What is Air Leak (Air Leak Syndrome (ALS))?
Air leak (AL) is a term used when air escapes from an area that normally contains it, moving to places where air isn’t usually found. This can sometimes cause accompanying symptoms like breathing difficulties, and this condition is known as air leak syndrome (ALS).
Examples of spaces in your body that normally contain air include areas in your upper airway, such as the bronchial tubes in your lungs, as well as your sinuses and parts of your gastrointestinal tract, including the esophagus and stomach.
When air leaks into spaces that don’t usually have it, vital organs can sometimes be put under pressure, which can create dangerous and even life-threatening situations. This can happen if a lung or major blood vessel is compressed by the presence of air, restricting the flow of blood or making it harder for gases to exchange in the lungs.
When air is found in a part of the body it’s not usually in, the word ‘pneumo’ is typically placed in front of the name for this area. Examples include pneumothorax, meaning air in the space around the lung, pneumopericardium, meaning air in the sac around the heart, and pneumoperitoneum, meaning air in the abdominal cavity.
The presence of air around the lung (pneumothorax) can be very significant to your health, as this can cause the lung to collapse. If air in this space presses against major blood vessels, this can lead to a serious condition called tension pneumothorax, which is a medical emergency.
Pneumothorax can happen spontaneously, either in healthy lungs or in lungs affected by diseases. It can also occur as a result of a traumatic injury or due to medical procedures, such as when a patient is on a high-pressure ventilator or a central line is placed in the chest. Air leaks can also happen during surgeries on the lung, heart, or surrounding structures.
To find out if a patient has an air leak, doctors can ask the patient to cough while observing a chest tube looking for air bubbles. If there are none, it means the space around the lung is free of air. The presence of air bubbles however, indicates air leaks. A constant amount of bubbles can suggest a significant or active leak, whereas a decreasing amount may indicate a small or passive leak.
One way to categorize an air leak is by their grade, from 0 to III. Grade 0 indicates there’s no leak, while a grade I leak means a few bubbles can be seen. For grade II, streams of bubbles can be observed, and a grade III leak has merged bubbles. A persistent air leak for more than five days after lung surgery is known as a prolonged air leak (PAL).
What Causes Air Leak (Air Leak Syndrome (ALS))?
Air leaks and a condition called ALS have various causes. Here are some of the things that can lead to these conditions:
Some are caused by medical procedures:
– Being put on a ventilator or receiving positive pressure ventilation can lead to air leaks from injury to the chest or other areas of the body.
– A procedure called central venous catheterization, which involves inserting a line into a vein in the chest, could allow air to enter the chest cavity. A chest X-ray is needed afterwards to check for air leakage.
– Operations within the chest area or using a scope to examine the chest can also lead to air leaks.
– Laparoscopic procedures, which use small incisions and a camera to carry out surgery, can cause air leaks.
– Tracheostomy, a surgical hole through the front of your neck into your windpipe, can cause subcutaneous emphysema, a condition where air gets into tissues under the skin, if not done properly.
Certain lung diseases can also cause air leaks and ALS:
In restrictive lung diseases, where the lungs are unable to fully expand, such as:
– Adult respiratory distress syndrome
– Respiratory distress syndrome
– Cystic fibrosis
– Idiopathic pulmonary fibrosis
In obstructive lung diseases, where the flow of air is blocked, such as:
– Asthma
– Bronchiolitis
– Chronic obstructive lung disease (COPD)
And other lung diseases including:
– Bronchopleural fistula
– Bullous lung disease
– Necrotizing pneumonia
– Sarcoidosis
– Sarcoma
– Marfan syndrome
– Pulmonary hemorrhage
– Pulmonary contusion
– Tuberculosis
– Aspergillosis
Risk Factors and Frequency for Air Leak (Air Leak Syndrome (ALS))
In a recent research involving 21,150 patients who had lung surgery, it was found that roughly 24.26% experienced a complication known as an air leak. Different factors that could increase the risk of this happening include:
- The type of lung surgery – like lobectomy, segmentectomy, wedge resection
- The surgical approach used in the operation
- The patient’s age
- The patient’s gender
- If the patient has chronic obstructive pulmonary disease (a type of lung disease)
The percentage of patients who experience a persistent air leak isn’t clearly known. However, for those who undergo a specific type of lung surgery called lung volume reducing surgery, up to 46% may experience this problem. After a lobectomy (a different type of lung surgery), the number of patients with a persistent air leak can vary anywhere from 5.6% to 38%, depending on different studies.
