Articles: general-anesthesia.
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Randomized Controlled Trial Clinical Trial
Clonidine decreases postoperative oxygen consumption in patients recovering from general anaesthesia.
Twenty ASA I patients, undergoing thyroid surgery were allocated randomly to receive at the end of surgery either an isotonic saline solution or clonidine 2 micrograms kg-1 i.v. administered over 20 min. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured during recovery in patients breathing spontaneously with a head canopy system. ⋯ The effect of clonidine was associated with a reduction in shivering. Sedative and analgesic properties of clonidine may also contribute to the reduction in metabolic demand during recovery from anaesthesia.
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Randomized Controlled Trial Clinical Trial
Nitrous oxide potentiates vecuronium neuromuscular blockade in humans.
This study was designed to measure the potency of vecuronium with and without nitrous oxide. Anaesthesia was induced with thiopentone and fentanyl in 56 adult patients. The subjects were randomly assigned to receive nitrous oxide, 70%, or intermittent boluses of thiopentone and fentanyl for maintenance of anaesthesia. ⋯ By analysis of covariance, the dose-response curves were shown to be shifted with respect to one another (P less than 0.05). Administration of nitrous oxide was associated with a 19.5% increase in potency (95% confidence limits: 1.7 to 40.4%). It is concluded that nitrous oxide has a slight potentiating effect on neuromuscular blockade, and that this effect occurs within five to ten minutes after the beginning of its administration.
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We present the results of intraoperative monitoring of motor evoked potentials from 34 patients undergoing spinal surgery under total anesthesia with intravenously administered propofol. Intraoperative recording was performed with transcranial electrical stimulation. Two groups of patients were studied: 1) a control population of 26 patients undergoing lumbar discectomy for prolapsed intervertebral disc, all of whom had normal preoperative motor conduction; and 2) a population of 8 patients undergoing neurosurgical procedures for spinal tumor (5 patients) and spinal arteriovenous malformation (3 patients), all of whom had abnormal preoperative neurological signs and abnormal preoperative motor conduction. ⋯ Intraoperative monitoring was successful in 87% of the patients in the pathological group. We observed significant changes in both amplitude (greater than 50%) and/or onset latency (greater than 3 ms) from the intraoperative baseline that indicated either improvement (3 patients) or deterioration (2 patients) in motor conduction within minutes of surgical maneuvers anticipated to alter spinal cord function. Only permanent complete loss of intraoperative motor conduction (1 patient) correlated with a significant change in the postoperative neurological state.(ABSTRACT TRUNCATED AT 250 WORDS)
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Surgery on the shoulder often causes severe pain and, therefore, requires high doses of opiates. As postoperative pain is frequently treated inadequately, it is desirable to seek alternatives for providing effective analgesia. In a prospective study we examined the efficacy of balanced anesthesia consisting of general anesthesia combined with interscalene brachial plexus blockade for intra- and postoperative analgesia for operations on the shoulder. ⋯ CONCLUSION. The combination of ISB and GA allows a reduction in intraoperative doses of opiates and facilitates postoperative pain management. Because of the low incidence of side effects, the lack of complications, and the high degree of patient acceptance, we recommend this type of balanced anesthesia for patients undergoing shoulder surgery.
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In EEG analysis an automatic pattern recognition is of interest. In this paper the usefulness of autoregressive parameters to classify EEG segments recorded during anesthesia is examined. ⋯ The results show that AR parameters have high discriminating power and that the lowest error classification rate (smaller than 3%) is obtained by using quadratic discriminant functions. Consequently autoregressive parameters are efficient for classifying EEG segments into general stages of anesthesia.