Definition – What is an air embolism?
Air embolism is the narrowing of a vessel due to an accumulation of air, up to a vessel occlusion. Normally, our body absorbs smaller air accumulations without any health consequences. An air embolism becomes dangerous when a larger amount of air is created in the right ventricle and the heart pumps less effectively. A distinction is made between arterial and venous air embolism.
Causes of an air embolism
A prerequisite for the development of an air embolism is that air finds a way to enter a vessel. Medical interventions are characteristic causes. A typical cause is an open i.v.
access (intravenous, into the vein) or an infusion system. If a three-way valve is opened in one of these accesses to a venous vessel and the infusion system is decoupled, air can enter. There may also be a leak in the infusion system or access due to a defective product or damage to the product.
If air enters a vein via one of these routes, the amount of air depends on the position of the person concerned and the height of the vein in relation to the height of the heart. Another typical cause of air embolism is incorrect filling or insufficient venting of the infusion system. Parallel infusions can also be the cause of air embolism.
Parallel infusions, in which, for example, gravity infusions and infusion pumps influence each other because they are connected together, can lead to a pearl cord effect, i.e. liquid – air – liquid. Air embolism can also occur if a port catheter or central venous catheter is handled carelessly or if a leaking catheter sucks in air. All catheter examinations (e.g. cardiac catheter examination) carry the risk of air embolism.
Other possible causes are injuries to larger veins, a pneumothorax and the birth process. The consequences of air embolism depend on how much air enters the bloodstream. An infusion is a common cause of air embolism.
An open infusion system can cause air to enter the vein due to an open three-way valve, decoupling in the infusion system or a leak in the system. Air embolism by infusion can also occur if the infusion system is either not properly filled or not sufficiently vented. Parallel infusions have an increased risk of causing air embolism because both infusions influence each other.
Birth carries the risk of an amniotic fluid embolism. Amniotic fluid enters the maternal organism via the uterus or placenta and causes an embolism. The risk is present at the induction of each birth and is increased in the event of birth complications such as a ruptured uterus, a ruptured cervix or a high vaginal tear. Other risk factors such as maternal age >35 years, previous caesarean sections or multiple pregnancies increase the risk of embolism.
