Der Anaesthesist
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Principles and characteristics of the recently introduced Microcuff paediatric tracheal tube (Microcuff, GmbH, Weinheim, Germany) with anatomically based depth markings, cuff-free subglottic tube shaft and short high volume-low pressure cuff with ultrathin cuff membrane are presented. First available tubes (ID 4.0 mm) were evaluated regarding cuff pressures required to seal the trachea and regarding the distance from the tube tip to the carina. ⋯ The new Microcuff paediatric tracheal tube with ultrathin high volume-low pressure cuff required tracheal sealing pressures below tracheal wall pressures usually required with uncuffed tracheal tubes for efficient sealing and ventilation at 20 cm H(2)O peak inspiratory pressure. The distance from the tube tip to carina was in the safe range in all patients.
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From a pharmacological perspective, anesthesia is concerned with controlling the time course of drug effect. Mathematical models are commonly used to relate the administered drug dose to the measured drug concentration (a pharmacokinetic model) and to relate the measured drug concentrations to the measured drug effects (a pharmacodynamic model). With such models, the time course of the drug effect for different drug regimens can be predicted. ⋯ An understanding of the "effect compartment concept" and the "time of the peak effect site concentration," together with the concepts of" context sensitive"half-time and "relevant decrement time,' contribute substantially to the anesthetist's understanding of the principles governing the onset and offset of drug effect. As part of a computer-controlled infusion system, the pharmacokinetic model facilitates optimized and rational dosing. These systems, also called target-controlled infusion systems (TCI), calculate the infusion rates for rapidly achieving and then maintaining a target concentration.
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The innate immune system succeeds against the majority of infections before the adaptive immune system is activated. New findings contribute to a better understanding of the pathophysiology of sepsis and lead to the development of new therapeutic strategies. The innate immune system, being responsible for the first response to infections, can trigger adaptive immune responses in case the initial response is ineffective. ⋯ The environment in sepsis can cause disseminated intravascular coagulation (DIC), but at the same time thrombin triggers the release of chemokines and adhesion molecules through endothelial cells, which represents a positive feedback mechanism for innate immune responses. New therapeutic strategies for sepsis try to establish a well-balanced immune response. Intervention is accomplished through inhibition of inflammatory cytokines, their receptors or through activation of immunostimulatory responses.
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Clinical Trial
[Feedback control of muscle relaxation with a varying on-off controller using cisatracurium].
Under clinical conditions constant neuromuscular blockade can also be maintained by a simple closed-loop system. However, delayed onset time, non-linearity of the dose-response curve and different sensitivity to muscle relaxants for each patient are limiting factors. ⋯ It can be concluded that a simple closed-loop system allows the safe use of the intermediate term muscle relaxant cisatracurium for the performance of surgical procedures.
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Clinical Trial
[The effects of active and passive humidification on ventilation-associated nosocomial pneumonia].
Airway humidification of ventilated patients in an intensive care unit may be established by heated humidifying systems (active) or by the means of a (passive) heat and moisture exchange filter (HMEF). There is a controversial discussion about the influence of the type of humidification on the rate of ventilator-associated pneumonia (VAP). Among 3,585 patients both methods were tested over a period of 21 months in an open, non-randomized cohort study. The aim of the investigation was to compare the incidence of VAP caused by a change of humidification strategy. ⋯ Our results showed that the rate of VAP could be significantly reduced by changing the strategy from active to passive humidification devices, especially concerning patients requiring long-term respirator therapy. A more physiological humidification and a reduced number of airway manipulations are discussed as a possible explanation.