Final answer:
The CCU nurse should prioritize maintaining and monitoring the patient's fluid balance, which is critical in treating diabetic ketoacidosis in the initial phase.
Step-by-step explanation:
During the initial phase of treatment for a patient admitted to the critical care unit (CCU) for diabetic ketoacidosis, a complication of type 1 diabetes, the CCU nurse should prioritize maintaining and monitoring the patient's fluid balance. Diabetic ketoacidosis can lead to severe dehydration due to the excess urination that occurs in an attempt to rid the body of excess glucose and ketones. Therefore, careful assessment of the patient's hydration status and administration of intravenous fluids are critical first steps. Moreover, monitoring blood-sugar levels is essential to manage hyperglycemia. While other assessments such as evaluating for dysrhythmias, level of consciousness, or signs of venous thromboembolism are also important, these may follow the immediate concern of correcting the patient's fluid and electrolyte imbalances and stabilizing blood glucose levels.