturbances, such as blurred vision or tunnel vision
  5. Confusion or altered mental status
  6. Seizures or unconsciousness

Diagnosing a gas embolism can be challenging due to its nonspecific symptoms. Physicians often rely on a combination of factors, including the patient’s diving history, the presence of risk factors, and the timing and nature of the symptoms. Imaging techniques, such as computed tomography (CT) scans or magnetic resonance imaging (MRI), may be used to confirm the diagnosis and assess the severity of the condition.

Prevention and Management

Preventing gas embolisms in scuba diving involves adherence to safe diving practices, proper equipment maintenance, and diver education. Key prevention strategies include:

  1. Gradual Ascent and Safety Stops

Divers should ascend slowly, no faster than 30 feet (9 meters) per minute, to allow inert gases to be eliminated safely from the body. Performing safety stops, such as a three-minute stop at 15 feet (4.5 meters), can further reduce the risk of DCS and gas embolism.

  1. Proper Breathing Techniques

Divers should avoid breath-holding during ascent to minimize the risk of lung overexpansion injuries. Breathing continuously and slowly helps maintain adequate ventilation and prevents gas trapping in the lungs.

  1. Regular Equipment Maintenance

Regular inspection and servicing of scuba diving equipment, particularly regulators and buoyancy compensator devices (BCDs), can help prevent equipment-related gas embolisms.

  1. Diver Education and Training

Divers should receive training on the risks, prevention, and management of gas embolisms from a reputable organization, such as the Professional Association of Diving Instructors (PADI) or Scuba Schools International (SSI).

Treatment of Gas Embolism

Immediate management of a gas embolism involves providing first aid and seeking professional medical help as soon as possible. Key treatment steps include:

  1. Surface and Administer Oxygen

If a diver is suspected of having a gas embolism, they should be brought to the surface safely and immediately. Once on the surface, the diver should be provided with 100% oxygen, which can help reduce the size of gas bubbles and improve oxygen delivery to the tissues.

  1. Maintain Airway, Breathing, and Circulation

Ensuring the diver’s airway is open, maintaining adequate breathing, and monitoring circulation are essential in managing a gas embolism. In some cases, cardiopulmonary resuscitation (CPR) or advanced life support may be required.

  1. Place the Diver in a Horizontal Position

The diver should be placed in a horizontal or slightly head-down position to minimize the risk of gas bubbles moving to vital organs, such as the brain or heart.

  1. Seek Emergency Medical Assistance

Gas embolism is a medical emergency, and immediate professional medical help should be sought. In many cases, recompression therapy using a hyperbaric chamber is the definitive treatment for gas embolisms. This therapy involves exposing the patient to increased pressure, which helps reduce the size of gas bubbles and facilitates their elimination from the body. Additional treatments, such as intravenous fluids, pain relief, and medications to control seizures or other symptoms, may also be necessary.


Gas embolism is a serious and potentially life-threatening condition that can occur during scuba diving. By understanding its causes, symptoms, and prevention strategies, divers can minimize their risk and enjoy safer diving experiences. In the event of a suspected gas embolism, prompt first aid and professional medical treatment are crucial for the best possible outcome. As with all aspects of scuba diving, proper training, vigilance, and adherence to safety protocols are key in preventing and managing gas embolisms.