Arterial gas embolism involves gas entering the arterial circulation with embolism to distal capillaries, resulting in ischaemia. This is possible to every organ system but the effects are particularly profound when embolism occurs in the cerebral or coronary circulation.
Venous gas embolism involves gas entering the venous circulation with gas passing into the right atrium, then into the right ventricle and onwards to the lungs where some or all of it can be filtered.
Large amounts of gas over a short period can lead to catastrophic right-sided cardiac failure and cardiovascular arrest. All causes potentially result in a life-threatening condition and should be regarded as a dire emergency. Intra-cardiac air may lead to cardiac arrest or, if the quantity allows ongoing cardiac output in a supine patient, embolisation usually to the right coronary artery, (but occasionally the left) leading to arrhythmia or cardiac ischaemia. In the sitting position (e.g. during neurosurgery) it would be more likely to embolise to the cerebral circulation.
It is also essential to keep in mind that most episodes of VGE are preventable and no effort should be spared to put in place essential preventative steps.