Signs and Symptoms of Air Leak (Air Leak Syndrome (ALS))
An air leak, or Air Leak Syndrome (ALS), in the lungs can be quite concerning. Knowing its cause can be helpful. Common symptoms usually include breathlessness and wheezing, and they depend on how long and where these occur. To figure out the cause, a healthcare provider might ask about the patient’s past medical conditions or if they have had any lung diseases or procedures recently.
If a patient wheezes and has a hard time breathing, it might suggest they have an obstructive lung condition, such as asthma or COPD. Symptoms like coughing, breathlessness, and fever might indicate pneumonia or Acute Respiratory Distress Syndrome. If a patient has been losing weight, coughing up blood, or running a fever at night, that might suggest they have tuberculosis or lung cancer. Any recent surgeries, especially those involving the lungs or surrounding areas, could also hint at the cause of an air leak
If a patient had a sudden drop in oxygen levels or changes in their blood flow while on a ventilator, that might be due to a collapsed lung or pneumothorax. Often, patients with a pneumothorax experience sudden chest pain and difficulty breathing. The bigger the pneumothorax, the worse these symptoms may feel.
The physical exam for someone with an air leak or ALS starts with a look at the patient’s overall appearance. If the air leak is small, the patient might not have any symptoms. If the air leak causes moderate to severe pneumothorax, healthcare providers might see certain signs:
- Breathlessness
- Rapid breathing
- Rapid heart rate
If a patient has subcutaneous emphysema, the skin might look swollen but feel painless. When touched, the skin might feel crinkly, like tissue paper. It’s also possible for the emphysema to spread deeper into the body, and in some cases, reach as far as the scrotum and the arms or legs. Healthcare providers can also tap on the chest wall to check for sounds that might signal a problem, such as a hollow sound over air-filled spaces. If the pneumothorax is large, they might not hear any breath sounds at all upon listening to the chest.
Testing for Air Leak (Air Leak Syndrome (ALS))
Figuring out if someone has an air leak in their lung typically involves a detailed review of the patient’s medical history and a physical examination. Additional studies may also be necessary to confirm the diagnosis.
The most common test used to diagnose air leaks is a chest X-ray. If a clear space of air is found in the lung with no signs of lung markings, it highly suggests a pneumothorax – a collapsed lung. It’s important to note that a pneumothorax can look different in a chest X-ray based on whether the patient is lying down or standing up. For patients using a ventilator, a pneumothorax could get bigger and turn into a tension pneumothorax. Some signs of a tension pneumothorax in an X-ray could be a shift in the heart and other areas, a reduction in lung size, a flattened heart, and a shadow in the blood vessels.
Pneumomediastinum, or air in the middle area of the chest, can also be seen in an X-ray when there is a trail of air there. If there’s a lot of air, it can move the thymus (a gland in your chest) and cause a thymic sail sign. A pneumopericardium, or air around the sac that encloses your heart, can also be noticed in a standard chest X-ray.
Chest ultrasounds are becoming more frequently used in diagnosing pneumothoraxes. They are close to 95% sensitive and 100% specific for detecting a pneumothorax, compared to a CT scan. They can help identify a pneumothorax that was not detected in a regular X-ray. However, if there is subcutaneous emphysema, or air trapped under the skin, this might affect the accuracy of the ultrasound.
In the ultrasound, a pneumothorax is indicated by the lack of ‘lung sliding’. Normally, during an ultrasound, you can see the space between two ribs with a line (pleural line) showing the pleura’s normal back and forth movement, or its “shimmering”. This movement is usually absent if there’s a pneumothorax.
