A 19-year-old man is brought to the emergency department due to abdominal pain, nausea, and vomiting for the past 2 days. He also reports increased thirst and frequent urination over the last week. His temperature is 37.1°C (98.8°F), pulse is 118/min, blood pressure is 90/60 mm Hg, and respirations are 26/min and deep. Mucous membranes are dry. Laboratory studies show:
| Parameter | Value |
|---|---|
| Serum glucose | 540 mg/dL |
| Serum sodium | 132 mEq/L |
| Serum potassium | 4.6 mEq/L |
| Serum chloride | 98 mEq/L |
| Serum bicarbonate | 10 mEq/L |
| Blood urea nitrogen | 32 mg/dL |
| Serum creatinine | 1.4 mg/dL |
| Urine ketones | large |
Arterial blood gas shows a pH of 7.15.
Arrange the following steps in the optimal chronological sequence for the management of this patient's condition.
- 1Administer a rapid bolus of intravenous 0.9% normal saline
- 2Initiate a continuous intravenous regular insulin infusion
- 3Add 5% dextrose to the maintenance intravenous fluids
- 4Transition to a subcutaneous insulin regimen
Answer
The correct sequence for managing diabetic ketoacidosis is: 1) Administer normal saline, 2) Initiate intravenous insulin, 3) Add dextrose to fluids, and 4) Transition to subcutaneous insulin.
The management of diabetic ketoacidosis (DKA) follows a strict, step-wise protocol to ensure safe correction of hypovolemia, hyperglycemia, and ketoacidosis. The most critical initial step is intravascular volume expansion with 0.9% normal saline to restore perfusion. Once fluids are started and potassium is confirmed to be safe (> 3.3 mEq/L), a continuous intravenous regular insulin infusion is initiated to halt lipolysis, reduce ketone production, and correct the anion gap acidosis. As glucose levels fall faster than ketones clear, 5% dextrose must be added to the intravenous fluids when blood glucose reaches approximately 200 mg/dL. This prevents hypoglycemia while allowing the continuous insulin infusion to remain running until the anion gap closes. Finally, once the ketoacidosis has resolved (closed anion gap, pH > 7.3) and the patient is alert and able to eat, they are transitioned to a subcutaneous insulin regimen.
Step-by-Step Solution
Key Concept
The chronological management sequence of diabetic ketoacidosis emphasizes volume expansion before insulin therapy, and maintaining insulin therapy with added dextrose until the anion gap closes.