How can gas enter the bloodstream and cause serious damage to the lungs or even death?

Gas can enter the bloodstream and cause serious damage to the lungs or even result in death through several mechanisms related to the pressures and behaviors of gas during diving.

One significant way is through ascending too fast. When a diver ascends rapidly, the pressure decreases quickly, which can lead to the formation of gas bubbles in the bloodstream. This phenomenon is known as decompression sickness, or "the bends," where nitrogen that was dissolved in the blood under higher pressure comes out of solution as bubbles, which can obstruct blood vessels and lead to serious injury or death.

Holding your breath underwater is another critical factor. If a diver ascends while holding their breath, the expanding gases in the lungs can cause lung overexpansion injuries, leading to ruptured alveoli and potentially allowing gas to escape into the bloodstream. This can also result in an air embolism, where gas bubbles enter the vascular system, creating blockages and leading to severe health complications.

Diving with respiratory congestion can exacerbate these risks. Congestion can make it more difficult to equalize pressures in the lungs and sinuses, increasing the likelihood of lung overexpansion or difficulty voiding air on ascent. This condition can also impair the normal exchange of gases in the lungs, increasing the risk