Der Anaesthesist
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Although the attempts to develop an oxygen-carrying alternative to red blood cells (RBC) have spanned the last 100 years, it has proven difficult to develop a clinically useful haemoglobin-based oxygen carrier. Four major problems have been shown to compromise the use of haemoglobin outside the RBC as an oxygen carrier: (1) the increased oxygen affinity due to the loss of 2,3-diphosphoglycerate; (2) dissociation into dimers and monomers with consequent renal and capillary loss of hemoglobin; (3) insufficient concentrations of prepared solutions under iso-oncotic conditions, and thereby reduced oxygen-carrying capacity; and (4) toxicity. Most of these limitations have been overcome by different modifications of haemoglobin, including pyridoxylation, intra- and intermolecular cross-linking, polymerisation, liposome encapsulation, conjugation to inert macromolecules, and genetic engineering. ⋯ Based on promising and reproducible results obtained from animal studies, clinical phase I and II trials with newer haemoglobin solutions have been started in the United States. Substantial knowledge has been gained in the development, production, and evaluation of haemoglobin-based oxygen carriers during the past years. It will probably not take another century before oxygen-carrying RBC substitutes will become available for clinical use.
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Clinical Trial
[Laryngeal surgery with a 3-D technique. Early results with the jet-laryngoscope in superimposed high-frequency jet ventilation].
Surgery by three-dimensional (3D) endoscopy is being used routinely in abdominal surgery and, in special cases, in thoracic surgery; however, it has not been reported as being used in microlaryngeal surgery. METHODS. We inserted a 3-D endoscope into a jet laryngoscope and studied the pressure properties at the tip of the laryngoscope as well as intrapulmonary pressures while applying superimposed high-frequency jet ventilation. ⋯ In the clinical application of 3-D endoscopy via a jet laryngoscope, it was possible to achieve sufficient ventilation, inspection of the surgical field, and performance of the surgical procedure. A CO2 laser was used without changing the ventilation regime. Although technical alterations would be desirable for its application to microlaryngeal surgery, it is presently possible to safely use the 3-D endoscope via the jet laryngoscope for microlaryngeal surgery, presenting the surgeon with new possibilities in voice-improving microsurgery of the larynx.
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Acute upper gastrointestinal bleeding in ICU patients has many possible causes: ulcer, adverse drug effects, gastric tube lesion, acute renal or liver failure, or stress-induced gastric mucosal lesion. Stress-induced gastric mucosal lesions typically are multiple superficial erosions, while ulcerations typically occur in patients with head trauma, neurosurgical operation or severe burns. Head trauma and neurosurgical patients are the only ones with increases gastric acid secretion; in general reduced acid secretion can be observed in ICU patients. ⋯ Active acid secretion depends on sufficient oxygen supply and mucosal ATP content. Hypotension and shock results in gastric mucosal ischaemia. These are the most important risk factors of stress bleeding.
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Clinical Trial
[Axillary blockade of the brachial plexus. A prospective study of blockade success using electric nerve stimulation].
Axillary block is a common anesthetic technique for operations on the hand and forearm. In our hospital, with many trainees in anaesthesia, only 250-300 axillary blocks per year are performed by about 30 colleagues. This implies a small number of blocks for each anaesthetist. ⋯ Prior to injection of the local anaesthetic, the current for nerve stimulation should be reduced to < 0.5 mA. The time between the end of injection and the beginning of surgery should be no less than 30 min because complete sensory blockade can more often be achieved. The dose of mepivacaine should be no less than 6 mg/kg body weight.
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Posttraumatic cardiopulmonary resuscitation (CPR) is associated with a poor outcome. When evaluating the literature according to the Utstein method, there were only 2 survivors (0.18%) out of 1,135 CPR attempts after trauma (Table 1). Differences in the study populations and levels of prehospital trauma care led us to analyse the results of a physician-staffed prehospital trauma care system in Cologne. ⋯ Survival has to be regarded as an individual fate; the overall results are discouraging. Even though this study analyses the largest population of posttraumatic CPR ever published, prognostic factors could not be identified due to the few survivors. Nevertheless, the result does not justify general omission of CPR after trauma as: (1) prognostic factors for survival have not been identified thus far; and (2) no significant additional costs arise from posttraumatic CPR.