Final answer:
If a nurse aspirates back blood while administering an IM injection, the correct action is to withdraw the needle and select a new injection site. The syringe and medication should be disposed of properly, and a new dose prepared for administration.
Step-by-step explanation:
When a nurse administers an IM (intramuscular) injection and aspirates back blood into the syringe, this suggests that the needle may have entered a blood vessel. In such a scenario, it is best practice for the nurse to withdraw the needle and choose a new injection site. Following this, the nurse should dispose of the syringe and medication according to the facility's protocol, prepare a new dose of medication, and attempt the injection again, ensuring to aspirate before injecting to confirm that the needle is not in a blood vessel. It is not necessary to notify the healthcare provider unless there is a significant issue or adverse reaction, nor is it appropriate to apply pressure to the injection site as this could cause discomfort or a hematoma if an injection of the medication inadvertently occurred into the tissue.