Divers who understand how pressure changes affect gas-filled cavities in the body, such as the ears and lungs, use different techniques to avoid tissue injury.
This section explains how to prevent barotrauma in scuba diving, with expert tips for treatment of the barotraumas that occur most often.
Important: The information in this help guide focuses on 'pressure injuries'. Another section contains more about the way that scuba diving rules comply with the official health and safety guidelines in most countries.
Some changes in barometric pressure can create medical problems as divers descend below the surface due to the increased water pressure.
Water is more dense (heavier) than air. As a result, even a small change in depth may cause significant changes in pressure underwater.
In general, experienced divers will already be familiar with the techniques used for equalising air spaces, especially when descending.
Even so, middle ear barotrauma is the most common diving injury. Yet, other lesser known pressure injuries (also called squeezes) include subconjunctival haemorrhage and aerogastria.
People who fly can get aerodontalgia, also called "flyer's toothache". It happens when changes in ambient pressure cause an expansion or contraction of the air cavity beneath a tooth filling.
Likewise, scuba divers with teeth problems can get barodontalgia (tooth squeeze). Hence, tooth pain from scuba diving occurs for the same reasons - pressure changes.
Pro Tip: Use any medication as directed by the manufacturer and visit a dentist without delay. You should avoid scuba diving (or flying) until you have completely recovered.
There are several terms used to describe decompression sickness, including the bends scuba diving hazard and generalised barotrauma.
Simply put, DCS is a pressure change injury caused by an uncontrolled decrease in the ambient pressure of air or water.
So, when scuba divers absorb an inert gas, usually nitrogen, it eventually reaches a pressure balance inside the tissues. But, ascending 'too quickly' can make dissolved nitrogen bubbles expand as the water pressure decreases.
DCS barotrauma can affect different body parts. Usually, it will depend on the exact location of the bubbles. In short, it happens because of (either):
Typical signs and symptoms of decompression sickness will be skin rash, bubbles under the skin, joint pain, fatigue, itching, chest pain, and localised swelling.
Decompression sickness (DCS) requires immediate medical attention and often results in hospitalisation or hyperbaric oxygen treatment.
Pro Tip: Check out another section that explains why decompression sickness is called the bends and how to prevent it.
A blocked auditory canal (tube running from the outer ear to the ear drum) is a common cause of external ear barotraumas.
This kind of 'ear squeeze' happens more often when you descend. The water pressure increases and the air pocket between the tympanic membrane (ear drum) and the blockage will shrink.
In most cases, ascending to a shallower depth will fix it. But, it is important that scuba divers are familiar with alternobaric vertigo symptoms and treatment in case the condition worsens.
In fact, facial barotrauma mask squeeze can injure blood vessels and nasal tissues, especially in periorbital regions (area covered by the orbicularis oculi), and the lower forehead.
Pro Tip: Another section contains further information about scuba diving mask squeeze with expert tips for beginners about how to prevent facial barotrauma. Do you dive in cold water? If so, you should also learn how to avoid a suit squeeze (e.g. from a tight-fitting dry suit).
Sometimes, the gas that divers 'swallow' during the dive will expand as they ascend. Despite it happening most often with learner divers, the pain is usually temporary and it is not considered as being one of the life-threatening scuba injuries.
Significant pressure differences can damage the internal parts of the ear. It happens most often when the diver uses a poor technique for equalisation (e.g. incomplete or too forceful).
It is not uncommon for the diver to experience perilymph fistula (a leak of inner-ear fluid). Even so, recent statistics show that inner-ear trauma is less common than middle ear squeeze in diving (MEBT).
Pro Tip: Seek medical evaluation without delay. For example, an otolaryngologist will try to differentiate inner-ear barotrauma from inner-ear decompression sickness.
Even though it happens most often during a descent, it can also happen while ascending, and sometimes while flying.
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.
Pro Tip: Divers with an upper respiratory infection (e.g. a cold) can also encounter a 'reverse squeeze' as they make their way back up to the surface.
Pulmonary overpressurization syndrome (abbreviated to POPS) refers to a burst lung. Failing to expel some air from inside the lungs during an ascent is the common cause for this serious injury.
The gas volume expands. This can cause severe damage if divers do not exhale the excess gas. In addition, pulmonary barotrauma can also result in a pneumothorax (collapsed lung).
Even though aggressive free-divers can get a lung squeeze, very few humans can actually hold the breath long enough at depth to suffer this kind of 'air trapping' injury.
Pulmonary barotrauma can occur if a diver holds their breath during an ascent, especially rapid or panicked uncontrolled ascents.
The gas pressure inside the lungs increases and so the likelihood of dysbarism squeeze also increases. This rise in pressure can result in a rupture, and air may also penetrate into the tissues around the lungs.
In most cases, the first aid treatment needed for pulmonary barotrauma results in hospitalisation. Patients will need fluid therapy and a constant supply of pure oxygen.
In fact, DAN considers a sinus squeeze as being the second most common diving condition. It can happen when divers are unable to equalise trapped inside an enclosed area as they descend.
The easiest way to avoid pressure injuries in scuba diving is to equalise the pressure in gas-filled cavities, especially the ears and the dive mask. So, to reduce the likelihood of barotrauma, you should:
Pro Tip: Avoid flying after scuba diving for the recommended periods. Check out our FAQs about in-water recompression and find out why the 'controversial' and risky technique still takes place in certain areas of the world.
Important: The short tutorial video [4:55 seconds] presented by DAN contains safety tips for beginners about preventing barotraumas in the ears and sinuses.