Use Of Electrical Nerve Stimulation Research Articles

Acute effect of tendon vibration applied during isometric contraction at two knee angles on maximal knee extension force production

The aim of the current study was to investigate the effect of a single session of prolonged tendon vibration combined with low submaximal isometric contraction on maximal motor performance. Thirty-two young sedentary adults were assigned into two groups that differed based on the knee angle tested: 90° or 150° (180° = full knee extension). Participants performed two fatigue-inducing exercise protocols: one with three 10 min submaximal (10% of maximal voluntary contraction) knee extensor contractions and patellar tendon vibration (80 Hz) another with submaximal knee extensor contractions only. Before and after each fatigue protocol, maximal voluntary isometric contractions (MVC), voluntary activation level (assessed by the twitch interpolation technique), peak-to-peak amplitude of maximum compound action potentials of vastus medialis and vastus lateralis (assessed by electromyography with the use of electrical nerve stimulation), peak twitch amplitude and peak doublet force were measured. The knee extensor fatigue was significantly (P<0.05) greater in the 90° knee angle group (-20.6% MVC force, P<0.05) than the 150° knee angle group (-8.3% MVC force, P = 0.062). Both peripheral and central alterations could explain the reduction in MVC force at 90° knee angle. However, tendon vibration added to isometric contraction did not exacerbate the reduction in MVC force. These results clearly demonstrate that acute infrapatellar tendon vibration using a commercial apparatus operating at optimal conditions (i.e. contracted and stretched muscle) does not appear to induce knee extensor neuromuscular fatigue in young sedentary subjects.

Use of electrical nerve stimulation to monitor lumbosacral epidural needle placement in cats

ObjectiveTo determine the minimal electrical threshold (MET) necessary to elicit muscle contraction of the pelvic limb or tail when an insulated needle is positioned outside (METout) and inside (METin) the lumbosacral epidural space in cats. Study designProspective, blinded study. AnimalsTwelve mixed-breed healthy adult cats, scheduled for a therapeutic procedure where lumbosacral epidural administration was indicated. MethodsUnder general anesthesia, an insulated needle was advanced through tissues of the lumbosacral interspace until its tip was thought to be just dorsal to the interarcuate ligament. An increasing electrical current (0.1 ms, 2 Hz) was applied through the stimulating needle in order to determine the MET necessary to obtain a muscle contraction of the pelvic limb or tail (METout), and then 0.05 mL kg−1 of iohexol was injected. The needle was further advanced until its tip was thought to be in the epidural space. The MET was determined again (METin) and 0.2 mL kg−1 of iohexol was injected. The cats were maintained in sternal position. Contrast medium spread was determined through lateral radiographic projections. ResultsThe radiographic study confirmed the correct needle placement dorsal to the interarcuate ligament in all cats. When the needle was placed ventrally to the interarcuate ligament, iohexol was injected epidurally in ten and intrathecally in two cats. The METout and METin was 1.76 ± 0.34 mA and 0.34 ± 0.07 mA, respectively (p < 0.0001). Conclusion and clinical relevanceNerve stimulation can be employed as a tool to determine penetration of the interarcuate ligament but not the piercing of the dura mater at the lumbosacral space in cats.

Electrical stimulation and ultrasound in regional anesthesia

Nerve localization can be achieved by eliciting either a functional needle endpoint (e.g. mechanical paresthesia, motor response to electrical stimulation) or anatomical endpoint (e.g. periarterial injection, ultrasonographic imaging). The most widely used method to determine a functional endpoint is by the use of electrical nerve stimulation. Increasingly, ultrasonographic guidance is being used to determine anatomical endpoint in conjunction with or in place of electrical nerve stimulation. Peripheral nerve stimulation utilizes an oscillating square wave (pulse) of electrical current at a given frequency, current amplitude, and pulse duration that are very accurate in locating peripheral nerves. Nerve stimulation is very specific but has been lacking in sensitivity. Newer technology, including sequential electrical nerve stimulation, maintains the accuracy while increasing the sensitivity of this modality. Ultrasonographic guidance can also be very specific and sensitive for nerve location. Compared to electrical nerve stimulation, compact portable ultrasound units are much more expensive. To date, no differences have been shown in block success or complication rates between the two techniques. It is important to maintain proficiency in the use of both electrical nerve stimulation and ultrasonographic guidance for optimal practice and teaching of peripheral nerve or plexus anesthesia. Ideally both techniques may often be used in conjunction, enabling the practitioner and patient the benefits of each technique during simultaneous use.

Implications of a Permanent Cardiac Pacemaker in Peripheral Nerve Blockade

Patients with permanent cardiac pacemakers (PPMs) are vulnerable to electromagnetic interference from electrical equipment used in the operating room environment. Electromagnetic interference may lead to PPM malfunction with potential harmful effects to the patient. Conventional techniques for peripheral nerve blockade include the use of electrical nerve stimulation (NS) for nerve localization. The hazards of NS, especially when applied near the implanted PPM sites, are not known. In the absence of available guidelines regarding the safe use of NS in the setting of an implanted PPM, we recommend a combined guidance approach for peripheral nerve blockade using ultrasound for nerve localization along with low-current NS for nerve identification.

Preventing pacemaker problems with nerve stimulators

Preventing pacemaker problems with nerve stimulators

Regional Anesthesia, Intraneural Injection, and Nerve Injury

Regional Anesthesia, Intraneural Injection, and Nerve Injury