Procedure: Accessing and Initiating CRRT

Ensure that patient and health care provider safety standards are met during this procedure including:

  • Risk assessment and appropriate PPE
  • 4 Moments of Hand Hygiene
  • Procedural Safety Pause is performed
  • Two patient identification
  • Safe patient handling practices
  • Biomedical waste disposal policies
  • Sharps handling


  1. Don PPE and Hand Hygiene
  2. Perform Safety Pause
  3. Prepare Catheter
  4. Prepare Sterile Tray
  5. Perform Hand Hygiene and PPE
  6. Cleanse Catheter
  7. Apply Sterile Towel
  8. Discard Gauze
  9. Prepare Access Limb
  10. Withdraw Blood
  11. Check for Clots
  12. Confirm Adequacy of Flow Rate and Flushes with Saline
  13. Repeat with Return Limb
  14. Connect CRRT Circuit

Accessing Dialysis Line Checklist

Deaccessing Dialysis Line Checklist

Equipment Required:

  • Appropriate PPE—always include a mask with a face shield
    Sterile dressing tray (the dressing tray includes the sterile drapes and a place to inject blood for clot inspection).
  • 2 pair non sterile gloves
  • 2 large (1.5 mL) chlorhexidine 2% swabs (without alcohol) (use 4 wipes if catheter or clamps are visibly soiled.
  • 2 empty 3 mL syringes
  • 2 - 4 10 mL NS syringes
  • 1 Sterile 4X4 gauze
  • Non-sterile gauze (for clot assessment)
  • Primed CRRT circuit (with one saline infusion attached to a stopcock and connected to the access end of the circuit).



Don PPE and Hand Hygiene

Perform hand hygiene, don appropriate PPE including mask with face shield.


Perform Safety Pause

Review the procedural steps and supply requirements.

Ensure CRRT circuit has been primed and flow rates programmed.

Review online Procedural Safety Pause


Prepare Catheter

Don non-sterile gloves and remove gauze and tape that is surrounding the catheter limbs and discard.

Place a non-sterile waterproof pad under the dialysis limbs to protect the bed linen.

Remove non-sterile gloves and perform hand hygiene.



Prepare Equipment

Open up a dressing tray.

Move the two waterproof (white) and the one non-waterproof towel (blue) out of the way.

Using the blue transfer forceps, place the sterile 4 X 4 gauze in the large cup of the tray (the gauze will be used to hold the catheter during cleaning).

Using transfer forceps, place the large (1.5. mL) chlorhexidine 2% wipes (without alcohol) into  an cup in the dressing tray (don't place them on top of the gauze square or they will dry out).

Open up one waterproof towel and place it beside the dressing tray.  Remove the 3 ml and 10 ml saline syringes from the package and place on the towel.   

Place the 2 non-sterile gauze 4X4s onto the waterproof towel, side-by-side (one gauze will be used to assess for clot in each limb)..

Turn back one corner of the blue non-waterproof towel to make it easier to pick up.

Open up the second waterproof towel and place it underneath the catheter limbs (to protect linen during cleaning). 

Maintain sterility while accessing lines. A separate swab stick will be used for each limb.

One waterproof towel will be placed under the limbs before cleansing to protect bed linen. The blue sterile towel will go on top of the waterproof towel AFTER the limbs are cleansed and the prep has dried.

The syringes are placed on the second waterproof sterile towel to maintain aseptic technique.  The non-sterile gauze is placed on the waterproof field to prevent blood exposure during clot assessment.


Prepare Catheter

Apply a clean pair of gloves and pick up the sterile 4X4 gauze square with your non-dominant hand. Using the gauze square, grip the catheter and use the gauze to hold the catheter during cleaning.

Hold the catheter firmly while lifting the limbs off the bed surface. The gauze will minimize any contact between the uncleaned catheter and your clean gloves.


