What do a scuba diver ascending from a deep dive and a mountaineer ascending the sides of a massive peak have in common? In both cases, they experience decreasing pressures. And in both cases, the pressure decreases can result in life-threatening sicknesses. For the scuba diver, ascending too quickly can cause bubbles to form in blood and tissues, a condition called the bends. For the mountaineer, failing to acclimate during an ascent—or sometimes just being unlucky—can result in acute mountain sickness(AMS). AMS can turn into high altitude pulmonary edema (HAPE) or high-altitude cerebral edema (HACE). The bends, HAPE, and HACE can all kill. Hyperbaric oxygen therapy (HBOT) can be effective in treating the bends, HAPE, or HACE. If done quickly enough, the diver or climber has a good chance for a full recovery. In this WebQuest, you will explore hyperbaric oxygen therapy.

Create a graphic illustrating the change in pressure from roughly 330 m (1100 ft) under the sea, the depth of the deepest scuba dive, to 8848 m (29,029 ft) above sea level, the height of Mount Everest. Then, place HBOT chambers on your graphic.

On your graphic, include the pressures you determined in your answers to the process questions. Note that air pressures for a given elevation vary, so the values you record should represent typical values. Also, include several landmark pressures of your own choosing—for example a typical air pressure for your hometown or the pressure 10 m under the surface of the sea. Label the pressures found in hospital HBOT chambers on your graphic. Remember that your pressures need to be compared to one another, so be sure to use the same units of pressure across the board. For the portable hyperbaric bags used by climbers, indicate a typical change in elevation represented by the pressures in the bags.