Canadian journal of anaesthesia = Journal canadien d'anesthésie
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The actions of desflurane, isoflurane and halothane on regional tissue perfusion were studied using radioactive microspheres in dogs chronically instrumented for measurement of arterial and left ventricular pressure, global (left ventricular dP/dtmax) and regional (percent segment shortening) contractile function, and diastolic coronary blood flow velocity. Systemic and coronary haemodynamics and regional tissue perfusion were measured in the conscious state and during anaesthesia with equihypotensive concentrations of desflurane, isoflurane, and halothane. All three volatile anaesthetics (P < 0.05) increased heart rate and decreased mean arterial pressure, left ventricular systolic pressure, and left ventricular dP/dtmax Myocardial perfusion was unchanged in subendocardial midmyocardial, and subepicardial regions by the administration of either dose of desflurane. ⋯ Concomitant decreases in hepatic resistance were observed during administration of desflurane and isoflurane. Dose-related decreases in intestinal and skeletal muscle blood flow were observed during halothane and isoflurane but not desflurane anaesthesia. The results suggest that desflurane maintains myocardial, hepatic, intestinal, and skeletal muscle blood flow while halothane and isoflurane decrease regional tissue perfusion in these vascular beds to varying degrees during systemic hypotension in the chronically instrumented dog.
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The effects of halothane, isoflurane, and enflurane on background neuronal activity and reactive capability in the central nervous system were studied in cats. The background neuronal activity was assessed by midbrain reticular cell firing, which was measured by the method of multi-unit activity, and the EEG in the cortex, amygdala, and hippocampus. The reactive capability was assessed by evoked responses in the visual neuronal pathway. ⋯ These results indicate that all the agents studied had suppressive actions on background neuronal activity in the order halothane < isoflurane = enflurane. The effects on reactive capability were divergent among agents, e.g., enflurane enhanced, halothane suppressed, and the actions of isoflurane were intermediate. We conclude that the anaesthetic effects on background activity and on reactive capability are divergent and that suppression of reactive capability is a factor in determining the ease of clinical application of the anaesthetics.
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Randomized Controlled Trial Clinical Trial
EMLA partially relieves the pain of EMG needling.
The aim of this study was to evaluate the efficacy of the topical analgesic cream EMLA in alleviating the pains caused by needling in electromyography (EMG). During the course of regular neurophysiology clinics, 34 Caucasian patients of both sexes, aged 21 to 69 yr (mean 38.5 +/- 11.4 SD), scheduled for electromyography, were studied. The EMLA was spread thickly on two EMG sites on each arm: E site, on the lateral dorsal aspect of the forearm and A site, on the thenar eminence. ⋯ The untreated E site (placebo) was less sensitive than the untreated A site (VAS = 3.10 +/- 1.75 vs 6.09 +/- 1.96, P = 0.0001). Muscle insertion on E site was less painful on the EMLA sites than placebo (VAS = 2.83 +/- 2.45 vs 5.73 +/- 2.30, P = 0.0001). The VAS scores for skin and muscle insertion on A site were identical whether EMLA or placebo had been applied.(ABSTRACT TRUNCATED AT 250 WORDS)
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Although the surgical advantages of laparoscopic cholecystectomy (LC) have been reported, the anaesthetic problems associated with this new technique have not been well described. For the first 101 patients undergoing laparoscopic cholecystectomy at our institution, we prospectively documented intraoperative critical observations and adverse outcomes in the PACU (Post-Anaesthetic Care Unit). In order to put the magnitude of these problems into perspective, we compared, in an identical manner, the anaesthetic management and outcomes of two more familiar surgical groups, cholecystectomy by laparotomy (C), and laparoscopy for gynaecological examination (LG). ⋯ We have documented considerable postoperative anaesthetic benefits for patients undergoing laparoscopic cholecystectomy compared with conventional cholecystectomy. However, there is still considerable perioperative morbidity compared with gynaecological laparoscopies. Now that specific problems have been identified, they may be amenable to specific anaesthetic interventions.