Study Supports Use of Variable Angle Needle Guidance in Nerve Block
An Ultrasound Needle Insertion Guide in a Porcine Phantom Model
S. Whittaker1 , G. Lethbridge2 , C. Kim2 , Z. Keon Cohen3 , I. Ng2 , 1 Provisional Fellow, Anaesthetic Department, Royal Melbourne Hospital, Melbourne, Vic., Australia 2 Staff Anaethetist, Anaesthetic Department, Royal Melbourne Hospital, Melbourne, Vic., Australia and 3 Provisional Fellow, Anaesthetic Department, Alfred Hospital, Melbourne, Vic., Australia
Anaesthesia, 2013; 68: 826-829
SUMMARY & METHODS
Thirty anaesthetists with varying levels of experience in performing regional nerve blocks participated in a crossover simulation study approved by the Melbourne Health Human Research Ethics Committee. Utilizing a porcine phantom model simulation, this study compared ultrasound guided free-hand technique and the use of a variable angle needle guide to test the hypothesis that the needle guide method will increase the percentage of time the needle tip is visualized during a regional blockade.
A metal rod was embedded 4cm below the skin surface within the porcine model and the participants were instructed how to insert a regional block Stimuplex® needle to complete the circuit which would trigger a light bulb. Each participant practiced five minutes with and without the Infiniti™ variable angle needle guide.
Participants were randomized into needle guide and free-hand technique users to perform the test. The results were recorded with the primary outcome being the amount of time the needle tip was viewed as a proportion of the total procedure time.
DISCUSSION & RESULTS
Participants were more satisfied with the needle guide method. There was a reduction in time taken to complete the task when using a variable angle needle guide verses a free-hand technique due to increased amount of time the needle tip was visualized in-plane. The training level of the user did not significantly affect the outcome. The Infiniti needle guide improved ultrasound guidance technique during the simulated RA nerve block and increased the needle tip visualization time during the procedure.
The authors reported study limitations including sonographic appearance and behavior of living nerves differing from that of a metal rod within a porcine phantom. Another limitation was the inability to block multiple nerves at the same time with one needle stick due to the design of the needle guide. The study’s findings suggest the Infiniti needle guide:
- increased needle visibility during in-plane simulated nerve blockades
- shortened procedural time for simulated nerve blockades
“The needle guide reduced the block time and the time that the needle was invisible, irrespective of anaesthetist experience.”