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Successful catheterization is defined as the “introduction of a catheter into the venous system with the tip in the desired location and the catheter functions for its intended use (eg, can be used to deliver medications or for dialysis)”. There are several veins which can be used for vascular access, the most common being the internal jugular, the subclavian, the femoral, and (less commonly) the axillary vein. Clinicians strive to achieve 100% success and 0% complications in achieving central venous access. However, there are many factors influencing the success rate of clinical procedures.

These factors include appropriate catheter and site selection, sufficient operator experience, technique, and proper catheter maintenance as well as patient factors such as age, size, obesity, coagulopathy and previous failed catheterization.

The use of ultrasound in central venous catheterization has become increasingly commonplace in recent years and was named one of their eleven practices to improve patient care by the Agency for Healthcare Research and Quality (AHRQ) in 2001 (US agency) as well as being mentioned by the National Institute for Clinical Excellence (NICE) guidelines of 2002 as a way to minimize complications associated with central line placement. Many papers outline the clinical advantage of using real-time ultrasound guidance for central venous catheterization (CVC) as visualization through ultrasound guidance minimizes several of the risk factors mentioned above during both internal jugular (IJ), subclavian, femoral, and axillary CVC.

Real-time ultrasound guidance during CVC has shown improved health outcomes over landmark techniques which have been called into question due to anatomical variation in practice as compared to standard anatomical texts. In a meta-analysis of CVC procedures in 1996, it was shown that ultrasound guidance significantly decreases internal jugular and subclavian catheter placement failure (relative risk 0.32, 95%CI: 0.18 – 0.55), as well as decreasing complications during catheter placement (relative risk 0.22, 95CI: 0.10 - 0.45) and the need for multiple placement attempts (relative risk 0.60, 95%CI 0.45-0.79) as compared to the traditional landmark placement technique.

Other studies cite a significant improvement of successful cannulation of 15.4% (95%CI: 3.8- 27.0) as well as a drop in complication rate, mean number of attempts until successful cannulation and decrease in mean access times. Further studies look specifically at success rates before and after guidelines such as those published by NICE in 2002 and find improvement after adoption of said guidelines. Further literature goes on to discuss the difference in health outcomes between using ultrasound only for pre scanning to achieve vascular access and using it dynamically, or in real-time, with the procedure. Specifically, dynamic ultrasound has an unadjusted success rate of 62%, while pre scan only had a success rate of 50%, and land mark techniques showed only a 23% first attempt rate of success. This article also goes on to state that while using ultrasound dynamically may provide superior health outcomes, it may require additional training and personnel.

Visualization may also help to reduce the claims related to central catheters with high severity of patient injury such as carotid artery puncture/cannulation, hemothorax, and pneumothorax as complications during CVC procedures decrease with the use of ultrasound. Studies have also shown that many of these benefits are especially applicable to high risk patients (either those with known or unknown medical conditions) or pediatric cases. Such studies show that central venous catheterization in critically ill children is a relatively safe procedure, with a 1.3% rate of serious complications and no mortality, especially when accessing the femoral or internal jugular vein.

Ultrasound may also help to minimize the risk incurred by operator experience. A variety of studies show that the use of ultrasound to assist central venous catheterization is especially beneficial to less experienced operators, as the reduction in failed attempts and catheterization for such operator groups is drastically reduced when using real-time ultrasound guidance for catheter placement over traditional landmark techniques. Simple two hour training with ultrasound is all that is required to affect such a change.