The volume of air required to produce a lethal air embolus depends on a number of factors.




presence of serious cardiorespiratory comorbid condition(s)

a person with comorbid cardiopulmonary condition may die from a smaller air embolus than a healthy young adult

location of air embolus

an air embolus lodging in a coronary artery or cerebral artery may be quite small

total volume

a larger air embolus is more likely to be lethal

speed of delivery

a single large bolus is more likely to be lethal than a slow, intermittent input of air


Volume of a venous air embolus large enough to be lethal:

(1) 300 mL in the adult

(2) 200 mL in an adult with comorbid conditions

(3) 3 to 5 mL per kg


Problems with determining a lethal volume of an air embolus:

(1) the total volume injected is not known with certainty

(2) the total volume may be difficult to determine at autopsy, especially if it was unsuspected


The volume of air required for a lethal embolism in the arterial circulation can be quite small (2-3 ml) if the embolus lodges in a vulnerable site of a coronary or cerebral artery.


A total body CT scan may be necessary to determine the total volume of air emboli. The diagnosis of air emboli as the cause of death requires exclusion of other causes.


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