Journal of anesthesia
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Journal of anesthesia · Sep 1994
Effects of dobutamine on the fatigued diaphragm: A comparison with dopamine.
We examined the effects of dopamine (DOA) 10 μg·kg(-1)·min(-1) I. V. and dobutamine (DOB) 10 μg·kg(-1). min(-1) I. V. on the contractility of the fatigued diaphragm in 26 anesthetized, mechanically ventilated dogs. ⋯ In each group, Pdi at both stimuli decreased after the cessation of administration. The integrated diaphragmatic electric activity (Edi) in the two groups did not change at any frequency of stimulation throughout the study. We conclude that DOB in comparison with DOA is more effective in improving the contractility of the fatigued diaphragm.
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Journal of anesthesia · Sep 1994
Differential effects of halothane and enflurane on end-systolic pressure-diameter relationship in anesthetized, mechanically ventilated dogs.
To clarify the difference of negative inotropic effects, we evaluated the effects of 0, 0.5, and 1 MAC halothane and enflurane on systolic performance in anesthetized, mechanically ventilated, vagotomized dogs. Left ventricular myocardial contractility was assessed by the slope of the end-systolic pressure-diameter relationship (EES), which have been reported to be independent of alterations in preload and afterload but sensitive to changes in myocardial contractility. Both anesthetics decreased heart rate and dose-dependently decreased left ventricular systolic pressure. ⋯ TheEES was decreased with increasing concentrations of enflurane. TheEES was significantly larger (P<0.05) with 1 MAC of halothane than with 1 MAC enflurane. These results suggest that halothane preserves myocardial contractility better than enflurane in the presence of fentanyl.
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Journal of anesthesia · Sep 1994
Nitrous oxide does not depress left ventricular contractility in ischemic rat heart.
The direct effects of nitrous oxide on left ventricular contractility and myocardial oxygen consumption (MVO2) in the ischemic isolated rat heart were studied. The rat heart was isolated and perfused by a Langendorf technique. The aortic stump was cannulated and the heart was perfused with Kumpeis solution bubbled with 95% O2 and 5% CO2 (control phase). ⋯ After 15 min of ischemic phase, the perfusion pressure was increased and the gas mixture was changed to the standard gas mixture (reperfusion phase). Nitrous oxide did not further depress myocardial contractility compared with nitrogen in the ischemic phase, and did not alter MVO2 in the ischemic phase compared with nitrogen. Halothane significantly depressed myocardial contractility and decreased MVO2 in the ischemic phase compared with the control.