How to manage hypotension in a patient undergoing hemodialysis (HD)?

Management of Hypotension in Hemodialysis Patients

The most effective approach to managing intradialytic hypotension involves immediate interventions to stabilize the patient, followed by systematic modification of the dialysis prescription to prevent recurrence, with ultrafiltration rate control being the single most critical factor. 1, 2

Immediate Acute Management

When hypotension occurs during dialysis, implement these interventions in sequence:

• Stop or reduce ultrafiltration immediately to prevent further blood pressure decline and allow vascular refilling 1, 2, 3
• Administer intravenous normal saline bolus (typically 100-250 mL) to rapidly expand plasma volume, though avoid routine saline administration for every episode as this perpetuates volume overload 2, 3
• Place the patient in Trendelenburg position (head down, legs elevated) to improve venous return and increase blood pressure 2, 3
• Provide supplemental oxygen to improve tissue oxygenation and reduce symptoms 1, 2, 3

Dialysis Prescription Modifications to Prevent Recurrence

Ultrafiltration Rate Management (Most Critical)

• Keep ultrafiltration rates below 6 mL/h/kg as rates exceeding this threshold are associated with higher mortality risk and increased hypotension 3
• Extend treatment time to minimum 4 hours per session to slow the ultrafiltration rate and allow adequate vascular refilling 1, 3
• 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, 3
• 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 1, 2, 3

Dialysate Modifications

• 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 1, 2

  • Caution: This may increase thirst, interdialytic weight gain, and hypertension 2

• 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% 1, 2

  • Caution: Some patients experience uncomfortable hypothermia 1, 2

• Switch from acetate-containing to bicarbonate-containing dialysate to prevent inappropriate decreases in total vascular resistance and venous pooling 1, 2

Pharmacological Management

• Administer midodrine (oral α1-adrenergic agonist) 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 1, 2, 4, 5
  • Midodrine raises blood pressure by increasing arteriolar vasoconstriction and venular constriction, improving both the lowest intradialytic blood pressure and reducing hypotensive interventions 1, 5
  • Note: Midodrine is removed by dialysis, so timing of administration is critical 4

Medication Review

• Review and reduce antihypertensive medications, particularly when patients are on four or more concurrent agents, as these prevent compensatory vasoconstriction during ultrafiltration 3
• Consider adjusting beta-blockers like carvedilol, which blunt compensatory tachycardia and cardiac output increases needed during volume removal 3

Long-Term Prevention Strategies

Patient-Directed Interventions

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

Optimization of Comorbidities

• Maintain hemoglobin at 11 g/dL per NKF-K/DOQI guidelines to improve oxygen-carrying capacity and cardiovascular compensation during ultrafiltration 1, 2, 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 3
• Do not routinely administer saline for every hypotensive episode, as this perpetuates volume overload and fails to address the underlying problem 3
• Do not ignore the ultrafiltration rate/weight ratio (UF/Wt): a threshold >0.04 is a potential alert for avoiding hypotension, especially in elderly and diabetic patients 6
• 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

Algorithm for Systematic Approach

1. Acute episode: Stop/reduce UF → Trendelenburg → Saline bolus → Oxygen
2. Assess UF rate: Calculate UF/Wt ratio—if >0.04 or >6 mL/h/kg, extend treatment time or increase frequency
3. Modify dialysate: Increase sodium to 148 mEq/L and reduce temperature to 34-35°C
4. Add midodrine: 30 minutes pre-dialysis if modifications insufficient
5. Review medications: Reduce antihypertensives, especially if ≥4 agents
6. Patient education: Sodium restriction and interdialytic weight gain <3% of body weight

1, 2, 3