MANILA, Philippines - The doomed light plane carrying Interior Secretary Jesse Robredo and two pilots has reportedly settled in a spot in the sea floor off Masbate approximately 200 feet deep.
Search and rescue operations have been hampered by the perils of deep-sea diving, which requires special equipment, training and good physical condition.
At 160 feet deep, a diver breathes six times as much as on the surface. Physical movement means more demand for breathing gas, and increases the risk of hypercapnia, or an excess of carbon dioxide in the blood.
“Rapture of the deep” or nitrogen narcosis can start with light-headedness before numbness and memory impairment.
Decompression stops are needed as one dives deeper. In case of an emergency, a rapid ascent from the deep can lead to decompression sickness or “the bends,” with inert gas forming bubbles in the blood and tissues.
When the bubbles form in the bones, it can cause speech and visual impairment and render a diver unconscious from air embolism. The life-threatening condition requires a recompression chamber.