RaFeVA (Rapid Femoral Vein Assessment), a new protocol, is a rapid and effective tool for the systematic ultrasound evaluation of the veins in the inguinal area and at mid-thigh, conclude Fabrizio Brescia (Unit of Anesthesia and Intensive Care Medicine, Vascular Access Team, Centro di Riferimento Oncologico di Aviano, IRCCS, Aviano, Italy) et al in The Journal of Vascular Access (JVA). Describing this new protocol step-by-step, the study authors say it is designed to evaluate patency and calibre of the common and superficial femoral veins and to help interventionalists choose the best venipuncture site before insertion of a femorally-inserted central catheter (FICC).
“In recent years, many factors have contributed to improving the practice of central venous access,” write Brescia and colleagues, enumerating: “adoption of biocompatible and high-pressure resistant materials, institution of multi-professional, multi-disciplinary teams focused on vascular access, and so on.” They go on to say that, “probably, the most important novelty of the 21st century in the field of venous access has been the adoption of ultrasound technology for minimising the costs and the complications associated with placement of central venous devices.”
Systemic and standardised approaches for the preliminary ultrasound evaluation before centrally-inserted central catheter (CICC) and peripherally-inserted central catheter (PICC) insertion have previously been developed, the authors state. The rapid central vein assessment—the RaCeVA protocol—is a systematic protocol of ultrasound evaluation of the veins of the neck and of the supra/infra-clavicular area before CICC insertion. According to Brescia and his co-authors, this protocol is “useful for teaching the different ultrasound-guided approaches to the central veins, for helping the operator to consider systematically all possible venous options, and for guiding the operator in choosing the most appropriate vein to be accessed, on a rational and well-informed basis”. The rapid peripheral vein assessment—RaPeVA—is the protocol developed in order to collect relevant anatomical information before positioning a PICC.
Rapid femoral vein assessment: RaFeVA
Brescia et al describe RaFeVA as “a clinical tool to evaluate different approaches to the veins of the groin and mid-thigh region, to provide operators with a systematic sequence for ultrasound evaluation of all the veins in the region with the aim of choosing the most appropriate vein for a tunnelled or non-tunnelled FICC”. It consists of seven steps, corresponding to seven different positions of the probe, and is always performed bilaterally. The seven steps of the RaFeVA protocol take into account the different possible visualisations of the vessels (along the short, long, or oblique axes), and propose different venipuncture techniques (out-of-plane and in-plane).
In brief, the seven steps go thus:
- Start at the inguinal groove with the probe in a transverse position, perpendicular to the skin. Identify the common femoral artery (CFA) and the common femoral vein (CFV), both in short axis. Assess by probe compression the CFV in terms of depth, size, and patency.
- Switch to a visualisation of the transition between the CFV and the external iliac vein (EIV) in long axis. Assess the longitudinal axis of the veins and its course.
- Rotate the probe by 90° to return to a short axis view. Move the probe caudally, to visualise the CFA, CFV, and saphenous vein (SV), in the short axis view.
- Slide the probe downward, far from the groin, still in a transverse view, to visualise the superficial femoral artery (SFA), the deep femoral artery (DFA), and the CFV, all in the short axis.
- Move the probe even more caudally to visualise simultaneously the SFA, the DFA, the superficial femoral vein (SFV), and the deep femoral vein (DFV), all in the short axis.
- Slide the probe caudally, toward mid-thigh, to visualise the SFA and the SFV in the short axis.
- Perform a 45° rotation of the probe to obtain an oblique axis view of the SFA and SFV.
Brescia and colleagues elaborate on why standardising the approach to preliminary ultrasound evaluation ahead of FICC insertion is beneficial: “As for the choice of the venous approach and the technique of venipuncture, the preference or the personal experience of the operator should not be regarded any longer as an appropriate criterion,” they opine. “The venous approach that is more ‘comfortable’ for the operator is not necessarily the venous approach associated with the maximal safety for the patient. A rational choice of the venous approach should be based on objective anatomical criteria, verified in the specific patient who is candidate to the procedure. This rational, objective evaluation of the anatomic characteristics of the vasculature of each patient is possible by adopting systematically a pre-procedural ultrasound scan of the anatomic area where the central venous access device will be inserted. The inappropriate, ‘automatic’ choice of a venous access based only on the habits of the operator is potentially associated with repeated punctures, waste of time, poor clinical outcomes and/or puncture-related complications, due to the lack of knowledge of the possible anatomical variations or pathologic abnormalities of the local veins or the lack of identification of the surrounding structures (arteries, nerve bundles, and organs).”
They conclude that, in all phases of venous cannulation procedures—from preliminary assessment to the early identification of puncture-related complications—a correct use of ultrasound improves performance, “making them safer, faster, and more effective”. As the RaFeVA protocol provides a detailed anatomical assessment in advance of the venous cannulation procedure, they claim, it enables optimisation of the manoeuvre through the reduction of cannulation time and of number of attempts, and the avoidance of surrounding structures that could be accidentally damaged during the venous catheterisation.