Final answer:
The hallmark finding for a patient with decompression sickness is the formation of gas bubbles in the blood and tissues.
Step-by-step explanation:
The hallmark finding for a patient with decompression sickness, also known as the bends, is the formation of bubbles of gas in the blood and tissues.
These bubbles can cause a variety of symptoms, including rashes, joint pain, paralysis, and even death.
To treat decompression sickness, hyperbaric oxygen therapy in pressurized vessels called decompression chambers is often used.