Barotrauma & Decompression Sickness (The Bends)

Written by Alyson Powell Key
Medically Reviewed by Melinda Ratini, MS, DO on February 14, 2025
10 min read

Barotrauma is a type of injury from sudden changes in surrounding air or water pressure. In divers, it happens due to sudden changes in water pressure while they explore beneath the surface. 

"If you break down the word, 'baro' is pressure and 'trauma' refers to injury. So it's injury caused by pressure," says Daniel Bachmann, MD, an emergency medicine physician at The Ohio State University Wexner Medical Center. "And when we think of barotrauma in the medical sense, we can see it both ways, up or down."

What is decompression sickness?

Decompression sickness, also called "the bends," is a specific type of barotrauma. It happens to divers when gases, usually nitrogen, mix with their tissues and become trapped. This results in gas bubbles forming in places they shouldn’t be.

As you dive down and remain at the bottom, your tissues absorb nitrogen until you achieve a pressure balance. When you rise at a comfortable pace, the gas gently diffuses from your tissues. But if you rise too quickly and don't allow enough time for diffusion, nitrogen bubbles can expand in your tissues as the pressure drops. 

Bachmann compares it to opening a can of soda. "While it's still closed, it's under pressure and the gas that's inside is liquid. As soon as you open that lid, that allows the pressure inside the can to decrease rapidly equivalent to the pressure around you. And suddenly [the gas] goes into a bubble form." With decompression sickness, "You've essentially got nitrogen inside your body that's going from a liquid where it's not causing problems to a bubble where it does cause problems."

Depending on where the bubbles are located, decompression sickness can affect different parts of your body.

Why is decompression sickness called the bends?

The common name “the bends” comes from the tendency to bend over in pain due to this condition.

Since water is heavier than air, even small depth changes while diving can cause major pressure shifts. This can lead to injuries called the "squeezes," which can happen when there's a difference in air or fluid pressure between the closed spaces in your body and your surrounding area. There are different types of squeezes:

External ear squeeze 

This happens when something such as earplugs or earwax blocks your ear canal. As you go farther down and water pressure builds up, the air pocket between the blockage and your eardrum gets smaller. This can hurt the tissue in your ear canal, especially your eardrum.

Middle ear squeeze 

Divers often get this when they can't equalize pressure in their middle ear. The eustachian tube, a small canal connecting your middle ear to the back of your nasal cavities, plays a key role in balancing pressure. If there's an issue with this tube, it can lower the volume in your middle ear, pulling your eardrum inward and leading to discomfort and pain.

Inner ear squeeze

This type of squeeze happens when there's a quick change in pressure between the middle and inner ear. It's less common than middle ear squeeze.

Other types of barotrauma

Some less common types of barotrauma happen when air gets trapped in a closed space that can't equalize as you dive down (descend). This creates a vacuum effect, which may lead to:

  • Sinus squeeze: This can happen when air is trapped in your sinuses due to congestion or cold symptoms.
  • Face mask squeeze: This happens if you don't exhale into the diver mask while descending.
  • Suit squeeze: This is caused when a dry diving suit hugs your skin too tightly.
  • Lung squeeze: This happens during free diving, but only to divers who can hold their breath at depths that cause this injury.

Barotrauma as you ascend

Barotrauma can also happen as you rise back to the surface (ascend):

  • Reverse squeeze: This happens in your middle ear or sinus when you have an upper respiratory infection and use nasal spray to clear your airways. As the spray's effects fade during your dive, tissue swelling can block airflow, creating pressure differences and discomfort.
  • Aerogastria: This happens when swallowed gas expands during ascent. It's more common in novice divers. It may cause temporary pain but usually not serious harm.
  • Pulmonary barotrauma. Also called burst lung, this happens if you don’t exhale during ascent. Rising causes gas in your lungs to expand, and failing to exhale the extra air can cause serious damage.
  • Air embolism: Diving can introduce gas bubbles into your circulatory system through tiny ruptured veins in your lungs. These bubbles expand as you ascend. They can block blood flow in the arteries of your brain or heart. Rapid ascent may lead to loss of consciousness, stroke, or other nervous system issues soon after surfacing.

