Air embolism

An air embolism, also known as a gas embolism, is a blood vessel blockage caused by one or more bubbles of air or other gas in the circulatory system. Air embolisms may also occur in the xylem of vascular plants, especially when suffering from water stress. Air can be introduced into the circulation during surgical procedures, lung over-expansion injury, decompression, and a few other causes. An air embolism, also known as a gas embolism, is a blood vessel blockage caused by one or more bubbles of air or other gas in the circulatory system. Air embolisms may also occur in the xylem of vascular plants, especially when suffering from water stress. Air can be introduced into the circulation during surgical procedures, lung over-expansion injury, decompression, and a few other causes. Divers can suffer from arterial gas embolisms as a consequence of lung over-expansion injury. Breathing gas introduced into the venous system of the lungs due to pulmonary barotrauma will not be trapped in the alveolar capillaries, and will consequently be circulated to the rest of the body through the systemic arteries, with a high risk of embolism. Inert gas bubbles arising from decompression are generally formed in the venous side of the systemic circulation, where inert gas concentrations are highest, these bubbles are generally trapped in the capillaries of the lungs where they will usually be eliminated without causing symptoms. If they are shunted to the systemic circulation through a patent foramen ovale they can travel to and lodge in the brain where they can cause stroke, the coronary capillaries where they can cause myocardial ischaemia or other tissues, where the consequences are usually less critical. The first aid treatment is to administer oxygen at the highest practicable concentration, treat for shock and transport to a hospital where therapeutic recompression and hyperbaric oxygen therapy are the definitive treatment. Symptoms include: Symptoms of arterial gas embolism include: Small amounts of air often get into the blood circulation accidentally during surgery and other medical procedures (for example, a bubble entering an intravenous fluid line), but most of these air emboli enter the veins and are stopped at the lungs, and thus a venous air embolism that shows any symptoms is very rare. Gas embolism is a diving disorder suffered by underwater divers who breathe gases at ambient pressure, and can happen in two distinct ways: Trauma to the lung can also cause an air embolism. This may happen after a patient is placed on a ventilator and air is forced into an injured vein or artery, causing sudden death. Breath-holding while ascending from scuba diving may also force lung air into pulmonary arteries or veins in a similar manner, due to the pressure difference. Air can be injected directly into a vein or artery accidentally during clinical procedures. Misuse of a syringe to meticulously remove air from the vascular tubing of a hemodialysis circuit can allow air into the vascular system. Venous air embolism is a rare complication of diagnostic and therapeutic procedures requiring catheterization of a vein or artery. If a significant embolism occurs, the cardiovascular, pulmonary, or central nervous system may be affected. Interventions to remove or mitigate the embolism may include procedures to reduce bubble size, or withdrawal of air from the right atrium. There have been rare cases of air embolism being caused by air entering the bloodstream from the uterus or tears in female genitalia. The risk appears to be greater during pregnancy. Cases have been reported that resulted from attempts to perform an abortion by syringing. These appear to have been due to damage to the placenta allowing air to enter the bloodstream.