Anesthesiology
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Randomized Controlled Trial Clinical Trial
Paralysis only slightly reduces the febrile response to interleukin-2 during isoflurane anesthesia.
Fever sometimes occurs during anesthesia. However, it is rare considering how often pyrogenic causes are likely to be present and how common fever is after surgery. This low incidence results in part from dose-dependent inhibition of fever by volatile anesthetics. Paralysis, however, may contribute by preventing shivering and the associated increase in metabolic heat production. Therefore the authors tested the hypothesis that paralysis during anesthesia decreases the febrile response to pyrogen administration. ⋯ Paralysis prevented shivering from increasing the metabolic rate. Consequently, body heat content decreased during paralysis, whereas otherwise it increased. Thermoregulatory vasoconstriction was nonetheless able to maintain similar peak and integrated core temperatures on each study day. Administration of muscle relaxants thus is not the primary explanation for the relative paucity of intraoperative fever.
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The ventilatory response to acute hypoxia is biphasic, with an initial rapid increase followed by a slower decline. In humans, there is evidence that the magnitude of the decline in ventilation is proportional to the size of the initial increase. This study was done to define the role of exogenous opioids in the ventilatory decline seen with prolonged hypoxia. ⋯ Alfentanil reduced the acute ventilatory response to hypoxia. The absolute value of hypoxic ventilatory decline was not increased, but a measure of residual hypoxic ventilatory decline (the ratio of ventilation between the second and first steps into hypoxia) was decreased, which supports the hypothesis that opioids potentiate centrally mediated ventilatory decline.
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Randomized Controlled Trial Clinical Trial
Dose-dependent reduction of the minimum local analgesic concentration of bupivacaine by sufentanil for epidural analgesia in labor.
The minimum local analgesic concentration (MLAC) has been defined as the median effective local analgesic concentration in a 20-ml volume for epidural analgesia in the first stage of labor. The aim of this study was to determine the local anesthetic-sparing efficacy of epidural sufentanil by its effect on the MLAC of bupivacaine. ⋯ This study showed a significant (P < 0.0001) dose-dependent reduction in the MLAC ofbupivacaine by sufentanil.