Anesthesiology
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Comparative Study
In vivo imaging of nitrous oxide-induced changes in cerebral activation during noxious heat stimuli.
Although previous studies have provided some insight into the pharmacologic aspects of nitrous oxide analgesia, the neural circuits mediating its antinociceptive effect remain relatively unexplored. Position emission tomography was used in nine volunteers to identify the loci of nitrous oxide-modulated cerebral responses to a peripheral noxious stimulus. ⋯ Nitrous oxide, at 20% concentration, appears to modulate pain processing in the brain's medial pain system, and also activates the infralimbic and orbitofrontal cortices. The potential contribution of the affected brain areas to nitrous oxide analgesia is discussed.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Comparison of remifentanil and fentanyl in patients undergoing craniotomy for supratentorial space-occupying lesions.
Remifentanil hydrochloride is an ultra-short-acting, esterase-metabolized mu-opioid receptor agonist. This study compared the use of remifentanil or fentanyl during elective supratentorial craniotomy for space-occupying lesions. ⋯ Remifentanil appears to be a reasonable alternative to fentanyl during elective supratentorial craniotomy.
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Randomized Controlled Trial Clinical Trial
Addition of epinephrine to intrathecal bupivacaine and sufentanil for ambulatory labor analgesia.
The intrathecal combination of sufentanil and bupivacaine provides rapid, effective analgesia for labor with a limited duration. Many anesthesiologists have concerns that the use of intrathecal local anesthetics precludes maternal ambulation. This prospective, randomized, double-blind study was designed to determine whether the addition of epinephrine to the combination of sufentanil and bupivacaine would prolong intrathecal analgesia for labor. Patients' ability to ambulate was also assessed. ⋯ The addition of 0.2 mg epinephrine to the intrathecal combination of sufentanil and bupivacaine significantly prolonged labor analgesia without causing adverse effects to the mother or fetus. The intrathecal combination of sufentanil and bupivacaine, with or without epinephrine, provided rapid, profound labor analgesia and allowed most patients to ambulate.
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Comparative Study Clinical Trial
Recovery of consciousness after thiopental or propofol. Bispectral index and isolated forearm technique.
Currently, there exists no effective monitor that can predict the probability of a patient being conscious during general anesthesia. The electroencephalogram-derived bispectral index (BIS) is a promising new method to assess anesthetic adequacy. This study used the BIS to predict the probability of recovery of consciousness after a single bolus induction dose of propofol or thiopental. ⋯ The BIS can be used to predict probability of recovery of consciousness after a single injection of either thiopental or propofol.
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Various systems to administer inhaled nitric oxide (NO) have been used in patients and experimental animals. We used a lung model to evaluate five NO delivery systems during mechanical ventilation with various ventilatory patterns. ⋯ NO delivery systems that inject NO at a constant rate, either continuously or during inspiration only, into the inspiratory limb of the ventilator circuit produce highly variable and unpredictable NO delivery when inspiratory flow is not constant. Such systems may deliver a very high NO concentration to the lungs, which is not accurately reflected by measurements performed with slow-response analyzers.