Air Embolism is a potentially serious medical condition in which air or gas bubbles enter a vein or an artery. This may result in a blockage in the passage of blood and pose a serious threat to the life of the affected individual. The severity of the symptoms is variable and depends on where the blockage occurs. Air Embolism is believed to be perhaps the leading cause of fatalities when it comes to deep sea diving, especially scuba diving. Air Embolism is also one of the deadliest complications of surgical procedures. It is believed that more than 50% of air embolism cases are seen with orthopedic surgeries.
Maximum fatalities due to air embolism occur during a surgical procedure. Since air embolism is mainly seen with endovascular techniques thus surgeons need to be weary of this complication when carrying out such a procedure. Specifically, procedures involving insertion of central venous catheters and arterial catheters which is a common practice in many hospitals are at highest risk for developing air embolism.
There are various clinical situations where air embolism can occur including procedure involving interventional radiology, procedures done for trauma, placement and removal of a PICC line, and most importantly neuro and cardiac surgery. This article explains as to how air embolism occurs and what can be done about it.
What Causes Air Embolism?
Deep sea diving is perhaps the most common cause of air embolism although several medical procedures can also cause it. As a matter of fact, maximum fatalities during deep sea diving occurs due to air embolism. Air embolism during deep sea diving occurs only when the individual is coming back to the surface of the sea even though there are two processes in play here with the same result of air embolism. These processes include:
The Bends: This is a process in which the deep sea diver tries to come to the surface of the water body too quickly. When the diver enters the water body along with the diving gear, there is immense pressure on his body and the gas that he breathes which is a combination of both oxygen and nitrogen.
The oxygen is used constantly by the diver but the nitrogen gets accumulated in the tissues of the diver. In this scenario if the diver rushes to reach the surface with the sudden release of pressure nitrogen does not get a chance to get absorbed back into the blood and exits the tissues in the form of gas bubbles which may enter the vein or artery causing air embolism. This process is also called as decompression sickness.
Pulmonary Barotrauma: This happens when the diver tries to reach the surface of the water quickly while holding the breath. When this occurs there can be significant damage inflicted on the tissue lining of the lungs. As and when the diver reaches the top there is a rapid decline in the pressure and more and more air enters the lungs.
Since the diver is holding the breath voluntarily it causes the air sacs in the lungs to rupture which allows gas to pass in to the blood.
Medical Interventions That Cause Air Embolism Include:
Catheterization: Air embolism is quite common during arterial or venous catheterization.
Hemodialysis: Air embolism can also occur at the time dialysis is done for kidney dysfunction.
Keyhole Surgery: In this procedure air is insufflated in the space between organs to facilitate the surgeon to perform surgery. This at times can lead to gas entering the bloodstream resulting in air embolism.
Cardiac Surgery: Specifically open heart surgeries carry an increased risk of causing air embolism.
Lung Biopsy: If an individual is diagnosed with a nodule in the lung then a biopsy of the tissue nodule is recommended. This is done by taking a piece of the nodule and sending it for analysis. This requires a procedure which carries an increased risk for air embolism.
Cesarean Section: If a female decides to give birth to a child through C-Section then a prominent risk factor explained to her is the chances of an air embolism.
ERCP: This is a procedure done to explore the pancreas and the bile ducts. In this procedure an endoscope is inserted and a dye is injected. During the process of injecting the dye and inserting the endoscope there is a high likelihood of development of air embolism.
As of now, there are no accurate of figures of the number of cases of air embolism due to surgical procedures. However, studies estimate that air embolism has the maximum chances of occurring during an orthopedic procedure. Additionally, for air to move into the blood the pressure in the vessels should be more than the atmospheric pressure.
This happens only in certain situations and thus air cannot enter the blood stream by way of normal cuts and wounds. Surgical procedures involving the head and the neck region has more chances of an air embolism since the pressure around this region is less than the atmospheric pressure.
What Can Be Done About Air Embolism?
Air Embolism is quite a serious situation and requires immediate treatment since it poses a threat to the life of the individual. The treatment approaches differ based on the cause of the air embolism. If diving is the cause of air embolism then the only treatment possible is through hyperbaric chamber. The individual will be made to lie in a vertical fashion and given mixture of gasses. This method is called as recompression.
This needs to be done on an immediate basis. This will decrease the size of the air embolism and normalize the blood flow. The pressure at which the gasses enter the body allows the nitrogen bubbles to get reabsorbed into the blood. This process takes quite a few hours as the pressure is slowly decreased. How many days the individual will take to recover will be determined by the severity of the embolism.
If air embolism is caused due to a surgical procedure and the air bubble gets trapped in the heart then it becomes an emergent situations. The treatment then involves placing the patient either in a Trendelenburg or a lateral decubitus position to prevent more damage to the heart.
Additionally, the patient will receive a mixture of gasses with a high percentage of oxygen to reduce the size of the air bubble and reverse the damage caused. This may be followed by recompression method to further reduce the size of the embolism and normalize the blood flow.