If a diver suspects decompression sickness, what should they do immediately?

When a diver suspects decompression sickness (DCS), the most critical action is to seek medical assistance and remain calm. Decompression sickness can occur when a diver ascends too quickly, leading to the formation of nitrogen bubbles in the body, which can cause various symptoms, including joint pain, dizziness, and respiratory issues. Recognizing the seriousness of these symptoms is crucial.

By seeking medical assistance immediately, the diver ensures that they receive the necessary care, such as hyperbaric oxygen therapy, which is essential to treat DCS effectively. Remaining calm helps to manage the situation better, as panic can exacerbate the diver’s condition or hinder the ability to communicate symptoms and needs effectively. Timely intervention is vital in reducing the risks associated with DCS and ensuring the diver's safety.

The other choices present actions that could significantly worsen the situation. Continuing to dive or descending deeper can increase the risk of more severe symptoms and complications. Ignoring the symptoms entirely disregards a serious medical condition that requires attention. Therefore, seeking medical assistance while staying calm is the correct and safest response.