Emergency oxygen

When a diver suffers from decompression sickness (DCS) or arterial gas embolism (AGE), excess inert gas (primarily nitrogen) forms bubbles in the blood and tissues. Administering 100% oxygen creates a steep gradient between the partial pressure of oxygen in the lungs and the partial pressure of nitrogen in the body. This gradient encourages the rapid off-gassing of nitrogen from the bubbles into the blood and then into the lungs, from where it is exhaled.

The high concentration of oxygen helps to shrink nitrogen bubbles by increasing the partial pressure of oxygen in the arterial blood, which subsequently allows more nitrogen to diffuse out of the bubbles. It also aids in reducing swelling (oedema) caused by tissue damage, alleviates hypoxia (lack of oxygen) in compromised tissues, and helps restore normal physiological functions. The goal is to stabilise the diver and reduce symptoms while awaiting definitive medical care, which often involves recompression treatment in a hyperbaric chamber.

Effective oxygen administration involves maintaining a continuous flow of 100% oxygen using a non-rebreather mask or, for more severe cases and trained personnel, a demand valve. The demand valve delivers oxygen only on inhalation, providing a very high concentration directly to the diver's lungs, which is particularly effective for conscious, breathing divers. Proper monitoring of the diver's condition and ensuring a secure seal of the mask are crucial for maximising oxygen delivery.

For divers considering a liveaboard trip, the presence and proper maintenance of emergency oxygen equipment are fundamental safety considerations. Liveaboards often operate in remote areas where access to shore-based medical facilities and hyperbaric chambers can be hours or even days away. Therefore, immediate and effective oxygen first aid on board becomes critical for managing diving emergencies.

Reputable liveaboard operators are legally and ethically obliged to carry adequate emergency oxygen supplies. This typically includes multiple oxygen cylinders to ensure a continuous supply for extended periods, especially during transit to medical care. Dive staff, including divemasters and instructors, are usually certified in emergency oxygen administration, meaning they are trained to recognise symptoms of diving injuries and apply oxygen correctly.

Before booking or boarding a liveaboard, divers may wish to confirm the vessel's emergency protocols, including the availability of oxygen and the staff's training. This diligence contributes to a safer diving experience and provides reassurance that, in the unlikely event of a diving emergency, appropriate immediate care can be provided. Blue Rides lists liveaboards worldwide, many of which proudly highlight their comprehensive safety provisions, including emergency oxygen availability.

Myth: Emergency oxygen can cure decompression sickness completely. Fact: Emergency oxygen is a crucial first aid measure that can significantly alleviate symptoms and stabilise a diver suffering from decompression sickness (DCS) or arterial gas embolism (AGE). However, it is not a definitive cure. Divers with suspected DCS or AGE still require immediate medical evaluation and, in most cases, recompression treatment in a hyperbaric chamber for complete resolution.

Myth: Any oxygen is fine; medical-grade isn't strictly necessary. Fact: For diving emergencies, only 100% medical-grade oxygen should be used. Industrial oxygen or oxygen mixtures are not suitable because they may contain impurities or incorrect concentrations that could be harmful to an already compromised diver. Medical-grade oxygen ensures purity and effectiveness in aiding off-gassing and supporting tissues.

Myth: Divers should wait for symptoms to worsen before administering oxygen. Fact: Time is critical in diving emergencies. Emergency oxygen should be administered as soon as a diving-related injury is suspected, even if symptoms are mild or vague. Early intervention can significantly reduce the severity of the injury, prevent further deterioration, and improve the overall prognosis for recovery.

Myth: Oxygen administration is only for unconscious divers. Fact: While oxygen is vital for unconscious divers, it is equally important, if not more so, for conscious divers exhibiting symptoms of decompression illness. A conscious diver can often cooperate with oxygen delivery devices like non-rebreather masks or demand valves, ensuring high-concentration oxygen delivery that is crucial for initial management. For unconscious divers, advanced airway management and assisted breathing with oxygen may be required.