Registered Nurses' Association of Ontario

Factors Contributing to Catheter Occlusion

  • Client factors
    • The nurse should assess clients for the following factors:
      • Disease processes and/or medications that may alter circulation and/or coagulation status;
      • History of clots such as Deep Vein Thrombosis (DVT) and pulmonary embolus;
      • Prior history of device occlusion(s);
      • Client adherence to catheter care protocols; and
      • Changes in intrathoracic pressure caused by persistent coughing, retching or vomiting, excessive crying, heavy lifting and vigorous exercise that can cause blood reflux into the CVAD
  • Device factors
    • In order to reduce the risk of occlusion and maintain catheter patency, the nurse, in concert with the health care team should:
      • Choose the appropriate device for the therapy considering the size of device (smaller lumens have increased chance of intra-luminal clots and less chance of extra-luminal clots whereas large lumen devices have less chance of intra-luminal clots and greater chance of extra-luminal clots)
      • Choose valve technologies that are designed to minimize blood reflux and reduce the occurrence of occlusion (e.g., Groshong®, PASV®, and positive pressure caps);
      • Minimize blood sampling through CVADs due to the increased risk of fibrin deposits and thrombus device occlusions.
      • Monitor clients regularly for altered tip position of CVADs. Tip position outside the superior vena cava increases the risk of vein thrombosis and subsequent device blockage.
      • Be knowledgeable of incompatibilities between infusates in order to choose locking and flushing techniques that will prevent/reduce occlusions.
  • Infusate factors
    • Certain intravenous solutions can also cause thrombus formation and device occlusion. These include:
      • Irritants whose pH lies outside the normal range (7.35 – 7.45 pH). The greater the deviation from normal pH, the more irritating the infusate and the more risk of luminal thrombosis.
      • Vesicants with pH less than 5 and greater than 9, and/or osmolarity greater than 500 Osmol/L increase the risk of luminal thrombosis and subsequent device blockage.
      • Medications that have the potential to precipitate and cause occlusion. The nurse should flush the VAD with sufficient amounts of normal saline following administration prior to locking, administering another medication or resuming infusion in order to clear the lumen of any residual buildup.
Clinical Management
Care and Maintenance to Reduce Vascular Access Complications
Point of Care Resources