Ultrasound in Central Vein Assessment – The Importance of Knowing

Thorough vascular assessment prior to any intravascular device insertion is of paramount importance – for both clinician and patient. It guides the clinician to evaluate the current state of vessel health, determining suitability of the veins, and to follow a pre-determined pathway that will lead to the best decision for the patient. The assessment phase alone in vascular access procedures highlights a number of important underlying anatomical structures, as there are frequently variances amongst many patient groups and it provides a platform to perform a thorough assessment of the vascular structures to evaluate vessel health, viability, size, and patency, including the location of other important and best-avoided anatomical structures – prior to performing any procedures. The success in complication-reduction alone drives the importance of patient safety and improved patient- and device-related outcomes, not to mention patient satisfaction and comfort.

Its use for assisting the proceduralist are many:

  • pre-procedural ultrasound assessment of the vascular anatomy provides a rational choice of the venous access most likely to be associated with an optimal clinical outcome;
  • real-time, ultrasound-guided puncture and cannulation of the vein reduces the risk of failure and/or damage to the surrounding structures;
  • ultrasound scan after the venipuncture allows an early/immediate detection of puncture-related complications such as pneumothorax or local hematoma;
  • ultrasound-based tip navigation verifies the proper direction of the guidewire and/or the catheter during its progression into the vasculature;
  • transthoracic echocardiography allows proper ultrasound-based tip location;
  • ultrasound is also useful for detection of late complications such as catheter-related venous thrombosis, tip migration, or fibroblastic sleeve.

A simple yet systematic approach to vessel assessment is the RaCeVA (Rapid Central Vein Assessment), a process manifested as a quick and highly effective process for performing vessel assessment in a compelling and methodical approach. It allows a systematic approach to exclude venous abnormalities such as thrombosis, stenosis, external compression, and anatomical variations of size and shapes; it also allows a full anatomic evaluation for optimum site selection and the best insertion approach for the patient. It also has many advantages: it takes only 30–40 seconds for each side, it is easy to teach, easy to learn, and it is a useful guide for a rational choice of the central vein to be accessed, in terms of patient safety and cost-effectiveness, since it helps the operator to choose the most favorable puncture site and the optimal insertion site, with an overall improvement of the clinical outcomes and patient satisfaction.

RaCeVA - table

The RaCeVA Steps

Important considerations include the following:

  1. size of the vein (internal diameter/caliber)
  2. depth of the vein (depth of target vessel from skin surface)
  3. respiratory variations (influence of respiratory cycle on vein diameter)
  4. compression by artery (influence of arterial pulsation on vein diameter)
  5. proximity to non-venous structures that must not be damaged (pleura, nerve, artery)
  6. exit site location – convenience/appropriateness in terms for best care and maintenance
Image 1

Overview of RaCeVA steps highlighting ultrasound transducer scanning points – courtesy of the author.

Utilization of the RaCeVA protocol throughout both pre- and post- device insertion stages offers multiple advantages: “before” (to define the anatomy and the best target vessel), “during” (with real-time techniques of ultrasound-guided venipuncture: short-axis in-plane, short-axis out-of-plane, long-axis in-plane), and “after” cannulation (to detect or rule out complications such as pneumothorax, malpositions, local hematoma).

 

As a tool, RaCeVA is designed (a) to teach the different ultrasound-guided approaches to the central veins, (b) to help the operator to scan systematically all possible venous options, and (c) to guide the operator in choosing the most appropriate vein to be accessed, on a rational and well-informed basis. Optimal training is mandatory, through formal programs and hands-on sessions that imply using vascular simulation phantoms – the latter being especially important for practitioners to perform repeated ultrasound-guided vascular cannulations without posing serious risks for patients and ultimately successfully transferring this practice to patients.

 

 

Comment below, or, AIUM members, continue the conversation on Connect, the AIUM’s online community to share your experience.

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Timothy R. Spencer, RN, DipAppSc, BHSc, ICCert, APRN, VA-BC™, is Director of Global Vascular Access, LLC, in Scottsdale, Arizona.

 

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