NCLEX-RNReduction of Risk PotentialHard
A client is admitted with diabetic ketoacidosis. Laboratory results show: glucose 468 mg/dL, pH 7.21, HCO3 9 mEq/L, PaCO2 29 mmHg, and serum potassium 3.1 mEq/L. An IV insulin infusion has been ordered. Which action should the nurse take first?
- AAdminister IV potassium chloride before starting insulin
- BBegin the insulin infusion as ordered
- CIncrease the rate of the normal saline infusion
- DAdminister sodium bicarbonate to correct the acidosis
Show answer & explanationAnswer & explanation
Correct answer: A. Administer IV potassium chloride before starting insulin
Insulin drives potassium into cells, which can precipitate severe, life-threatening hypokalemia and cardiac dysrhythmias in a client already hypokalemic at 3.1 mEq/L. Potassium must be replaced and brought to a safer level (typically above 3.3 mEq/L) before starting insulin therapy in DKA.
Why the other options are wrong
- B. Starting insulin before correcting hypokalemia risks fatal dysrhythmias from a further potassium drop.
- C. Fluid resuscitation is important but does not address the immediate risk of severe hypokalemia from insulin.
- D. Bicarbonate is not routinely given in DKA unless pH is extremely low (<6.9) and can worsen hypokalemia.
DKA Management Priority - Potassium
In diabetic ketoacidosis, serum potassium must be checked and corrected (if <3.3 mEq/L) before starting insulin, because insulin shifts potassium intracellularly, worsening hypokalemia.
- DKA labs: glucose >250, pH <7.3, HCO3 <18, ketones present
- Insulin lowers serum K+ by driving it into cells
- Hold insulin if K+ <3.3 mEq/L until replaced
- Fluids (0.9% NS) are started first, then K+, then insulin
Memory trick: 'Fluids first, potassium next, insulin last.'