Central Venous Catheters (CVC)

Requirements for CVCs

  • Difficult IV access
  • Requirement to administer multiple drugs simultaneously
  • Administration of drugs that can cause tissue irritation if they extravasate (vesicants)
  • Administration of parenteral nutrition
  • Monitoring CVP

Monitoring central venous pressure (CVP)

  • People have historically used the CVP (if measured in the superior vena cava) as method of assessing right atrial pressure and fluid responsiveness. The assumption being that if the CVP is low, then right pressure and therefore right ventricular preload is also low.
  • The debate surrounding CVP is enormous and evidence surrounding certain numbers that will predict fluid responsiveness limited.
  • Too much value shouldn’t be assigned to one isolated CVP number. Extreme high or low readings may provide some clinical utility and help complement clinical examination.
    • For example, if the CVP was 22mmHg and the history and examination correlates, this likely adds more evidence that there is right ventricular dysfunction.
  • Additionally, CVP measurement and waveform will confirm CVC placement as venous.

Troubleshooting CVCs

Issues at insertion

  • Failed vessel puncture
  • Arterial cannulation or puncture
    • These risks are minimised by use of real time USS in transverse and longitudinal views and adequate confirmation of line placement (manometry, or blood gas confirmation).
    • If coagulopathy present a compressible site (internal jugular (IJ) or femoral) should be selected to mitigate increased risk of bleeding.
  • Pneumothorax
    • Higher risk on left IJ as lung apex sits more cephaled.
  • Air embolism
    • Ensure reverse Trendelenburg (head down) if placing an IJ line, flush all lumens prior to insertion, and cover any open needles/cannulas with finger.
  • Arrhythmia
    • Usually related to guidewire – if arrhythmia occurs then withdraw guidewire until stops. It is important to see ECG monitoring throughout insertion.

Delayed Issues

  • Infection
    • Important to select catheter with fewest number of lumens required and adhere to strict sterile technique for insertion.
    • Should review clinical need for line daily on ward round and assess for signs of infection. Typically remain in situ for 7-10 days, then should be considered for replacement if still required.
  • Air Embolism on removal
    • Ensure IJ lines are removed in reverse Trendelenburg position.
    • If entering venous system, need 100-300ml air to obstruct right ventricular outflow tract.
      • However if enters arterial system (e.g. through a PFO) a few mls can obstruct coronary or cerebral arteries.
    • Management includes supportive treatment, attempting to withdraw air from RA via CVC (if available) and positioning patient in left lateral decubitus and head down. This allows air to move out of right ventricular outflow tract.
  • Inability to aspirate
    • Ensure CVP re-confirms venous position, and insertion depth unchanged.
    • Ensure line not kinked
    • Could consider repeat CXR to see position of CVC tip as may be abutting vessel wall. This may require small withdrawal or complete removal of CVC.

References and Further Reading

Author: George Walker

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