BACKGROUND
NICE guidelines state that 2-D ultrasound should now be used for the venous puncture step in the insertion of all internal jugular central venous catheters and considered in the placement of subclavian/femoral catheters.1 Using ultrasound to locate and puncture the vein involves delicate operator co-ordination between the hand holding the needle and syringe, the hand holding the probe over the vein and the eyes watching the image on the screen of the portable ultrasound machine. These skills naturally take time to master. A simple, inexpensive simulator for ultrasound-guided venous puncture is presented which allows surgical trainees to practice their hand–eye co-ordination in locating and puncturing the vein before attempting the procedure under appropriate supervision in patients.
TECHNIQUE
The simulated vessels are constructed by cutting the finger portions from small latex gloves, filling them with water and tying a knot in the end. These are then glued together to lie side by side analogous to the anatomical arrangement of vein and artery. (Fig. 1). The ‘vessels’ are then placed in the bottom of a small kitchen storage tub. The tub is filled with standard lubricating jelly to simulate the surrounding tissues. A further glove is then placed around the tub and tied to ensure a good seal to stop leakage of the jelly. The ‘vessels’ cannot be seen through the glove looking into the model. In exactly the same fashion as performing the procedure in patients, the probe is placed on the top of the tub allowing visualisation of the simulated vein and artery below (Fig. 2). One of the vessels is designated the simulated vein and selected as a target for puncture. The needle is then advanced towards the simulated vein (simV) and away from the simulated artery (simA) using ultrasound to monitor the progress of the needle through the surrounding tissues (Fig. 3). The ultrasound images of the simulated artery and vein obtained with the model are similar to those obtained in patients (Fig. 4). Puncture of the simulated vein corresponds with free water aspiration from inside the model into the syringe and loss of the ultrasound image of the vessel. The model can then easily be prepared for further use.
Figure 1.
Simulated vein and artery lying side by side used in the model.
Figure 2.
Advancing the needle towards the vein under ultrasound guidance.
Figure 3.
Ultrasound image of needle approaching simulated vein on model.
Figure 4.
Ultrasound image of the author's internal jugular vein and common carotid artery.