Acid base imbalance

A 56-year-old male, with chronic renal insufficiency (CRF), comes with the complaints of lethargy and dizziness. His EKG shows tall T waves and increased PR interval. His serum K+ is 6.4 meq/L. A bolus of calcium gluconate is given and the patient is started on hemodialysis. As the patient is suffering from active peptic ulcer disease, you decide to go for citrate hemodialysis, instead of heparin hemodialysis. Which of the following acid base imbalance is likely to occur in this patient because of this type of hemodialysis?

A. Anion gap metabolic acidosis.
B. Non-anion gap metabolic acidosis.
C. Metabolic alkalosis.
D. Respiratory acidosis.
E. Respiratory alkalosis.

correct answer is C

Explanation:

This patient is having dialysis for his resistant hyperkalemia. However, because active peptic ulcer disease is a contraindication for heparin use, this patient is given citrate instead of heparin hemodialysis. Citrate is an alkaline compound and high doses of citrate in a patient with CRF can lead to citrate intoxication and metabolic alkalosis secondary to citrate accumulation. In this patient, as citrate is used for hemodialysis and he already has severe CRF, he runs a high risk of developing metabolic alkalosis secondary to citrate intoxication. Infusion of more than eight units of bank blood (anticoagulated with acid-citrate-dextran) is also associated with citrate intoxication.

Metabolic acidosis is also possible because of underlying renal disease but not due to citrate hemodialysis.

Primary respiratory acid base disorders due to CRF or hemodialysis are not usually seen.