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.