Cleanse Catheter

Using your dominant hand, pick up one of the two chlorhexidine wipes. Vigorously scrub the cap, hub, external lumen and clamp of the Access limb of the dialysis catheter for at least 15 seconds. Repeat with a second swab limb is visibly soiled.

Pick up the second wipe and repeat the procedure with the Return limb.

Continue to hold the limbs with your non-dominant hand until the cleansing solution is completely dry.

Well maintained perm caths can remain in place for many years. The IHD program has identified premature catheter failure due to cracking of hub when alcohol based cleaning preps are used, particularly with perm caths.


Create Sterile Field

With your dominant hand, grab the blue sterile towel by the edge and open it up.  Place it on top of the waterproof (white) towel.

The towel creates a sterile field to minimize contamination of the cleansed catheter limbs and maintain aseptic technique.


Discard Gauze

Rest the limbs on the sterile towel.

Discard the gauze that was used to hold the catheter.

This will create a wider sterile field and minimize the chance to contaminate your gloves through contact with the uncleansed portion of the catheter.


Prepare Access Limb

Ensure that the clamp on the access limb (red) is closed. Remove the cap from the end and attach an empty 3 mL syringe.

To prevent air entry into the dialysis catheter during opening of the catheter


Withdraw Blood

Open the clamp and vigorously aspirate 5 mL of blood. Note the ease with which the blood can be withdrawn.

Removing this volume will ensure that any clots and/or the citrate anticoagulant are removed from the limb.



Reclamp the limb and remove the syringe after clamping.

Reclamping prevents air entry or blood loss from the limb.


Check for Clots

Slowly inject the aspirated blood onto one non-sterile 4 X 4 gauze (that is on top of the waterproof towel). Disperse the blood over a large area of the gauze using a back and forth motion. Observe for fibrin or clot.

If clots are present, draw off more blood and repeat visible inspection until clear of clots.

The white background and weave of the gauze allows for visualization of any clots.


Confirm Adequacy of Flow Rate and Flushes with Saline

Attach an empty 10 mL syringe to the Access Limb. Vigorously aspirate and immediately return 10 mL of blood (pull-push technique).  Assess for ease of flow and completion of pull-push within 3 seconds. This indicates that the limb is adequate for flow rates of at least 200 ml/min.
Note: If flow rates from the access limb are inadequate, do not connect access tubing to access limb. Treatment should either be delayed until correction of any catheter problems or should be initiated with lines reversed (access tubing connected to return limb).

Once flow rate has been evaluated, vigorously flush the access lumen with 10 ml 0.9% normal saline using a stop-start technique. Clamp limb.

If the dialysis circuit is flushed and ready to connect, you can proceed to connect to the circuit (Step 15). If CRRT initiation will not be immediate, instill 2 mL of sodium citrate locking solution into the limb before clamping, and place a primed Luer-lock cap on the end of the limb. Each blocked limb should be wrapped with gauze and have a medication sticker added to identify any blocking medication (e.g., sodium citrate).


Repeat for Return Limb

Repeat steps 8-13 for the return limb (blue)

Connect the return limb to the return tubing.

15. Connect the Circuit

Confirms Blood Flow Rates

Set the flow rate as per orders. Set initial blood flow rate to 250 ml/min and fluid removal to 0 ml/hour.  The PrisMax will ramp up to this speed as tolerated.  Fluid removal can be started once patient has stabilized.

Adds Saline Flush

Rescue Line: Prime a bag of normal saline with regular IV tubing. Place a stopcock on the end with the saline infusion connected at 90 degrees to the flow (to reduce flow restriction, the access limb and access tubing should be in a straight line. Leave the stopcock off to the saline with any clamps on the IV tubing open (this allows for rapid flushing/return of blood if needed).

