What should be done for a diver that is symptom-free upon surfacing with in-water DCS treatment?

Administering 100% oxygen and proceeding to a treatment table, specifically TT-5, is the appropriate response for a diver who is symptom-free upon surfacing after in-water decompression sickness (DCS) treatment.

Oxygen therapy is critical in managing decompression sickness, as it helps to eliminate nitrogen bubbles from the body more effectively than air. By providing 100% oxygen, the body can better absorb the gas, speeding up the healing process. Additionally, moving to a treatment table like TT-5 ensures that the diver receives appropriate medical attention and monitoring, as this stage can still carry risks even if the diver appears symptom-free.

This approach prioritizes the diver's safety and health, as it addresses the potential for delayed symptoms or complications associated with DCS. The treatment tables provide a controlled environment for administering oxygen under specific pressures, which can enhance the efficacy of the treatment.

Monitoring and waiting for symptoms to develop or attempting rapid ascents are not acceptable courses of action, as they could increase the risk of serious complications or exacerbate the diver's condition. Immediate and proactive treatment is essential in managing potential DCS effectively.