Barotrauma means damage from pressure. This can be pressure from the air or from water. Damage tends to arise when there is a pressure gradient across the eardrum. If the pressure is high but equal on both sides of the eardrum then damage does not usually occur. There are several causes of ear barotrauma.
Scuba-diving. For every 10 m that a scuba diver descends the volume of air in a compressible container halves. This means that the air in the lungs and in the middle ear space will both reduce in volume by a half. Thankfully, both of these air spaces are able to be equalised with this change in pressure. The lungs can be equalised by breathing in and out, the ears are equalised by performing a Valsalva. This is also known as popping the ears. The Eustachian tube opens and air from the nasal passage either flows into or out of the middle ear space.
Sometimes the Eustachian tube does not open. This can happen when the diver has Eustachian tube dysfunction. There are several reasons for this. A simple viral cold can be enough to cause the problem. Tonsillitis and enlarged adenoids can cause difficulty equalising the pressure. Allergies are also a problem. It is advised that divers should not dive if they find it hard to equalise the pressure in the ears.
Flying. Flying in an aeroplane results in a drop in your ambient pressure. This is because the further you are from the ground the less atmosphere there is above your head pressing down on you. This causes the air in your middle ears to increase in volume. Usually the extra volume escapes down the Eustachian tube on the way up and extra air enters via the same passage on the way back down. For the reasons outlined above, barotrauma may occur. Wearing ear plugs for flying will help protect the ears as they are slowing down the pressure change which the ear experiences. Decongestants and anti-inflammatories can helpbefore going flying in a pressurised plane. They are safe as the pressure change in this case is only small. It is not advisable to use any of these preventatives for scuba-diving. Always speak to a doctor if you have a problem with your ears. If you are going to fly or scuba-dive with an ear problem seek medical advice.
Dr Toby Bateson for zenplugs.com/