Der Anaesthesist
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The perioperative risk for patients with pacemakers or implanted cardioverter/defibrillators (ICD) is mainly dependent on the underlying disease. However, severe to life-threatening complications of the implanted system can occur due to electromagnetic interference in the environment of the operation. These complications can be prevented or adequately treated by taking special precautions and measures. Even though the currently available data on the optimal perioperative management to pacemakers and ICDs is still unsatisfactory, the increasing clinical relevance of this topic was the reason for the formulation of recommendations by an interdisciplinary working group in Austria.
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The force of cardiac contraction is strongly influenced by myocardial fibre length at the beginning of systole. Because the length of cardiac sarcomers and muscle fibres primarily depends on the end-diastolic ventricular volume, filling pressures a priori can only act as indirect parameters of cardiac preload. Central venous pressure (CVP) gives information on right ventricular end-diastolic pressure, which parallels changes in left ventricular end-diastolic pressure as long as ventricular function is not impaired. ⋯ Variables which more directly represent end-diastolic ventricular volume (e.g. intrathoracic blood volume or end-diastolic ventricular area) offer a higher validity as estimates of cardiac preload. Furthermore, dynamic parameters of ventricular preload, such as pulse pressure variation or stroke volume variation, seem to be more predictive of volume responsiveness in ventilated patients than CVP. These limitations, however, do not impair the importance of CVP as the downstream pressure of the systemic venous system.
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Review
[Regional anaesthesia as advantage in competition between hospitals. Strategic market analysis].
The German Social Act V section sign 12 is aimed towards competition, efficiency and quality in healthcare. Because surgical departments are billing standard diagnosis-related group (DRG) case costs to health insurance companies, they claim best value for money for internal services. Thus, anaesthesia concepts are being closely scrutinized. The present analysis was performed to gain economic arguments for the strategic positioning of regional anaesthesia procedures into clinical pathways. ⋯ Regional anaesthesia is a considerable value driver in clinical pathways by shortening length of stay. The present analysis further demonstrates that time for regional block performance is covered by anaesthesia reimbursement within the DRG costing schedule.
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The trends in central venous pressure (CVP) are more informative than the isolated values. The CVP should always be evaluated in the context of the patient's clinical condition. It indicates the relationship between circulating blood volume and the capacity of the heart at a given time. ⋯ The CVP is a meaningful parameter if it is measured correctly. For accurate measurement the transducer must be zeroed and leveled to a correct external reference level for the right atrium. Only a CVP measured at the end of expiration can be compared on condition that the catheter is placed correctly in the central venous system.
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Values of intramural or even transmural central venous pressure (CVP) as well as values of pulmonary artery occluded pressure do not correlate with the values of measured circulating blood volume or with responsiveness to fluid challenge. The veins contain approximately 70% of the total blood volume and are 30 times more compliant than arteries, therefore, changes in blood volume within the veins are associated with relatively small changes in venous pressure. The main reason for a lack of correlation between CVP values and blood volume is that the body does everything possible to maintain homeostasis and adequate transmural CVP is a must for cardiovascular function. ⋯ Stressed volume determines MCFP and directly affects venous return and cardiac output whereas unstressed volume is a reserve of blood that can be mobilized into circulation when needed. Both stressed and unstressed volume cannot be adequately measured. Therefore, considering the complexity of the physiologic feedback and clinical picture, robust reflexes and homeostatic mechanisms, CVP is insufficient as a surrogate parameter for assessing the volume status.