RESUMEN
The authors studied the effects of pancuronium, 14--200 micrograms/kg, on epinephrine-induced arrhythmias (premature ventricular contractions) in dogs anesthetized with halothane, 1.4 MAC. Neither muscle relaxant significantly affected the arrhythmogenic dose of epinephrine. This finding indicates that the usual guidelines for the administration of epinephrine during halothane anesthesia are not affected by concomitant administration of the two nondepolarizing muscle relaxants studied.
Asunto(s)
Arritmias Cardíacas/inducido químicamente , Epinefrina/efectos adversos , Halotano , Pancuronio/farmacología , Tubocurarina/farmacología , Anestesia General/métodos , Animales , Presión Sanguínea/efectos de los fármacos , Perros , Relación Dosis-Respuesta a Droga , Frecuencia Cardíaca/efectos de los fármacos , MasculinoRESUMEN
Arrhythmogenic doses of epinephrine were determined in six mongrel dogs anesthetized at 1.4 MAC halothane initially in the absence of local anesthetics and then at increasing arterial plasma levels of lidocaine, bupivacaine, and etidocaine. The authors gave epinephrine intravenously at 5 microgram/kg/min and calculated the arrhythmogenic dose as a function of time until two or more premature ventricular contractions occurred within a 10-sec period. The control arrythmogenic dose of epinephrine was 4.66 +/- 0.46 microgram/kg (mean +/- SEM). Arrythmogenic doses of epinephrine were increased significantly after each dose of lidocaine, bupivacaine, and etidocaine. With the largest doses studied, local anesthetic plasma levels were frequently in the toxic range. The data show that lidocaine, bupivacaine, and etidocaine equally protect against epinephrine-induced arrhythmias in dogs anesthetized with halothane.
Asunto(s)
Acetanilidas/uso terapéutico , Anestesia por Inhalación , Arritmias Cardíacas/prevención & control , Bupivacaína/uso terapéutico , Etidocaína/uso terapéutico , Halotano , Lidocaína/uso terapéutico , Animales , Arritmias Cardíacas/inducido químicamente , Bupivacaína/sangre , Perros , Epinefrina , Etidocaína/sangre , Lidocaína/sangreRESUMEN
The minimum alveolar concentration (MAC) of aliflurane was measured in ten dogs. A value of 1.84 volumes per cent was determined, which correlates well with predictions based on lipid solubility. Induction of anesthesia and recovery were rapid, as would be anticipated with an agent of relatively low solubility in blood (blood-gas partition coefficient = 1.7). Circulatory responses over a relatively narrow range of aliflurane concentrations (0.8 to 1.4 MAC) remained stable, but the development of tachypnea, irregular ventilatory patterns, and increased muscle tone were frequently encountered during aliflurane anesthesis.