What is the initial management for hypotension during haemodialysis (hemodialysis)?

Management of Hypotension During Hemodialysis

For patients experiencing hypotension during hemodialysis, the initial management should focus on slowing the ultrafiltration rate, increasing dialysate sodium concentration, and administering midodrine if symptoms persist. 1

Initial Interventions for Acute Hypotension

• Reduce or temporarily stop ultrafiltration to prevent further blood pressure drop 1
• Administer intravenous normal saline bolus to rapidly expand plasma volume 1
• Place patient in Trendelenburg position (head down, legs elevated) to improve venous return 1
• Administer supplemental oxygen to improve tissue oxygenation and reduce symptoms 1

Pharmacological Management

• Administer midodrine (an oral selective α1-adrenergic agonist) within 30 minutes before dialysis initiation to prevent hypotension; this raises blood pressure by increasing peripheral vascular resistance and enhancing venous return 1, 2
• Typical midodrine dosing ranges from 2.5-10 mg given 15-30 minutes before dialysis 2
• Midodrine has been shown to significantly increase minimal systolic pressure from 93.1 to 107.1 mmHg and elevate mean diastolic pressure from 52.3 to 57.9 mmHg during hemodialysis 3

Dialysate Modifications

• Increase dialysate sodium concentration to 148 mEq/L, especially early in the dialysis session, to prevent hypotension 1
• Consider sodium profiling (starting with higher sodium concentration and gradually decreasing it) to maintain vascular stability 1
• Switch from acetate-containing dialysate to bicarbonate-containing dialysate to minimize hypotension by preventing inappropriate decreases in total vascular resistance 1
• Reduce dialysate temperature from 37°C to 34-35°C to increase peripheral vasoconstriction and cardiac output 1

Ultrafiltration Strategies

• Slow the ultrafiltration rate by extending treatment time when possible 1
• Consider performing sequential ultrafiltration/clearance (ultrafiltration alone followed by diffusive clearance) 1
• Reevaluate the patient's estimated dry weight, as hypotension may indicate that it is set too low 1

Prevention Strategies for Recurrent Hypotension

• Limit fluid intake between dialysis sessions to reduce interdialytic weight gain 1
• Avoid food intake immediately before or during hemodialysis as it causes decreased peripheral vascular resistance 1
• Consider raising hemoglobin to 11 g/L to improve oxygen-carrying capacity 1
• Review and potentially adjust antihypertensive medications, as these may contribute to intradialytic hypotension 1

Monitoring and Follow-up

• Monitor blood pressure frequently during dialysis, especially in the first hour when most hypotensive episodes occur 4
• Assess for symptoms of hypotension (dizziness, nausea, cramps, fatigue) 4
• Evaluate for potential causes of chronic hypotension in patients with recurrent episodes 5

Cautions and Considerations

• Increased dialysate sodium may lead to increased thirst, interdialytic weight gain, and hypertension 1
• Reduced dialysate temperature may cause uncomfortable hypothermia in some patients 1
• For patients with chronic hypotension (5-10% of hemodialysis patients), consider longer-term strategies including evaluation for cardiac dysfunction 5
• Patients with diastolic dysfunction may be more sensitive to reduced cardiac filling during ultrafiltration 6

By implementing these strategies, the risk of intradialytic hypotension can be significantly reduced, improving patient comfort, dialysis adequacy, and potentially long-term outcomes.