Test Your Knowledge: Acid-Base Disturbances in the Hemodialysis Patient

Abnormal bicarbonate levels in end-stage-renal disease (ESRD) patients are a treatment challenge. How and when to intervene has little or no evidence. In a recent article in AJKD, Drs. Lisawat and Gennari discuss correction of bicarbonate values in the ESRD patient. Test your knowledge with the following questions on this topic:

1. Which of the following is NOT a cause of metabolic alkalosis in ESRD patients on dialysis?

A. Malnutrition

B. Hypercapnea

C. Nasogastric suction.

D. Massive blood transfusion

E. Plasmapheresis with fresh frozen plasma

F. Crack cocaine

 2. What is the KDOQI recommended pre-dialysis serum bicarbonate in adults?

A. < 20 mEq/L

B. 20-22 mEq/L

C. >22mEq/L

 3. How is standard hemodialysis solution buffered?

A. Bicarbonate and chloride

B. Bicarbonate alone

C. Bicarbonate and citrate

D. Bicarbonate and glucose

4.  A 45-year-old obese woman with hypertensive nephrosclerosis is started on intermittent hemodialysis. Although she tolerates the dialysis sessions well, she is noted to have pre-dialysis serum bicarbonate levels consistently below 20 mEq/L. She is dialyzed with a standard dialysate, and post-dialysis bicarbonate level ranges between 24-28 mEq/L. Infectious work-up and lactate level are unremarkable. Her appetite is good, with a protein catabolic rate of 1 g/kg per day. Her inter-dialytic weight gain is approximately 4-5 kg. What is the next step in optimizing her acid-base status?

A. Continue current dialysis prescription without any changes. Her acid-base status will improve over time.

B. Continue current dialysate prescription without any changes. Her bicarbonate level is acceptable.

C. Increase dialysate bicarbonate concentration to 40 mEq/L.

D. Fluid restriction and low-sodium diet to decrease inter-dialytic weight gain.

 5. A 75-year-old man with ESRD secondary to diabetic nephropathy has been on maintenance hemodialysis for 20 years. He was recently hospitalized for pneumonia complicated by respiratory failure requiring a brief period of intubation. He was transferred to a nursing home for rehabilitation. His pre-dialysis serum bicarbonate levels, which were previously within the recommended range, are now persistently elevated above 27 mEq/L. He has no complaints. What is the next step in evaluating the metabolic alkalosis?

A. Assess normalized protein catabolic rate

B. Check arterial blood gas levels to rule out chronic hypercapnia

C. No additional work up needed

D. Decrease dialysate bicarbonate concentration to 25 mEq/L

Post prepared by eAJKD Contributor Dr. Ritu Soni from the University of Pittsburgh.

To see answers, please click here.

To view the article abstract or full-text (subscription required), please visit AJKD.org.

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