The Characteristics of Nerve Stimulators in Peripheral Nerve Block

ABSTRACT

OBJECTIVE: To find the characteristics of the nerve stimulator for the peripheral nerve blockade. METHOD: We studied four different nerve stimulators currently available in the clinical setting. The output characteristics(wave shape, voltage and duration of the stimulus impulse) were measured for each stimulator using an oscilloscope. Target current from 0 mA to 5 mA and load resistances from 200 ohm to 10 kohm were selected to model the normal ranges of operating current and tissue impedance when performing peripheral nerve block technique. RESULTS: There was a marked variation in performance of nerve stimulators depending on the target current value and resistances. Measured pulse width was not identical to the target pulse width in three nerve stimulators. Measured voltage with a fixed resistance was smaller in two nerve stimulators than the target voltage which was supposed to be produce in target current value of same resistance. One nerve stimulator showed the differences of calculated current value according to the used resistances. CONCLUSION: For the successful nerve block, it is important for the operator to be aware of the design and functional limitations of the nerve stimulator being used in clinical practice.