What is the management for intradialytic postural hypotension?

Management of Intradialytic Postural Hypotension

Nonpharmacological strategies should be prioritized first for managing intradialytic postural hypotension, followed by pharmacological interventions only when necessary. 1

Assessment and Target Weight Optimization

• Any symptomatic decrease in BP or a nadir intradialytic SBP of <90 mm Hg should prompt reassessment of BP management 2
• Review the current estimated dry weight (EDW) in patients with recurrent hypotension, as an inappropriately low EDW is a common cause of intradialytic hypotension 1
• Look for clues that the EDW may be too low, such as increased dietary intake with improving nutrition markers in the presence of hypotension 1
• In some cases, consider maintaining the patient slightly above the estimated dry weight, weighing the benefits against risks of chronic volume overload 2

Ultrafiltration Modifications

• Limit ultrafiltration rates to below 6 ml/h per kg to reduce mortality risk and prevent end-organ ischemia 2
• Extend dialysis treatment time to lower the hourly ultrafiltration rate for patients with large fluid intake 1
• Consider sequential ultrafiltration/clearance to improve hemodynamic stability 1
• Encourage patients to decrease their fluid intake between dialysis sessions to reduce interdialytic weight gain 1
• For chronically hypotensive patients, consider increasing dialysis time or evaluating whether peritoneal dialysis might be better tolerated 2

Dialysate Modifications

• Implement sodium profiling by increasing dialysate sodium concentration early in the session, followed by a decrease later in the treatment 1
• Use bicarbonate-containing dialysate instead of acetate-containing dialysate to minimize hypotension 1
• 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
• Cool dialysate has been shown to preserve central blood volume and cardiac output during dialysis 3

Pharmacological Interventions

• Administer midodrine 30 minutes before hemodialysis at doses of 5-10 mg to increase peripheral vascular resistance 4
• Midodrine is the most widely used pharmacological option for intradialytic hypotension, acting as an alpha1-agonist that increases vascular tone 5, 1
• Midodrine has been shown to significantly improve lowest intradialytic systolic blood pressure (from 96.6 to 114.7 mm Hg) and diastolic blood pressure (from 53.2 to 59.0 mm Hg) 4
• Monitor for potential side effects of midodrine including supine hypertension, bradycardia, and urinary retention 5
• Individualize the timing of antihypertensive medication administration based on interdialytic blood pressure patterns 2
• Consider avoiding nondialyzable antihypertensive medications in patients with frequent intradialytic hypotension 2

Additional Strategies

• Avoid food intake immediately prior to or during hemodialysis, as it causes a decrease in peripheral vascular resistance 1
• Consider raising hemoglobin to 11 g/L and/or administering supplemental inhaled oxygen to reduce intradialytic hypotension 1
• Use lung ultrasound with B-line quantification before dialysis to assess fluid status and predict IDH risk (fewer than 8 B-lines overall or fewer than 20 B-lines in NYHA class 3-4 patients indicates higher IDH risk) 6
• For patients with autonomic dysfunction, a multifaceted approach targeting both cardiac output preservation and vascular tone is necessary 7

Algorithm for Managing Intradialytic Hypotension

1. First-line interventions:

   • Reassess and potentially increase estimated dry weight 1
   • Reduce dialysate temperature to 34-35°C 1, 3
   • Limit ultrafiltration rate to <6 ml/h per kg 2

2. Second-line interventions:

   • Administer midodrine 5-10 mg 30 minutes before dialysis 4
   • Implement sodium profiling 1
   • Extend dialysis time to reduce hourly ultrafiltration rate 1

3. For refractory cases:

   • Consider alternative dialysis modalities (peritoneal dialysis) 2
   • Evaluate for other causes of hypotension (cardiac dysfunction, sepsis) 8
   • Consider additional pharmacological agents (vasopressin, sertraline, fludrocortisone) 2

Common Pitfalls and Caveats

• Sodium profiling may increase interdialytic weight gain and interdialytic blood pressure 1
• Withholding antihypertensive agents before dialysis has unknown effectiveness in reducing intradialytic hypotension 2
• Midodrine can cause marked elevation of supine blood pressure (>200 mmHg systolic) and should be used cautiously 5
• Avoidance of intradialytic hypotension should not come at the expense of maintaining euvolemia or ensuring adequate dialysis time 2
• Patients using midodrine should take their last daily dose 3-4 hours before bedtime to minimize nighttime supine hypertension 5