Der Anaesthesist
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Although the local anaesthetic prilocaine is less cardio- and neurotoxic than lidocaine, it bears the disadvantage of the formation of methaemoglobin by the metabolite o-toluidine. Prilocaine is often successfully used, especially for the blockade of the brachial plexus, but one problem of this technique is the failure rate of 3-10%, with the consequence that general anaesthesia after administration of prilocaine is frequently necessary. Methaemoglobin formation after prilocaine administration has been thoroughly investigated. ⋯ Three explanations seem plausible: (1) Thiopental blocks the hydroxylase of the endoplasmic reticulum, with the result that o-toluidine cannot be further metabolised, leading to higher o-toluidine and methaemoglobin levels. (2) Isoflurane improves the blood supply of the liver. This results in increased metabolism of prilocaine to o-toluidine. (3) The results were accidental. To clarify which of these explanations is correct, further investigation is necessary.
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Clinical Trial
[Continuous breath alcohol analysis. Monitoring of irrigation absorption syndrome in transurethral prostate resection].
The absorption of large volumes of irrigation fluid is a major problem in transurethral prostatic surgery (TUR-P). Various indicators have been tested to monitor fluid absorption with regard to continuous registration and sufficient accuracy. The volumetric fluid balance is not suitable as a routine method because of its inaccuracy. ⋯ As shown in other studies, serum Na (r2 = 0.68) and Hct (r2 = 0.39) correlated poorly with the irrigation fluid as determined by serum alcohol levels. In contrast, the expiratory alcohol measurements with the Alcotest 7110 (r2 = 0.93) and Normac devices (r2 = 0.85) were closely related. Continuous monitoring of the expiratory alcohol concentration with a Normac monitor closely reflects blood alcohol concentration, and may hence serve as a useful semiquantitative monitor of irrigation fluid absorption during TUR-P.
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Randomized Controlled Trial Comparative Study Clinical Trial Controlled Clinical Trial
[Propofol-alfentanil reduced cerebrovascular CO2 reactivity in comparison with isoflurane].
The present study compared the effects of propofol/alfentanil versus isoflurane anaesthesia on cerebral vascular reactivity to changes in carbon dioxide (CO2) using transcranial Doppler sonography (TCD). METHODS. Seventeen ASA class I patients undergoing minor elective surgery were studied following IRB approval and informed consent. ⋯ The data show that although CO2 reactivity is maintained during both isoflurane and propofol/alfentanil anaesthesia, the cerebral vascular response to CO2 was lower in propofol/alfentanil compared to isoflurane patients. This is likely due to propofol/alfentanil-induced cerebral vasoconstriction. These data suggest that CO2 reactivity is a function of the pre-existing cerebral vascular tone induced by the anaesthetic.
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Randomized Controlled Trial Comparative Study Clinical Trial
[Continuous monitoring of critical patients with a newly developed pulmonary arterial catheter. A cost analysis].
The introduction of flow-directed pulmonary artery (PA) catheters has helped to improve our knowledge of cardiovascular physiology. There have been several developments of this equipment in recent years, including continuous monitoring of mixed-venous O2 saturation (SvO2) and cardiac output (CO). The high purchase price, however, is an obstacle to its use in the critically ill. ⋯ Costs for laboratory analyses can blunt the advantage of lower costs for the standard PA catheter. Intermittent (standard) monitoring of SvO2 and CO was significantly more time-consuming than the continuous methods. It can be summarised that although purchase costs for the more advanced PA catheters are higher than for standard PA catheters, the use of these continuous monitoring devices in the critically ill can be justified from a financial point of view.