A central venous catheter (CVC), also called a central line, is similar to an intravenous line but is more often used for critically ill patients who require longer treatments. It is a common bedside procedure performed using sterilize equipment. It requires an expert hand since faulty placement can present many complications that include arrhythmias, hematomas, pneumothorax and arterial punctures. Procedures administered by 5.4% of experienced and 11% of inexperienced professionals lead to complications.
This begs the question: How do you keep complications to a minimum?
Ultrasound-guided line insertion is recommended as it will reduce the incidence of immediate complications to 4%. However, many regard the anatomical landmark technique as a sufficient alternative as it has a shorter insertion time while being a relatively safe method when performed by experienced clinicians.
Let’s compare the two by exploring studies on ultrasound guidance vs the landmark technique.
Ultrasound Guidance vs Anatomical Landmarks During Catheterization
A CVC can be inserted into the internal jugular, subclavian, or femoral vein.
Let’s consider their placement with ultrasound guidance vs the landmark technique. We’ll also cover radial artery catheterization for a more comprehensive overview.
The femoral site is the last choice for CVCs and arterial lines as it presents a higher risk of infection, DVT and hematoma in adults. However, the same hasn’t been observed in pediatrics.
Although CVCs have traditionally been placed based on anatomical landmarks, research suggests that the placement of CVCs should be performed with ultrasound guidance as the technique has a higher success rate on the first attempt, better overall success in cannulation, and a lower risk of puncturing the femoral artery.
This same is true for arterial line placement.
The internal jugular vein (IJV) has the lowest risk of venous stenosis and thrombosis.
A 2015 review found that two-dimensional ultrasound was better than the landmark technique. It reduced the rate of total complications by 71%, the number of participants with an inadvertent arterial puncture by 72%, increased the chance of success on the first attempt by 57%, reduced the chance of hematoma formation, and decreased the time to successful cannulation by 30 seconds.
The same team reviewed 13 studies conducted over 17 years. Again, the addition of ultrasound guidance proved to be the superior choice as it reduced the risk of arterial puncture and severe bruising in subclavian vein catheterization.
However, research shows that it did not lead to a significant difference in complication rates or in the time taken to cannulate, making matters less conclusive.
But, there may be certain factors that experienced practitioners will want to consider.
According to a controlled study, the success rates of subclavian vein puncture with the landmark-guided method differed widely from 44% to 94%. It is also associated with adverse complications like pneumothorax and accidentally puncturing the subclavian artery. This could lead to the formation of hematoma or massive hemothorax if the subclavian artery is dilated and the catheter is removed by the operator which is potentially fatal.
More than 10 million arterial lines are placed annually worldwide.
Before the introduction of point-of-care ultrasound, landmark-guided palpation was the standard technique. However, as anatomical landmarks can be misleading in many scenarios, ultrasound-guided placement emerged as a superior method.
A meta-analysis explored the benefits and risks of ultrasound guidance and traditional palpation for radial artery catheterization. It established that dynamic 2D ultrasound guidance significantly reduced first-attempt failure, mean attempts and time to success, and hematoma complications, and has thus been recommended as an adjunct.
Taking Stock of Ultrasound Guidance vs the Landmark Technique
Ultrasound is useful for achieving accurate and useful results. However, it can lengthen the CVC procedure marginally but is still safer than landmark-guided subclavian line placement if you have the luxury of time to prepare. Ultrasound-guided central line insertion allows confirmation that the wire is in the vein and not in the artery prior to the dilatation step that provides an extra safety step to prevent subclavian/carotid/femoral arterial line insertion.
On that note, evidence suggests that it could benefit difficult and moderately difficult cases with increased first‐pass success and overall higher cannulation success rates. In cases where it’s easy to define the site and dimensions of the vein, practitioners should palpate and identify the anatomical landmarks for central venous catheter access during cannulation.
Note that no significant difference was detected in terms of the patient’s discomfort.
Which is superior: ultrasound guidance or the landmark technique?
Ultrasound guidance shows immense potential for successful central venous catheter insertions, going so far as to eliminate multiple access attempts and reduce the risk of complications among intensive care patients with IJV cannulation. It is also safer and more efficient than the landmark approach for subclavian vein cannulation.
Across studies and meta-analyses, the findings are robust and demonstrate that ultrasound-guided central line placement is the standard of care if time allows. It must also be noted that there is a lack of equipment and access to ultrasound education and training in low- and middle-income countries.
While it’s important to bring ultrasound training to medical practitioners, they must also have good landmark skills to provide quality care when ultrasound equipment isn’t available. As the literature suggests, traditional palpation must be attempted only when ultrasound equipment isn’t available. The landmark-guided placement of subclavian catheters was found to use up to 40% more catheter kits per patient than sonographically guided placement.
With the advent of ultrasound-guided procedures, the landmark technique may seem less relevant but knowledge of biologically significant areas is still of great importance in healthcare. However, because ultrasound guidance can increase the procedure’s success rates, it is just as important to become proficient in it.
Even a single one-hour training session can aid clinicians’ ultrasound-guided techniques. To master the procedure, enroll in Hospital Procedure Consultants’ ultrasound-guided CVC placement training course. It covers landmark-based and ultrasound-guided central line insertion for vascular access.
Brass, P. Hellmich, M. Kolodziej, L. Schick, G. Smith, A. Ultrasound guidance versus anatomical landmarks for internal jugular vein catheterization. Cochrane Database Syst Rev. 2015 Jan; 2015(1): CD006962
Brass, P. Hellmich, M. Kolodziej, L. Schick, G. Smith, A Ultrasound guidance versus anatomical landmarks for subclavian or femoral vein catheterization. Review Cochrane Database Syst Rev. 2015 Jan 9;1(1):CD011447
Gu, WJ. Wu, XD, Wang, F. Ma, Z. Gu, XP. Ultrasound Guidance Facilitates Radial Artery Catheterization: A Meta-analysis With Trial Sequential Analysis of Randomized Controlled Trials. Meta-Analysis Chest. 2016 Jan;149(1):166-79. doi: 10.1378/chest.15-1784