Anesthesiology
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Hyperglycemia generates reactive oxygen species and prevents isoflurane-induced preconditioning. The authors tested the hypothesis that scavenging reactive oxygen species with N-acetylcysteine will restore protection against myocardial infarction produced by isoflurane in vivo. ⋯ Acute hyperglycemia abolishes reductions in myocardial infarct size produced by isoflurane, but N-acetylcysteine restores these beneficial effects. The results suggest that excessive quantities of reactive oxygen species generated during hyperglycemia impair isoflurane-induced preconditioning in dogs.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
A multicenter, randomized, controlled trial comparing bupivacaine with ropivacaine for labor analgesia.
A meta-analysis of studies comparing high doses of bupivacaine with ropivacaine for labor pain found a higher incidence of forceps deliveries, motor block, and poorer neonatal outcome with bupivacaine. The purpose of this study was to determine if there is a difference in these outcomes when a low concentration of patient-controlled epidural bupivacaine combined with fentanyl is compared with ropivacaine combined with fentanyl. ⋯ There was no difference in the incidence of operative delivery or neonatal outcome among nulliparous patients who received low concentrations of bupivacaine or ropivacaine for labor analgesia.
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Postcesarean section pain is a common cause of acute pain in obstetrics, yet pain relief and patient satisfaction are still inadequate in many cases. The present study was conducted to determine whether preoperative assessment of experimental pain perception by quantitative sensory tests could predict the level of postcesarean section pain. ⋯ The results show that a simple and quick preoperative test is useful in identifying those women who will experience greater pain after a cesarean section. This test may be suggested for caregivers to tailor the postoperative treatment to specific patient needs and to improve postoperative outcome and patient satisfaction.
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Comparative Study
Assessment of differential blockade by amitriptyline and its N-methyl derivative in different species by different routes.
Increasing the duration of local anesthesia and/or creating greater differential blockade (i.e., selective block of pain-transmitting nerve fibers) has been attempted by modifying currently available agents. Most drugs show a different profile depending on the model or species studied. This study was designed to investigate the differential nerve-blocking properties of amitriptyline and its quaternary ammonium derivative in rats and sheep. ⋯ Amitriptyline and N-methyl amitriptyline are potent Na+ channel blockers and show greater differential blockade in sheep than in rats. This differential blockade in sheep is greater than that produced by lidocaine or bupivacaine.
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Gabapentin, a gamma-aminobutyric acid analog anticonvulsant, has been shown to possess antinociceptive effects in animal models and clinical trials. An endogenous binding site of [3H]gabapentin has been revealed to be the alpha(2)delta subunit of voltage-dependent Ca2+ channels. Magnesium chloride, ruthenium red, and spermine have been shown to modulate [3H]gabapentin binding to this binding site in vitro. In this study, the authors examined whether intrathecal magnesium chloride, ruthenium red, or spermine could affect the antiallodynic effect of intrathecal gabapentin in a rat model of postoperative pain. ⋯ These results provide behavioral evidence to support that the alpha(2)delta subunit of Ca2+ channels may be involved in the antiallodynic action of intrathecal gabapentin in the postoperative pain model.