Regional anesthesia and pain medicine
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Reg Anesth Pain Med · May 2007
Comment Biography Historical ArticleHoward Fields, M.D.: Bonica lecturer.
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Opioids acting at the mu opioid (MOP) receptor produce powerful analgesia. They also produce an intensely rewarding effect that can lead to addiction. The analgesic effect of MOP receptor agonists derives from a direct inhibitory effect on pain transmission at the spinal-cord level and through activation of a descending pain-modulatory pathway. ⋯ Pain is one of many competing motivational states, and endogenous opioids suppress responses to noxious stimuli in the presence of conflicting motivations, such as hunger or a threatening predator. When a food reward is available, MOP agonists microinjected into the mesostriatal circuit promote its consumption, while concomitantly suppressing responses to noxious stimulation. The mesostriatal "reward" circuit, thus, appears to perform a function critical to decision making and can either amplify or suppress responses to noxious stimuli.
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Reg Anesth Pain Med · Mar 2007
Case ReportsDemonstration of the spread of injectate with deep cervical plexus block: a case series.
The authors conducted a scanographic study in order to characterize the local anesthetic spread of injectate resulting from a single-injection technique of deep cervical plexus block. ⋯ The authors showed that deep cervical plexus block was associated with a wide spread of injectate. The data show that the spread of injectate is enclosed within to the prevertebral layer of the deep cervical fascia.
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Reg Anesth Pain Med · Mar 2007
Electrical stimulation of the epidural space using a catheter with a removable stylet.
Electrical stimulation can be used to verify the location of epidural catheters. With the traditional technique, the latter must be primed with saline to allow for electrical conduction: any air lock will, thus, hinder the flow of current. Therefore, we set out to explore an alternative mode of stimulation by use of a catheter containing a removable stylet. This study examines the reliability of this new technique. ⋯ We conclude that the TheraCath, because of the removable stylet, provides effective electrostimulation of the epidural space. Its use was simple and devoid of complications. Nonetheless, further studies are required before implementing its routine use in clinical settings.