During a rescue, what is the best practice for managing a diver with suspected DCS?

The best practice for managing a diver with suspected Decompression Sickness (DCS) is to provide immediate oxygen and monitor symptoms. Oxygen serves multiple purposes in this scenario; it helps to reduce the size of nitrogen bubbles that may have formed in the diver’s tissues and blood, promotes healing, and alleviates some symptoms associated with DCS. Administering oxygen as soon as possible can significantly improve the diver’s condition and is a critical step in the management of suspected DCS.

Monitoring symptoms is equally important, as it helps the responder track any worsening or improvement in the diver's condition and make informed decisions about further medical intervention. This practice underscores the importance of being vigilant and ready to escalate care if necessary, such as preparing for transport to a hyperbaric chamber.

The other choices do not reflect best practices. Swimming to shore could exacerbate the condition by increasing stress and potentially leading to further complications. Leaving a diver to decompress on their own risks delaying necessary medical treatment, which can worsen outcomes. Rapid ascent to the surface is dangerous, especially for a diver suspected of having DCS, as it can lead to further injury or complications. Therefore, providing immediate oxygen and closely monitoring symptoms is the appropriate and effective response in such a situation.