What Is Wet Lung?

Wet lung is a serious condition resulting from the body’s inability to receive enough oxygen to the lungs. If oxygen cannot get into the body’s organs, this can lead to infections, pneumonia, muscle weakness, kidney failure, and other serious and life-threatening complications. Wet lung is also known as acute respiratory distress syndrome (ARDS).

Wet lung can affect anyone regardless of age, but it seems to be less common and less fatal in children. Wet lung is often seen in people exposed to chemical irritants such as chemical vapors, ammonia, and bleach. Wet lung is also caused by an existing lung infection, injury, or serious medical condition. If left untreated, wet lung can progress quickly and even become fatal.

Here is what you need to know about wet lung syndrome, including symptoms, causes, diagnosis, and treatment.

Wet Lung Symptoms

According to the American Lung Association (ALA), most people that develop wet lung are already in the hospital following a trauma, infection, or other illness. The ALA recommends going to the nearest emergency room if you start to experience signs and symptoms of wet lung.

Signs and symptoms of wet lung include:

• Shortness of breath—This symptom is very severe in people with lung problems. Having wet lung causes you to breathe faster and your heart to beat hard. You may also experience pain when you breathe.
• A dry hacking cough
• Rales—abnormal rattling sounds heard when examining lungs with a stethoscope
• Low blood pressure—a condition called hypotension
• Extreme fatigue and/or drowsiness
• Lightheadedness
• Confusion
• Fever
• Blueish lips and nails—due to oxygen in the blood falling

In 2011, a joint team of American and European doctors attempted to define wet lung in what has become known as the Berlin definition. The Berlin definition classifies wet lung as mild, moderate, or severe. Severity may also predict patient outcomes and the length of time a person may need breathing support.

Causes

When you breathe, air enters from your nose and mouth into your lungs. Once in the lungs, air enters the alveolar ducts and the alveoli. The alveolar ducts are tiny ducts connecting the respiratory bronchioles to the alveolar sacs, which contain the alveoli, the tiny mucus-lined sacs lining the airways of the lungs.

Small blood vessels—called capillaries—go through the alveoli. Oxygen enters the alveolar sacs, passing into the capillaries, and finally entering the bloodstream to travel throughout the body to your heart, liver, kidneys, brain, and other organs.

In someone with wet lung, fluid will accumulate in the alveolar sacs from swelling of the lungs and proteins that have leaked out from the capillaries into the alveoli. Bleeding into the lungs may also occur. When the lungs are not working correctly, they cannot fill up with air or rid the body of carbon dioxide effectively. 

There are many different conditions, illnesses, and triggers of wet lung. These may include:

• A lung or chest infection, such as pneumonia
• Severe flu types, including bird flu
• Other infections—33 percent of wet lung cases are the result of infections in the body
• Surgery complications
• Blood transfusions
• Lung clots
• Chemical inhalation
• Accidental inhalation of vomit or food
• Acute pancreatitis, as inflammation can spread
• Inflammation from sepsis, a burn, or a medication
• Smoke inhalation from a fire, for example
• Near drowning
• Low blood pressure from shock
• Overdose of drugs, such as methadone or aspirin
• Seizure
• Stroke
• Pulmonary sepsis—a lung infection accounting for 46% of all the cases of wet lung.

Risk Factors

Some people are more at risk of developing wet lung than others in the general population. Risk factors for wet lung include:

• Lifestyle habits—Heavy alcohol use, drug use, and smoking can harm your lungs and may increase your risk for wet lung
• Race—The risk for wet lung is higher among non-whites
• Oxygen use for another lung condition
• Chemotherapy
• High-risk surgeries
• Gender—Among children, it seems that boys have an increased risk for wet lung than are girls.
• Environment—Exposure to air pollution for weeks or months

Diagnosis

A diagnosis of wet lung syndrome can be made in several ways, but there is no one definitive testing method for diagnosing wet lung. Your doctor can make a diagnosis based on medical history, a physical exam, and the results of any testing. Wet lung can be mistaken for other lung conditions, so it important to pay attention to the symptoms.

Medical history: Your doctor will ask you about any medical conditions and circumstances that would increase your risk for wet lung. Your doctor will also ask you about symptoms and whether you have a heart or lung condition.

Physical exam: Your doctor will want to examine you for signs of wet lung. This will include listening to your lungs to check for unusual sounds, such as crackling in the lungs, checking for any breathing difficulties, examining the skin and lips for a bluish tint, which is a sign of low blood oxygen levels, looking for signs of body swelling or fluid, and measuring blood pressure and oxygen levels.

