Der Anaesthesist
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Randomized Controlled Trial Comparative Study Clinical Trial
[Combined 3-in-1 sciatic block. Prilocaine 500 mg vs. 650 mg].
The objective of the study was to investigate the clinical effectiveness of increasing the dosage of prilocaine for a combined 3-in-1/sciatic nerve block from 500 to 650 mg (open study with 29 patients compared with 30 patients from a former study) and to validate these findings in a second stage (randomised study comparing two groups of 30 patients each). Not only was clinical effectiveness improved by increasing the dose to 650 mg, but methaemoglobinaemia and toxicity were not relevant problems. With the higher dosage, development of the block was slightly faster (onset and completion); there were fewer unsatisfactory blocks; and clinically relevant plasma levels of methaemoglobin did not occur.
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ANAESTHETICS, ENDOCRINE SYSTEM, AND STRESS: The effects of anaesthetics on the nervous system are invariably associated with endocrine reactions, which are of great importance for the general characterization of anaesthetics or anaesthetic regimens. In this context, the endocrine stress response is mainly represented by adrenaline (A), noradrenaline (NA), antidiuretic hormone/vasopressin (ADH), adrenocorticotropic hormone (ACTH), and cortisol. PHARMACOLOGICAL PROFILE AND ANAESTHETIC ACTION OF KETAMINE: The pharmacological profile of ketamine is characterized by the term "dissociative anaesthesia." At the present time, the anaesthetic action of ketamine cannot be explained by a single mechanism. ⋯ The combination of S-(+)-ketamine and midazolam has weaker sympathomimetic and general endocrine-stimulating properties, and can be used for analgosedation in patients with cardiovascular instability and exogenous catecholamine requirements. In combination with propofol, the sympathomimetic and general endocrine-stimulating effects of S-(+)-ketamine are less pronounced because of contrasting properties of both drugs. This combination might be useful in patients with endocrine deficits and for analgosedation, when rapid recovery is necessary and negative circulatory effects should be avoided.
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In a recent German multicenter study, 25% of the patients who suffered a witnessed cardiac arrest outside the hospital were resuscitated successfully and were discharged from the hospital. Approximately 100,000 people suffer a fatal cardiac arrest in Germany annually, which is about ten times more than deaths resulting from motor vehicle accidents. New devices and techniques for cardiopulmonary resuscitation (CPR) have been developed in order to enhance the efficacy of chest compressions during CPR. ⋯ In summary, since the rediscovery of chest compressions more than 35 years ago, this intervention has not changed significantly. Objective data from laboratory and clinical studies such as systolic blood pressure, CPP, and the gold standard for the efficacy of CPR, long-term survival and neurological outcome, will determine if a new device or technique can replace standard-CPR. Despite the new developments, it is mandatory to perform standard CPR correctly with a chest compression rate of 80-100/min and a depth of 38-50 mm.
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Ketamine is a racemic mixture containing equal parts of S-(+)-ketamine and R-(-)-ketamine. Their potency relation is approximately 4:1. In early human studies S-(+)-ketamine was presumed to produce the desired anaesthetic effects and R-(-)-ketamine the undesired psychic emergence reactions. ⋯ With only one exception, the recovery phase was clearly shorter after S-(+)-ketamine compared to racemic ketamine irrespective of its application as a single bolus, a bolus followed by continuous infusion, or an intramuscular injection. However, the incidence of psychic emergence reactions was lower after S-(+)-ketamine in only a single study. In conclusion, S-(+)-ketamine should be always combined with a hypnotic or sedative drug in clinical anaesthesia.