Anesthesiology
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The authors investigated myocardial epinephrine sensitization by subanesthetic concentrations of halothane. The dose-response relationship for the action of halothane was examined with etomidate plus varying subanesthetic concentrations of halothane in dogs. The arrhythmogenic threshold of epinephrine was decreased in a dose-dependent manner at end-tidal concentrations of halothane between 0.1 and 0.3%. ⋯ The plasma concentrations of epinephrine producing four or more premature ventricular contractions in 15 s were 201.3 +/- 34.3, 98.1 +/- 13.9, 60.3 +/- 8.63, 57.9 +/- 12.8, 54.5 +/- 8.61, and 53.9 +/- 4.86 ng/ml (mean +/- SEM), at 0, 0.1, 0.3, 0.5, 1.0, and 1.5% of halothane at end-tidal concentrations, respectively. The results suggest that in the presence of etomidate, halothane produces myocardial sensitization to epinephrine at subanesthetic concentrations as low as 0.1%. Increasing halothane to 0.3% produces a further reduction in the arrhythmogenic dose of epinephrine.
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Randomized Controlled Trial Clinical Trial
Addition of clonidine enhances postoperative analgesia from epidural morphine: a double-blind study.
This study was undertaken to evaluate the analgesic effect of the combination of epidural morphine and clonidine versus epidural morphine alone in patients with postoperative pain. A randomized double-blind design was used, and 91 patients scheduled for post-operative pain relief by epidural morphine were studied. Patients received either a continuous epidural infusion of morphine and clonidine (group 1; n = 45) or morphine alone (group 2; n = 46) over the 72 h after major abdominal surgery. ⋯ Although the total consumption of analgesics was significantly higher in group 2 (P less than 0.05), pain scores were lower in group 1 than group 2 during the entire observation period (P less than 0.05). Epidural clonidine produced a significant decrease (P less than 0.05) in heart rate and blood pressure, whereas the respiratory rate was not affected. Due to the better pain relief in group 1, the forced vital capacity was increased (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Long-term cognitive and social sequelae of general versus regional anesthesia during arthroplasty in the elderly.
This study compared the effects of general and regional anesthesia on cognitive and psychosocial functioning in elderly persons. Sixty-four patients between 60 and 86 yr of age undergoing knee arthroplasty were randomly assigned to receive either general or regional anesthesia. ⋯ The results indicated that there were no cognitive or psychosocial effects of general or regional anesthesia after 3 months in elderly persons undergoing knee arthroplasty. In this patient population, general anesthesia poses no more risk to long-term mental function than regional anesthesia.