Anesthesia and analgesia
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Anesthesia and analgesia · Dec 1994
Randomized Controlled Trial Clinical TrialBalanced postoperative analgesia: effect of intravenous clonidine on blood gases and pharmacokinetics of intravenous fentanyl.
Agonist interactions in antinociceptive effects between clonidine and opioids can be used to reduce opioid requirements in surgical patients. However, clonidine can cause marked sedation and associated respiratory dysfunction. Thus, the benefit of using clonidine to reduce opioid use on respiration is questionable. ⋯ Naloxone was required in six patients and oxygen in two patients of the fentanyl group (versus none in the group receiving clonidine). Dopamine, 10 micrograms.kg-1.min-1, was required in one patient of the clonidine-fentanyl group to correct hypotension. Mean arterial blood pressure, plasma clearance, and the elimination rate constant of fentanyl were lower in the clonidine-fentanyl group than in the fentanyl 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.
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Anesthesia and analgesia · Dec 1994
Comment Letter Randomized Controlled Trial Clinical TrialMivacurium ED95 recalculated.