Final answer:
A critical care nurse should assess the hemofilter every 6 hours for signs of clotting while providing dialysis treatment under the direct supervision of a registered nurse, ensuring patient safety and treatment effectiveness.
Step-by-step explanation:
The critical care nurse monitoring a patient receiving continuous renal replacement therapy (CRRT) plays a crucial role in ensuring effective treatment and patient well-being. Duties typically performed under the direct supervision of a registered nurse include a rigorous assessment to recognize any immediate patient needs and ensure the safe operation of the dialysis equipment. Specifically, for the options given in the question, the most accurate responsibility is to assess the hemofilter every 6 hours for signs of clotting, among other tasks such as taking and reporting the patient's vital signs, preparing equipment, and ensuring sterile procedures are followed.