Voltage fields surrounding needles used in regional anaesthesia

Abstract

Using a bench model, we have studied the voltage fields surrounding both insulated and uninsulated needles used in regional anaesthesia. The findings were compared with earlier computer predictions which suggested that the fields would be markedly different for the two types of needle. The results confirm that the fields differ markedly and suggest that the use of insulated needles may not necessarily improve the accuracy of nerve location and that uninsulated needles may be more appropriate. © 1992 British Journal of Anaesthesia.