Decompression Illness (DCI)

The umbrella term covering both decompression sickness and arterial gas embolism, used because first aid and chamber treatment are the same for both.

Decompression illness is the umbrella term that covers the two serious bubble-related diving injuries: decompression sickness (DCS), where dissolved inert gas forms bubbles in tissue and blood after ascent, and arterial gas embolism (AGE), where lung overexpansion forces gas directly into the arterial circulation. The two have different mechanisms, one is about gas loading over the whole dive, the other about a breath-holding or lung injury event on ascent, but in a real casualty they can be hard to tell apart.

That is exactly why the term exists. Rescuers in the field do not need to diagnose which one they are looking at, because the response is identical: lay the diver down, give 100 percent oxygen, keep them hydrated, monitor breathing, and call the DAN emergency line to organize evacuation to a hyperbaric chamber, where recompression treats both conditions. Timing offers a rough clue, AGE typically strikes within minutes of surfacing while DCS more often develops over the following hours, but treatment does not wait on certainty.

In practice you will see DCI used in incident reports, dive medicine texts, and insurance paperwork, while divers chatting on the boat still say bends or DCS. If you are ever involved in a suspected DCI case, the dive profile matters: computer downloads and logbook entries for the last 48 hours are among the first things the dive physician will ask for.