Blood tests: Your doctor will request blood work to determine oxygen levels using samples taken from an artery. A low blood oxygen level might be a sign of wet lung. Your doctor may also check blood for signs of infection or heart and kidney problems.

Imaging: Chest X-rays and computerized tomography (CT) scans can produce images of your lungs. Your doctor will want to look for any fluid accumulation or heart enlargement. A CT can offer more detailed information about heart and lung structures. If an X-ray or CT reveals fluid in the air sacs of the lungs, a diagnosis of wet lung can be confirmed.

Other blood oxygen level testing: Pulse oximetry can check blood oxygen levels using a sensor attached to the skin or placed on your hand or foot.

Echocardiogram or electrocardiogram: These tests can rule out a heart condition.

Lung biopsy: A lung biopsy involves taking a sample of tissue from the lung to help rule out other conditions.

Treatment

The goals of treatment for wet lung include improving blood oxygen levels to prevent organ damage and treating the injury or condition that caused wet lung to develop in the first place. Treatment may include breathing support, medications, and other therapies.

Breathing Support

Depending on the seriousness of your case, your doctor may recommend breathing support. Supplemental oxygen is used for milder cases or as a temporary treatment. Oxygen is delivered through a mask that fits over the nose and mouth. Some people may need the help of a mechanical ventilator to breathe. This machine pushes air into the lungs and helps to force some of the fluid out of the alveoli.

Medications

Medications can relieve symptoms of wet lung by treating the underlying causes or preventing complications. Medications may include:

• Acid-reducing drugs to prevent stress ulcers that might cause intestinal bleeding
• Antibiotics to prevent infections. If you are on a ventilator, your doctor may do additional testing to check for infections.
• Blood thinners to prevent and stop blood clots from developing or getting worse
• Muscle relaxers to prevent coughing or gagging while on a ventilator
• Pain medications as needed
• Sedatives to manage anxiety and make it easier for you to breathe on a ventilator or on your own.

Other Treatments

Additional treatments your doctor may recommend include:

• A blood transfusion to improve the delivery of oxygen to the body’s organs
• Extracorporeal membrane oxygenation (ECMO) or a similar device if ventilation isn't enough to deliver enough oxygen. An ECMO also works as an artificial lung, removing carbon dioxide and pumping oxygen-rich blood throughout the body.
• Fluid management to monitor and balance out the fluid in the body to keep blood pressure regulated and help oxygen reach the organs
• Nutritional support if on a ventilator to make sure you are getting the right nutrients
• Physical therapy to maintain muscle strength and prevent sores. Movement can shorten the time on the ventilator and improve recovery after a person leaves the hospital.
• Positioning the body facedown to help more oxygen get into the lungs

While recovering from wet lung, you should do everything you can to protect your lungs. This includes:

• Quitting smoking if you smoke. You should also avoid secondhand smoke whenever you can.
• Getting vaccinated yearly with the flu shot and the pneumonia vaccine every five years to reduce your risk for lung infections.

Prognosis

Most will recover fully with little or no long-term lung problems. People who require ventilator support may experience lung scarring. Fortunately, scarring can decrease within a few months after the person is off the ventilator.

In some instances, if lung scarring is extensive, it can impair lung function and be noticeable enough to affect your ability to do day-to-day activities. It is possible to experience lung function problems with any type of lung scarring, which can be felt when the lungs are stressed, such as with exercise. In addition to lung scarring, a person may experience damage to muscles or nerves around the scarred area, which can cause pain and weakness.

Most people with wet lung will survive. Around 30% to 40% of cases of wet lung are fatal, according to a 2010 report in the World Journal of Gastroenterology. This is a significant improvement from 20 years earlier when the mortality rate was up to 70%. In rare cases where wet lung is fatal, it is usually because of a complication, such as kidney or heart failure.

A Word From Verywell

Wet lung is a medical emergency and it can be life-threatening if left untreated, which is why it is important to seek prompt medical attention, especially if you are someone with risk factors for the condition. And because recovery from wet lung will be long, you will need all the support you can get. Make sure you are asking help from loved ones, especially when you first come home from the hospital. It is also important you go to pulmonary rehabilitation so that you learn how to resume normal activities.

It is not unusual for people who have had wet lung or another lung condition to experience depression. If you find you are feeling depressed or struggling to cope, joining a support group with others living with lung conditions or getting in touch with a mental health professional can be helpful. Treating depression can manage depressive symptoms and also aid in your full recovery from wet lung.