CVC position, Arterial or Venous? Time to be 100% Sure
A 56-year-old man was admitted to the Intensive Therapy Unit for haemofiltration and vasopressor support, following the development of acute kidney injury and rhabdomyolysis secondary to dehydration and self-neglect. He required vasopressor support with noradrenaline via a central venous catheter, placed under ultrasound guidance. After three days of treatment it was discovered however, that blood aspirated from the central line appeared arterial in colour. The sample was found to have SaO2 of 96.8% and a PaO2 of 9.6 kPa, confirming that the line was placed within the arterial system and not in the internal jugular vein, despite patient notes and radiologist-reported X-ray appearances confirming venous placement.
A CT neck and thorax confirmed the line had gone through the right internal jugular vein and straight into the right carotid artery at the site of insertion in the neck, with the tip ending in the aortic arch.
The CVC was safely removed and external compression applied for 20 minutes without the patient suffering any adverse consequences.
Discussion: Failure to recognize the arterial puncture has resulted in subsequent placement of a large-bore catheter into an artery, ranging from 0.1% to 1.0% of attempted CVC placements in reported series. (1) (2) (3) (4) (5)
Inadvertent arterial placement of a large bore catheter may result in hemorrhage, pseudo aneurysm, (6) stroke, or death. (7) (8)Most practitioners regard measurement of blood gases as impractical due to the delay. (9)In 2009, Ezaru et al published a retrospective analysis of 9,348 CVC placements over a 15-year period in a single institution, requiring mandatory use of tube manometry to verify venous access after a similar case was reported of a patient death. There were no cases of arterial cannulation since introducing manometry. (10)
Pressure transduction is considered a highly reliable method to prevent inadvertent arterial cannulation. (11) It may be viewed as cumbersome by some practitioners. (9)
Manometry can detect arterial punctures not identified by blood flow and color. (12)
Inadvertent arterial cannulation has not been eliminated by ultrasound alone. (9) However, ultrasound guidance and pressure measurement are best seen as complementary rather than as alternative methods. (9)
A survey of the Critical Care Units in West Midlands suggests variability in practice. All centres use Ultrasound routinely to confirm placement of the CVC.
Chest X-ray is used to confirm position of the CVC tip.
However, these are unable to rule out arterial placement conclusively as seen in our case. Transducers are only used in the Intensive Care setting and are unavailable for patients on routine wards.
One death was reported in our region following inadvertent placement of CVC in carotid artery where inotropes were administered.
The ASA task Force suggested a 3 stage verification (13).
1. Confirming that the Catheter or Thin-wall Needle Resides
in the Vein.
2. Confirming Venous Residence of the Wire.
3. Confirming Residence of the Catheter in the Venous System.
In the wake of our experience from this case, In Intensive Care setting, we propose: National 3 stage verification and Documentation of Central Venous Cannulation.
2. Confirm Venous Residence of the guide Wire before dilator use or threading the catheter using Ultrasound.
3. Confirm final residence of the catheter and catheter tip location in the venous system, using Chest X-ray and Manometry
- Connect all CVCs to a pressure transducer to visualise a wave form
- or use manometry as a confirmatory test