Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1995
Clinical Trial Controlled Clinical TrialA pharmacokinetic and pharmacodynamic evaluation of milrinone in adults undergoing cardiac surgery.
Milrinone can reverse acute postischemic myocardial dysfunction after cardiopulmonary bypass, although neither the appropriate bolus dose nor its pharmacokinetics has been established for cardiac surgical patients. Consenting patients undergoing cardiac surgery received milrinone (25, 50, or 75 micrograms/kg) in an open-label, dose-escalating study if their cardiac index was < 3 L.min-1.m-2 after separation from bypass. Heart rate, mean arterial blood pressure, pulmonary capillary wedge pressure, and cardiac index were determined before and after the administration of milrinone. ⋯ Similarly, the following clearances were estimated for the three compartments: Cl1 = 0.067 L/min, Cl2 = 1.05 L/min, and Cl3 = 0.31 L/min. The 50-micrograms/kg loading dose appeared more potent than the 25-micrograms/kg dose, and, as potent, but with possibly fewer side-effects than the 75-micrograms/kg dose. The short context-sensitive half-times of 6.7 or 10.2 min after 1- or 10-min bolus infusions underscore the need for prompt institution of a maintenance infusion when milrinone concentrations must be maintained.(ABSTRACT TRUNCATED AT 400 WORDS)
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Anesthesia and analgesia · Oct 1995
Comparative StudyComparison of isoflurane and desflurane anesthetic depth using burst suppression of the electroencephalogram in neurosurgical patients.
We compared the anesthetic effects of desflurane and isoflurane using percent burst suppression of the electroencephalogram (EEG) as an end-point in 10 neurosurgical patients. The EEG was recorded from frontal leads and processed variables were analyzed as a function of increasing isoflurane and desflurane concentration with age and baseline delta EEG power (0.5-3.75 Hz) as independent variables. Isoflurane and desflurane (0.5, 1.0, 1.5, 2.0 minimum alveolar anesthetic concentration [MAC]) were incrementally administered until the EEG was quiesecent at least 40% of the time. ⋯ Patients with baseline delta EEG power > 80% of total power produced no change in EEG frequency with increasing anesthesia but revealed a greater sensitivity to the development of burst suppression. These results show that isoflurane and desflurane produce similar EEG suppression in neurosurgical patients. If the EEG is initially slow, further slowing cannot be used to assess anesthetic depth.
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Anesthesia and analgesia · Oct 1995
The effect of midazolam on left ventricular pump performance and contractility in anesthetized patients with coronary artery disease: effect of preoperative ejection fraction.
Forty patients undergoing coronary artery bypass grafting were studied, of whom 24 had depressed global left ventricular (LV) function at preoperative catheterization, to evaluate the effects of midazolam on LV pump performance and contractility. Transesophageal echocardiography and simultaneous hemodynamic measurements were used to assess LV preload, afterload, and systolic performance during inhalation of 100% O2 and after 0.1 mg/kg of midazolam. Systolic function indices were expressed as a percent of the predicted value for observed end-systolic stress to estimate LV contractility. ⋯ As a result, systolic function decreased in relation to observed end-systolic stress, providing evidence of reduced LV contractility. Thus, midazolam administration (0.1 mg/kg) caused no change in cardiac pump performance but decreased LV contractility in the entire population. Myocardial contractility was lower at baseline and after the administration of midazolam in the depressed ejection fraction group, but the decrease in contractility was not exaggerated in the depressed ejection fraction group.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Oct 1995
Randomized Controlled Trial Multicenter Study Clinical TrialIntravenous regional guanethidine in the treatment of reflex sympathetic dystrophy/causalgia: a randomized, double-blind study. Guanethidine Study Group.
This double-blind, randomized, multicenter study was designed to determine the short-term and long-term efficacy of intravenous regional block with guanethidine in patients with reflex sympathetic dystrophy (RSD)/causalgia. Sixty patients were enrolled to receive four intravenous regional blocks at 4-day intervals with either guanethidine or placebo in 0.5% lidocaine. Each patient was randomized to receive either one, two, or four blocks with guanethidine. ⋯ At 4 days after the initial block, the group treated with placebo experienced a greater decrease in pain scores than those treated with guanethidine, although this difference was not statistically significant. On long-term followup there was no difference in pain scores between groups receiving one, two, or four guanethidine blocks. Overall, only 35% of patients experienced clinically significant relief on long-term followup even though all were treated early in the evolution of RSD.
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Anesthesia and analgesia · Oct 1995
Randomized Controlled Trial Comparative Study Clinical TrialSevoflurane for outpatient anesthesia: a comparison with propofol.
Three different anesthetic techniques were compared in 146 healthy outpatients undergoing ambulatory surgery. In Groups I and II, anesthesia was induced with propofol (1.5-2.0 mg/kg, intravenously [iv]) and maintained with nitrous oxide (N2O) 60% in oxygen and either a propofol infusion, 75-160 micrograms.kg-1.min-1 IV, or sevoflurane, 1%-2% end-tidal, respectively. In Group III, anesthesia was induced and maintained with sevoflurane, 1%-4% end-tidal and N2O 60% in oxygen. ⋯ The use of sevoflurane for induction and/or maintenance of anesthesia was associated with a higher incidence of postoperative emetic sequelae compared with propofol. Finally, the times at which patients were considered "fit for discharge" and the actual discharge times were similar in all three groups. Sevoflurane is an acceptable alternative to propofol for induction and maintenance of outpatient anesthesia.