Question
Is there any oral medication to prevent or treat hypotension induced by hemodialysis?
Response from Joseph Li, MD
Hypotension is a potential complication of hemodialysis. Up to 50% of patients experience symptomatic reductions in blood pressure following hemodialysis.[1] There are many potential causes of this disorder.[2] Depending on the underlying problem, treatment with medication may or may not result in effective management. Therefore, it is imperative to appropriately identify the cause of hemodialysis-associated hypotension.[3]
Hypotension associated with hemodialysis can be a symptom of a number of serious medical conditions, including myocardial infarction, cardiac arrhythmias, pericardial tamponade, sepsis, or air embolism.[3] These diagnoses must be in the differential when examining the patient who becomes hypotensive.
More frequently, hemodialysis-associated hypotension is a result of other factors. For example, food ingestion during hemodialysis is a documented cause of hypotension. The mechanism of action is decreased systemic vascular resistance.[4] The obvious solution for this cause of hypotension is to stop food ingestion before and during hemodialysis.
Hypotension can also represent a reaction to the hemodialysis membrane.[5] Approximately 3% to 5% of patients who are dialyzed with cellulosic membranes may experience side effects, including hypotension.[6] These symptoms may improve as dialysis is continued; however, if they persist, switching to a dialysis machine with another form of membrane may solve the problem.
Accurate assessment of the patient's "dry weight" is important for all patients undergoing hemodialysis. Unfortunately, there is presently no perfect way to ascertain this measurement. In fact, dry weight may change over time, depending on such variables as hematocrit and concurrent illness.[3] An inaccurate dry weight may lead to inappropriate dialysis, which in turn can result in hypotension. Continual reassessment of a patient's dry weight may prevent this problem.
Appropriate dialysate sodium concentration is also an important consideration in the prevention of hemodialysis-associated hypotension.[7] The use of a dialysate with a higher sodium concentration helps maintain the plasma osmolality during hemodialysis by decreasing the osmotic drive of fluid into the intracellular compartment.[8]
Suboptimal cardiac function can also cause hemodialysis-associated hypotension.[9] For patients with poor left ventricular function, treatment to optimize cardiac function can minimize this problem.
Finally, autonomic neuropathy can lead to hypotension in patients with or without hemodialysis. Midodrine is a selective alpha-a agonist that has been used in the treatment of patients with hypotension due to autonomic neuropathy.[10] It has also been used in patients without autonomic neuropathy who have hemodialysis-associated hypotension recalcitrant to other treatments.[3]
This response discusses only some of the many potential causes of hemodialysis-associated hypotension. In most instances, treatment with medication is rarely indicated. Identifying the reason why your patient is experiencing hemodialysis-associated hypotension is the most important step in understanding whether medical therapy is indicated.
Medscape Internal Medicine. 2003;5(2) © 2003 Medscape
Cite this: Joseph Ming Wah Li. Medication for Hemodialysis-Induced Hypotension - Medscape - Nov 13, 2003.
