A 24-year-old woman with a history of type 1 diabetes mellitus presents to the emergency department with nausea, vomiting, and profound weakness for the past 24 hours. She has been unable to tolerate oral intake. Her blood pressure is 90/60 mm Hg, pulse is 122/min, and respirations are 28/min and deep. Laboratory studies show:
- Serum glucose: 580 mg/dL
- Arterial blood gas pH: 7.12
- Serum bicarbonate: 11 mEq/L
- Serum potassium: 3.1 mEq/L
- Serum sodium: 132 mEq/L
- Serum creatinine: 1.4 mg/dL
Arrange the following management steps in the most appropriate chronological order of execution.
- 1Administration of 0.9% sodium chloride bolus
- 2Intravenous potassium chloride supplementation
- 3Intravenous regular insulin infusion
- 4Addition of 5% dextrose to intravenous fluids
Answer
The correct sequence is: 1) Administration of 0.9% sodium chloride bolus, 2) Intravenous potassium chloride supplementation, 3) Intravenous regular insulin infusion, 4) Addition of 5% dextrose to intravenous fluids.
The management of diabetic ketoacidosis follows a strict sequential protocol to minimize complications. The very first step is restoring intravascular volume with isotonic saline. Next, before giving any insulin, the physician must check the potassium level. Because this patient's potassium is dangerously low (3.1 mEq/L), potassium must be aggressively replaced first. Once the potassium is ≥ 3.3 mEq/L, an intravenous insulin infusion is started to resolve the acidosis. Finally, as the glucose falls (typically ≤ 200 mg/dL), 5% dextrose must be added to the intravenous fluids to prevent hypoglycemia, allowing the insulin drip to continue running until the anion gap is completely closed.
Step-by-Step Solution
Key Concept
In diabetic ketoacidosis, normal saline is the first step, followed by ensuring serum potassium is ≥ 3.3 mEq/L before starting insulin, and adding dextrose when glucose reaches ≤ 200 mg/dL.