If the return limb is going to be used as the access (lines are reversed), the rescue line stays with the access tubing.  If the saline line is opened and stopcock closed to the catheter limb, the CRRT machine will pull saline at the set blood flow rate (e.g., 250 ml/min). Blood can be retransfused at this rate in less than one minute. A smaller volume can be used to check for clots - observe as the saline moves up through the filter. To identify saline volume, time the duration that the saline line is open (e.g., 30 seconds at 250 ml/min would be a saline bolus of 125 ml).

A rescue line should never be added to the return tubing.  If the stopcock became disconnected, this could result in blood being pulled from the patient and returned into the bed at up to 250 ml/min. The stopcock could create enough resistance to prevent a "return disconnect alarm".  A return disconnect alarm will be activated if the return pressure falls below a pressure of +10 mmHg.

Connect the circuit to the catheter as follows:

Follow the on screen instructions for connecting the effluent tubing to the effluent bag and return tubing to the Y connection of the priming solution.

Bring clamp both limbs of the Y connector.

Bring the clamp on the access and return tubing close to the end for ease of access. Clamp the access and return tubing.

Check to ensure all other clamps (including the PBP) are open before proceeding.

Bring the priming bag with access and return tubing still connected to the Y connector to the bedside.

Heparin Bolus:

If a heparin bolus has been ordered (for heparin filter anticoagulation prescription), administer the bolus directly into the access limb (red) just prior to connecting the circuit as follows (the volume of heparin must be less than the volume of the catheter). This technique ensures that the first blood to hit the filter will be heparinized, but prevents the patient from receiving a direct heparin bolus.

  1. Clamp the access limb of the catheter
  2. Attach the heparin containing syringe to the access limb (red) of the dialysis catheter (e.g., 5,000 in 0.2 ml)
  3. Open the access limb clamp.
  4. Inject the heparin into the access limb.
  5. Reclamp the access limb.

Confirm Circuit Connections:

  1. Connect the rescue line stopcock/saline infusion to the access (red) end of the CRRT circuit. 
  2. Connect the limb of the patient catheter that is being used for access (red line unless lines are reversed) to the rescue line stopcock. If lines are reversed, ensure that the rescue line remains connected to the access tubing (not the return tubing).
  3. Connect the return limb (blue) of the patient catheter to the return (blue) end of the CRRT circuit.

Ensure all clamps are open before starting treatment:

  1. Open the access and return clamps on the catheter.
  2. Close the stopcock on the rescue line "off" to the saline infusion.
  3. Open the roller clamp of the saline infusion.
  4. Ensure that all clamps in the CRRT circuit are open - double check the clamp on the PBP line (close to access connection), effluent line and all infusions.

Initiates Treatment:

  1. Initiate treatment following on screen prompts
  2. Observe catheter connections for blood leak
  3. Monitor circuit closely for leakage or air bubbles and be prepared to raise the deaeration chamber level quickly to prevent air in return alarm


If treatment is started with lower blood flow rates, the access pressure will be too low (i.e., less negative). As blood flow increases, the access pressure becomes more negative (more “suck” is required to pull the larger blood flow volume). If the access pressure is less negative than minus 10, the CRRT machine will interpret this as a disconnected access limb and generate an alarm. To avoid access disconnection alarms, escalate the blood flow rate quickly during initiation of treatment. Starting at 250 mL/min will usually prevent this from happening.

If pump pressures permit, increase the blood flow rate as quickly as possible to 300 mL/min (as tolerated). Higher blood flow rates can reduce filter clotting by shortening the duration of time that blood remains in the filter. Blood flow rates must be increased as quickly as possible for maximum clotting reduction benefit. Access and return pressures will increase as blood flow rate increases - once blood flow is stable, these pressures should also stabilize.

Once the circuit is connected, all clamps should remain open. Any time that a high priority alarm is activated, the blood pump automatically stops and the blood flow circuit closes (safe mode).

If therapy is initiated with any clamps closed, the CRRT machine will immediately alarm and shut down. Repeated alarms during initiation may lead to treatment failure/shut down.

Developed: November 30, 2017, Revised January 19, 2022

Brenda Morgan CNS CCTC