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Johans Thomas G. MD; Carr, George MS
Anesthesia & Analgesia: December 1985

Regional nerve blockade is considered to be less painful and more successful when a peripheral nerve stimulator (PNS) is used to localize the nerve (1,2). Because the needle is placed with more accuracy, the chance for nerve damage and local anesthetic toxicity is decreased.

Although this technique can be performed without insulated needles (3), there is recent evidence (4,5) that supports the use of an insulated needle. It is unfortunate however, that such needles are expensive and not readily available.

In 1969, Koons (2) overcame these drawbacks by using the “Rochester” intravenous (IV) “extra-cath” as an insulated needle. To conduct the stimulating electrical impulses to the needle tip, he attached the stimulating electrode of the PNS via a stainless steel stopcock to the stainless steel hub of the obturator needle. Unfortunately, obturator needles used in commercially available IV extra-cath today are manufactured with nonconductive plastic hubs. Hence this otherwise ingenious and inexpensive insulated needle is no longer used.

We thought that if an electrocardiographic impulse could be conducted along a saline-filled catheter during right atrial electrocardiography (6), then the impulse of the PNS possibly could be conducted through the local anesthetic that fills the plastic hub of the IV extra-cath. This innovation would then reestablish the IV extra-cath needle as an inexpensive, ubiquitously available, insulated block needle. The purpose of this report is to illustrate that the equipment apparatus described by Koons remains applicable even without stainless steel obturator needle hubs, to present a modification that makes the technique more aseptic and less cuMDersome, and to provide supporting evidence that the increased resistance imposed by this modification does not preclude its use.

Address correspondence to Dr. Johans, Department of Anesthesiology, St. John's Mercy Medical Center, 621 South New Ballas Road, St. Louis, MO 63141.

© 1985 International Anesthesia Research Society