What are the management strategies for complications during hemodialysis, including hypotension, cramps, nausea, and vascular access issues?

Management of Hemodialysis Complications

Hypotension Management

For acute intradialytic hypotension, immediately stop or reduce ultrafiltration, place the patient in Trendelenburg position, and administer supplemental oxygen—these interventions address the immediate hemodynamic crisis while avoiding the pitfall of routine saline boluses that perpetuate volume overload. 1, 2

Immediate Interventions

• Stop or reduce ultrafiltration immediately to prevent further blood pressure decline 1, 2
• Place patient in Trendelenburg position (head down, legs elevated) to improve venous return and increase blood pressure 1
• Administer supplemental oxygen to improve tissue oxygenation and reduce symptoms 3, 1
• Administer intravenous normal saline bolus only when necessary for rapid plasma volume expansion, but avoid routine use as this perpetuates volume overload 1, 2

Preventive Dialysate Modifications

• Reduce dialysate temperature from 37°C to 34-35°C to increase peripheral vasoconstriction and cardiac output—this decreases symptomatic hypotension incidence from 44% to 34% 3, 1
• Increase dialysate sodium concentration to 148 mEq/L, especially early in the session, or implement sodium profiling (starting high and gradually decreasing) to maintain vascular stability 3, 1
• Switch from acetate-containing to bicarbonate-containing dialysate to prevent inappropriate decreases in total vascular resistance and reduce nausea, vomiting, and headaches 3, 1

Ultrafiltration Strategy Adjustments

• Maintain ultrafiltration rates below 6 mL/h/kg to prevent higher mortality risk and increased hypotension 2
• Extend treatment time to minimum 4 hours per session to slow ultrafiltration rate and allow adequate vascular refilling 2
• Consider increasing dialysis frequency from twice to three times weekly to reduce interdialytic weight gain and lower required ultrafiltration rates 2
• Perform isolated ultrafiltration (sequential ultrafiltration followed by diffusive clearance) for patients with excessive weight gain, but extend total treatment duration to compensate for time lost for diffusive clearance 3
• Reevaluate estimated dry weight as hypotension may indicate the target is set too low 1

Pharmacological Prevention

• Administer midodrine (oral selective α1-adrenergic agonist) within 30 minutes before dialysis initiation to increase peripheral vascular resistance and enhance venous return, reducing hypotensive events 3, 1
• Review and adjust antihypertensive medications, particularly when patients are on four or more concurrent agents that prevent compensatory vasoconstriction, or carvedilol which blunts compensatory tachycardia 1, 2

Long-Term Prevention Strategies

• Limit sodium intake to <5.8 g/day to reduce thirst and interdialytic weight gain 2
• Restrict interdialytic weight gain to <3% of body weight between sessions to prevent excessive ultrafiltration requirements 2
• Maintain hemoglobin at 11 g/dL per NKF-K/DOQI guidelines to improve oxygen-carrying capacity and cardiovascular compensation 3, 1, 2
• Avoid food intake immediately before or during hemodialysis as this causes decreased peripheral vascular resistance leading to hypotension 3, 1

Critical Pitfalls

• Continuing twice-weekly dialysis forces dangerously high ultrafiltration rates exceeding 6 mL/h/kg and inadequate solute clearance 2
• Routinely administering saline for every hypotensive episode perpetuates volume overload rather than addressing the underlying cause 2
• Increased dialysate sodium may lead to increased thirst, interdialytic weight gain, and hypertension—monitor these effects 1, 4
• Reduced dialysate temperature may cause uncomfortable hypothermia in some patients—assess tolerance 3, 1, 4

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Muscle Cramps Management

Reduce ultrafiltration rate by extending treatment time and increase dialysate sodium concentration to 148 mEq/L early in the session—muscle cramps account for 70% of premature dialysis terminations and these interventions directly address the pathophysiology of inadequate vascular refilling. 3, 4

Dialysis Prescription Modifications

• Reduce ultrafiltration rate by extending treatment time when possible to allow adequate vascular refilling 3, 4
• Increase dialysate sodium concentration to 148 mEq/L, especially early in the session, with sodium profiling (higher sodium early, gradual reduction later) 3, 4
• Reduce dialysate temperature from 37°C to 34-35°C to increase peripheral vasoconstriction, though monitor for symptomatic hypothermia 3, 4
• Consider isolated ultrafiltration for patients with excessive weight gain to separate volume removal from diffusive clearance 3, 4

Pharmacological Interventions

• Administer midodrine 30 minutes before dialysis to increase peripheral vascular resistance and enhance venous return, reducing hypotensive events and associated cramps 3, 4
• Use baclofen (muscle relaxant) at 10 mg/day with weekly increases up to 30 mg/day for persistent muscle cramps 4

Acute Interventions

• Administer supplemental oxygen during cramping episodes to alleviate symptoms 3, 4

