Precautions
The pressure difference between the middle ear and the outside, if not released, can result in a burst eardrum. This damages hearing, and if this occurs underwater, cold water in the middle ear chills the inner ear, causing vertigo. The pressure difference can also cause damage to other body air spaces, such as the paranasal sinuses. This can also be caused by damaged sinus ducts.
To allow successful equalization when diving, it is important that the diving suit hood does not make an airtight seal over the outside ear hole, and that earplugs are not worn. It is not recommended to dive when a eustachian tube is congested or blocked, e.g. with the common cold, as this may cause what is known as a reverse block. Descent is uninhibited as the valsalva maneuver may still clear the eustachian tubes temporarily by force, but during ascent a blockage may stop the air in the middle ear (which is now at depth pressure) from escaping as the diver ascends. The eardrum then bursts outwards, causing the same hazards as with an ordinary burst eardrum, such as cold water in the middle ear deranging the working of the sense organs of balance in the inner ear.
Read more about this topic: Ear Clearing
Famous quotes containing the word precautions:
“It is so manifestly incompatible with those precautions for our peace and safety, which all the great powers habitually observe and enforce in matters affecting them, that a shorter water way between our eastern and western seaboards should be dominated by any European government, that we may confidently expect that such a purpose will not be entertained by any friendly power.”
—Benjamin Harrison (1833–1901)
“The aim of every political constitution is, or ought to be, first to obtain for rulers men who possess most wisdom to discern, and most virtue to pursue, the common good of the society; and in the next place, to take the most effectual precautions for keeping them virtuous whilst they continue to hold their public trust.”
—James Madison (1751–1836)
“A multitude of little superfluous precautions engender here a population of deputies and sub-officials, each of whom acquits himself with an air of importance and a rigorous precision, which seemed to say, though everything is done with much silence, “Make way, I am one of the members of the grand machine of state.””
—Marquis De Custine (1790–1857)