13.2 Central venous access devices: taking a blood sample for vacuum sampling

Essential equipment

  • Personal protective equipment
  • Sterile dressing pack
  • Extra 10 mL blood bottle without heparin
  • Vacuum system container holder (shell)
  • Vacuum system adapter
  • Clean tray or receiver
  • Trolley
  • Appropriate vacuumed blood bottles or needleless injection cap (as necessary)

Medicinal products

  • 10 mL syringe containing 0.9% sodium chloride
  • Flushing solution as per policy
  • 10 mL syringe
  • 2% chlorhexidine in 70% alcohol swab

Pre‐procedure

ActionRationale

  1. 1.
    Introduce yourself to the patient, explain and discuss the procedure with them, and gain their consent to proceed. Check forms to ascertain sample bottles required and check patient's identity.
    To ensure that the patient feels at ease, understands the procedure and gives their valid consent (NMC [165], C). To ensure correct bottles are used and blood is taken from the correct patient (NPSA [166], C; RCN [211], C).

Procedure

  1. 2.
    Wash hands with bactericidal soap and water or alcohol‐based handrub and allow to dry.
    To reduce the risk of cross‐infection (NHS England and NHSI [155], C).
  2. 3.
    Prepare a tray or trolley and take it to the bedside. Clean hands as above. Open sterile pack and prepare equipment.
    To reduce the risk of contamination of contents (DH [46], C; RCN [203], C).
  3. 4.
    If intravenous fluid infusion is in progress, switch it off.
    To prevent spillage of fluid following disconnection. E
  4. 5.
    Where required, disconnect the administration set from the catheter and cover the end of the set with a sterile cap.
    To reduce the risk of contaminating the end of the administration set. E
  5. 6.
    Clean hands with an alcohol‐based handrub.
    To minimize the risk of introducing infection into the catheter. To enable the disinfection process to be completed (Loveday et al. [128], R; RCN [203], C).
  6. 7.
    Put on non‐sterile gloves.
    To prevent possible contamination of the practitioner (NHS England and NHSI [155], C).
  7. 8.
    Clean hub or needle‐free cap thoroughly with a 2% chlorhexidine in 70% alcohol swab for at least 15 seconds and allow to dry before accessing the system.
    To enable the disinfection process to be completed (Loveday et al. [128], R).
  8. 9.
    Connect the vacuum container holder and adapter to the needleless injection cap and release the lumen clamp.
    To maintain a closed system and prevent contamination of the practitioner or air entry. E
  9. 10.
    Attach the extra sample bottle; fill and discard.
    To remove blood, heparin, drugs and intravenous fluids from the ‘dead space’ of the catheter. Samples from this dead space are likely to cause inaccuracies in blood tests. Using a spare bottle keeps the system closed (WHO [257], C).
  10. 11.
    Attach the required sample bottles in the correct order of draw (see Table 13.4) for the requested specimens.
    To obtain the sample. It is not necessary to clamp the catheter when changing collection bottles, as the system is not open. E
  11. 12.
    Re‐clamp the lumen/catheter and detach the vacuum container holder.
    To prevent blood loss or air embolism. E
  12. 13.
    Flush with 10 mL 0.9% sodium chloride, using the push–pause method (i.e. 1 mL at a time).
    To create turbulence, ensure removal of all blood in the catheter and prevent occlusion (Goossens [71], C; Gorski [73], C).
  13. 14.
    Reconnect the administration set, unclamp the catheter and recommence infusion or attach a new needle‐free injection cap. Release the clamp and flush the catheter through the injection cap using the push–pause method and finishing with the positive pressure technique.
    To prevent the catheter clotting between uses (Dougherty [52], E; Goossens [71] C; Gorski et al. [74], E).
  14. 15.
    Ensure that the blood samples have been placed in the correct containers and invert as necessary (see Table 13.4) to prevent clotting.
    To make certain that the specimens, correctly presented and identified, are delivered to the laboratory, enabling the requested tests to be performed and the results to be returned to the correct patient's records (NMC [165], C; RCN [211], C; WHO [260], C).
  15. 16.
    Label the samples with the patient's name, number, date of birth, etc. at the patient's side and send them to the laboratory with the appropriate forms.
    To prevent mislabelling when away from the patient. To maintain accurate records and provide accurate information for laboratory analysis (NMC [165], C; Weston [255], E; WHO [260], C).

Post‐procedure

  1. 17.
    Remove gloves and discard waste, making sure it is placed in the correct containers (e.g. sharps into a designated receptacle).
    To ensure correct clinical waste management and to reduce the risk of cross‐infection (DH [48], C).
  2. 18.
    Document the procedure in the patient's records.
    To ensure timely and accurate record keeping (NMC [165], C; WHO [260], C).