Articles: general-anesthesia.
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We have used Median Power Frequency (MPF) to study changes in the electroencephalogram during propofol infusions in 52 women about to undergo gynaecological surgery. Patients were allocated to receive propofol by one of nine different manually-controlled infusion schemes designed to achieve and maintain a stable blood propofol concentration between 1.0 and 6.0 micrograms ml-1, covering a range of states between conscious sedation and full anaesthesia. We recorded the changes in MPF and the response to clinical signs of loss of consciousness at these different doses and concentrations of propofol. ⋯ The EC50 for loss of consciousness was a propofol concentration of 2.3 (1.8-2.7) micrograms ml-1 and for 50% suppression of MPF was 3.1 (2.7-3.5) micrograms ml-1. The dose required for 50% suppression of MPF was 7.1 (6.2-8.0) mg kg-1 h-1. After 30 min, at blood propofol concentrations > 4.0 micrograms ml-1, consistent with stable anaesthesia, the mean MPF was 5.6 (4.5-6.3) Hz.
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Rev Esp Anestesiol Reanim · Jan 1994
Randomized Controlled Trial Comparative Study Clinical Trial[Effects on the newborn infant of thiopental and propofol used in anesthetic induction in cesarean section].
To compare the effects of an anesthetic induction dose of thiopental to that of propofol on the vitality of the neonate, as measured by Apgar score and the interval between extraction of the newborn and unassisted respiration. ⋯ If the induction-extraction interval is 10 min or less, both thiopental (4 mg/kg) and propofol (2 mg/kg) given in a single dose for induction of general anesthesia in all types of cesarean section are equally safe for the newborn infant.
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Anaesthesiol Reanim · Jan 1994
Comparative StudyA comparison of the accuracy of the Siemens injection vaporizer and the Enfluratec 3 vaporizer.
The accuracy of two Siemens injection vaporizers was examined under operating theatre conditions. For comparison, two Enfluratec 3 vaporizers were tested. The concentrations of enflurane produced by the vaporizers were measured both by an anaesthetic agent monitor and by chromatography. ⋯ The former vaporizers seem to be less robust than the Enfluratecs and should be used according to the manufacturer's recommendations. The pressures in the central system were higher than those called for. In addition, improper coupling of the Siemens apparatus to the ventilator may well have influenced the results.
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Flow-volume loops were monitored continuously in 39 patients undergoing thoracic surgery requiring one-lung ventilation. In 26 of the 39 patients (67%), auto-positive end-expiratory pressure (auto-PEEP) was seen on the flow-volume curves during both two-lung and one-lung ventilation. Eighty-seven percent of the patients whose trachea was intubated with a smaller size (35- and 37-French gauge) double-lumen tracheal tube exhibited auto-PEEP, compared with patients in whom the tube used was larger (39- or 41-French gauge: 54% and 50%, respectively). Before operation, mean airway resistance was significantly greater in patients who exhibited auto-PEEP during anaesthesia (2.4 cm H2O litre-1 s) than in patients without auto-PEEP (1.7 cm H2O litre-1 s).
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Anesthesia and analgesia · Jan 1994
Comparative StudyCombined epidural analgesia and general anesthesia induce ischemia distal to a severe coronary artery stenosis in swine.
Epidural analgesia combined with general anesthesia may improve cardiac function and reduce the work of the heart by decreasing the rate pressure product. However, the effect of this combined technique has not been studied in the presence of severe coronary artery stenosis. Therefore, we investigated epidural analgesia combined with general anesthesia in a swine model with a tight coronary artery stenosis. ⋯ Myocardial wall thickening in the LAD bed decreased 31%, although it remained unchanged in the normal myocardium. Epidural bupivacaine added to general anesthesia resulted in moderate hypotension. Distal to the coronary stenosis was a moderate decrease in regional myocardial function and a severe reduction in blood flow.