Ultrasound Guided Central Venous Vascular Access - Novel Needle Navigation Technology Compared With Conventional Method

Introduction Central venous catheter (CVC) insertion is a very common procedure in the intensive care setting. A recent international guideline advocates the use of ultrasound for routine internal jugular central venous catheter insertion1. The needle navigation technology is a new innovation, also known as guided positioning system (GPS) which allows clinician to visualize the needle position and trajectory in real time as it approaches the target. We hypothesised that the use of GPS would increase success rate and decrease performance time in vascular access procedures. The objectives of this study are to compare the success, efficacy and safety of central venous catheter insertion via internal jugular vein using the ultrasound guidance with conventional method versus needle navigation technology.

Methods:

This was a prospective randomized controlled study. It was conducted in a single centre - intensive care unit (ICU), University of Malaya Medical Centre, Kuala Lumpur, Malaysia from February 2016 to October 2016. The ethic committee approval was obtained from the Malaysian medical research and ethics committee, MREC at the www.nih.gov.my (NMRR-16-334-29476).

The inclusion criterion was patients in the ICU who required central venous vascular access. The exclusion criteria were refusal to participate in this study by patient or their legal representative and patient with known history of difficult central venous access at internal jugular vein (IJV). The procedure operators were doctors in anaesthesia residency program with various level of experiences classified into 3 groups: 1 to < 2 years, 2 to < 3years, 3 years and above. Simply speaking all the operators have had previous training in ultrasound guided vascular access procedure. This would ensure that patient's safety is not compromised.

Study would be proceeded after obtaining consent from patient or the next of kin. The emergency verbal consent would be taken if the next of kin was not immediately available with subsequent written consent to follow. The available operator would perform CVC insertion via IJV using ultrasound guidance out of plane approach either with conventional method or needle guidance technology.

Study Protocol:

After obtaining consent, a computer generated randomisation would be assigned to either using the conventional or GPS method. Identified operators using GPS method would receive a standard 5 minute briefing on the needle guidance technology and got to practice with the new technology using the vascular phantom (Blue Phantom Inc., Bothell, WA, USA). The operators were allowed to practice until they were ready to perform on real patient.

All procedure would be performed using the ultrasound machine, eZono 4000 with eZGuide (eZono, Jena, Germany) and linear array transducer L3-12NGS (3-12 MHz). This ultrasound machine2 has a built-in adaptive needle recognition software called eZGuide. The navigation technology of the ultrasound device is based on an electromagnetic field that communicates with a transducer and an electromagnetic sensor sheathed by a vascular access needle. Needle movements and related magnetic field variation allow navigation system to compute the locations of the transducer and needle in the three dimensional space. The ultrasound screen would display colour coded alignment of the needle and the position of the tip relative to the imaging plane (Figure 1). Superimposed on the image is the real-time electronic needle guidance system. The dashed line represents the predicted needle trajectory. The red box represents the depth that the needle will cross the plane of the ultrasound. The solid lines on either side of the dashed line represent the actual depth of the needle. The top left corner shows a diagram of the transducer-needle relation. This allowed the user to identify the correct needle trajectory, prior to puncturing the patient's skin and maintain the chosen route to the target anatomy. Operators assigned to use GPS method would have activated the eZGuide software while those performing conventionally would have the software technology turned off when using the ultrasound machine.

The procedure time was measured in seconds using a stopwatch. The performance time was defined as time measured from placing the needle on the skin to successful vessel puncture as indicated by blood withdrawn into the syringe.