What happens to a body that breathes gas under high pressure, and what goes wrong on the way back up. Decompression sickness (caisson disease) is examiners’ favourite, set at every length from a two-mark answer to an essay, with nitrogen narcosis and SCUBA next. Most questions are short notes on a single hazard.
Topics, in the book’s order
- Hazards of deep sea diving · pp. 954–955 · asked 7 times
When you’ve read them: Quiz 111 · Hazards of Deep Sea Diving and Increased Barometric Pressure, 13 questions.
After this chapter you should be able to
- list the hazards of deep sea diving
- explain the physiology behind each hazard, and how each is prevented
- explain how decompression sickness arises, and the physiological basis of its prevention and treatment
Viva checklist
- How much the pressure rises for each 10 m of depth, and the pressure at 100 ft
- Why a diver must breathe gas at high pressure
- The five hazards of deep sea diving
- Nitrogen narcosis: the depths where it starts and becomes severe, and its features
- Three reasons helium–O₂ is preferred to N₂–O₂
- HPNS: its cause according to your book, and its features
- Why CO₂ is removed and O₂ cut to about 20% in diving mixtures
- Features of acute O₂ toxicity
- Decompression sickness: definition, and the three settings that cause it
- How the bubbles form, and what they do at each site
- When the features appear, and why the percentage fall in pressure matters
- Prevention and treatment of caisson disease
- Air embolism: how it happens, and how a diver avoids it
- What SCUBA is, and what its cylinders contain