DECOMPRESSION SICKNESS The Bends

Overview Can affect people under high pressures (divers) or low pressures (pilots, astronauts, etc.) Caused by formation of gas bubbles in the body Can occur anywhere in the body Typically the joints, more rare in the spine or skin

Henry’s Law The solubility of a gas in a liquid is directionally proportional to the gas pressure As the pressure increases, the solubility increases and vice versa Think of a Coke can: when under high pressure of CO 2, more CO 2 dissolves in the liquid Open the can, reduce the pressure, the gas comes out of solution

SCUBA Self Contained Underwater Breathing Apparatus Invented by Jacques Cousteau Use pressurized gas to reach greater depths To get deeper, use helium instead of nitrogen Helium has lower solubility in water than nitrogen

Prevention and Treatment Divers ascend using decompression schedules Allow the body to adjust to pressure changes and the dissolved gases to be exhaled Schedule varies with gases used (He escapes faster than N 2 ) Use tables or computer programs to determine schedule

Treament Immediate treatment is pure oxygen followed by pure oxygen in a hyperbaric chamber Pressure reduces the size of the bubbles Pure O 2 keeps blood oxygenated and displaces nitrogen from bubbles O 2 bubbles easily absorbed by blood