Understanding the history of your dive is important for your doctors when treating any diving-related issues. They’ll want to hear about the overall plan for your dive and what specific part you were doing when the issue or injury happened.

  • Barotrauma, such as squeezes, commonly happens during descent. Symptoms often stop a diver from reaching their desired depth.
  • Symptoms of aerogastralgia, pulmonary barotrauma, air embolism, and decompression sickness happen both during and after ascent.

Here are some symptoms of specific pressure problems:

  • External ear squeeze: Pain in your ear canal and ear bleeding
  • Middle ear squeeze: A feeling of fullness in your ear, pain, eardrum rupture, confusion, nausea, hearing loss, and vomiting
  • Inner ear barotrauma: A feeling of fullness in the ear, nausea, vomiting, ringing in the ear, dizziness, and hearing loss
  • Sinus squeeze: Sinus pressure, pain, and nasal bleeding
  • Face mask squeeze: Bloodshot eyes , redness, and bruising
  • Lung squeeze: Chest pain, cough, bloody cough, and shortness of breath
  • Aerogastralgia: Abdominal fullness, severe colicky pain that comes and goes, belching, and flatulence
  • Pulmonary barotrauma - Hoarseness, a feeling of fullness in the neck, chest pain several hours after diving, shortness of breath, painful swallowing, and loss of consciousness
  • Air embolism: A sudden loss of consciousness shortly after surfacing, along with paralysis and numbness of different parts of the body at the same time, blindness, deafness, dizziness, seizures, confusion, and trouble speaking
  • Decompression sickness: Rashes, itching, or bubbles under your skin. Other symptoms can include:
    • Lymphatic obstruction, which can lead to some swelling in specific areas
    • Musculoskeletal symptoms, including joint pain that worsens with movement and especially affects your elbows and shoulders
    • Nervous system aftereffects, including paralysis, sensory changes, and bladder problems, which can result in trouble peeing
    • Pulmonary symptoms, including chest pain, cough, and shortness of breath

Symptoms of decompression sickness usually appear within an hour of surfacing, but they might be delayed for up to six hours. In rare cases, symptoms may not appear until 48 hours after you dive.

If you fly in a commercial aircraft after diving, you can get "the bends." That's because the cabin pressure is less than the pressure at sea level.

Air embolism is a serious condition that needs urgent attention. Here are some steps to plan ahead:

  • Know the location of the nearest emergency facility and recompression (hyperbaric) chamber before you dive.
  • Keep emergency phone numbers and a phone handy during your dive.
  • The Divers Alert Network at Duke University keeps a list of recompression facilities and is available 24/7 at 919-684-9111.
  • If a diver collapses within 10 minutes of diving, suspect an air embolism and get emergency help right away. Most communities have an emergency access number (911). These divers need oxygen and emergency life support. Lay the person flat and keep them warm until help arrives. Follow all instructions from the 911 operator.

Decompression sickness requires immediate attention, though your symptoms might not show up as quickly as those of an air embolism.

You should be aware of recompression chambers. You can usually find this information by contacting 911. If you’re a diver with symptoms that suggest decompression sickness, call a doctor or go to the emergency department at your local hospital.

Call 911 right away if a diver loses consciousness, has paralysis, or shows any stroke symptoms.

If you have chest pain or shortness of breath minutes or hours after diving, call 911 at once. While these symptoms can be related to diving, they could also be a sign of another condition, such as a heart attack.

Decompression sickness might require a visit to the emergency department for pain management while arranging recompression services. These services use specialized equipment that you can find only at regional centers dedicated to treating barotrauma.

Dizziness or pain from a squeeze may also require emergency attention. When in doubt, contact your doctor or a local emergency department for advice.

In many cases, pulmonary barotrauma and lung squeeze require careful attention in the emergency department. Doctors typically conduct the necessary studies to assess symptoms and explore treatment options at a hospital.

If you have barotrauma, get medical attention right away and avoid diving again until your doctor gives you the green light.

