Final answer:
The nurse should quickly assess the patient for signs of bleeding and immediately inform the physician due to the possibility of circulatory shock, requiring urgent medical intervention.
Step-by-step explanation:
The nurse's best response to a patient with a significant drop in level of consciousness and blood pressure (BP), along with scant urine output after a nephrectomy is immediate action, as these symptoms may indicate circulatory shock due to hemorrhage, which is a life-threatening condition. This is supported by the patient's symptoms post-surgery, which resemble the signs of hypovolemic shock such as low blood pressure, altered mental status, and low urine output. Therefore, the nurse should assess the patient for signs of bleeding and inform the physician immediately as per standard postoperative protocol.
The nurse should not delay action by merely monitoring vital signs or repositioning the patient, as prompt intervention is critical. Additionally, palpating flanks might cause further discomfort and is not the immediate priority over assessing for hemorrhage and notifying the physician.