Anesthesia and analgesia
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Anesthesia and analgesia · May 2007
Comparative StudyThe effects of general anesthetics on P2X7 and P2Y receptors in a rat microglial cell line.
Microglial cells play important roles in coordinating the inflammatory brain responses to hypoxia and trauma. Ionotropic P2X receptors and metabotropic P2Y receptors (P2YRs) expressed in microglia can be activated by extracellular adenosine triphosphate (ATP) derived from damaged cells or astrocytes, and participate in the signaling pathways evoked in brain insult. Although several inhaled and IV anesthetics produce neuroprotective effects through neuronal mechanisms, little is known about how general anesthetics modulate microglial responses in the pathological state. We examined the effects of various general anesthetics on purinergic responses in a rat microglial cell line. ⋯ Our results suggest that IV anesthetics, particularly thiopental and propofol, may modulate microglial functions through P2X7Rs in pathological conditions.
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Anesthesia and analgesia · May 2007
Randomized Controlled Trial Comparative StudyEpidural clonidine for postoperative pain after total knee arthroplasty: a dose-response study.
Combinations of epidural clonidine, local anesthetics, and opioids have improved postoperative analgesia after total knee arthroplasty. In this study we sought to determine the optimal epidural bolus dose of clonidine, which provides the best analgesia and fewest side effects. ⋯ The optimal amount of epidural clonidine in a solution of morphine and ropivacaine for postoperative pain management is 1.0 microg/mL.
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Anesthesia and analgesia · May 2007
Randomized Controlled Trial Comparative StudyThere is no dose-escalation response to dexamethasone (0.0625-1.0 mg/kg) in pediatric tonsillectomy or adenotonsillectomy patients for preventing vomiting, reducing pain, shortening time to first liquid intake, or the incidence of voice change.
Tonsillectomy is associated with postoperative nausea and vomiting (PONV) if no prophylaxis is administered. Previous studies have shown that a single dose of dexamethasone decreases the incidence of PONV. The most effective dose of dexamethasone to affect clinical outcome is yet to be defined. ⋯ We conclude that the lowest dose of dexamethasone (0.0625 mg/kg) was as effective as the highest dose of dexamethasone (1.0 mg/kg) for preventing PONV or reducing the incidence of other secondary outcomes following tonsillectomy or adenotonsillectomy. There is no justification for the use of high-dose dexamethasone for the prevention of PONV in this cohort of children.
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Anesthesia and analgesia · May 2007
Comparative StudyPerineural resiniferatoxin prevents the development of hyperalgesia produced by loose ligation of the sciatic nerve in rats.
The vanilloid receptors (TRPV1) are found in peripheral nerve fibers; their stimulation by capsaicin leads to release of calcitonin gene-related peptide and other neuropeptides participating in neuroinflammation. On the other hand, various inflammatory mediators, released after nerve damage, can activate or sensitize the TRPV1 receptors. These findings together suggest a protective effect of TRPV1 receptor blockade in neuropathy. In the present study, we tested the hypothesis that perineural resiniferatoxin (RTX) can prevent the development of hyperalgesia caused by placing loosely constrictive ligatures around the sciatic nerve. ⋯ Perineural RTX prevents the development of neuropathy caused by placing loosely constrictive ligatures on the sciatic nerve. Perioperative use of drugs acting via the TRPV1 receptors may hold the promise for preventing neuropathic pain after surgery on peripheral nerves.
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Anesthesia and analgesia · May 2007
Case ReportsUltrasound-guided infraclavicular block in an anticoagulated and anesthetized patient.
The author describes the use of ultrasound to facilitate a continuous infraclavicular brachial plexus block in a patient who had been anticoagulated with 5000 U of heparin. The procedure was done 2 h after the patient was anticoagulated, and his activated clotting time was 203 s. The patient had vascular checks with a laser Doppler monitor every hour and neurological checks every 12 h.