Ultrasound Guidance Eases Central Venous Catheterization

ATHENS, Greece, Nov. 17 -- For critical-care patients, ultrasound-guided catheterization of the internal jugular vein proved quicker, easier, and safer than the traditional landmark-guided method, found researchers here.

In a prospective randomized controlled trial that compared 450 critical-care patients given ultrasound-guided cannulation with 450 similar landmark-guided patients, cannulation of the internal jugular vein was successful in all the ultrasound patients versus 94.4% of the landmark group (P <0.001), according to an online report in Critical Care.

The real-time ultrasound method was also less likely to result in puncture of an artery or bloodstream infection, said Dimitrios Karakitsos, M.D., of the General State Hospital of Athens, and colleagues in Greece, The Netherlands, and the U.S.

Complications of the landmark-guided technique, in which the needle is passed along the anticipated line of the vein, are influenced by body-mass index, site of attempted access, and operator experience, the researchers said. Furthermore, they said, studies show that inability to cannulate the vessel may occur in up to 19.4% of cases.

Patients in the Athens study were stratified by age, gender, and body mass index. The patients in both groups were comparable in all values pertinent to the procedures, including risk factors for difficult venous cannulation.

The investigators said they believed this was the first time such a controlled comparison has been done between the methods. It is important because no other factors, other than the technique itself, should have affected the results.

The results were:

• The average access time (skin to vein) and number of attempts were significantly reduced in the ultrasound group compared with the landmark group (P<0.001), the investigators reported.
• The ultrasound-guided technique led to few cases of carotid puncture (1%) or hematoma (0.4%), and no cases of hemothorax or pneumothorax..
• Puncture of the carotid artery occurred in 10.6% of the landmark patients, hematoma in 8.4%, hemothorax in 1.7%, and pneumothorax in 2.4%.
• 16% of the landmark patients, had a catheter-associated bloodstream infection versus 10.4% in the ultrasound group (P<0.001).
• In several ultrasound patients in whom carotid puncture occurred, the internal jugular vein overlay the carotid artery rather than being more lateral to it. A sideways approach of puncturing the jugular vein was used instead of the perpendicular approach.

Although in the past the ultrasound method has compared favorably with the landmark technique, its widespread use has been hampered by unavailability of the specially designed ultrasound devices or sterile scanner manipulation, and lack of trained personnel, Dr. Karakitsos said.

The clinical notion that the additional equipment and manipulation associated with the ultrasound method might have increased the rate of catheter-related infection was not confirmed by the data. The number of infections in the total study population was significantly related to the number of needle passes, the researchers said.

For example, a possible explanation for a significantly higher incidence of coagulase-negative Staphylococci in the landmark group may be related to the increased access time and the number of average attempts documented in the landmark group versus the ultrasound group.

Although venous thrombosis was detected in slightly more ultrasound patients than landmark patients, ultrasound imaging is an important tool in identifying cases of preexisting thrombus formation and anatomic variations in the jugular vein location, the investigators pointed out.

The major impediment to the widespread implementation of the ultrasound-guided cannulation is the purchase cost of the ultrasound machine. However, past studies have provided sufficient economic arguments supporting the notion that ultrasound-guided central venous cannulation is cost effective, the investigators said.

Finally, the researchers wrote that the ultrasound method is technically demanding, requiring a well-trained operator and adequate experience in performing it. The benefits of this method, they said, may not accrue until after an initial learning period for operators already used to the landmark technique.

However, Dr. Karakitsos summed up, saying, "We believe that ultrasound imaging is a readily available technology and may be employed by inexperienced operators to facilitate the placement of a central vein catheter and by experienced operators to improve the safety of the procedure."

In a commentary in the same Critical Care issue, Andrew Bodenham, M.D., of Leeds General Infirmary in England wrote that skeptics of the ultrasound technology should urgently appraise their practice.

Dr. Bodenham noted that he is regularly invited as an expert witness in Britain to comment on fatal and nonfatal complications of central venous access. In the past, he said, it was possible to defend clinicians not using ultrasound on the basis that it was not yet routine or of proven benefit, but he thinks this position will become increasingly untenable in the future.

Other considerations like patient discomfort with multiple needle passes are also significant. You should ask yourself, he wrote, if faced by the prospect of central venous access, often under local anesthesia alone, what would you prefer? A landmark technique with the risks cited by Dr. Karakitsos following multiple needle passes, or the near 100% success rate with minimal passes and a near zero procedural complication rate with the use of ultrasound.

"The low overall cost of ultrasound devices compared with many other interventions now means that you and your patient can no longer afford complacency in this area," he concluded.