What is the purpose of having the diver breathe 100% oxygen upon arriving at the recompression chamber?

The purpose of having the diver breathe 100% oxygen upon arriving at the recompression chamber is primarily to enhance recovery from decompression sickness. When a diver experiences decompression sickness, it is often due to nitrogen bubbles forming in the body because of rapid ascent from a dive. Breathing pure oxygen helps to reduce the size of these bubbles and facilitate their elimination from the body. This process occurs through a mechanism called hyperoxia, where increased oxygen levels in the blood promote the absorption of nitrogen bubbles. Furthermore, the elevated partial pressure of oxygen in the chamber increases the rate of tissue healing and improves cellular metabolism, both of which are crucial for effective recovery from decompression sickness.

Breathing 100% oxygen is a standard treatment protocol in hyperbaric medicine, as it creates an environment that supports the body in reabsorbing nitrogen more efficiently, leading to a quicker and more effective recovery process.