Which of the following methods is most effective for treating a diver with arterial gas embolism?

Administering pure oxygen in a recompression chamber is the most effective method for treating a diver with arterial gas embolism because it addresses the underlying issue of gas bubbles in the bloodstream. When a diver ascends too quickly or experiences a significant change in pressure, nitrogen dissolved in the body can form bubbles, leading to serious complications like arterial gas embolism.

By placing the diver in a recompression chamber and providing pure oxygen, the bubbles are subjected to increased pressure, allowing them to reduce in size and be more easily absorbed by the body. The high concentration of oxygen promotes better healing and reduces the risk of further neurological damage caused by the bubbles obstructing blood flow. This treatment significantly enhances the chances of recovery by facilitating the elimination of nitrogen from the bloodstream more effectively than other methods.

Other options like immediate ascent, increasing physical activity, or providing warm fluids do not directly manage the gas bubbles or address the critical need for pressure stabilization, making them less effective in providing the necessary treatment for this condition.