Chronic Barotrauma: Causes And Long-Term Effects

Definition of barotrauma and its types

Barotrauma is the type of damage caused by a difference in pressure between a closed space inside the body and the gas or fluid around it. When the space filled with gas enlarges, it might get overstretched and damage the neighbouring structures. It is the damage caused by a lack of adjustment of the body’s cavities to the outside pressure changes. 

Physicist Robert Boyle discovered the inverse relationship between the pressure of the gas and its volume under a constant temperature, what is known as Boyle’s law today. Boyle’s law explains the mechanism underlying barotrauma.¹ 

Barotrauma can be divided into two categories - acute and chronic based on the duration and frequency of the injuries related to the pressure.

Barotrauma can also be classified depending on the specific part of the body affected. The most affected parts are the sinuses, middle ear, face, teeth, digestive system and lungs.¹

A brief explanation of chronic barotrauma

Acute barotrauma happens suddenly and immediately, whereas chronic barotrauma happens as a result of repeated or long-term exposure to pressure changes causing persistent or recurrent pressure-related injuries.

Chronic barotrauma usually occurs in people who are exposed to pressure changes due to their occupation or leisure activities. 

It's important to note that both acute and chronic barotrauma can have serious consequences on health, and seeking appropriate medical care is essential for accurate diagnosis, treatment, and prevention of complications.

Causes of chronic barotrauma

Repeated exposure to changes in pressure

Considering the underlying mechanism of barotrauma, repeated exposure to pressure changes is one of the causes of chronic barotrauma. As long as there is a change in pressure, there is a risk of barotrauma. 

Certain professionals, such as people in the aviation profession and divers, are the most common group of individuals exposed to pressure changes as part of their job. Apart from that, leisure activities related to pressure changes include diving activities, flying, mountaineering or skiing. Other potential causes of chronic barotrauma are hyperbaric oxygen treatment, which is a kind of oxygen therapy given inside a high-pressure chamber, and treatment with mechanical ventilation.¹ 

Scuba diving and other activities involving pressure changes

SCUBA, or Self-Contained Underwater Breathing Apparatus, has been widely used by recreational, exploration, scientific and military divers since its discovery and development after World War II by Jacques-Yves Cousteau and Émile Gagnan.²

SCUBA diving has gained increasing popularity over the years. Although it is a way for humankind to enjoy the beauties of the underwater world, it comes with health risks, especially if done improperly. Improper diving carries a risk of injury to different parts of the body, including the lungs, ears and the brain. Approximately 80% of diving-related health concerns are related to the ear, nose, or throat, with the ear being the most affected organ.³

Other activities involving pressure changes include snorkelling, free diving, and flying. Furthermore, activities which involve different altitudes, such as mountain climbing, hiking at high elevations or skiing result in atmospheric pressure change.

All of the activities involving pressure changes come with their own risks and safety considerations. Therefore, it is very important to get advice or training from experts or professionals beforehand to be on the safe side.

Ear infections and congestion

Whether in the water or in the air, pressure increases during descent causing the volume of the gas entrapped into a space compressed. This can result in a relative negative pressure in rigid- or semi-rigid walled air-containing spaces in the body, such as the middle ear or sinuses. On the contrary, the volume of the gas inside the air-containing spaces expands during ascent. This expansion might result in injuries such as ear membrane perforation or accumulation of air in the brain through damaged sinuses.⁴

The outer ear canal extends towards and ends at the ear membrane, which is the tympanic membrane in medical terms. Behind the tympanic membrane, there is middle ear space which is connected to the throat via a canal called the Eustachian tube. 

