How to manage a patient with intradialytic hypotension during hemodialysis (HD)?

Management of Intradialytic Hypotension

When a patient develops intradialytic hypotension, immediately stop or reduce ultrafiltration, place them in Trendelenburg position, and administer supplemental oxygen—then systematically modify the dialysis prescription to prevent recurrence, with ultrafiltration rate control being the single most critical factor. 1

Immediate Acute Management

When hypotension occurs during dialysis, take these immediate steps:

• Stop or reduce ultrafiltration immediately to prevent further blood pressure decline and allow vascular refilling 1, 2
• Administer intravenous normal saline bolus (typically 100-250 mL) to rapidly expand plasma volume, though avoid routine saline for every episode as this perpetuates volume overload 1, 2
• Place the patient in Trendelenburg position (head down, legs elevated) to improve venous return and increase blood pressure 1, 2
• Provide supplemental oxygen to improve tissue oxygenation and reduce symptoms 1, 2

Dialysis Prescription Modifications to Prevent Recurrence

After stabilizing the acute episode, modify the dialysis prescription to prevent future occurrences:

Ultrafiltration Rate Management

• Keep ultrafiltration rates below 6 mL/h/kg as rates exceeding this threshold are associated with higher mortality risk and increased hypotension 1
• Extend treatment time to minimum 4 hours per session to slow the ultrafiltration rate and allow adequate vascular refilling 3, 1
• Increase dialysis frequency from twice to three times weekly when patients have excessive interdialytic weight gain requiring aggressive ultrafiltration that exceeds vascular refilling capacity 1

Dry Weight Reassessment

• Reassess the estimated dry weight if hypotension is recurrent, as the target may be set too low—a common pitfall is underestimating true dry weight in patients with residual urine output 3, 1
• Look for clues that dry weight is too low: increased dietary intake accompanied by biochemical signs of improving nutrition (increasing serum albumin and/or creatinine concentration, and/or normalized protein catabolic rate) in the presence of hypotension 3
• Remember that hypotension cannot be used to define intravascular volume status—you must reevaluate the entire clinical picture 3

Dialysate Modifications

Manipulating dialysate composition is highly effective for preventing intradialytic hypotension:

Sodium Concentration

• Increase dialysate sodium concentration to 148 mEq/L, especially early in the dialysis session, or implement sodium profiling (starting higher and gradually decreasing) to maintain vascular stability 3, 1, 2
• Be aware that increased dialysate sodium may lead to increased thirst, interdialytic weight gain, and variable increases in interdialytic blood pressure 3, 2

Temperature Reduction

• Reduce dialysate temperature from 37°C to 34-35°C to increase peripheral vasoconstriction and cardiac output through increased sympathetic tone, which decreases symptomatic hypotension from 44% to 34% 3, 1, 4
• This intervention is beneficial even in patients with excessive weight gains 3
• Cold dialysis does not compromise urea clearance or increase urea rebound 3
• Be aware that reduced temperature may induce mild to intolerable symptomatic hypothermia in some patients 3, 2

Buffer Type

• Switch from acetate-containing to bicarbonate-containing dialysate to prevent inappropriate decreases in total vascular resistance and venous pooling 3, 1, 2
• Bicarbonate dialysate also results in fewer headaches and less nausea and vomiting 3

Pharmacological Management

Midodrine

• Administer midodrine (oral α1-adrenergic agonist) within 30 minutes before dialysis initiation at a mean dose of 8 mg (range 2.5-25 mg) to increase peripheral vascular resistance and enhance venous return 3, 1, 2, 4
• Midodrine raises blood pressure by increasing peripheral vascular resistance (arteriolar vasoconstriction) and enhancing venous return and cardiac output (venular constriction) 3
• The drug is well tolerated and associated with few side effects 3
• The hemodynamic benefits of hypothermic dialysis alone or in combination with midodrine were comparable across interventions 3

Other Pharmacological Options

Alternative medications with weaker evidence include arginine-vasopressin, sertraline, droxidopa, amezinium metilsulfate, fludrocortisone, and carnitine, though the evidence base for these strategies is relatively weak 3, 5

Antihypertensive Medication Review

• Review and reduce antihypertensive medications, particularly when patients are on four or more concurrent agents, as these prevent compensatory vasoconstriction during ultrafiltration 1
• Consider adjusting beta-blockers like carvedilol, which blunt compensatory tachycardia and cardiac output increases needed during volume removal 1
• The effectiveness of withholding antihypertensive agents before dialysis in reducing intradialytic hypotension is unknown and should not be routine practice 3, 6
• Consider intradialytic BP patterns with regard to drug dialyzability—it may be prudent to avoid nondialyzable medications in the setting of frequent intradialytic hypotension 3
• Antihypertensive drugs should be given preferentially at night to reduce the nocturnal surge of blood pressure and minimize intradialytic hypotension, which may occur when drugs are taken the morning before a dialysis session 3

Long-Term Prevention Strategies

Dietary and Behavioral Modifications

• Limit sodium intake to <5.8 g/day (2-3 g/day per some guidelines) to reduce thirst and interdialytic weight gain, as water intake adjusts to match salt intake 3, 1
• Restrict interdialytic weight gain to <3% of body weight between sessions to prevent excessive ultrafiltration requirements 3, 1
• Avoid food intake immediately before or during hemodialysis, as this causes decreased peripheral vascular resistance and may precipitate hypotension 3, 1, 2
• Provide education and regular counseling by dietitians 3

Anemia Management

• Maintain hemoglobin at 11 g/dL per NKF-K/DOQI guidelines to improve oxygen-carrying capacity and cardiovascular compensation during ultrafiltration 3, 1, 4
• Supplemental inhaled oxygen may also reduce the incidence of intradialytic hypotension, especially for patients with cardiovascular or respiratory disease 3

Critical Pitfalls to Avoid

• Do not continue twice-weekly dialysis in patients with recurrent hypotension, as this forces dangerously high ultrafiltration rates and inadequate solute clearance 1
• Do not routinely administer saline for every hypotensive episode, as this perpetuates volume overload and fails to address the underlying problem 1
• Do not assume hypotension defines intravascular volume status—reevaluate the estimated dry weight if patients show signs of improving nutrition (increasing serum albumin, creatinine, or normalized protein catabolic rate) alongside hypotension 1
• Avoidance of intradialytic hypotension should not come at the expense of maintaining euvolemia or ensuring adequate dialysis time 3
• Any symptomatic decrease in BP or a nadir intradialytic SBP of <90 mm Hg should prompt reassessment of BP management, including UF rate, dialysis treatment time, interdialytic weight gain, dry-weight estimation, and antihypertensive medication use 3

Special Considerations

Intradialytic hypotension is associated with vascular access thrombosis, inadequate dialysis dose, and mortality 3. The prevalence ranges from 15% to 50% of HD treatments, depending on the definition 3. Major contributors to intradialytic hypotension are insufficient intravascular volume to support the desired UF rate and inadequate cardiovascular compensatory responses 3. Risk factors include diabetes, excessive interdialytic weight gain, low ejection fraction, and low left ventricular volume 7.