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| {{Air embolism}} | | {{Air embolism}} |
| {{CMG}}
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| {{SK}} Gas embolism | | {{CMG}}; {{AE}} |
| ==Overview==
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| An ''air embolism'', or more generally ''gas embolism'', is a medical condition caused by [[gas]] bubbles in the bloodstream (''[[embolism]]'' in a medical context refers to any large moving mass or defect in the blood stream). Small amounts of air often get into the blood [[circulation]] accidentally during [[surgery]] and other medical procedures, but most of these in [[vein]]s are stopped at the lungs, and a [[venous]] air [[embolism]] that shows [[symptom]]s is very rare. Death may occur if a large bubble of gas becomes lodged in the heart, stopping blood from flowing from the right [[Ventricle (heart)|ventricle]] to the [[lungs]] (this is similar to vapor lock in engine fuel systems). However, the amount of gas necessary for this to happen is quite variable, and also depends on a number of other factors, such as body position.
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| Gas embolism into an [[artery]], termed [[artery|arterial]] gas [[embolism]], or AGE, is a more serious matter than in a [[vein]], since a gas bubble in an [[artery]] may directly cause stoppage of blood flow to an area fed by the [[artery]]. The [[symptom]]s of AGE depend on the area of blood flow, and may be those of [[stroke]] or [[myocardial infarction|heart attack]] if the brain or heart (respectively) are affected. | | {{SK}} Gas embolism; |
| ==Pathophysiology==
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| Air embolism can occur whenever a blood [[vessel]] is open and a pressure gradient exists favoring entry of gas. Because the pressure in most [[artery|arteries]] and [[vein]]s is greater than [[atmospheric pressure]], an air [[embolus]] does not always happen when a blood [[vessel]] is injured. In the [[vein]]s above the heart, such as in the head and neck, the pressure is less than atmospheric and an injury may let air in. This is one reason why [[surgery|surgeon]]s must be particularly careful when operating on the [[brain]], and why the head of the bed is tilted down when inserting or removing a [[central venous catheter]] from the [[jugular vein|jugular]] or [[subclavian vein]]s.
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| When air enters the [[vein]]s, it travels to the right side of the heart, and then to the lungs. This can cause the [[vessel]]s of the lung to constrict, raising the pressure in the right side of the heart. If the pressure rises high enough in a patient who is one of the 20% to 30% of the population with a [[patent foramen ovale]], the gas bubble can then travel to the left side of the heart, and on to the brain or [[coronary circulation|coronary arteries]]. Such bubbles are responsible for the most serious of gas [[embolus|embolic]] [[symptom]]s.
| | ==[[Air embolism overview|Overview]]== |
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| [[physical trauma|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 artery|pulmonary arteries]] or [[vein]]s in a similar manner, due to the pressure difference. | | ==[[Air embolism historical perspective|Historical Perspective]]== |
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| Air can be injected directly into the [[vein]]s either accidentally or as a deliberate act. Examples include misuse of a [[syringe]], and [[industrial injury]] resulting from use of compressed air. However, despite being employed by writers of fiction as a clandestine method of murder, amounts of air such as would be administered by a single small syringe are not likely to suddenly stop the heart, nor cause instant death. Single air bubbles in a [[vein]] do not stop the heart, due to being too small. However, such bubbles may occasionally reach the arterial system through a [[patent foramen ovale]], as noted above, and cause random [[ischemic]] damage, depending on their route of [[artery|arterial]] travel.
| | ==[[Air embolism classification|Classification]]== |
| ===Gas Embolism in Diving===
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| ''Gas embolism'' is one of the [[diving disorders]] SCUBA divers sometimes suffer when they receive [[barotrauma|pressure damage]] to their lungs following a rapid ascent where the breath is inappropriately held against a closed [[glottis]], allowing pressure to build up inside the lungs, relative to the blood. It is termed "gas" because the diver may be using a diving [[breathing gas]] other than [[air]]. The gas bubbles can impede the flow of oxygen-rich blood to the brain and vital organs. They can also cause [[clot]]s to form in [[blood]] [[vessel]]s.