Addressing Underlying Factors

• Correct anemia to hemoglobin levels per NKF-K/DOQI guidelines to improve oxygen-carrying capacity and reduce cramp frequency 3, 4
• Evaluate nutritional status as poor nutrition may contribute to cramping 4
• Ensure patient adherence to complete prescribed dialysis session to optimize dialysis adequacy 4
• Limit fluid intake between sessions to reduce interdialytic weight gain and prevent excessive ultrafiltration requirements 1, 4

Important Considerations

• Monitor for increased interdialytic weight gain and hypertension when using higher sodium dialysate 4
• Assess for symptomatic hypothermia when using cooler dialysate 4
• Older patients with anemia (hematocrit <27%) have significantly higher risk of developing cramps—age >65 years shows 25% complication rate versus 0% in age <40 years 5
• Fluid removal primarily occurs from leg extracellular fluid, which may explain the high incidence of leg cramps 6

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Nausea and Vomiting Management

Switch from acetate-containing to bicarbonate-containing dialysate to minimize nausea and vomiting, as acetate contributes to these symptoms through inappropriate vasodilation and increased myocardial oxygen consumption. 3

Primary Interventions

• Convert from acetate-containing to bicarbonate-containing dialysate to reduce nausea, vomiting, and headaches 3
• Reduce dialysate temperature to 34-35°C to improve hemodynamic stability and reduce associated symptoms 3
• Avoid food intake immediately before or during dialysis to prevent hemodynamic changes that contribute to nausea 3, 1

Addressing Contributing Factors

• Slow ultrafiltration rate as rapid volume removal contributes to nausea 3
• Ensure adequate dialysis adequacy as uremic symptoms may manifest as nausea 3
• Review for dialysis disequilibrium syndrome in new patients—nausea typically stabilizes after 13 dialysis treatments (approximately one month) 7

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Vascular Access Issues

Review hemodialysis log for extracorporeal pressures, particularly prepump arterial pressure values ≥200 mmHg, and assess for dialyzer clotting which may warrant review of anticoagulation protocol—these indicate access dysfunction that compromises delivered dialysis dose. 3

Assessment and Monitoring

• Review extracorporeal pressures on hemodialysis log, particularly prepump arterial pressure for values ≥200 mmHg indicating access problems 3
• Assess for dialyzer clotting which may indicate inadequate anticoagulation or access dysfunction 3
• Review anticoagulation protocol if recurrent clotting occurs 3
• Verify blood pump calibration accuracy by reviewing kinetic modeling results on other patients using same equipment 3
• For delivery systems with computers, review total liters of blood processed to ensure adequate treatment 3

Prevention of Access Thrombosis

• Avoid protracted hypotension during hemodialysis as this increases risk of vascular access thrombosis 8
• Maintain adequate blood flow rates to prevent stasis and clotting 3

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Patient Adherence and Behavioral Optimization

Address patient nonadherence systematically as 55% of premature treatment terminations are due to medical reasons (70% cramps, 48% feeling sick, 15% symptomatic hypotension), which directly compromises delivered dialysis dose and patient outcomes. 3

Assessment and Intervention

• Evaluate reasons for patient nonadherence including missed sessions, late arrivals, treatment interruptions, or premature terminations 3
• Review patient arrival time and transportation needs to address logistical barriers 3
• Assess understanding of treatment components with both patient and patient care staff 3
• Modify hemodialysis prescription to prevent intradialytic symptoms that adversely affect patient comfort and adherence, without compromising delivered dose 3

Critical Understanding

• When hypotension or cramps occur, many healthcare teams respond by decreasing blood flow and ultrafiltration rate, resulting in patients receiving less than prescribed dose and not meeting ultrafiltration goals 3
• Protracted hypotension during hemodialysis may exaggerate urea rebound, further compromising dialysis adequacy 3
• Patients should not be considered "stable" for investigation of technique changes until after 1.5 months of dialysis, as symptoms stabilize at different rates (hypotension and cramps after 13 treatments, hypertension after 17, vomiting after 20) 7

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Hemodynamic Changes During Dialysis

Recognize that changes in arterial tone occur within 20 minutes of starting hemodialysis when minimal ultrafiltration has occurred, indicating that volume changes are not the only cause of intradialytic hypotension—this requires early intervention strategies rather than waiting for symptoms to develop. 9

• Systolic blood pressure declines significantly within 20 minutes of dialysis initiation, before substantial ultrafiltration occurs 9
• Aortic augmentation index decreases dramatically within 20 minutes, indicating reduced arterial tone 9
• The combination of falling systolic blood pressure and rising diastolic reflection area suggests reduced coronary blood flow, consistent with reports of "myocardial stunning" during hemodialysis 9
• Blood pressure conservation during ultrafiltration depends on increasing peripheral vascular resistance—failure of this response causes intradialytic hypotension 6

3, 1, 4, 2, 7, 9, 8, 5, 6