Air embolism is a medical condition characterized by an air/gas bubble or bubbles in the bloodstream, which cause a variety of problems ranging from blockage of blood supply to organs, stroke like symptoms, and possible cardiac arrest if it reaches the heart.
The primary causes for air embolism other than Scuba diving is through air entering the bloodstream during surgery, massive trauma, air bubbles in injections, and intravenous feeds. The severity of air embolism depends upon on the size of the air bubbles in the bloodstream. Air bubbles in arteries obstruct the flow of blood through the body, and depending on its location, can cause severe complications. For example an air bubble near a artery supplying blood to a vital organ such as a kidney can cause kidney failure. Often the embolism blocks supply of blood to the brain causing stroke like symptoms where the person loses consciousness.
Air Embolism in Scuba Diving can be caused by two reasons:
Pulmonary Baratrauma is caused when air bubbles enter the bloodstream as a result of severe trauma or injury to the lungs caused by rapid ascent while holding breath. During rapid ascent the air in the lungs expand, causing lung over expansion and rupture releasing bubbles into the bloodstream. Divers probably won’t even realize their lungs have ruptured as lungs give little warning in the form of pain. Symptoms to spot Pulmonary Barotrauma are the diver surfacing in pain and discomfort, blood or frothy blood from the mouth. Divers showing symptoms of pulmonary barotraumas should immediately be treated for air embolism as well.
Decompression Sickness (DCS)
If the gas dissolved by the bloodstream isn’t given enough time to escape the body through decompression stops, then the trapped air is likely to form air embolism, which much less noticeable symptoms . Air embolism caused through DCS is often difficult to spot and are potentially more dangerous as they can form in the arterial system, the bubbles are smaller and they can travel to and lodge in the brain where they can cause stroke. (Read: Decompression Sickness: All About Scuba Diving & The Bends)
First aid treatment for both forms of diving air embolism is to administer oxygen, place the diver in the Trendelenberg position, a slanted position with the head facing down. This is designed to trap the air bubble in the apex of the ventricle, if it has reached the heart, and also slows the rate of travel, making the embolism less likely to reach the brain or heart. The effected diver must be taken to a hospital for treatment which often involves administering of pure oxygen, and placing the patient in a hyperbaric chamber under high pressure which will force the gases in the embolism to dissolve into the blood, clearing the embolism.