The Eustachian tube provides the flow of any fluid produced in the middle ear space as well as air. The exchange of air through the Eustachian tube allows to maintain equal pressure between the middle ear space and the outer ear canal. This is known as the equalisation of the middle ear pressure. When there is a failure to equalise the pressure to the external environment, there is a risk of middle ear barotrauma.⁵

Any condition that blocks the Eustachian tube increases the risk of middle ear barotrauma. Swelling of the soft tissue lining in the throat or within the Eustachian tube might happen as a result of an infection or oedema due to allergies or acid reflux. The most common infections which cause dysfunction of the Eustachian tube are upper respiratory tract infections.⁶ However, it is not clear whether ear infections are the cause of ear barotrauma or a result of barotrauma itself.⁷

Allergies and sinus problems

Sinuses are small, air-filled cavities behind our cheekbones and forehead. When there is insufficient ventilation inside these chambers during pressure changes, what is called sinus barotrauma occurs. 

Swelling or oedema inside the sinuses due to an upper respiratory infection or allergies makes equalisation more difficult and results in barotrauma. There are a number of case reports and publications in the literature demonstrating the association between upper respiratory tract infections and allergies with sinus barotrauma.⁸

Flying in an aeroplane

Commercial aircrafts have pressurised cabins to maintain a comfortable and safe environment for passengers. The cabin pressure is set to a pressure equal to an altitude of 7,000 to 10,000 feet above sea level. 

During descent, the external pressure increases, causing an elevation in the cabin pressure and leading to discomfort as well as potential health issues for passengers. If the Eustachian tube fails to function correctly, the pressure in the middle ear cannot equalise effectively and might result in middle ear barotrauma.

However, during ascent, the reverse occurs. Therefore, it is important to be aware of these potential problems and take appropriate measures to ensure equalisation in the middle ears.⁶

Long-term effects of chronic barotrauma

Barotrauma symptoms are numerous depending on the part of the body affected:

• Pulmonary barotrauma might present with cough, shortness of breath, haemoptysis, chest pain, choking, change in voice, difficulty swallowing, turning blue, and if severe enough, cardiac arrest and death⁹
• Sinus barotrauma might cause facial pain, headaches, nosebleeds, and congestion¹⁰
• Ear barotrauma is the most common type of barotrauma and might present with severe ear pain, bleeding from ears, vertigo, dizziness, and hearing loss⁹ 
• Dental barotrauma might present with tooth pain, gum swelling, and increased sensitivity
• Digestive system barotrauma causes abdominal pain, bloating, nausea and vomiting and change in bowel movements

Some of the symptoms caused by barotrauma can be acute; however, some of them can be long-lasting or even permanent.

Hearing loss

Barotrauma can be the cause of partial or complete hearing loss. Hearing loss can be classified into 2 types - conductive and sensorineural. Conductive hearing loss occurs due to an abnormality or dysfunction of the ear canal, eardrum, or the tiny bones in the middle ear, whereas sensorineural hearing loss involves the brain, the inner ear and the eighth nerve, which is the nerve responsible for hearing. 

Despite being uncommon, dive-related permanent hearing loss resulting from ear barotrauma is possible. Although both-sided hearing impairment is not necessarily an indication of exclusion from diving, it might cause difficulties in communication while underwater, thus posing a danger of injuries or even death.¹¹ 

Middle ear barotrauma might cause eardrum perforation, which can result in conductive hearing loss if equalisation is not ensured via the Eustachian tube. In the case of a severely blocked Eustachian tube, inner ear barotrauma might occur due to a large pressure gradient. The structures (the round and the oval windows) may rupture, resulting in sensorineural hearing loss.¹

Tinnitus

Tinnitus is the perception of ringing that is not actually present. It can be due to many reasons, including ear barotrauma.

Eardrum perforation due to middle ear barotrauma, injury to the inner ear structures due to inner ear barotrauma as well as alternobaric vertigo are the underlying mechanisms of tinnitus caused by barotrauma.¹

Other possible causes of tinnitus include head trauma, tumour, ear infection, migraine, noise, and some medications.¹¹

Eardrum perforation

During descent, the pressure builds up between the ear canal, eardrum and throat. When the pressure gradient exceeds 30mmHg, it can cause ear pain, known as ear squeeze or barotrauma pain. If the pressure gradient further increases to 100mmHg or more, the Eustachian tube may not be able to open and may fail to equalise the pressure in the throat to the ambient pressure, resulting in rupture of the eardrum. 

