Anesthesiology
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Clinical Trial
Effect of a vecuronium-induced partial neuromuscular block on hypoxic ventilatory response.
A previous study has demonstrated a decrease in the hypoxic ventilatory response in volunteers partially paralyzed with vecuronium. However, in this study, hypocapnia was allowed to occur. Because hypocapnia counteracts the ventilatory response to hypoxia during partial vecuronium-induced neuromuscular block and isocapnia, the hypoxic ventilatory response (HVR) was tested in 10 awake volunteers. ⋯ We conclude that a vecuronium-induced partial neuromuscular block impairs HVR more than it does HCVR in humans, suggesting an effect of vecuronium on carotid body hypoxic chemosensitivity.
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The subcutaneous injection of formalin in the rat paw results in several minutes of flinching (phase 1) followed by cessation of activity then resumption of flinching (phase 2), which depends on facilitation of spinal transmission evoked by C-fiber activity generated immediately after the noxious stimulus. It was hypothesized that suppression of dorsal horn activity during and immediately after formalin injection by inhalation anesthetics or intrathecal opiates would block spinal facilitation and inhibit phase 2 flinching, even if the anesthetic or opiate were eliminated before phase 2. ⋯ Isoflurane, even at high concentrations, administered during and shortly after a noxious stimulus produces only a modest reduction in facilitation of afferent processing. The addition of intrathecal morphine during the period of nociceptor activity results in marked attenuation of the facilitated state.
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Randomized Controlled Trial Comparative Study Clinical Trial
The effect of flumazenil on midazolam-induced depression of the ventilatory response to hypoxia during isohypercarbia.
While flumazenil reverses benzodiazepine-induced sedation, its ability to antagonize the ventilatory depressant effects of benzodiazepines has not been fully established. A randomized, double-blind study was conducted to determine whether flumazenil effectively reverses midazolam-induced depression of the hypoxic ventilatory response. ⋯ It was concluded that, after sedation with midazolam, flumazenil causes a greater increase in hypoxic ventilatory response during isohypercarbic conditions than does placebo, and may, therefore, be useful in the treatment of midazolam-induced ventilatory depression.
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The pharmacokinetic and pharmacodynamic properties of propofol indicate that this may be an appropriate agent for induction and maintenance of anesthesia in obese patients. This study was designed to assess the rates of recovery and the pharmacokinetics of propofol infusions in morbidly obese patients. ⋯ Results from this study confirm the absence of propofol accumulation in morbidly obese patients when the current dosing scheme is used. Dosing schemes expressed in mg.kg-1 are the same as those in normal patients.
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Basal cytotoxic activity of NK cells, a subtype of lymphocytes involved in the nonspecific immune response to viruses, tumors, and some bacteria, is altered in the postoperative period. The current study examines the effects of halothane and isoflurane on interferon-induced stimulation of NK cell cytotoxicity in vivo and in vitro. ⋯ Halothane and isoflurane inhibit interferon stimulation of NK cytotoxicity in naive (unstimulated) NK cells of the splenic mononuclear cell pool without affecting the cytotoxicity of previously stimulated (interferon) NK cells. This could occur directly by preventing the NK cell from responding or indirectly by altering other cells in the splenic mononuclear cell pool (T cells, macrophages), which then inhibit NK cell induction.