Contrast media injectors: risk of air embolism

Background
Incidents involving patient death and injury resulting from air embolism are rare. However, injections of air rather than contrast media could lead to a fatality. Local procedures for the operation of contrast media injectors in CT, MRI, cardiology and angiography departments should include operator checks that syringes are correctly loaded and filled, and that connecting lines are also filled.
 
Examples of incidents include:

• An air-filled syringe was thought to be full of contrast medium and was injected into a patient, who died from an air embolism.
• An empty, unused syringe was left in the injector at the end of a session. Staff using the equipment in a following session mistakenly assumed the syringe had been filled.

In some types of injector, new syringes are loaded with the plunger fully retracted to keep the barrel of the syringe free from contamination and to aid plunger connection. Some injectors also provide a second barrel and line as a saline flush.
Air-detection systems are now available on some models, and may be useful in preventing air embolism

Best practice

• Staff using contrast media injectors should be trained in their use and be familiar with current operating procedures.
• The procedures for using contrast injectors should be available locally and should include checks to ensure that syringes are correctly loaded and filled with contrast media in accordance with the manufacturer’s instructions. This may include making visual checks on syringes and connecting lines when prompted by the display device prior to the injection.
• Users should ensure that, if the injector design requires syringes to be loaded in such a way that they are initially fully of air, the operator first moves the plunger forward to empty the syringe. This is to reduce the risk of an air-filled syringe being mistaken for one full of contrast medium.
• Empty syringes should not be left in injectors at the end of a procedure. When connecting catheters and syringes, steps should be taken to ensure that no air is introduced into the system.
• Staff should be aware of the risks associated with the injection of air.

 Please contact Cliff Double or Richard Glover if you need more information.