Interest of Ultrasound Coupled to a Guidance System (GPS) for Central Venous Catheters (CVC) Insertion.

Overview

The GPS system would simplify the technical implementation of central venous catheter under ultrasound guidance. We can assume that the introduction of deep venous pathways (as a reference, the internal jugular) will be faster, and this, whatever the level of expertise. By checking this hypothesis, this technique could be applied to much less frequent situations establishment of difficult central venous catheters (hemodynamic status precarious, hypovolemia, or cardiac arrest). The main objective of this study is to evaluate the time savings provided by the ultrasound assisted GPS guidance for installing central venous catheters in the internal jugular. Central venous catheters are inserted in the operating room under conditions scheduled in advance that is to say outside emergency. The installation time for the central venous catheter is compared with that obtained by using the ultrasound machine without the GPS guide ("conventional" technique).

The techniques of reference for the central venous access (internal jugular, subclavian or femoral) are based on anatomical landmarks and the low probability of anatomical variations. With these techniques, the central venous puncture, with Seldinger method, is associated to complications both in adults and in children (pneumothorax, hemothorax, infection, thrombosis, arterial puncture, inappropriate location). The frequency of these adverse events is highly variable and ranges between 1 and 20% of central venous catheters in place. Ultrasound, visualizing anatomical structures before (echo tracking) or during (ultrasound guidance) the puncture, improves about 80% the success of the first puncture, and decreases by 50% the complications. The ultrasound guidance is better than echo tracking to reduce the time of implementation of the central venous catheter. However, this technique requires more practice. On the other hand, visualization of the needle path is not always easy especially for the subclavian access, because it requires a puncture in the ultrasound plane. GPS system (Guidance Positioning System) is an original system of guidance. This is a simple navigation system for projecting the theoretical position of the puncture needle in the ultrasound plane. The guidance system consists of a receiver and two motion sensors. The receiver is connected to the system. A motion sensor is incorporated into the end of the needle. Another motion sensor is located within the ultrasound probe. The relative positions and the axes of the needle and the ultrasound probe are transmitted with coordinates in three dimensions. The puncture can be carried out of the plane (ultrasound probe perpendicular to the axis puncture) and the direct visualization of the needle is not necessary. Before the puncture, the end of the needle is placed on the skin. The direction and the axis of the needle relative to the skin are adjusted, before the puncture, depending on the position of the target to be achieved, displayed by a mark on the screen. Throughout the puncture, a projected image of the needle is displayed on the screen.