Anesthesiology
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Clinical Trial
Differential sensitivity of abdominal muscles and the diaphragm to mivacurium: an electromyographic study.
Respiratory muscles are considered to be more resistant to muscle relaxants as compared with peripheral muscles. However, the relative sensitivity of respiratory muscles participating to the pump function has not been compared. We used electromyography to compare pharmacodynamic parameters of the diaphragm and abdominal muscles after mivacurium. ⋯ Diaphragm and abdominal muscles have differential sensitivity to mivacurium. The diaphragm is more resistant to mivacurium than abdominal muscles are.
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Comparative Study
Isoflurane and sevoflurane anesthesia in pigs with a preexistent gas exchange defect.
Decreased arterial partial pressure of oxygen (PaO2) during volatile anesthesia is well-known. Halothane has been examined with the multiple inert gas elimination technique and has been shown to alter the distribution of pulmonary blood flow and thus PaO2. The effects of isoflurane and sevoflurane on pulmonary gas exchange remain unknown. The authors hypothesized that sevoflurane with a relatively high minimum alveolar concentration (MAC) would result in significantly more gas exchange disturbances in comparison with isoflurane or control. ⋯ In pigs with an already existent gas exchange defect, sevoflurane anesthesia but not isoflurane anesthesia causes significantly more gas exchange disturbances than propofol anesthesia does.
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Spinally administered opioids show decreased potency and efficacy in the treatment of neuropathic pain. As reported previously, morphine stimulates spinal opioid receptors to effect adenosine release, which acts at adenosine receptors to produce analgesia. The authors hypothesized that morphine induces less adenosine release in neuropathic compared with normal rats, explaining its reduced potency and efficacy. ⋯ Morphine normally stimulates spinal release of adenosine, a potent antihypersensitivity compound. Because this effect of morphine is diminished in spinal nerve ligation animals, one explanation for decreased efficacy and potency of opioids in the treatment of neuropathic pain may be a dipyridamole-sensitive disruption in the opioid-adenosine link in the spinal cord.