Final answer:
The nurse should continue to provide care, document all actions, and page the attending physician if unable to reach the resident to ensure timely patient care.
Step-by-step explanation:
When a nurse receives an abnormal result on a critical test for a patient and is unable to reach the resident for guidance, the most appropriate action would be to continue to provide care for the patient, document all actions in the medical record, and escalate the communication to a higher authority, such as paging the attending physician. This ensures that there are no delays in the patient receiving the care they need. It is also important for the nurse to be aware of the hospital's protocols on escalation of care and to follow these procedures, which may include multiple attempts to contact the resident or immediate notification of the attending physician if the situation is dire.