Articles: general-anesthesia.
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Awareness during anesthesia is as old as anesthesia itself. Using muscle relaxing drugs, operations can be done on a relaxed but fully aware patient. ⋯ This article reviews the subject from some aspects including its causes, signs, tests and medico-legal points. Awareness during anesthesia can be looked at as 'the invisible scars of surgery.'
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Randomized Controlled Trial Clinical Trial
Effect of ketanserin on intraoperative blood loss during total hip arthroplasty in elderly patients under general anaesthesia.
We have studied the effect of ketanserin, a selective serotonin S2-receptor antagonist, on surgical bleeding in a double-blind, placebo-controlled study in elderly patients undergoing total hip arthroplasty. One group of patients (n = 9) received ketanserin 10 mg i.v. followed by an infusion of 0.075 mg kg-1 h-1. The second group (n = 8) received placebo. ⋯ In the ketanserin group, mean arterial pressures tended to be less than in the placebo group. Reductions in central venous pressure were similar in both groups. There were no complications in relation to the use of ketanserin.
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Randomized Controlled Trial Comparative Study Clinical Trial
The haemodynamic effects of bronchoscopy. Comparison of propofol and thiopentone with and without alfentanil pretreatment.
The haemodynamic response to bronchoscopy under general anaesthesia was investigated. Forty patients were allocated at random to receive either thiopentone or propofol; half the patients in each group received in addition 18 micrograms/kg of alfentanil one minute before induction of anaesthesia. The heart rate, noninvasive blood pressure and Holter ECG was monitored in all patients. ⋯ No significant haemodynamic changes were seen in either of the groups which received propofol. ST segment changes on subsequent Holter analysis were seen in four patients, but there were no significant differences between the groups. Anaesthesia with propofol alone provides adequate haemodynamic stability for bronchoscopy and the addition is superfluous.
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Randomized Controlled Trial Comparative Study Clinical Trial
[Acoustic evoked potentials of medium latency and intraoperative wakefulness during anesthesia maintenance using propofol, isoflurane and flunitrazepam/fentanyl].
Auditory evoked potentials have been used as an indicator of awareness. During combined local and general anesthesia clinical signs of adequate anesthesia are difficult to evaluate. In the present study we combined peridural analgesia with three techniques of general anesthesia. ⋯ CONCLUSIONS. The maintenance of MLAEP and the primary cortical complex Na/Pa correlates with the incidence of motor signs of wakefulness. During the combination of regional and general anesthesia, isoflurane and propofol seem to provide better suppression of intraoperative wakefulness than bolus injections of flunitrazepam/fentanyl.
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To evaluate the possible interaction between clonidine and ephedrine, the authors studied hemodynamic responses to intravenous ephedrine in 80 patients who received either clonidine pre-anesthetic medication of approximately 5 micrograms.kg-1 orally (n = 40) or no medication (n = 40). The patients were studied while they were either awake (n = 40) or anesthetized with enflurane and nitrous oxide in oxygen (n = 40). ⋯ The enhanced pressor responses to ephedrine observed in both awake and anesthetized patients in the presence of clonidine may be attributed to increased catecholamine storage at sympathetic nerve endings due to clonidine, enhanced sensitivity of tissue receptors to which ephedrine binds, potentiation of alpha-adrenoceptor mediated vasoconstriction of both agents, or all of these. It is concluded that oral clonidine preanesthetic medication of 5 micrograms.kg-1 does augment rather than attenuate the pressor responses to intravenous ephedrine in patients both prior to and during general anesthesia.