What initial treatment is required for mediastinal and subcutaneous emphysema?

Breathing 100 percent oxygen at the surface is the initial treatment required for mediastinal and subcutaneous emphysema because it helps to reabsorb the air trapped in the tissues and the mediastinum. High concentrations of oxygen facilitate the absorption of nitrogen and reduce the partial pressure of gases within those areas. This approach effectively helps to reduce the volume of air trapped in the tissues, promoting resolution of the emphysema without the need for more invasive procedures.

The other options, while they may have their own merits in certain medical situations, do not address the immediate need for treating emphysema effectively. Immediate surgery is typically reserved for more severe or complicated cases where there are additional life-threatening factors involved. Administering pain medication can be useful for managing discomfort but does not treat the underlying cause of emphysema. Hydration with IV fluids can support overall health but does not directly impact the presence of air in the tissues. Hence, breathing 100 percent oxygen stands out as the most directly effective initial treatment.