Perforation of the eardrum usually happens as a result of the Eustachian tube dysfunction or with significant pressure differentials. Interestingly, it results in a decrease in pain. However, later on, several potential symptoms may occur, such as hearing loss, vertigo, tinnitus and bloody drainage.¹

Vertigo and dizziness

Vertigo is a false sensation of spinning, swaying or whirling movement of oneself or the surrounding environment. There are many causes of vertigo, and barotrauma is one of them. It usually happens after middle or inner ear barotrauma and is associated with nausea as well as vomiting in severe cases.¹¹

Alternobaric vertigo usually happens when the pressure gradients are different on the left and right ears and exceed 45 mmHg. It might result in disorientation, nausea, vomiting, and tinnitus.¹

Middle ear infections

Barotrauma can increase the risk of developing a middle ear infection, especially when there is a rupture in the eardrum, by providing easy access for the infectious agents to the middle ear. It can also cause the collection of fluid inside the middle ear space, which increases the risk of infection.

Although middle ear infections can occur as a complication of barotrauma, antibiotics are typically not indicated without the presence of infection signs and symptoms.⁵

Chronic pain and discomfort

One of the complications of barotrauma can be chronic pain and discomfort.⁵ The exact mechanism behind chronic pain after barotrauma is not fully understood and it might vary depending on the type of the barotrauma or from person to person. Possible mechanisms are nerve damage and inflammation.

Treatment and prevention of chronic barotrauma

Treatment and preventive measures depend on the type and severity of barotrauma as well as the Eustachian tube dysfunction (ETD) cause. In primary ETD, the cause of barotrauma is due to a change in ambient pressure; in secondary ETD, there is an underlying issue or medical condition to cause barotrauma.⁵

Barotrauma-related injuries are usually self-limiting. For this reason, the prognosis is usually good.¹ 

Medications for congestion and allergies

Pain due to middle ear barotrauma and sinus barotrauma is usually treated conservatively and resolved without using medical intervention. Most of the mild injuries resolve within hours as middle ear pressure adjusts to ambient pressure over time. Swelling of the eardrum, fluid accumulation or bleeding in the middle ear might last days to weeks before disappearing. A tear in the eardrum usually heals within weeks. Vertigo and tinnitus can also resolve over time.

Simple painkillers such as paracetamol or ibuprofen, antihistamines (allergy medications), and decongestants are used as required for mild middle ear or sinus injuries. Topical or systemic steroids may also be used for mild middle ear barotrauma. However, there is no evidence to support their effectiveness. 

Antibiotics are only indicated if there is a sign of infection and a rupture of the eardrum.⁶ 

Bed rest and avoiding certain movements that increase pressure transmission (coughing, straining, loud noises, etc.) may be helpful after inner ear barotrauma in terms of conservative therapy. 

Surgery for severe cases

Severe injuries caused by barotrauma are an indication for a referral to the Ear Nose Throat specialist. After severe barotrauma, there might be a leakage of fluid from the inner ear to the middle ear, and this might lead to vertigo and sensorineural hearing loss. There is also a risk of conductive hearing loss and middle ear infection as a result of eardrum perforation. For these reasons, an immediate referral to the Ear Nose Throat specialist is necessary for individuals presenting with vertigo, hearing loss or a ruptured eardrum larger than 25 % to prevent any complications.⁶

Surgical intervention may be required for some cases with severe or persistent symptoms. Myringotomy is a procedure in which there is a small incision done on the eardrum. It can be used both for treatment and prevention. However, it is not suitable for wet diving activities due to the risk of water entry into the middle ear space.⁵ 

Sometimes, myringotomy incision closes quickly before the injuries heal. Therefore, another operation called tympanoplasty may be necessary to ensure the healing. In tympanoplasty, a tube is placed in the eardrum to keep the hole open for a longer time.⁶

Preventive measures during scuba diving and flying

You can prevent barotrauma by taking certain measures or avoiding exposure to pressure changes. 

