Assessing Anemia Secondary to Hemolysis in Hemodialysis Patients

Nephrology Nursing Journal, April, 2001 by Jamie Behrens

Hemolysis that appears in a number of patients who are dialyzing at the same time, regardless of whether the onset is sudden or slow, is most frequently caused by central water treatment malfunctions. Sporadic episodes of hemolysis occurring in different patients are frequently caused by a malfunctioning dialysis machine, hyperocclusion, or contamination with formaldehyde or another disinfectant toxin. The results of this clinical evaluation should allow the offending substance to be removed or the procedure that needs to be corrected to be identified (Kjellstrand, 1993).

Case Study: Occult Hemolysis

RL is a 74-year-old hemodialysis female with ESRD secondary to glomerulonephritis. Her Hb levels had stabilized at about 10.1 g/dL and did not respond to progressively higher doses of Epoetin alfa. Assessments of blood loss, iron parameters, and other common etiologies known to contribute to hyporesponse to Epoetin alfa were negative. While the reticulocyte count was elevated, there was no increase in Hb level. A review of dialysis practices over the past 3 months revealed an average prepump arterial pressure reading of -250 mmHg. In an attempt to obtain the prescribed blood flow of 350 mL/minute, the staff routinely ran this patient with lower than accepted prepump arterial pressure readings. The staff suspected hemolysis, which was confirmed by a haptoglobin test.

Discussion: Hemolysis is often, but not always, accompanied by changes in the color of the blood. The potential for excessive negative prepump arterial pressure (less than -250 mmHg) is probable when the ordered blood pump speeds exceed the ability of the access to provide that amount of flow per minute. This situation is commonly seen in patients whose catheters demonstrate less than optimal or impaired flow rates.

In this case, the importance of adhering to the prescribed Qb, but being alert to the safety issue of avoiding excessive negative arterial pressure, were addressed with staff members. The Epoetin alfa dose was maintained, and the Hb gradually increased to 11.8 g/dL. The patient care staff received in-service training on the importance of prepump arterial monitoring and the need to report pressures in excess of -220 mmHg. Staff members were also reminded that they need to obtain orders to reduce the Qb immediately when any access does not support the ordered amount.

Conclusion

Dialysis patients are susceptible to hemolysis from many sources. While overt hemolysis is easily detectable, occult hemolysis is not visibly apparent and may be overlooked. Patients who exhibit hyporesponse to Epoetin alfa therapy and who are not affected by more common etiologies, such as blood loss, inadequate Epoetin alfa dosage, iron deficiency, infection, inflammation, and secondary hyperparathyroidism, should be evaluated for hemolysis. Ongoing assessment can help clinicians proactively prevent, detect, and manage hemolysis to minimize its effect on Hb levels.

References

Denker, B.M., Chertow, G.M., & Owen, W.F. Jr. (2000). Hemodialysis. In: Brenner, B.M. (Ed)., The Kidney, 6th ed. (p. 2425). Philadelphia, PA: W.B. Saunders Company.