This may happen after a patient is placed on a ventilator and air is forced into an injured vein or artery, causing sudden death.

[citation needed] 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.

[11] Venous air embolism is a rare complication of diagnostic and therapeutic procedures requiring catheterization of a vein or artery.

[9][12] Interventions to remove or mitigate the embolism may include procedures to reduce bubble size, or withdrawal of air from the right atrium.

[13] Air embolism can occur whenever a blood vessel is open and a pressure gradient exists favoring entry of gas.

[14] This is one reason why surgeons 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 or subclavian veins.

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 arteries.

[10] Human case reports suggest that injecting more than 100 mL of air into the venous system at rates greater than 100 mL/s can be fatal.

[21][22] A PFO test may be recommended for divers intending to expose themselves to relatively high decompression stress in deep technical diving.

[5] Symptoms of arterial gas embolism may be present but masked by environmental effects such as hypothermia, or pain from other obvious causes.

Dive history may eliminate decompression sickness in many cases, and the presence of symptoms of other lung overexpansion injury would raise the probability of gas embolism.

Left lateral decubitus positioning helps to trap air in the non-dependent segment of the right ventricle (where it is more likely to remain instead of progressing into the pulmonary artery and occluding it).

[11] Oxygen first aid treatment is useful for suspected gas embolism casualties or divers who have made fast ascents or missed decompression stops.

[25] Most fully closed-circuit rebreathers can deliver sustained high concentrations of oxygen-rich breathing gas and could be used as an alternative to pure open-circuit oxygen resuscitators.

[28] William Davis, formerly a nurse in Texas, was convicted in October 2021 of murdering four and injuring two patients by injecting air into their arterial lines following heart surgery.

[31] Air embolism was the method used by an insane nurse to euthanize seven terminally ill patients in the episode "Amazing Grace" of the TV series Shadow Chasers.

[33] Air embolisms generally occur in the xylem of vascular plants because a fall in hydraulic pressure results in cavitation.