For individuals with secondary ETD, the underlying cause needs to be addressed to prevent further barotrauma injuries. If there is an ongoing upper respiratory tract infection causing nasal congestion or congestion in the throat, the congestion should be treated and any pressure change should be avoided until successful equalisation is ensured. In case of any damage to the Eustachian tube due to radiation therapy, medical therapy or myringotomy may be required. 

Any long-term middle ear infection should be treated accordingly. It may also interfere with the function of the Eustachian tube by causing an accumulation of fluid, also known as effusion, in the middle ear space.

There is no consensus regarding taking medications before any exposure to pressure changes as a preventive measure. Pseudoephedrine, which is a type of decongestant, may reduce the risk of sinus or ear damage due to barotrauma during flight in adults. 

However, its effectiveness is unclear in children. Pseudoephedrine taken prior to diving may also decrease ear and sinus barotrauma incidence as well as severity. Despite that, its use before diving remains controversial due to concerns over side effects and the possibility of the wear off of its action before the completion of a dive.⁵

Myringotomy operation with an ear tube placement may be advised by the ear nose-throat specialist for individuals with primary ETD. However, it is only suitable for those engaging in dry pressure-related activities such as hyperbaric oxygen treatment, tunnelling work, and flying. It is not recommended routinely for adults without symptoms.⁵

Ear plugs aiming to slow down pressure changes during flying are available. They provide more time to equilibrate, but pressure equalisation is still needed. Their effectiveness in preventing barotrauma has not been clearly demonstrated in research studies. It is also important to note they are not suitable for diving.⁶ 

Proper technique for equalising pressure in the ears

Yawning, swallowing, chewing gum, or sucking on hard candies might help open the Eustachian tube during pressure changes and prevent barotrauma.⁶ 

There are also some techniques available to help with equalisation:¹²

Valsalva manoeuvre

It involves pinching your nostrils and then blowing through your nose. Although it is a commonly used one, it has two downsides. Firstly, it does not contract the muscles responsible for opening the Eustachian tubes. That means it may not be effective if the tubes are already blocked. Secondly, there is a chance of damaging some structures, especially in the inner ear, if blown too hard against blocked nostrils.

Toynbee manoeuvre

It requires you to pinch your nose and then swallow.

Frenzel Maneuver

It is done by pinching your nose and then making the sound of the letter “K”.

Lowry technique

It is a combination of Valsalva and Toynbee. It requires you to pinch your nose, and then blow and swallow.

Edmonds technique

It involves tensing the soft tissue at the back of the roof of your mouth as well as throat muscles and then blowing and moving the jaw forward and down.

Try to equalise as early and often as possible. Using multiple techniques can also be helpful for individuals having difficulties.⁵ 

Summary

Barotrauma is a type of injury or damage that can occur in the body after exposure to rapid or significant pressure change. It can affect different parts of the body, such as the sinuses, ears, lungs, teeth, and digestive system. Barotrauma can be acute or chronic, depending on the frequency and duration of the symptoms. 

Exposure to frequent pressure changes due to profession or leisure activities might be the reason for chronic barotrauma. Diving or flying are the most common reasons to be exposed to pressure changes. Barotrauma can vary in severity, ranging from mild symptoms to potentially life-threatening conditions. 

Therefore, it is important to seek medical attention in case of any symptoms or injuries related to barotrauma. Treatment depends on the location and the severity of barotrauma. It is possible to prevent barotrauma from happening by using proper techniques for pressure equalisation and following safety guidelines. 

It is important to consult with healthcare professionals or experts in specific activities for personalised advice based on your individual circumstances and health conditions.