Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Mar 2010
ReviewClinical presentation of local anesthetic systemic toxicity: a review of published cases, 1979 to 2009.
The classic description of local anesthetic systemic toxicity (LAST) generally described in textbooks includes a series of progressively worsening neurologic symptoms and signs occurring shortly after the injection of local anesthetic and paralleling progressive increases in blood local anesthetic concentration, culminating in seizures and coma. In extreme cases, signs of hemodynamic instability follow and can lead to cardiovascular collapse. To characterize the clinical spectrum of LAST and compare it to the classic picture described above, we reviewed published reports of LAST during a 30-year period from 1979 to 2009. ⋯ However, in the remainder of cases, symptoms were substantially delayed after the injection of local anesthetic, or involved only signs of cardiovascular compromise, with no evidence of central nervous system toxicity. Although information gained from retrospective case review cannot establish incidence, outcomes, or comparative efficacies of treatment, it can improve awareness of the clinical spectrum of LAST and, theoretically, the diagnosis and treatment of affected patients. The analytic limitations of our method make a strong case for developing a prospective, global registry of LAST as a robust alternative for educating practitioners and optimizing management of LAST.
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Although new drugs and techniques may improve outcomes when unintended high blood levels of local anesthetics occur, the primary focus of daily practice should remain the prevention of such events. Although adoption of no single "safety step" will reliably prevent systemic toxicity, the combination of several procedures seems to have reduced the frequency of systemic toxicity since 1981. These include the use of minimum effective doses, careful aspiration, and incremental injection, coupled with the use of intravascular markers when large doses are used. ⋯ Fentanyl has also been confirmed to produce sedation in pregnant women when used as an alternative. The use of ultrasound observation of needle placement and injection may be useful, but has also been reported as not completely reliable. Constant vigilance and suspicion are still needed along with a combination of as many of these safety steps as practical.
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Reg Anesth Pain Med · Mar 2010
ReviewUltrasound-guided interventional procedures in pain management: Evidence-based medicine.
Recently, there has been a growing interest in the application of ultrasonography in pain medicine because ultrasound provides direct visualization of various soft tissues and real-time needle advancement and avoids exposing the health care provider and the patient to the risks of radiation. The machine itself is more affordable and transferrable than a fluoroscopy, computed tomography scan, or magnetic resonance imaging machine. These factors make ultrasonography an attractive adjunct to other imaging modalities in interventional pain management especially when those modalities are not available or feasible. The present article reviews the existing evidence that evaluates the role of ultrasonography in spine interventional procedures in pain management.
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Reg Anesth Pain Med · Mar 2010
ReviewModels and mechanisms of local anesthetic cardiac toxicity: a review.
Cardiovascular collapse, even death, may occur after intoxication with bupivacaine or related amide local anesthetic agents. The problem has been studied in myriad laboratories for more than 20 years. Nevertheless, there is consensus neither regarding which animal model best mimics this clinical catastrophe nor as to which ion channel, enzyme, or other local anesthetic binding site represents the point of initiation for the process. This review aimed to define the various credible mechanisms that have been proposed to explain cardiovascular collapse and death after administration of local anesthetics, particularly after bupivacaine and related agents.
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Reg Anesth Pain Med · Sep 2009
ReviewCorrelation between ultrasound imaging, cross-sectional anatomy, and histology of the brachial plexus: a review.
The anatomy of the brachial plexus is complex. To facilitate the understanding of the ultrasound appearance of the brachial plexus, we present a review of important anatomic considerations. A detailed correlation of reconstructed, cross-sectional gross anatomy and histology with ultrasound sonoanatomy is provided.