The doctor will take the time to understand your dive experience and conduct a thorough physical exam, focusing mainly on your areas of pain and your nervous system. The doctor will:

  • Take your vital signs, measuring blood pressure, pulse, breathing rate, and temperature
  • Measure your blood oxygen level by placing a sensor on your finger or earlobe (pulse oximetry)
  • Treat you with oxygen and IV fluids
  • Check your ear canal and eardrum for damage

Depending on your condition, the doctor might send you to a recompression (hyperbaric) chamber. Air embolism and decompression sickness often involve recompression therapy along with physical examinations. You may also need more testing, including:

  • A CT scan or MRI to test for any problems with your brain and nervous system
  • An EKG and chest X-ray
  • Hearing and balance tests to check for inner ear problems

Medications

Sinus and ear squeezes usually require oral and nasal decongestants. Doctors may prescribe antibiotics for a squeeze involving the frontal sinuses or if you've had a rupture, previous infection, or dove in polluted waters. You may also need pain medicine.

Oxygen therapy

Also called supplemental oxygen, this treatment involves giving you extra oxygen to breathe. You could use it at a hospital or home. Hyperbaric oxygen therapy (HBOT) is a type of oxygen therapy that uses a pressurized chamber or tube to help you breathe three times more oxygen than normal.

Pulmonary barotrauma may result in a collapsed lung (pneumothorax). If the collapse is relatively small, you can often be treated with supplemental oxygen and observation.

Recompression therapy

This therapy involves getting 100% oxygen in a pressurized, sealed chamber. This process typically lasts several hours and gradually returns to normal atmospheric pressure.

The most serious diving complications — air embolism and decompression sickness — require recompression therapy. 

There's no special treatment for face mask and suit squeezes, and these conditions usually disappear in a few days.

Aerogastralgia symptoms also tend to clear up on their own and don't require attention unless your stomach pain worsens or doesn't go away in a few hours.

Over-the-counter pain relievers, such as acetaminophen (Tylenol), ibuprofen (Motrin, Advil), or naproxen (Aleve), can treat pain from ear or sinus squeezes. But you should visit your doctor first to rule out possible serious ear injuries.

"The most sensitive part of your body to pressure change is the tiny pocket of air behind your eardrum," Bachmann explains. "There's not a whole lot that needs to be done with any barotrauma there. The eardrum will typically heal with time. The most important thing you can do is not subject yourself to further pressure change while it's healing."

The best way to avoid barotrauma is to properly prepare for your dive:

  • Make sure you're in good health with no upper respiratory or sinus problems.
  • Get the proper training and always use the buddy system (never dive alone).
  • Ensure that your equipment is in good working order.
  • Know your local emergency phone numbers in advance and have a way to contact help to find out the location of your nearest recompression facility.
  • Use a newer "dive computer" to enhance safety and enable longer dives with shorter decompression stops. Be sure you know how to use one before depending on it.
  • Avoid flying in an airplane within 12 to 48 hours after diving (depending on your diving history) to lower your chances of getting "the bends" caused by the cabin's lower air pressure.
  • Most divers heal from diving accidents and can take part in future dives.
  • Air embolism is the most serious problem from diving accidents, but taking quick action like recompression can help avoid disabilities.
  • Decompression sickness is treatable and has high recovery rates, especially when you use recompression, even if it's a few days after symptoms begin.
  • Pulmonary barotrauma, which can lead to a pneumothorax (collapsed lung), might require a few days in the hospital if doctors decide to use a chest tube. This condition can come back, and full recovery usually takes weeks to months.
  • Mild ear squeezes usually heal in one to two weeks, but more serious cases, such as eardrum rupture, may take longer. You may need surgery, depending on the damage.

Can barotrauma kill you?

Yes, in severe cases, barotrauma can be life-threatening, especially when it affects your lungs (pulmonary barotrauma).

What does decompression sickness feel like?

Decompression sickness can make you feel extremely tired (fatigued) and cause joint pain, numbness, or tingling. You may also have dizziness, headaches, and trouble breathing. In very serious cases, you may have symptoms of a stroke.

How long does ear barotrauma last?

Ear barotrauma (airplane ear), which creates pain or pressure in one or both of your ears, is caused by a sudden change in air pressure during airplane takeoff or landing. It usually gets better during or after your flight. But it can sometimes linger for days or weeks if you have a ruptured eardrum.

Can barotrauma cause tinnitus?

Yes, another possible health problem of barotrauma is tinnitus or ringing in your ears.