What is the first action if a diver shows signs of decompression sickness?

• A. Stop diving and begin emergency response
• B. Ascend safely
• C. Continue the dive as planned
• D. Seek medical attention after emergency response

Answer: (A)

When decompression sickness signs appear, the immediate priority is to stop diving and start emergency response. This is a medical emergency, so halting the dive prevents any further exposure to high pressure and gives the diver the best chance for rapid treatment. While you implement this, provide 100% oxygen if available to help reduce bubble size and improve tissue oxygenation, and get emergency services on the line or arrange transport to a recompression facility as quickly as possible.

Continuing the dive or ascending without addressing the symptoms can worsen the condition by increasing bubble formation or delaying critical treatment. Waiting to seek medical attention after “emergency response” delays care; the first action should already involve initiating that response and getting professional help, with oxygen support provided in the meantime.