Der Anaesthesist
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Several methods have been developed to quantify central anaesthetic effects and monitor awareness during general anaesthesia. The most important of these are the PRST score, calculated from changes in blood pressure, heart rate, sweating, and tear production, the isolated forearm technique, where the patient is allowed to move during surgery, the processed electroencephalogram (EEG) and the derived parameters median frequency (MF) and spectral-edge frequency (SEF), and mid-latency auditory evoked potentials (MLAEP). In clinical practice, the application of individual doses of anaesthetics is generally guided by autonomic vegetative clinical signs such as changes in blood pressure, heart rate, sweating, and tear production, quantified as the PRST score. ⋯ MLAEP are suppressed in a dose-dependent fashion by many general anaesthetics and correlate with wakefulness, awareness, and explicit and implicit memory during anaesthesia and seem to be a promising method of monitoring awareness during anaesthesia. Nevertheless, future studies will have to determine threshold values for the different MLAEP parameters for intraoperative awareness and explicit and implicit recall of intraoperatively presented information for the different commonly used anaesthetics. Only then will it be possible to determine the usefulness of the method in clinical practice.
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Clinical Trial
[Preclinical blood gas analysis. Technical description--initial experiences--indications].
A new portable device for blood gas analyses (BGA) has been examined for prehospital application. ⋯ One advantage of BGA over the non-invasive methods pulse oximetry and capnography is that it does not interfere with factors like peripheral vasoconstriction or inequality of the pulmonary ventilation/ perfusion ratio. Moreover, it is the only method for controlled buffering of acid-base disturbances. This means more security in diagnostics and therapeutical interventions for the patient in danger of dying. The device has proved to be a useful addition to the monitoring methods for prehospital application.
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Erythropoietin, the hematopoietic growth factor, is synthesised in the kidneys and liver and regulates red blood cell production. Within the last few years, recombinant DNA technology has produced synthetic erythropoietin (rhEPO). Some patients, especially Jehovah's Witnesses, will not accept blood transfusion. The perioperative administration of rhEPO increases the patients' hematocrit (HCt) to a higher than physiological level. ⋯ The case report describes perioperative management using human rhEPO in Jehovah's Witnesses. Treatment with rhEPO increases preoperative Hb levels to a point making it possible to compensate for operative blood loss. RhEPO combined with daily iron substitution may be useful in patients who refuse transfusion based on religious convictions.
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Three cases are presented dealing with rare lethal complications during the insertion of pulmonary artery catheters (PAC). Complications resulting from catheter insertion have been reported on numerous occasions; we report further examples of inadequate insertion techniques. ⋯ Based on our observations, we believe the low complication rate associated with PAC insertion has led to deviations from the normal guidelines by some physicians. Despite adequate precautions and insertion technique, iatrogenic lesions cannot be avoided in all cases because of pre-existing risk factors. For the evaluation of catheter-induced complications and the development of a risk profile, more autopsies as well as more detailed clinical documentation would be necessary.