Air can escape from the lungs into the blood vessels (arterial gas embolism) or nitrogen bubbles can form in the blood vessels (decompression sickness or "the bends"). Air or gas embolisms can cause serious and potentially fatal conditions, such as a stroke or heart attack.
A single air bubble in a vein does not stop the heart as it is very small. However, such accidentally introduced bubbles may occasionally reach the arterial system through a patent foramen ovale and can cause random ischaemic damage, depending on their route of arterial travel.
A small air embolism often doesn't cause any symptoms at all. Many such air embolisms may never be detected and they eventually go away on their own.
When air enters the circulation it can cause an air embolism, which can result in air bubbles that travel to the brain, heart or lungs. The air bubbles can cause a heart attack, stroke, or respiratory failure. These can occur in your arteries and veins.
An air bubble might be 0.2 cc and still look pretty significant in the IV tubing. The minimum amount that is likely to cause symptoms is a hundred times that, 20 cc, but it's likely to take much more than that to be fatal, usually in excess of 150 cc.
They can develop within 10 to 20 minutes or sometimes even longer after surfacing. Do not ignore these symptoms – get medical help immediately.
To produce symptoms, it is estimated that more than 5 ml/kg of air has to be introduced into the venous system. However, complications can occur with even 20 ml of air. Sometimes even injection of 1 to 2 ml of air into the CNS can be fatal.
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.
It's not for the reason most people think. An air bubble in an insulin syringe poses no direct health threat. If you inject air into your body along with your insulin, it won't kill you because you are injecting the insulin into the fat layer under the skin, not directly into a vein.
Precordial Doppler ultrasonography is the most sensitive noninvasive method for detecting venous air emboli. This modality is capable of detecting as little as 0.12 mL of embolized air (0.05 mL/kg). Transcranial Doppler ultrasonography is another imaging modality commonly used to detect cerebral microemboli.
Air embolism has been reported with insertion or removal of intravenous catheters at an estimated incidence of 1 in 47 to 1 in 3000. Though the risk of air introduction is present with any vascular intervention,8 few cases of air embolism have been reported from intravenous access alone.
In the great majority of cases, venous air embolisms spontaneously resolve. Temporary supportive measures such as supplemental oxygen and patient positioning allow the air to dissipate and not cause any permanent damage.
Highlights. Air-bubble formation in blood samples is associated with hemolysis. Bubble-induced hemolysis is a major contributor to PTS-induced hemolysis. Prevention of air-bubble formation protects blood samples from PTS-induced hemolysis.
The arterial pressure should be allowed to passively push the air back out. This can be enhanced by turning the system vertically, which will cause air bubbles to rise. In the event of venous air embolism, the system should be dropped to minimize further entrainment of air.
An air embolism is a potential complication of IV therapy and can enter a patient's blood system through cut tubing, unprimed IV tubing, access ports, and drip chambers with too little fluid (Perry et al., 2014). It is unknown how much air will cause death, but deaths have been reported with as little as 10 ml of air.
Also, when transferring fluid from its original packaging or when two or more fluids are mixed, it can result in air bubbles being entrapped in the syringe. These air bubbles should be removed in order to ensure the accuracy of the dispense.
After any injection, swelling and irritation (inflammation) can occur at the site where the needle entered the skin. This is a reaction to the needle or to the medicine that was injected. Or it may be a reaction to both. The reaction may happen right away.
This time you decrease the pressure of the air inside the syringe—and its volume increases. As a result the air-filled balloon expands and grows in size: a perfect demonstration of Boyle's law!
If you suspect an air embolism, begin your intervention immediately. Put the patient in Trendelenburg's position on the left side. This encourages the air to enter the right atrium and possibly disperse through the pulmonary artery. Administer oxygen and summon the physician.
The estimated adult lethal dose of air has been estimated at between 200 and 300 mL (3–5 mL/kg) [1], an amount which can be introduced in just 2–3 s with a 14-gauge needle and a pressure gradient of 5 cm H2O [11].
Vascular air embolism (VAE) is preventable critical medical emergency.
Air emboli can cause iatrogenic stroke during a procedure when air has an opportunity to enter blood vessels. This is a rare occurrence that should be considered when a person who has had a procedure suddenly develops acute stroke symptoms.