A 24-year-old woman with type 1 diabetes mellitus presents to the emergency department. She is awake but drowsy and has a heart rate of 115 bpm, respiratory rate of 30 breaths per minute, and blood pressure of 90/60 mmHg. Laboratory results show a blood glucose of 420 mg/dL, arterial pH of 7.25, and serum bicarbonate of 15 mEq/L. Her urine is positive for ketones. Which of the following therapeutic interventions should be prioritized?
Intravenous phosphate replacement
Administration of supplemental oxygen
Intravenous glucose infusion
Initiation of intravenous fluid resuscitation and insulin therapy