Anesthesiology
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Randomized Controlled Trial Clinical Trial
Epidural anesthesia impairs both central and peripheral thermoregulatory control during general anesthesia.
The authors tested the hypotheses that: (1) the vasoconstriction threshold during combined epidural/general anesthesia is less than that during general anesthesia alone; and (2) after vasoconstriction, core cooling rates during combined epidural/general anesthesia are greater than those during general anesthesia alone. Vasoconstriction thresholds and heat balance were evaluated under controlled circumstances in volunteers, whereas the clinical importance of intraoperative thermoregulatory vasoconstriction was evaluated in patients. ⋯ These data indicate that epidural anesthesia reduces the vasoconstriction threshold during general anesthesia. Furthermore, the markedly reduced rate of core cooling during general anesthesia alone illustrates the importance of leg vasoconstriction in maintaining core temperature.
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Repetitive C-fiber stimulation induces a state of facilitated processing of sensory information in the dorsal horn, while chronic nerve compression gives rise to a hyperalgesic state, characterized by spontaneous neuronal activity generated by voltage-sensitive sodium channels, as well as spinal facilitation. This study investigates the effects of systemic local anesthetic on thermal hyperalgesia evoked by chronic nerve compression and on the pain behavior responses to subcutaneous formalin. ⋯ Intravenous lidocaine acts by distinct mechanisms to diminish the hyperesthetic state induced by peripheral nerve injury and to reduce the degree of spinal sensitization induced by C-afferent fiber activation.
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The hemodynamic effects of isoflurane have been studied extensively. However, most data are obtained from volunteers or patients in the absence of surgical stimulation. The hemodynamic responses to various stimulation patterns of different intensity have not been evaluated. ⋯ Isoflurane used as a sole agent is unable to suppress hemodynamic reactions (blood pressure and heart rate) to painful stimuli. A "normal" blood pressure following stimulation can be achieved only if prestimulation blood pressure is depressed to levels that may be clinically unacceptable. The lack of motor response is not an accurate predictor of the ability of an agent to depress hemodynamic reaction.
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Randomized Controlled Trial Comparative Study Clinical Trial
Recovery characteristics of desflurane versus halothane for maintenance of anesthesia in pediatric ambulatory patients.
Desflurane is a new potent, inhaled anesthetic agent with low blood-gas solubility that should allow for the rapid induction of and emergence from anesthesia. However, its extreme pungency makes desflurane unacceptable for induction of anesthesia in children. This study was undertaken to determine the airway properties of desflurane administered by mask after anesthetic induction with halothane and nitrous oxide, and to compare the emergence and recovery properties of minimum alveolar concentration (MAC)-equivalent concentrations of desflurane or halothane in nitrous oxide in pediatric patients undergoing ambulatory surgery. ⋯ In children premedicated with intranasal midazolam, desflurane maintenance anesthesia allows for a faster recovery. However, depending on the institution's criteria for ambulatory surgical patient discharge, desflurane may or may not affect the overall hospitalization time.