How is intradialytic (during dialysis) postural hypotension (low blood pressure) managed?

Management of Intradialytic Postural Hypotension

Nonmedication strategies for treating intradialytic hypotension, such as cardiovascular status optimization, ultrafiltration rate minimization, and target-weight reassessment, should be prioritized before considering pharmacological interventions. 1

Ultrafiltration Modifications

• Review the current estimated dry weight (EDW) in patients with severe recurrent hypotension, as an inappropriately low EDW may contribute to hypotension 1
• Limit ultrafiltration rates to below 6 ml/h per kg to reduce mortality risk and prevent end-organ ischemia 1
• Extend dialysis treatment time to lower the hourly ultrafiltration rate for patients with large fluid intake 1
• Consider sequential ultrafiltration/clearance (performing ultrafiltration separately from diffusive clearance) to improve hemodynamic stability 1
• Encourage patients with excessive weight gain to decrease their fluid intake between dialysis sessions 1

Dialysate Modifications

• Implement sodium profiling by increasing dialysate sodium concentration (148 mEq/L) early in the session, followed by a continuous or stepwise decrease later in the treatment 1
• Use bicarbonate-containing dialysate instead of acetate-containing dialysate to minimize hypotension by preventing inappropriate decreases in vascular resistance 1, 2
• Reduce dialysate temperature from 37°C to 34-35°C to increase peripheral vasoconstriction and cardiac output, particularly beneficial for patients with frequent episodes of hypotension 1, 3
• Monitor for symptomatic hypothermia when using cooler dialysate, as some patients may experience uncomfortable cold sensations 1, 3

Pharmacological Interventions

• Administer midodrine (an oral selective α1-adrenergic agonist) 30 minutes before hemodialysis to increase peripheral vascular resistance and enhance venous return 1, 4
• Consider midodrine as the most widely used pharmacological option for intradialytic hypotension, though efficacy data are limited 1, 5
• Other medication options include arginine-vasopressin, sertraline, droxidopa, amezinium metilsulfate, fludrocortisone, and carnitine, though evidence for these is relatively weak 1, 5
• Individualize the timing of antihypertensive medication administration based on interdialytic blood pressure patterns and frequency of intradialytic hypotension 1
• Consider avoiding nondialyzable antihypertensive medications (like carvedilol) in patients with frequent intradialytic hypotension 1

Target Weight Assessment

• Recognize that target weight is a critical element of dialysis prescription that may vary from treatment to treatment 1
• Look for clues that the EDW may be too low, such as increased dietary intake accompanied by biochemical signs of improving nutrition (increasing serum albumin and/or creatinine) in the presence of hypotension 1
• In some cases (e.g., acute illness, severe symptoms), consider maintaining the patient slightly above the estimated dry weight, weighing the benefits against risks of chronic volume overload 1

Additional Strategies

• Avoid food intake immediately prior to or during hemodialysis, as it causes a decrease in peripheral vascular resistance and may result in hypotension 1
• Consider raising hemoglobin to 11 g/L and/or administering supplemental inhaled oxygen to reduce intradialytic hypotension, especially for patients with cardiovascular or respiratory disease 1, 3
• For chronically hypotensive patients, consider increasing dialysis time or evaluating whether peritoneal dialysis might be better tolerated 1
• Educate patients about the importance of adherence to the hemodialysis regimen to optimize outcomes 1, 6

Common Pitfalls and Caveats

• Sodium profiling may be associated with increased interdialytic weight gain and variable increases in interdialytic blood pressure 1, 3
• The ideal dialysate sodium concentration remains uncertain, with ongoing research to determine optimal levels 1
• Withholding antihypertensive agents before dialysis to reduce intradialytic hypotension has unknown effectiveness 1
• Recognize that intradialytic hypotension is associated with increased cardiovascular and all-cause mortality, making prevention crucial 7, 6
• Repeated episodes of hypotension may lead to vascular access thrombosis and reduced dialysis efficiency 2