What are the guidelines for safely closing a hemodialysis session in patients with end-stage renal disease (ESRD) or acute kidney injury (AKI) to prevent complications such as hypotension?

Guidelines for Safely Closing a Hemodialysis Session

To safely close a hemodialysis session, immediately stop or reduce ultrafiltration and dialysate flow, decrease blood flow to 50-100 mL/min for 15 seconds to clear access recirculation, then draw the postdialysis blood sample using the slow flow/stop pump technique before returning blood and disconnecting the patient. 1

Critical End-of-Session Blood Sampling Protocol

The NKF-K/DOQI guidelines mandate a specific technique to ensure accurate measurement of delivered dialysis dose and prevent sampling errors that falsely inflate treatment adequacy 1:

Slow Flow/Stop Pump Sampling Technique

At treatment completion:

• Turn off dialysate flow and decrease ultrafiltration rate to 50 mL/h or the lowest transmembrane pressure setting 1
• If the machine does not allow turning off dialysate flow, decrease it to minimum setting 1
• Decrease blood flow to 50-100 mL/min for 15 seconds to fill the arterial needle tubing with non-recirculated blood 1
• Manually adjust venous pressure limits downward to prevent pump shut-off 1

Blood sample collection (choose one method):

• Slow flow technique: With blood pump running at 50-100 mL/min, draw blood from the arterial sampling port closest to the patient 1
• Stop pump technique: Immediately stop the blood pump, clamp arterial and venous blood lines, then draw blood from the arterial sampling port or directly from arterial needle tubing after disconnection 1

Critical timing: Blood must be drawn within 0.25-0.50 minutes after dialysis ends to avoid falsely elevated BUN from urea rebound, which begins immediately due to cardiopulmonary recirculation and compartment effects 1

Managing Hypotension During Session Closure

If hypotension occurs during the closing phase:

• Stop or reduce ultrafiltration immediately to prevent further blood pressure decline 2, 3
• Place patient in Trendelenburg position (head down, legs elevated) to improve venous return 2, 3
• Administer supplemental oxygen to improve tissue oxygenation 2, 3
• Consider intravenous normal saline bolus (100-250 mL) only if necessary, avoiding routine administration that perpetuates volume overload 2

Prevention of Common Closing-Phase Complications

Avoid premature discontinuation errors that reduce effective treatment time:

• Do not terminate dialysis early for staff convenience or scheduling conflicts 1
• Do not honor patient requests for early termination without medical justification 1
• Account for all treatment interruptions (equipment alarms, needle manipulation, dialyzer clotting) when calculating actual dialysis time 1
• Use synchronized dialysis unit clocks rather than wristwatches to measure treatment intervals 1

Safety Measures for Central Venous Catheter Patients

For patients with CVCs receiving intensive hemodialysis:

• Use closed connector devices (InterLink, Tego, Swan-Lock) to prevent potentially fatal air embolism and bleeding during disconnection 1
• Ensure proper connection technique, as improper use can paradoxically cause the complications these devices prevent 1
• Provide assistance to patients with limited manual dexterity to ensure correct device usage 1

Documentation Requirements

Accurate time recording is essential:

• Document exact initiation and termination times to calculate effective dialysis time 1
• Record any interruptions during treatment that reduced actual dialysis time 1
• Avoid clerical deficiencies that render effective dialysis time unknown 1
• Wrong patient disconnection represents a critical safety error requiring verification protocols 1

Common Pitfalls to Avoid

Blood sampling errors that compromise adequacy assessment:

• Never draw postdialysis BUN before dialysis ends, as this increases the measured BUN and falsely suggests inadequate dialysis 1
• Never draw postdialysis BUN more than 5 minutes after dialysis, as urea rebound significantly elevates the value 1
• Never draw predialysis BUN after starting dialysis, as this lowers the measured value through dilution and recirculation 1
• Never dilute the predialysis sample with saline, which reduces true BUN concentration 1

Treatment time errors:

• Do not calculate time incorrectly or read initiation/completion times inaccurately 1
• Do not fail to account for dialysate bypass periods when conductivity or temperature alarms occur 1
• Do not assume continuous treatment without verifying no interruptions occurred 1