Anesthesia and analgesia
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Anesthesia and analgesia · Dec 1994
Comment Letter Case ReportsSpinal anesthesia after failed epidural anesthesia.
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Anesthesia and analgesia · Dec 1994
Randomized Controlled Trial Clinical TrialThoracic epidural anesthesia during coronary artery bypass surgery: effects on cardiac sympathetic activity, myocardial blood flow and metabolism, and central hemodynamics.
The effects of high thoracic epidural anesthesia (TEA) on cardiac sympathetic nerve activity, myocardial blood flow and metabolism, and central hemodynamics were studied in 20 patients undergoing coronary artery bypass grafting (CABG). In 10 of the patients, TEA (T1-5 block) was used as an adjunct to a standardized fentanyl-nitrous oxide anesthesia. Hemodynamic measurements and blood sampling were performed after induction of anesthesia but prior to skin incision and after sternotomy. ⋯ None of the patients in the TEA group had metabolic (lactate) or electrocardiographic signs of myocardial ischemia. Three patients in the control group had indices of myocardial ischemia prior to and/or during surgery. We conclude that TEA attenuates the surgically mediated sympathetic stress response to sternotomy, thereby preventing the increase in myocardial oxygen demand in the pre-bypass period without jeopardizing myocardial perfusion.
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Anesthesia and analgesia · Dec 1994
Randomized Controlled Trial Comparative Study Clinical TrialEffects of enoximone and R 80122, a new selective phosphodiesterase III inhibitor, on hemodynamics and myocardial energetics in patients with ischemic heart disease.
The present study was designed to compare the effects of enoximone and R 80122, a highly selective phosphodiesterase (PDE) III inhibitor, on left ventricular hemodynamics and myocardial blood flow and metabolism in patients with coronary artery disease. Twenty male, anesthetized patients, ASA physical status III, were studied before they underwent coronary artery bypass grafting (CABG) surgery. They were allocated randomly to receive either 0.3 mg/kg R 80122 (Group 1) or 1 mg/kg enoximone (Group 2) intravenously (IV). ⋯ There were increases in heart rate (HR) by 10% and 19%, respectively, and in contractility (dp/dtmax) by 18% and 38%, respectively. Coronary perfusion pressure (CPP) decreased by 23% and 22%, respectively, and coronary vascular resistance (CVR) by 38% and 21%, respectively. Myocardial blood flow (MBF) and myocardial oxygen uptake (MVO2) increased in both groups, the increase in MBF being statistically significant (+34%) only in Group 1, whereas the changes in myocardial metabolism were not significant in either group.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Dec 1994
Comparative StudyEffect of intracoronary infusions of amrinone and dobutamine on segment shortening, blood flow, and oxygen consumption in in situ canine hearts.
Previous in vivo studies assessing the effects of amrinone on myocardial contractility used intravenous infusions, and thus were complicated by varying cardiac loading conditions. Accordingly, the present study was performed in 15 open-chest, anesthetized (fentanyl and midazolam) dogs using infusions of amrinone and dobutamine directly into the left anterior descending artery (LAD). In the LAD bed, percentage of segment shortening (%SS), an index of local myocardial contractility, was assessed with ultrasonic crystals. ⋯ Amrinone and dobutamine caused individually increases in %SS that were comparable (range, 20%-45%). Myocardial oxygen consumption increased in parallel with %SS for both amrinone and dobutamine. For amrinone, coronary blood flow increased more than myocardial oxygen consumption, resulting in a modest (at highest dose approximately 10%) decrease in oxygen extraction; whereas for dobutamine, coronary blood flow increased in proportion to myocardial oxygen consumption, resulting in no change in oxygen extraction.(ABSTRACT TRUNCATED AT 250 WORDS)
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The scalp electroencephalogram (EEG), the long latency cognitive P300 auditory evoked response (AER), and reaction times were recorded in 10 volunteers sedated with a computer-controlled infusion of propofol to target plasma concentrations of 0.3, 0.6, 0.9, and 1.2 micrograms/mL. The observed mean +/- SE venous plasma concentrations were 0.152 +/- 0.042, 0.372 +/- 0.078, 0.679 +/- 0.104, and 1.065 +/- 0.112 micrograms/mL, respectively. Scalp EEG topographic mapping revealed that beta 1 activation was primarily frontal and central with relative sparing of the temporal lobes. ⋯ Mean +/- SE reaction times were increased by propofol sedation from 347 +/- 35 ms (control) to 391 +/- 48, 460 +/- 70, 549 +/- 64, and 622 +/- 120 ms at increasing mean venous plasma propofol concentrations. The mean percentage +/- SE of correct responses decreased from 98.1 +/- 2.0 (control) to 99.1 +/- 1.7, 87.4 +/- 9.2, 82.8 +/- 12.9, and 69.8 +/- 20.9 at increasing propofol concentrations. Dramatic alterations in the EEG, P300 response, and reaction times were observed, especially with the higher plasma concentrations which produced conscious sedation.