Der Anaesthesist
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Randomized Controlled Trial Clinical Trial
[Perfusion changes in hemodilution. The effect of extensive isovolemic hemodilution with gelatin and hydroxyethylstarch solutions on cerebral blood flow velocity and cutaneous microcirculation in humans].
Quantifying the influence of extreme isovolemic hemodilution (NH) with different colloids on cerebral blood flow velocities (transcranial Doppler sonography) and cutaneous microcirculatory blood flow (laser Doppler flowmetry) in healthy, non-premedicated volunteers was the aim of this study. ⋯ The two plasma expanders studied show a close inverse correlation between the alterations of blood flow velocities in the middle cerebral artery and systemic hemoglobin and hematocrit values. In both groups the change in blood flow velocities is comparable. For the first time the results of relative changes in blood flow velocities following hemodilution and retransfusion in healthy volunteers are described that correspond closely by relative cerebral blood flow alterations found in animal studies as well. Moreover, a non-linear correlation of cutaneous microcirculation was shown by means of HES, but also by GEL. Obviously, there was the GEL group to be responsible for pronounced differences in cutaneous circulation.
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In an investigation of infection control methods for respirator systems in 89 randomly selected German intensive care units as a part of the NIDEP study (Nosocomial Infections in Germany--Surveillance and Prevention), it was found that respirator systems were exchanged daily in about 50% of the intensive care units. However, Craven et al. found that changing circuits (including tubing and exhalation valve and the attached humidifier) every 24 h rather than every 48 h was independently associated with the occurrence of nosocomial pneumonia. On the basis of these results and recent studies, the current situation in the literature was analyzed in order to make recommendations for exchanging ventilator circuits. ⋯ The available studies show clear advantages of not routinely exchanging the ventilator circuit, including tubing, exhalation valve and the attached humidifier, more often then every 7 days for an individual patient. Based on these findings, the current practice in most German intensive care units should be reevaluated.
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Supported by two case reports we show that resistance to atracurium can develop postoperatively. Both patients had septic complications after elective thoracic surgery. A 39-year-old patient developed a bronchial fistula and a superinfection of the remaining thoracic cavity after pneumonectomy. ⋯ In contrast to the first anaesthesia the intubation dose of atracurium had to be increased significantly (70 vs. 40 mg), and even with this amount the neuromuscular blocking effect was not complete. Furthermore to accomplish a convenient state of relaxation the maintenance dose had to be raised considerably (11.8-16.5 vs. 5.5 micrograms/kg per minute). These reports show that even within a short period of time resistance to atracurium can develop and we must suppose that the severe inflammatory reaction caused these changes.
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Clinical Trial
[The effect of fresh-gas decoupling on respiratory volume. Draegar Sulla 808V anesthesia ventilator].
In order to perform accurate low-flow anaesthesia ventilation, it is desirable to avoid the influence of fresh gas flow (FGF) and inspiration duration (ID) on the resulting minute volume (MV). The Sulla 808V anaesthesia ventilator (Draeger, Luebeck, Germany) is originally not equipped with a fresh-gas decoupling (FGD) device. Therefore, changes of FGF and ID settings applied during controlled ventilation may lead to alterations of the resulting MV. Recently, a low-cost FGD device (Carbamed, Bern-Liebefeld, Switzerland) has been developed, which can be inserted into the circle system. We investigated the effect of this device on MV in the Sulla 808V anaesthesia apparatus. ⋯ The tested FGD device can easily be integrated into the circle system of conventional anaesthesia machines such as the Draeger Sulla 808V, and is available at a reasonable cost. It allows constant ventilation parameters to be maintained that remain unaffected by wide FGF and ID variations. With this FGD the performance of the ventilator can be improved considerably, and low-flow anaesthesia can be used more extensively.
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Neurogenic pulmonary edema (NPE) is a rare but always life-threatening complication in patients with central nervous system lesions. NPE is evident if patients shortly after cerebral lesions suddenly develop pulmonary edema and other causes of the symptoms, such as aspiration of gastric content, congestive heart failure and direct toxic exposure, are ruled out. ⋯ NPE is always a life-threatening symptom after increased ICP, where immediate therapeutic interventions are imperative. A rational therapeutic approach needs to be focused on decreasing ICP as primary goal. Additionally, attempts should be made to optimize body oxygenation, decrease pre- and afterload and increase myocardial contractility. Postictal patients suspicious for incipient ventilation problems must be admitted to hospital for further evaluation.