Abstract ID: A13

Abstract Title: Electrical nerve stimulation using a stimulating catheter: what is a safe lower limit?

Poster Type: Poster

ABSTRACT BODY

Background and Objectives: To minimize the risk of intraneural injection when performing nerve blocks, some authors caution against injecting through a needle placed with motor responses observed at nerve stimulator output settings of 0.2 mA or less. We present a case of placing a continuous cervical paravertebral catheter with brisk motor response while stimulating the catheter at 0.02 mA with no adverse sequelae.

Case Report: A 56-year-old man scheduled for rotator cuff repair received a continuous cervical paravertebral block for intraoperative and post operative pain control. A stimulating catheter (StimuCath, Arrow Intl, Reading, PA) was used for the block. During catheter placement, nerve stimulator output was decreased to 0.025 mA at 300 µs and the motor response remained brisk. The patient was not significantly sedated and experienced no pain during placement or with injection through the catheter. The catheter provided complete surgical anesthesia and satisfactory postoperative pain control. Because of concerns related to the low stimulation current, catheter position was evaluated by fluoroscopy. The nerve trunks of C5 and C6 were clearly visible with 1 mL of Omnipaque (iohexol). The catheter was removed the next day. At the follow-up visit two weeks later, the patient’s neurologic examination remained unremarkable.

Conclusion: We believe that the risk of intraneural injection is very low with the StimuCath catheter, even when a motor response occurs at very low nerve stimulator output settings.

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ATTACHED FILES

A13_Figure 1.doc

Reg Anesth Pain Med 2004; 29(2):A13