MEBT (also called ear squeeze) is the most common injury in scuba diving. More often than not, it happens during the descent, sometimes while ascending, but you can also get it while flying.
This guide explains why some divers get middle-ear barotraumas, a checklist of the associated symptoms, and the best treatment for these painful pressure injuries.
Human ears contain three distinct sections, and each component has a different purpose:
Note: The inner ear forms part of the central nervous system and has two main functions. The cochlea converts soundwaves into electrical impulses for the brain. Whereas, the canals contribute some control over the way we balance and position ourselves.
No matter whether you're a beginner or a professional, equalizing pressure while diving is a fundamental part of the process. But, failing to equalise the pressure in the air space of the middle ear with the surrounding pressure (ambient) is a frequent cause of MEBT - especially with inexperienced divers.
Health surveys suggest middle-ear barotrauma affects around 80% of divers at some time or another. So, why do some divers suffer this medical complication more than others?
Here's the thing:
In simple terms, any kind of obstruction in the eustachian tube reduces a diver's ability to achieve equalisation. In most cases, this 'blockage' is likely to be a contributing factor for MEBT.
It happens most often during abrupt pressure changes, such as when descending. But, divers can also encounter a 'reverse squeeze' on the way back up to the surface.
Factors that often create equalisation problems for scuba divers include:
You want to avoid creating a relative vacuum (negative pressure) in the middle ear air-filled cavities. Otherwise, an imbalance occurs if the pressure in the tympanic cavity is lower than that of the surrounding tissue.
As a result, the eardrum starts to bulge inward as delicate tissue swells. Any leakage of fluid can create a situation where any ruptured vessels may also start to bleed.
If this happens, any further attempts to equalise ear spaces may be pointless. Plus, divers who perform a forceful Valsalva manoeuvre can actually cause injury to the inner ear.
But, if the eardrum ruptures (known as tympanic membrane perforation), you may feel some relief from the pain associated with middle-ear barotrauma (MEBT). But, you want to avoid this outcome where possible.
Furthermore, divers with incomplete (or insufficient) equalisation may also suffer the effects of alternobaric vertigo (a spinning sensation) during the latter stages of a dive.
Important: In most cases, the middle ear is a sterile air space. As such, the risk of getting a middle ear infection will increase if it's exposed to bacteria and pathogens in any surrounding water.
In general, nasal decongestant sprays (e.g. anti-inflammatory drugs, mucolytic agents) will be an effective first aid treatment for MEBT.
The medication should help to open the blocked Eustachian tubes if it can reduce the swelling around the mucous membranes. Thus, the natural drainage of excess fluid in the air space of the middle ear can take place.
You should avoid putting any drops deep inside the ear canal. In most cases, the condition will worsen if you cause a rupture of the tympanic membrane.
Any signs or symptoms of hearing loss, vertigo, or nystagmus (involuntary eye movements) could indicate a case of inner-ear barotrauma. If so, you should not dive again until you get medical clearance from a specialist.
As with many common scuba diving injuries, you should seek professional medical evaluation. In this case, an ENT specialist (ear, nose, and throat) may be the best choice for assessing the vestibular function.
It's important to be sure about your fitness to dive if you have suffered MEBT. According to the Diver Alert Network (DAN), you should avoid diving after a middle ear barotrauma until:
Note: Any hard blow (including shock waves) that impacts the outer ear may also cause a middle-ear barotrauma injury. Plus, scuba diving while wearing earplugs can cause external-ear barotrauma.
Inadequate equalisation during descent may be due to:
Anyone who is running a dive shop will have certain responsibilities for their customers. As a consequence of this, you should have any injured divers evaluated by a medical professional - without any unnecessary delay.
There is no legal requirement for a dive operator to refer a diver with a middle-ear barotrauma (MEBT) to a specialist doctor with dive medicine experience. However, an ENT doctor (otolaryngologist) would be best to treat ear and sinus problems.
Note: The video presented by DAN answers many common questions about ear barotraumas and how to reduce pressure injuries while scuba diving.