Anaesthesiologie und Reanimation
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Anaesthesiol Reanim · Jan 1995
Comparative Study[Interactions between renal and general hemodynamics in fentanyl, droperidol, ketamine, thiopental and in peridural anesthesia--animal studies].
The main focus of this paper is to show regulative interactions between cardiac index (CI) and renal blood flow (RBF) with various intravenous anaesthetics under steady state conditions. Several experimental series were carried out on dogs with the following anaesthetic doses (as given per hour and per kilogram body weight-h-1 x kg-1): fentanyl 50 micrograms, ketamine 4 and 10 mg, and thiopentone 10 and 20 mg. The basic anaesthesia used was halothane (0.7 vol.%) in N2O/O2 (ratio about 3:1), because renal function, renal autoregulation and responsiveness to renally effective drugs remain nearly unaltered by this anaesthetic procedure. ⋯ The effect of each anaesthetic drug on RBF has principally to be taken as regulative adaptation to altered circulatory conditions. Increasing plasma renin levels are mainly a compensatory reaction following a decline in arterial blood pressure due to anaesthesia induced sympathicolysis. With regard to renal function, the additional use of epidural anaesthesia (functional "denervation" of the kidney) can be recommended especially for highly invasive surgical procedures to antagonize reduction of RBF, which is often induced sympathetically by pain or by commonly used anaesthetic drugs.
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In the present study the disposition of alfentanil after cessation of a constant rate infusion was compared with intravenous bolus injections. In 11 patients undergoing intervertebral disk surgery general anaesthesia was induced with midazolam, alfentanil and vecuronium; anaesthesia was maintained with a constant rate infusion (1.5 to 2 micrograms/kg/min, 1.0 micrograms/kg/min at the end of the infusion period) of alfentanil. The parameters of bolus injections were obtained from 5 patients undergoing lithotripter therapy; an intravenous bolus of 15 micrograms/kg was given. ⋯ There were no significant correlations between the total clearance of alfentanil and the total dose and between the duration of infusion and total clearance. The clinical implications of our study: After prolonged continuous infusions of alfentanil a significant reduction of the elimination rate has to be considered. The patients must be observed very carefully in the recovery room in order to prevent a possible respiratory depression.
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For an exact evaluation of the risks of operations it is necessary to assess both co-existing and concomitant diseases before the performance of anaesthesia. The relatively low incidence of neurological and muscular diseases (0.02 to 0.7/1,000) and the low probability of an operation of a patient suffering from these diseases lead to higher anaesthesiological risks during the operation and the perioperative period. The anaesthetist is usually not always aware of all the special pathophysiological problems which have to be taken into consideration when these patients have to be anaesthetized. In order to reduce the risk of anaesthesia of these patients, we discuss the most important of these uncommon neurological diseases regarding their special anaesthesiological management.
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Anaesthesiol Reanim · Jan 1994
Clinical Trial Controlled Clinical Trial[Mixtures of different local anesthetics for subaxillary plexus anesthesia].
In a prospective clinical study, 76 patients were scheduled for subaxillary plexus block in order to investigate onset time, duration of action and quality of motor and sensitive blockade of various mixtures of local anaesthetics. Sixty-one patients were allocated to four groups. Each of them received 15 ml of bupivacaine 0.5% with either 15 ml of lidocaine 1% (n = 14), of mepivacaine 1% (n = 16), of prilocaine 1% (n = 15) or of etidocaine 1% (n = 15). ⋯ But regarding the quality of motor block, the mixture of bupivacaine and lidocaine was less effective than the other combinations, of which the mixture of bupivacaine and prilocaine showed the best motor block. The combination of the two long-acting local anaesthetics bupivacaine and etidocaine had the longest effect and, therefore, this mixture is a real alternative to subaxillary block via catheter technique. Specific electric stimulation of the radial nerve leads to higher success rate of subaxillary plexus block.
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Anaesthesiol Reanim · Jan 1994
Randomized Controlled Trial Comparative Study Clinical Trial[Mechanomyographic and electromyographic studies of endotracheal intubation with 2 different rocuronium dosages].
Rocuronium is a new, intermediate-acting, nondepolarizing relaxant with rapid onset of action leading to both good and very good intubation conditions. It was the aim of our study to investigate the onset of action, the intubation conditions and the course of relaxation using two different dosage regimes. Thirty consenting ASA 1 and 2 patients received either 0.6 mg/kg (2 x ED 95; group 1) or 0.06 mg/kg as priming dose followed by an intubating dose of 0.24 mg/kg rocuronium (group 2) four min later. ⋯ The clinical duration of action was significantly longer in group 1 (28.4 +/- 8.0 min) than in group 2 (14.8 +/- 2.5 min). It can be concluded that rocuronium which has shorter intubation times than atracurium and vecuronium is very useful for endotracheal intubation in both dosage regimes in long and very long lasting operations. Using the "priming principle" the patient has to be carefully controlled during priming time.