Discuss management of a positive aspiration.

A positive aspiration in which blood is visible in the cartridge requires an immediate response. If the aspiration test results in a small trickle of blood or wormlike thread into the cartridge and does not obstruct clear vision of a subsequent aspiration, the needle can be repositioned slightly and aspiration can be repeated. After a second test that is negative, the clinician may continue with the injection and deposit the drug. If the aspiration test results in a burst of blood, creating a cloudy and reddened solution in the cartridge or if the clinician, for any reason, is concerned about the ability to see subsequent aspiration results clearly, the needle should be withdrawn, the cartridge replaced, and the needle flushed or replaced before reinitiating the injection.