Dialysis-Induced Hypotension: Mechanisms and Management

Introduction to Dialysis-Induced Hypotension

Approximately 25% of all hemodialysis sessions are affected by low blood pressure (hypotension), a condition known as intradialytic hypotension (IDH), which is defined as a decrease in systolic blood pressure by ≥20 mmHg or a decrease in mean arterial pressure by 10 mmHg, accompanied by symptoms such as abdominal discomfort, nausea, dizziness, and anxiety, according to the American Journal of Kidney Diseases 1

Ultrafiltration and plasma refilling: Rapid removal of fluid during dialysis can exceed the rate at which fluid refills from tissue spaces into the vascular compartment, leading to reduced blood volume and hypotension, as reported by the American Journal of Kidney Diseases 2
Autonomic dysfunction: Many dialysis patients, particularly those with diabetes, have impaired autonomic nervous system function, resulting in inadequate vasoconstriction in response to volume removal, according to the American Journal of Kidney Diseases 1
Reduced vascular responsiveness: Dialysis patients have defective reactivity of resistance and capacitance vessels during hemodialysis sessions, as noted by the American Journal of Kidney Diseases 1
Cardiac factors: Pre-existing cardiac conditions like left ventricular hypertrophy, diastolic dysfunction, or systolic dysfunction can contribute to hypotension during dialysis, as stated by the American Journal of Kidney Diseases 1

Diabetic kidney disease is a risk factor for intradialytic hypotension, according to the American Journal of Kidney Diseases 1
Cardiovascular disease (especially LVH and heart failure) increases the risk of intradialytic hypotension, as reported by the American Journal of Kidney Diseases 1
Poor nutritional status and hypoalbuminemia are risk factors for intradialytic hypotension, as noted by the American Journal of Kidney Diseases 1
Uremic neuropathy or autonomic dysfunction can contribute to intradialytic hypotension, according to the American Journal of Kidney Diseases 1
Severe anemia is a risk factor for intradialytic hypotension, as stated by the American Journal of Kidney Diseases 1
High ultrafiltration requirements increase the risk of intradialytic hypotension, as reported by the American Journal of Kidney Diseases 1
Predialysis systolic BP ≤100 mmHg is a risk factor for intradialytic hypotension, according to the American Journal of Kidney Diseases 1
Age ≥65 years is a risk factor for intradialytic hypotension, as noted by the American Journal of Kidney Diseases 1
Female sex is a risk factor for intradialytic hypotension, as stated by the American Journal of Kidney Diseases 1
Use of nitrates before dialysis increases the risk of intradialytic hypotension, according to the American Journal of Kidney Diseases 1

Reduce or temporarily stop ultrafiltration to prevent further blood pressure drop, as recommended by Praxis Medical Insights 3
Administer intravenous normal saline bolus to rapidly expand plasma volume, as suggested by Praxis Medical Insights 3
Place patient in Trendelenburg position (head down, legs elevated) to improve venous return, as recommended by Praxis Medical Insights 3
Provide supplemental oxygen to improve tissue oxygenation and reduce symptoms, as suggested by Praxis Medical Insights 3
Slower ultrafiltration rate by extending treatment time when possible, as recommended by Praxis Medical Insights 3
Cool dialysate (34-35°C instead of 37°C) to increase peripheral vasoconstriction and cardiac output, as suggested by Praxis Medical Insights 3
Sodium profiling (starting with higher sodium concentration and gradually decreasing it) to maintain vascular stability, as recommended by Praxis Medical Insights 3
Use bicarbonate-containing dialysate instead of acetate-containing dialysate to prevent inappropriate decreases in vascular resistance, as suggested by Praxis Medical Insights 3
Limit fluid intake between dialysis sessions to reduce interdialytic weight gain, as recommended by Praxis Medical Insights 3
Avoid food intake immediately before or during hemodialysis to prevent decreased peripheral vascular resistance, as suggested by Praxis Medical Insights 3
Optimize hemoglobin levels to improve oxygen-carrying capacity, as recommended by Praxis Medical Insights 3

Dry weight assessment: Regularly reevaluate the patient's estimated dry weight, as hypotension may indicate it is set too low, as recommended by Praxis Medical Insights 3
Medication review: Evaluate and potentially adjust antihypertensive medications that may contribute to hypotension, as suggested by Praxis Medical Insights 3
Blood pressure paradox: Some dialysis patients exhibit a "U-shaped" relationship between blood pressure and mortality, with excess mortality risk in patients with both the lowest and highest blood pressure levels, as reported by the American Journal of Kidney Diseases 5
Lag phenomenon: In 90% of patients, extracellular fluid volume normalizes within a few weeks of achieving dry weight, but elevated blood pressure may continue to decrease for another 8 months or longer, as noted by the American Journal of Kidney Diseases 2

Attempting to achieve NKF/KDOQI blood pressure targets may lead to more frequent episodes of intradialytic hypotension in some patients, as reported by Circulation 6
For patients approaching dry weight, the ultrafiltration rate should be reduced toward the end of dialysis to accommodate the reduced vascular refilling rate, as recommended by the American Journal of Kidney Diseases 2