Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Recovery profile after desflurane-nitrous oxide versus isoflurane-nitrous oxide in outpatients.
Thirty-eight healthy outpatients undergoing elective surgical procedures lasting 1-3 h were randomly assigned to receive either desflurane 3% (approximately 0.5 MAC) or isoflurane 0.6% (approximately 0.5 MAC) for maintenance of general anesthesia with nitrous oxide 60% in oxygen after a standardized induction sequence consisting of fentanyl 3 micrograms.kg-1, thiopental 4 mg.kg-1, and succinylcholine 1-1.5 mg.kg-1, intravenously. Although anesthetic conditions were similar during operations in the two treatment groups, significant differences were noted in the recovery profiles as measured by elimination kinetics, psychometric testing, and visual analog scales (to assess subjective feelings). The time required for the end-tidal concentration to decrease by 50% was 2.5 +/- 0.8 min for desflurane vs. 9.5 +/- 3.4 min for isoflurane (mean +/- standard deviation [SD]). ⋯ Postoperatively, patients who received desflurane exhibited less impairment of cognitive function (as measured using the Digit-Symbol Substitution Test) than did those who received isoflurane. Furthermore, visual analog scores indicated that patients receiving desflurane experienced significantly less discomfort (pain), drowsiness, fatigue, clumsiness, and confusion in the early postoperative period. We conclude that desflurane may offer clinical advantages over isoflurane when used for maintenance of anesthesia during outpatient surgical procedures.
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Randomized Controlled Trial Comparative Study Clinical Trial
Desflurane and isoflurane in surgical patients: comparison of emergence time.
In order to examine the clinical potential of desflurane (difluoromethyl-1-fluoro-2,2,2-trifluoroethyl ether) in humans, a randomized, controlled study was designed to compare time of emergence from anesthesia in patients undergoing elective surgery under desflurane anesthesia to that of patients under isoflurane anesthesia. Twenty-eight patients were randomly divided into four groups. Group 1 received isoflurane 0.65 MAC; group 2, desflurane 0.65 MAC; group 3, isoflurane 1.25 MAC; and group 4, desflurane 1.25 MAC. ⋯ Patients receiving isoflurane 0.65 MAC responded to commands 15.6 +/- 4.3 min after discontinuation of the anesthetic; patients in the desflurane 0.65 MAC group responded in 8.8 +/- 2.7 min (P less than 0.01). Emergence time for isoflurane 1.25 MAC was 30.0 +/- 11.0 min; for desflurane 1.25 MAC it was 16.1 +/- 6.0 min (P less than 0.05). Our results confirm that emergence from desflurane anesthesia is more rapid than from isoflurane.
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Cardiac morbidity and mortality after coronary artery bypass graft (CABG) surgery continue to be significant problems. To determine the prevalence, characteristics, and prognostic importance of postoperative myocardial ischemia after CABG surgery, the authors monitored 50 patients continuously for 10 perioperative days with the use of two-lead electrocardiography (ECG). ECG changes consistent with ischemia were defined as a reversible ST depression of 1 mm or greater or an elevation of 2 mm or greater from baseline, lasting at least 1 min. ⋯ Five adverse cardiac outcomes occurred on the day of surgery; all five were preceded by postoperative ischemia, three by intraoperative ischemia before bypass, and none by preoperative ischemia. Patients with late postoperative ischemia did not have an adverse cardiac outcome. The authors conclude the following: 1) ischemia is more prevalent postoperatively than preoperatively or intraoperatively before bypass; 2) the incidence of postoperative ischemia peaks shortly after revascularization, during which time it is symptomatically silent, difficult to detect, and related to adverse cardiac outcome; 3) late postoperative ischemia also is silent, but it is less prevalent and not associated with in-hospital adverse cardiac outcome; and 4) a relationship between ischemia and persistently elevated postoperative heart rate may exist and warrants additional investigation.
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Comparative Study
Comparison of the systemic and coronary hemodynamic actions of desflurane, isoflurane, halothane, and enflurane in the chronically instrumented dog.
The systemic and coronary hemodynamic effects of desflurane were compared to those of isoflurane, halothane, and enflurane in chronically instrumented dogs. Since autonomic nervous system function may significantly influence the hemodynamic actions of anesthetics in vivo, a series of experiments also was performed in the presence of pharmacologic blockade of the autonomic nervous system. Eight groups comprising a total of 80 experiments were performed on 10 dogs instrumented for measurement of aortic and left ventricular pressure, the peak rate of increase of left ventricular pressure (dP/dt), subendocardial segment length, coronary blood flow velocity, and cardiac output. ⋯ In summary, at equianesthetic concentrations, desflurane and isoflurane produced similar hemodynamic effects; however, in the absence of drugs that inhibit autonomic reflexes, desflurane had less negative inotropic activity and produced less decrease in arterial pressure. The coronary vasodilator actions of desflurane and isoflurane within the limitations of this model were not similar. When the increase in heart rate and rate-pressure product produced by desflurane were prevented in dogs with autonomic nervous system blockade, desflurane produced no change in coronary blood flow velocity.
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Comparative Study
Percutaneous lumbar sympathectomy: a comparison of radiofrequency denervation versus phenol neurolysis.
A new percutaneous approach to sympathectomy using radiofrequency denervation has seemed to offer longer duration and less incidence of postsympathetic neuralgia as compared to phenol sympathetic blocks. To compare these techniques, 17 patients underwent either phenol lumbar sympathetic blocks (n = 9) or radiofrequency denervation (n = 8). ⋯ Results indicate that 89% of patients in the phenol group showed signs of sympathetic blockade after 8 weeks, as compared to 12% in the radiofrequency group (P less than 0.05). Although the incidence of post sympathetic neuralgia appears to be less with radiofrequency denervation, further refinement of needle placement to ensure complete lesioning of the sympathetic chain will be required before the technique can offer advantages over current phenol techniques.