Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2006
Intrathecal administration of a cylcooxygenase-1, but not a cyclooxygenase-2 inhibitor, reverses the effects of laparotomy on exploratory activity in rats.
Studies of hypersensitivity to mechanical stimuli after incisional surgery suggest that cyclooxygenase (COX)-1, but not COX-2, in the spinal cord participates in postoperative pain. In the current study, we sought to determine the role of COX isoenzymes after laparotomy, examining spontaneous exploratory behavior rather than withdrawal reflexes. Adult male Sprague-Dawley rats underwent subcostal laparotomy surgery under isoflurane anesthesia or received anesthesia without surgery. ⋯ These data with exploratory behavior and laparotomy agree with studies with reflexive withdrawal responses after incisional surgery and indicate that COX-1 inhibition reduces pain responses after surgery. Spinal COX-1 inhibition completely restores exploratory activity, including rearing behavior that stretches the abdominal muscles. These data suggest that targeting COX-1 in the spinal cord may produce postoperative analgesia.
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Anesthesia and analgesia · Sep 2006
The involvement of the nociceptin receptor in the antinociceptive action of nitrous oxide.
Nociceptin and its receptor are widely expressed in the central nervous system and are involved in the modulation of nociception. We have previously reported that the minimum anesthetic alveolar concentrations for volatile anesthetics do not differ between nociceptin receptor knockout (NOP-/-) mice and wild-type (NOP+/+) mice. In the present study, we investigated whether the nociceptin system is involved in the antinociceptive action of nitrous oxide. ⋯ Furthermore, when anesthetized with a mixture of halothane and nitrous oxide (70%), intraperitoneal injection of acetic acid resulted in an increase of plasma adrenocorticotropic hormone concentrations in NOP-/- mice but not in NOP+/+ mice. An immunohistochemical study showed that nitrous oxide exposure induced c-Fos expression in the spinal cords of NOP+/+ mice but not in those of NOP-/- mice. These results together suggest that the antinociceptive action of nitrous oxide is, at least partly, mediated by the nociceptin system.
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Anesthesia and analgesia · Sep 2006
Letter Case ReportsLong-term use of the laryngeal mask airway in a neonate.
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Anesthesia and analgesia · Sep 2006
Randomized Controlled TrialHypercapnia improves tissue oxygenation in morbidly obese surgical patients.
Risk of wound infection is increased in morbidly obese surgical patients, in part because a major determinant of wound infection risk, tissue oxygenation, is marginal. Unlike in lean patients, supplemental inspired oxygen (Fio2) only slightly improves tissue oxygenation in obese patients. Mild hypercapnia improves tissue oxygenation in lean patients but has not been evaluated in obese patients. ⋯ Demographic characteristics, cardiovascular measurements, and Pao2 (222 +/- 48 versus 230 +/- 68 mm Hg in normocapnic versus hypercapnic; mean +/- sd; P = 0.705) were comparable in the groups. Tissue oxygen tension, however, was greater in hypercapnic than in normocapnic patients (78 +/- 31 versus 56 +/- 13 mm Hg; P = 0.029). Mild hypercapnia increased tissue oxygenation by an amount believed to be clinically important and could potentially reduce the risk of surgical wound infection in morbidly obese patients.