Finally, a CT scan can be really helpful for patients who have a continuous air leak. This scan can tell apart lung diseases that create air-filled sacs (bullous disease) from a pneumothorax. It can also help distinguish other diseases affecting the lung and pleura. CT scans are commonly viewed as the best tool for diagnosing air leaks and ALS. However, they do expose the patient to radiation, and can be tricky to conduct on a patient who is critically ill and on a ventilator, as moving the patient for the scan might be risky.
Treatment Options for Air Leak (Air Leak Syndrome (ALS))
Dealing with a persistent air leak in a patient can be challenging, as there isn’t a clear-cut guideline on tackling this issue. However, the general agreement is to consult a surgeon if the air leak continues even after four days.
For most cases of primary pneumothorax, a procedure called simple aspiration is recommended. This involves inserting a needle into the chest cavity and aspirating, or suctioning out, the excess air. The process is performed under sterile conditions with needle insertion happening between the fourth or fifth ribs. It’s completed once the practitioner feels resistance or a sense that air removal is complete due to the patient’s coughing or the lung reaching full expansion.
In critical situations like tension pneumothorax, a larger needle is inserted into the second rib space, and the needle is left there. If it’s connected to an underwater seal and bubbles appear, this is a sign that it’s working correctly.
If simple aspiration doesn’t work, the next plan of action is inserting a chest tube connected to a drainage system. Whether you use a large or small tube depends on the patient’s condition, with a small tube being sufficient if there’s no pooling of blood, or hemothorax. The tube stays put until the lung is fully expanded again and there’s no more leakage.
To avoid pneumothorax reoccurring, several preventative measures can be taken:
1. Medical pleurodesis: a procedure that involves the instillation of substances like bleomycin or talc into the chest cavity, sealing the pleural cavity permanently.
2. Pleural tenting: a technique first suggested in the mid-1950s that partially separates the chest-lining tissue from the chest wall and attaches it to the surface of the lung. Phrenoplasty is sometimes performed alongside this procedure.
3. Surgical Pleurodesis: a method that triggers an inflammatory response in the chest cavity to seal it by stripping and abrading the parietal pleura.
Persistent air leaks, those lasting more than 4 to 5 days after surgery, are common post-operative complications. Where the leak originates from, either the alveolus or a bronchial structure, dictates the initial treatment strategy.
Various techniques exist to manage persistent air leaks:
– Pneumoperitoneum method: a surgical process dating back to the eighties, which creates an artificial pneumoperitoneum to address the issue.
– Blood Patch: a procedure where the patient’s blood is infused into the pleural cavity to act as a sealant.
– Intrabronchial Valve: a less invasive approach using a one-way valve introduced into the bronchus.
– Heimlich Valve (Flutter Valve): a one-way valve allowing air to flow in one direction, reducing inpatient stay length.
When all these interventions aren’t cutting it, a video-assisted thoracoscopy (VAT) is performed. VAT provides visual access to the pleural cavity, identifies the leak, and allows for the application of substances to scar and close the leak. In some circumstances, pleurotomy, the surgical opening of the pleural cavity, is also done.
What else can Air Leak (Air Leak Syndrome (ALS)) be?
When doctors are trying to figure out if someone has an air leak or air leak syndrome, they consider all the reasons that might cause what we call a pneumothorax (a condition where air gets into the area between the lungs and the chest wall). Some of these reasons are:
- Iatrogenic: caused by a medical procedure or treatment,
- Spontaneous: happens suddenly without a clear reason,
- Traumatic: caused by an injury,
- Direct and indirect causes: Direct causes might be chest injuries, while indirect causes could be certain medical conditions like lung diseases.
Doctors also consider both primary and secondary causes of pneumothorax. Primary causes are usually related to an underlying lung disease while secondary causes can be external factors like air pressure changes. It’s important for doctors to look into all of these factors thoroughly when they try to identify the exact condition.
