Der Anaesthesist
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Comparative Study Clinical Trial
[Comparison of APACHE-II AND APACHE-III for classification of disease severity of intensive care patients].
The Acute Physiology and Chronic Health Evaluation model (APACHE II, APACHE III) is used to describe the severity of illness and predict the outcome in critically ill patients. APACHE III, introduced in 1991, has not yet been validated in Europe. We calculated APACHE II and APACHE III scores in patients after admission to the intensive care unit (ICU) and compared the prognostic value on hospital mortality. ⋯ APACHE II and APACHE III were both found to have good prognostic value in general ICU patients. Our results suggest that the APACHE III version includes a more precise prediction of hospital mortality than APACHE II. A new aspect of APACHE III is an expanded modification of the Glasgow Coma Scale to assess neurologic derangements.
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Preventive strategies aim to reduce gastric acidity (H2-antagonists, antacids), to strengthen mucosal defence mechanisms (sucralfate, antacids, pirenzepine) and to normalize gastric mucosal microcirculation (sucralfate, pirenzepine). Thus, the most important prophylactic measure is an optimized emergency and ICU regime aiming to improve oxygenation and microcirculation. All specific drugs used for stress ulcer prophylaxis have been shown to be effective in prospective controlled studies. ⋯ The most important adverse effect of stress ulcer prophylaxis is nosocomial pneumonia due to gastric alkalinization. This may occur in long-term ventilated patients with a gastric pH > 4 and may account for up to 50% of all nosocomial pneumonias in certain groups of patients. Mortality is not influenced by antacids or H2-antagonists, while sucralfate has been shown to reduce mortality, most probably by inhibition of bacterial translocation.
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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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Comparative Study Clinical Trial
[CT-epidurography. A comparison of conventional and CT-epidurography with contrast medium injection through a thoracic peridural catheter].
Epidurography with contrast medium is used to verify the correct position of an epidural catheter and to detect malpositioning. There is great variability in the distribution of contrast medium according to the individual morphology of the epidural space and the way it is injected. Results of investigations of the anatomy of the spinal canal and epidural space performed with anatomic specimens, epiduroscopy, and conventional and computed tomographic (CT) epidurography are sometimes contradictory. ⋯ CONCLUSIONS. CT epidurography is a valuable tool to provide better insight into the morphology of the epidural space when filled with fluid (contrast medium, local anaesthetics), complementing findings using epiduroscopy and anatomic specimens. It stands to reason that this time- and cost-expensive method can never replace conventional epidurographies, but can help to interpret them properly.
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Thermodilution measurements of cardiac output (CO) by means of Swan-Ganz catheters, in a strict sense, represent pulmonary arterial blood flow (PBF). In principle, this is also true in the presence of intracardiac left-to-right shunts due to atrial or ventricular septal defects. However, early recirculation of indicator may give rise to serious methodological problems in these cases. ⋯ PBF at extremely high shunt ratios, however, cannot be assessed by monoexponential extrapolation in principle (Fig. 6). Insufficient elimination of indicator recirculation resulted in flow values that closely resembled systemic rather than PBF. This finding is in accordance with a mathematical analysis of the underlying Steward-Hamilton equation if an infinite number of recirculations would be