Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2008
Case ReportsAcute neck cellulitis and mediastinitis complicating a continuous interscalene block.
We report a case of acute neck cellulitis and mediastinitis complicating a continuous interscalene brachial plexus block. A 61-yr-old man was scheduled for an elective arthroscopic right shoulder rotator cuff repair. A continuous interscalene block was done preoperatively and 20 mL of 0.5% bupivacaine and 20 mL of 2% mepivacaine were injected through the catheter. ⋯ The infection was treated with surgery, the site was surgically debrided, and a 2-mo course of vancomycin, imipenem, and oxacilline. The technique of drawing local anesthetic from the bottle and filling the elastomeric pump was the most likely cause of infection. This case emphasizes the importance of strict aseptic conditions during puncture, catheter insertion, and management of the local anesthetic infusate.
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Anesthesia and analgesia · Oct 2008
The effect of injectate conductivity on the electric field with the nerve stimulator needle: a computer simulation.
Electrical neural stimulation is commonly used to localize neural structures and place local anesthetic for regional anesthesia. The sharp tip of the stimulating needle gives rise to an electric field which is highly localized. The electrostatic effect of the injected solution on the field distribution and strength has not previously been modeled. ⋯ The electric field magnitude in the vicinity of the needle tip decayed more slowly with distance than predicted by Coulomb's law. This was independent of the presence of injectate. The near instantaneous abolition of muscle twitch with injection of small volumes of local anesthetic is consistent with an electrostatic effect, rather than a pharmacological or mechanical one. The change in field strength depended upon the volume of the injectate and its conductivity relative to that of the surrounding tissue. In this simulation, even tiny volumes of injectate lead to significant changes in field and therefore threshold current, which may have clinical implications.
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Anesthesia and analgesia · Oct 2008
Case ReportsPerioperative management of patients with an intrathecal drug delivery system for chronic pain.
The use of intrathecal medications in the treatment of chronic pain is becoming more commonplace. As such, the incidence of encountering patients receiving therapy via an intrathecal drug delivery system in the perioperative period will also increase. In this case series, we discuss anesthetic management and postoperative analgesic issues in three patients with indwelling intrathecal drug delivery systems placed for treatment of chronic pain.
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Anesthesia and analgesia · Oct 2008
Spatial memory is intact in aged rats after propofol anesthesia.
We have previously demonstrated that aged rats have persistent impairment of spatial memory after sedation with nitrous oxide or general anesthesia with isoflurane-nitrous oxide. Propofol has different receptor mechanisms of action and a favorable short-term recovery profile, and it has been proposed that propofol is devoid of enduring effects on cognitive performance. No studies have investigated this question in aged subjects, however, so we designed an experiment to examine the long-term effects of propofol anesthesia on spatial working memory. ⋯ In aged rats, propofol anesthesia is devoid of the persistent memory effects observed with other general anesthetics in this model. Thus, while it appears that the state of general anesthesia is neither necessary nor sufficient for development of postanesthetic memory impairment, the choice of anesthetics may play a role in late cognitive outcome in the aged.
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Anesthesia and analgesia · Oct 2008
The inhibition of human neutrophil phagocytosis and oxidative burst by tricyclic antidepressants.
Tricyclic antidepressants are being investigated as long-acting analgesics for topical application in wounds or IV for postoperative pain relief. However, it remains unclear if tricyclic antidepressants affect the host defense and if reported toxic effects on neutrophils are of relevance in this setting. We therefore investigated the effects of amitriptyline, nortriptyline, and fluoxetine on human neutrophil phagocytosis, oxidative burst, and neutrophil toxicity in a human whole blood model. ⋯ Phagocytosis and intracellular host defense are largely unaffected by antidepressants in concentrations of 10(-4) M and below. Our results confirm that antidepressants are highly toxic to neutrophils in millimolar concentrations. The neurotoxic effects and clinical side effects, but not effects on neutrophil functions, therefore, are likely to be the limiting factors in using antidepressants as analgesics.