What are the initial steps to manage emergencies during hemodialysis, including hypotension, hypertension, fluid overload, and dialyzer reactions?

Management of Hemodialysis Emergencies

Intradialytic Hypotension

For acute hypotension during hemodialysis, immediately reduce or stop ultrafiltration, place the patient in Trendelenburg position, and administer normal saline bolus while providing supplemental oxygen. 1, 2

Immediate Interventions

• Stop or reduce ultrafiltration rate to prevent further blood pressure decline and maintain mean arterial pressure ≥65 mmHg to ensure adequate tissue perfusion 1, 3
• Place patient in Trendelenburg position (head down, legs elevated) to improve venous return and increase blood pressure 1, 2
• Administer intravenous normal saline bolus to rapidly expand plasma volume, though this may compromise ultrafiltration goals 1
• Provide supplemental oxygen to improve tissue oxygenation and reduce symptoms 4, 1, 2

Dialysate Modifications for Prevention

• Increase dialysate sodium concentration to 148 mEq/L, particularly early in the dialysis session, to maintain vascular stability 4, 1, 2
• Implement sodium profiling (starting high and gradually decreasing) to prevent hypotension, though this may increase thirst and interdialytic weight gain 1, 2
• Switch from acetate to bicarbonate-buffered dialysate to minimize hypotension by preventing inappropriate decreases in total vascular resistance 4, 1, 2
• Reduce dialysate temperature from 37°C to 34-35°C to increase peripheral vasoconstriction and cardiac output, reducing symptomatic hypotension incidence from 44% to 34% 4, 1, 2

Ultrafiltration Strategy Adjustments

• Slow the ultrafiltration rate by extending treatment time beyond 4 hours when possible to allow better hemodynamic stability 4, 1, 3
• Limit ultrafiltration rate to <6 mL/h/kg to reduce mortality risk and prevent end-organ ischemia 3
• Perform isolated ultrafiltration (sequential ultrafiltration followed by diffusive clearance) if needed, though total treatment time must be extended to maintain adequate dialysis dose 4
• Reevaluate estimated dry weight as hypotension may indicate the target is set too low, particularly if accompanied by improving nutrition markers (increasing serum albumin, creatinine, or normalized protein catabolic rate) 4, 1, 3

Pharmacological Prevention

• Administer midodrine 8 mg (range 2.5-25 mg) within 30 minutes before dialysis initiation to increase peripheral vascular resistance and prevent hypotensive events 1, 2, 5
• Correct anemia to hemoglobin 11 g/dL per NKF-K/DOQI guidelines to improve oxygen-carrying capacity and cardiovascular compensation 4, 1, 2
• Review and adjust antihypertensive medications, particularly those taken morning of dialysis, switching to nighttime dosing when possible 3

Critical Pitfalls to Avoid

• Never continue aggressive ultrafiltration in a hypotensive patient as this causes end-organ ischemia and increases mortality risk 3
• Avoid assuming all hypotension requires more aggressive ultrafiltration as excessive ultrafiltration may be causing the problem 3
• Do not use dopamine as first-line vasopressor as norepinephrine is more efficacious for correcting hypotension in septic shock scenarios 4, 6
• Recognize that increased dialysate sodium may lead to increased thirst, interdialytic weight gain, and hypertension 1, 2

Intradialytic Hypertension

For paradoxical blood pressure increases during dialysis, aggressively manage fluid overload as the primary intervention, as this phenomenon is consistently associated with extracellular volume excess. 7

Management Approach

• Reassess and lower dry weight target by 0.5-1.0 kg incrementally over subsequent sessions to address volume overload 3, 7
• Extend treatment time or increase frequency (>3 times weekly) to allow more gradual fluid removal 3
• Avoid administering normal saline during sessions as this worsens volume overload 4

Important Considerations

• Target predialysis blood pressure of 110-140 mmHg systolic for most patients, as both very low (<110 mmHg) and very high pressures are associated with increased mortality 3
• Recognize the "lag phenomenon" where blood pressure continues to decrease for 8 months or longer after extracellular volume normalizes 4
• Systematically taper antihypertensive medications as patients lose excess fluid and hypertension improves 4

Muscle Cramps

Reduce ultrafiltration rate by extending treatment time and increase dialysate sodium concentration to 148 mEq/L early in the session to address intradialytic muscle cramps. 2

• Slow ultrafiltration rate as cramps are often related to rapid volume removal 4
• Increase dialysate sodium concentration to maintain vascular stability 2
• Correct anemia to hemoglobin levels per NKF-K/DOQI guidelines to improve oxygen-carrying capacity 2
• Avoid excessive ultrafiltration by reassessing dry weight and limiting interdialytic weight gain to <3 kg 3

Nausea and Vomiting

Switch from acetate-containing to bicarbonate-containing dialysate to minimize nausea and vomiting during hemodialysis. 2

• Use bicarbonate-buffered dialysate as acetate contributes to nausea, vomiting, and headaches 4, 2
• Reduce dialysate temperature to 34-35°C to improve hemodynamic stability and reduce associated symptoms 2

Dialyzer Reactions

Life-threatening dialyzer reactions require immediate recognition and management, though they are rare with modern equipment and protocols. 8, 9

• Stop dialysis immediately if severe allergic reaction suspected 8, 9
• Do not return blood to patient if anaphylaxis occurs 9
• Administer appropriate emergency medications per anaphylaxis protocols 9

Vascular Access Complications

Monitor extracorporeal pressures continuously, particularly prepump arterial pressure ≥200 mmHg, which indicates access problems requiring immediate attention. 4, 2

• Review A/V needle placement, proximity, and orientation if access dysfunction suspected 4
• Perform hydraulic compression test during next dialysis if recirculation suspected 4
• Assess for dialyzer clotting which may indicate inadequate anticoagulation or access dysfunction 4, 2

Patient Adherence Optimization

Address intradialytic symptoms aggressively as 55% of premature treatment terminations are due to medical reasons, with 70% caused by cramps, 48% by feeling sick, and 15% by symptomatic hypotension. 4

• Modify hemodialysis prescription to prevent symptoms without compromising delivered dose 4, 2
• Evaluate reasons for nonadherence including missed sessions, late arrivals, or premature terminations 4, 2
• Avoid decreasing blood flow and ultrafiltration rate in response to symptoms as this compromises dialysis adequacy 4

Prevention Strategies

• Limit interdialytic fluid intake to reduce weight gain to <3 kg between sessions 3
• Avoid food intake immediately before or during dialysis as this causes splanchnic vasodilation and worsens hypotension 3
• Maintain sodium intake at 2-3 g/day with regular dietitian counseling 3
• Implement home blood pressure monitoring as it provides more accurate assessment than pre- or post-dialysis measurements 3