Der Anaesthesist
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Randomized Controlled Trial Clinical Trial
[The effects of cimetidine on the pharmacodynamics of rocuronium].
Cimetidine is a commonly used H2-receptor antagonist that has been recommended for the prevention of acid aspiration syndrome and has been shown to potentiate vecuronium-induced neuromuscular block. The present study was designed to investigate the influence of a single IV dose of cimetidine on the neuromuscular effects of rocuronium, an analogue of vecuronium with a short onset time. ⋯ The results of the present study demonstrate that cimetidine does not increase the duration of rocuronium neuromuscular blockade. Inhibition of the cytochrome P450 system or a direct effect at the neuromuscular junction have been suggested as the mechanisms of drug interaction associated with cimetidine. Impairment of hepatic microsomal drug metabolism results in a prolonged duration of action of vecuronium, which appears to be eliminated primarily via the liver. Data on the elimination pathway of rocuronium in humans are not available. The fact that cimetidine does not alter the recovery from rocuronium-induced neuromuscular block confirms a previous suggestion that rocuronium may not be eliminated principally by the liver. A direct effect of cimetidine on the neuromuscular junction could not be confirmed by this study. Therefore, cimetidine can be given as premedication without a risk of prolonged rocuronium block.
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Randomized Controlled Trial Clinical Trial
[Movement of the temporomandibular joint during tracheal intubation].
Laryngoscopy causes temporary postoperative dysfunction of the temporomandibular joint (TMJ): during iatrogenic TMJ manipulation in anaesthetised patients, the TMJs have lost the protection afforded by the tone of the surrounding muscles. Thus far, the exact type and extent of TMJ movements have not been known. The purpose of this study was to develop a method to visualise and assess TMJ movements during intubation by means of electronic axiography, a diagnostic monitor of TMJ movements used in dentistry: registration of the hinge axis (HA) as an equivalent of the condylar paths on extra-oral sagittaly mounted, parallel plates. ⋯ MOTs and EITs were recorded and analysed with the system described and typical EIT patterns were identified: bland, clinically uneventful intubations (n = 7), massive distraction and laterotrusion of the EIT compared to the MOT (n = 24), and blocked or limited TMJ movements resulting in intubation problems (n = 1). With the method presented, TMJ movements could be visualised during endotracheal intubation for the first time. It can be used to assess techniques, routes, and instruments for intubation as well as to evaluate potential traumatising movements during endotracheal intubation.
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Randomized Controlled Trial Clinical Trial
[Adaptive lung ventilation (AVL). Evaluation of new closed loop regulated respiration algorithm for operation in the hyperextended lateral position].
The lateral decubitus position is the standard position for nephrectomies. There is a lack of data about the effects of this extreme position upon respiratory mechanics and gas exchange. In 20 patients undergoing surgery in the nephrectomy position, we compared a new closed-loop-controlled ventilation algorithm, adaptive lung ventilation (ALV), which adapts the breathing pattern automatically, to the respiratory mechanics with conventionally controlled mandatory ventilation (CMV). ⋯ However, an adaptation to individual respiratory mechanics was clearly evident with ALV. In conclusion, we found that the effects of positioning for nephrectomy are minor and may give rise to problems only in patients with restrictive lung disease. The novel ALV controller automatically selects ventilatory parameters that are clinically sound and are better adapted to the respiratory mechanics of ventilated patients than the standardized settings of CMV are.
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Randomized Controlled Trial Clinical Trial
[The interaction of nitrous oxide and enflurane on the EEG median of 2-3 Hz is additive, but weaker than at 1.0 MAC].
The aim of this study was to quantify the interaction of enflurane and nitrous oxide at a constant median EEG frequency. ⋯ The interaction of enflurane and nitrous oxide in the dose range from 0 to 75 vol.-% on median EEG frequency is compatible with additivity. The potency of nitrous oxide as a substitute for enflurane is less than might be expected when adding up the MAC values.
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Randomized Controlled Trial Clinical Trial
[Perioperative physiological and cognitive functions following oral premedication with 3.75 mg midazolam in operations with retrobulbar anesthesia].
The number of surgical procedures performed as day surgery has significantly increased in recent years. Therefore, a safe and short postoperative recovery period has become increasingly important. The aim of the present study was to investigate perioperative cognitive and physiological function after oral premedication with low-dose midazolam (3.75 mg), especially during the postoperative period. ⋯ Oral administration of low-dose midazolam (0.049 +/- mg/kg) seems to be appropriate for premedication before ambulatory surgical procedures in elderly patients. In the interest of patient safety, standardised oral premedication with 3.75 mg midazolam may not be sufficient for some of the patients.