If blood enters the dental cartridge during aspiration, what should be your immediate action?

When blood enters the dental cartridge during aspiration, the immediate action should be to remove the needle and replace the cartridge. This is critical because the presence of blood in the cartridge indicates that the needle has likely penetrated a blood vessel. Continuing with the procedure or injecting a small dose after seeing blood could lead to complications, such as inadvertent intravenous administration of the anesthetic, which could pose serious health risks to the patient.

Replacing the cartridge ensures that you are using a safe and sterile solution for anesthesia, free from contaminants that could enter the patient's bloodstream. It also reinforces safe practices in administering local anesthesia, as it minimizes patient risk and ensures that the procedure proceeds smoothly once a clear cartridge is in use. Notifying the supervising dentist may be appropriate in certain contexts but does not address the immediate safety concern presented by continuing with the procedure under these circumstances.