Pain & Central Nervous System Week

Research on anesthesiology discussed by scientists at University of Rochester, Medical Department

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"The authors determined the minimally required stimulation threshold to elicit a motor response outside and inside the most superficial part of the brachial plexus during high-resolution, ultrasound-guided, supraclavicular block. After Institutional review board approval, ultrasound-guided, supraclavicular block was performed on 55 patients. with neurologic dysfunction were excluded. Criteria for extraneural and intraneural stimulation were defined and assessed by independent experts. To determine success rate and any residual neurologic deficit, qualitative sensory and motor examinations were performed before and after block placement. At 6 month follow-up, the patients were examined for any neurologic deficit. Thirty-nine patients met all set stimulation criteria. Median +/- SD (interquartile range) minimum stimulation threshold outside was 0.60 +/- 0.37 mA (0.40, 1.0) and inside 0.30 +/- 0.19 mA (0.20, 0.40). The difference of 0.30 mA was statistically significant (P < 0.0001). Stimulation currents of 0.2 mA or less were not observed outside the trunk in any patient. Significantly higher thresholds were observed in diabetic patients. Success rate was 100% after 20 min. Thirty-four patients had normal sensory and motor examination at 6 months. Five patients were lost to follow-up. Within the limitations of this study and the use of ultrasound, a stimulation current of 0.2 mA or less is reliable to detect intraneural placement of the needle," wrote P.E. Bigeleisen and colleagues, University of Rochester, Medical Department.

The researchers concluded: "Furthermore, stimulation currents of more than 0.2 and no more than 0.5 mA could not rule out intraneural position."

Bigeleisen and colleagues published their study in Anesthesiology (Extraneural versus Intraneural Stimulation Thresholds during Ultrasound-guided Supraclavicular Block. Anesthesiology, 2009;110(6):1235-1243).

For more information, contact P.E. Bigeleisen, University of Rochester, School Medical, Dept. of Anesthesiology, Box 604, 601 Elmwood Avenue, Rochester, NY 14614, USA.

Publisher contact information for the journal Anesthesiology is: Lippincott Williams & Wilkins, 530 Walnut St., Philadelphia, PA 19106-3621, USA.

Keywords: United States, Rochester, Life Sciences, Nerve Injury, Anesthesiology, University of Rochester, Medical Department.

This article was prepared by Pain & Central Nervous System Week editors from staff and other reports. Copyright 2009, Pain & Central Nervous System Week via NewsRx.com.