Anesthesiology
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Randomized Controlled Trial Clinical Trial
Prophylactic atenolol reduces postoperative myocardial ischemia. McSPI Research Group.
Perioperative myocardial ischemia occurs in 20-40% of patients at risk for cardiac complications and is associated with a ninefold increase in risk for perioperative cardiac death, myocardial infarction, or unstable angina, and a twofold long-term risk. Perioperative atenolol administration reduces the risk of death for as long as 2 yr after surgery. This randomized, placebo-controlled, double-blinded trial tested the hypothesis that perioperative atenolol administration reduces the incidence and severity of perioperative myocardial ischemia, potentially explaining the observed reduction in the risk for death. ⋯ Perioperative administration of atenolol for 1 week to patients at high risk for coronary artery disease significantly reduces the incidence of postoperative myocardial ischemia. Reductions in perioperative myocardial ischemia are associated with reductions in the risk for death at 2 yr.
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Randomized Controlled Trial Clinical Trial
Psychedelic effects of ketamine in healthy volunteers: relationship to steady-state plasma concentrations.
Ketamine has been associated with a unique spectrum of subjective "psychedelic" effects in patients emerging from anesthesia. This study quantified these effects of ketamine and related them to steady-state plasma concentrations. ⋯ Subanesthetic doses of ketamine produce psychedelic effects in healthy volunteers. The relation between steady-state venous plasma ketamine concentrations and effects is highly linear between 50 and 200 ng/ml.
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Randomized Controlled Trial Clinical Trial
Bispectral analysis of the electroencephalogram predicts conscious processing of information during propofol sedation and hypnosis.
The bispectral index (BIS) measures changes in the interfrequency coupling of the electroencephalogram (EEG). The purposes of this study were (1) to determine whether BIS correlates with responses to command during sedation and hypnosis induced by propofol or propofol and nitrous oxide, and (2) to compare BIS to targeted and measured concentrations of propofol in predicting participants' responses to commands. ⋯ Bispectral index accurately predicts response to verbal commands during sedation and hypnosis with propofol or propofol plus nitrous oxide. Accuracy is maintained in situations likely to be encountered during clinical use: when propofol concentrations are increasing or decreasing and when repeated measurements are made over time.
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Randomized Controlled Trial Clinical Trial
Low-dose ondansetron with dexamethasone more effectively decreases vomiting after strabismus surgery in children than does high-dose ondansetron.
Ondansetron and dexamethasone have been observed to decrease the incidence of vomiting by children after general anesthesia. This study compared the effect of high-dose (150 microg/kg) ondansetron with low-dose (50 microg/kg) ondansetron plus 150 microg/kg dexamethasone on the incidence of vomiting after strabismus in children. ⋯ Low-dose ondansetron plus dexamethasone is an effective prophylactic antiemetic combination for children undergoing strabismus surgery.
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Randomized Controlled Trial Clinical Trial
Physostigmine prevents postanesthetic shivering as does meperidine or clonidine.
Postanesthetic shivering develops in as many as one half of patients recovering from isoflurane anesthesia. Cholinergic stimulation of the hypothalamic-pituitary-adrenal axis and adrenal medulla by physostigmine enhances secretion of arginine vasopressin, epinephrine, and norepinephrine. Because the hypothalamus is the dominant thermoregulatory controller in mammals, and these neurotransmitters may be involved in body temperature control, physostigmine administration may influence the incidence of shivering. Accordingly, the authors tested the hypothesis that physostigmine administration inhibits postanesthetic shivering. Its efficacy was compared with that of saline (negative control) and meperidine and clonidine (positive controls). ⋯ Physostigmine inhibited shivering as well as did two established treatments, meperidine and clonidine. These data suggest that cholinergic systems contribute to the genesis and control of postanesthetic shivering.