Related Experiment Video
Updated: Aug 12, 2026
04:56
In Vivo Electrophysiological Measurement of the Rat Ulnar Nerve with Axonal Excitability Testing
Published on: February 6, 2018
Somatosensory evoked potential quantification of ulnar nerve blockade
Anesthesia and Analgesia
|August 1, 1986
Summary
Somatosensory evoked potentials (SSEPs) can objectively monitor ulnar nerve sensory blockade. Reduced C-7 amplitude duration accurately predicts sensory block duration, offering a reliable objective measure.
Area of Science:
- Neuroscience
- Anesthesiology
- Biomedical Engineering
Background:
- Assessing sensory blockade objectively is crucial for regional anesthesia.
- Somatosensory evoked potentials (SSEPs) offer a potential non-invasive method.
Purpose of the Study:
- To evaluate the efficacy of SSEPs in monitoring ulnar nerve sensory blockade.
- To compare saline and lidocaine with and without epinephrine for ulnar nerve blockade.
Main Methods:
- Eight volunteers received four randomized treatments: saline, saline with epinephrine, lidocaine, and lidocaine with epinephrine.
- Sensory blockade intensity was assessed using a visual analogue scale (SVAS).
- Ulnar nerve SSEPs were recorded at Erb's point, C-7, and the sensory cortex.
Main Results:
- Lidocaine injections (with/without epinephrine) produced significant sensory blockade (SVAS > 8), lasting longer with epinephrine (248 min vs. 83 min).
- SSEPs showed decreased amplitude and increased latency at Erb's point and C-7 following lidocaine.
- Reduced C-7 amplitude duration correlated strongly (r=0.96) with sensory block duration.
Conclusions:
- SSEPs, particularly C-7 amplitude changes, serve as a reliable objective monitor for ulnar nerve sensory blockade.
- This objective monitoring can enhance the safety and efficacy of regional anesthesia procedures.
