Equalising our ears is a very important factor
during decent on a dive. If we don’t do this, or don’t do it often enough it can have undesirable consequences. As Instructors, we have the opportunity, during training to emphasise to our student divers the importance of equalising our ears. Thus, helping ‘new’ divers to avoid ear problems and injuries.
For a better understanding, we need to remember our physics. The first metre of decent subjects our ears to a 10% increase in ambient pressure. Progressing our descent to 2 metres, gives us an increase of 20%. When we arrive at 3 metres, the ambient pressure is great enough to cause ear injuries, if we do not equalise often enough. At 3 metres, the pressure is enough to cause blood vessels to burst, blood and fluid will then be drawn into our middle ear. Statistics show that divers do not equalise often enough upon descent. It is not only in training that we should emphasise equalisation, but in our dive briefings as well.
This injury is caused either, by failure to equalise or perhaps an obstruction in the Eustachian tubes. The obstruction is often mucus that blocks, or partially blocks the tubes. Middle-ear barotrauma occurs when pressure in the middle-ear space is much lower than the pressure outside the ear. The pressure differential causes a vacuum inside the ear, causing it to bulge inward, tissue in the ear will swell up. The blood vessels will rupture, allowing blood and fluid to pass into the middle-ear. When we ascend and exit the water, the affected ear will be stuffy and feel clogged. Sound transmission and voices are not clear, due to the fluid in the middle ear. Discomfort is often a symptom, which can later lead to severe pain.
Failure to equalise is often the main cause of a rupture to the tympanic membrane – Eardrum – A forceful Valsalva maneuver can also be the cause. Diving with a cold or congestion, as well as rapid descents plays a large role is this type of injury. The perforation is often painful and you may suffer from vertigo. After the perforation has taken place, pain will subside due to the relieve of pressure inside the ear.
Once perforated, water can enter the middle ear, creating a large risk for infection. Often the rupture will heal on its own, requiring a few weeks though to fully close. In some cases surgical procedure might be required. After a perforation has taken place doctors advice and examination should be sought, this is crucial if you wish to continue diving after the healing process.
This injury is similar to the above, the cause is often failure to equalise our ears or, an aggressive Valsalve maneuver. Here we have differential pressures between the ambient pressure outside the ear and the pressure inside the middle ear. This can result in the round window bulging outwards in the inner ear, leaving the diver with an inner-ear barotrauma. It may not necessarily lead to a rupture of the ear drum, but divers can suffer vertigo, tinnitus, loss of hearing or a sensation of the ear being full or fuzzy. In some cases the diver might become involuntary movements of the eye, which is known as nystagmus. When the round window is ruptured, loss of fluid will occur, and can lead to damage of hearing and balance organs. Surgical repair may be required if the rupture is significantly severe. A doctors examination and advice should be sort.
Due to increased pressure in the middle ear, a facial baroparesis may occur. This is a reversible paralysis of the facial nerve. In some divers and aircraft passengers, people might experience impaired circulation to a facial nerve, which is located close to our ear. This can result in tingling, numbness, weakness and paralysis of the face, leading to a droop in the facial appearance. The droop usually resolves itself, but may cause concern at the time. If the facial droop arises, we should have it checked out by a doctor to make sure there is no underlying issues.
Equalisation is a technique used in scuba diving and should be mastered right at the beginning. Learning to dive is great fun and very enjoyable, discomfort should not be a part of learning, at any time. If you are not a diver and would like to try, why not take a lesson and participate in the PADI Discover Scuba Diving
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