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| Gas [[embolism]] and [[decompression sickness]] (DCS) may be difficult to distinguish, as they may have similar [[symptom]]s, especially in the [[central nervous system]]. The treatment for both is the same, because they are both the result of gas bubbles in the body. In a diving context, the two are often called [[decompression illness]] (DCI).
| | ==[[Air embolism pathophysiology|Pathophysiology]]== |
| ==Treatment==
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| ===Medical Therapy=== | | ==[[Air embolism causes|Causes]]== |
| Recompression is the most effective treatment of an air [[embolism]]. Normally this is carried out in a recompression chamber. This is because as pressure increases, the solubility of a gas increases.
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| | ==[[Air embolism differential diagnosis|Differentiating Any Disease from other Diseases]]== |
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| | ==[[Air embolism epidemiology and demographics|Epidemiology and Demographics]]== |
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| | ==[[Air embolism risk factors|Risk Factors]]== |
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| | ==[[Air embolism screening|Screening]]== |
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| | ==[[Air embolism natural history, complications and prognosis|Natural History, Complications, and Prognosis]]== |
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| [[Oxygen first aid]] treatment is useful for suspected gas [[embolism]] casualties or divers who have made fast ascents or missed decompression stops. Most fully closed-circuit [[rebreather]]s can deliver sustained high concentrations of oxygen-rich [[breathing gas]] and could be used as an alternative to pure open-circuit oxygen [[resuscitator]]s.
| | ==Diagnosis== |
| ===Primary Prevention=== | | [[Air embolism history and symptoms|History and Symptoms]] | [[Air embolism physical examination|Physical Examination]] | [[Air embolism laboratory findings|Laboratory Findings]] | [[Air embolism electrocardiogram|Electrocardiogram]] |[[Air embolism chest x ray|Chest X Ray]] | [[Air embolism CT|CT]] | [[Air embolism MRI|MRI]] | | [[Air embolism other imaging findings|Other Imaging Findings]] | [[Air embolism other diagnostic studies|Other Diagnostic Studies]] |
| If an [[artery|arterial]] gas [[embolism]] resulting from [[patent foramen ovale]] is suspected, an exam by [[echocardiography]] may be performed to [[diagnosis|diagnose]] the defect. In this test, very fine (microscopic) bubbles are introduced into a patient's vein by agitating saline in a [[syringe]] to produce the bubbles, then injecting them into an arm [[vein]]. A few seconds later, these bubbles may be clearly seen in the [[ultrasound]] image, as they travel through the patient's [[right atrium]] and [[ventricle]]. At this time, bubbles may be observed directly crossing a septal defect, or else a [[patent foramen ovale]] may be opened temporarily by asking the patient to perform the [[Valsalva maneuver]] while the bubbles are crossing through the right heart-- an action which will open the [[foramen ovale|foramen]] flap and show bubbles passing into the left heart. Such bubbles are too small to cause harm in the test, but such a [[diagnosis]] may alert the patient to possible problems which may occur from larger bubbles, formed during activities like scuba diving.
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| ==References== | | ==Treatment== |
| {{reflist|2}}
| | [[Air embolism medical therapy|Medical Therapy]] | [[Air embolism surgery|Surgery]] | [[Air embolism primary prevention|Primary Prevention]] | [[Air embolism secondary prevention|Secondary Prevention]] | [[Air embolism cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Air embolism future or investigational therapies|Future or Investigational Therapies]] |
| [[Category:Diving medicine]] | |
| [[Category:Medical emergencies]] | |
| [[Category:Emergency medicine]] | |
| [[Category:Intensive care medicine]] | |
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| [[it:Embolia gassosa arteriosa]]
| | ==Case Studies== |
| [[pl:Zator gazowy]]
| | [[Air embolism case study one|Case #1]] |
| [[pt:Aeroembolismo]]
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| [[tr:Hava ambolisi]] | |
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| | [[Category:Pulmonology]] |
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