Registered Nurses' Association of Ontario

Nursing Best Practice Guidelines

Catheter Patency

To check patency the nurse should aspirate the CVAD and check for the presence of blood return without resistance.

If resistance is met or there is absence of blood return, the nurse will take further actions to assess the device and take or seek appropriate intervention(s) to restore patency before administration of medications or solutions. These actions include:

  • Ruling out the presence of mechanical obstruction or problems (e.g., closed clamps, kinks, device damage);
  • Attempting to flush the device – if resistance is met, no attempt should be made to continue flushing and/or using additional pressure as a thrombus may be dislodged, causing a pulmonary embolism (Haire & Herbst, 2000; INS, 2000; RCN, 2003);
  • Flushing the device (if no resistance is noted) with normal saline in a 10 mL syringe using the turbulent flush technique;
  • Checking for blood return again – a smaller barrel syringe exerts less negative pressure when withdrawing blood and may result in more success. If blood withdrawal is not obtained, do not infuse medications or solutions through the device; and
  • Documenting the assessment and actions taken in the client’s chart to provide continuity of care. When documenting blood return, indicate “no complications noted” or specify the complication (e.g., no blood return obtained; or blood return obtained with resistance). Thrombus formation may be present as a fibrin sleeve outside the device or as a partial or complete obstruction of the internal lumen of the device progressing to central venous obstruction (RCN, 2003).