Der Anaesthesist
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Randomized Controlled Trial Comparative Study Clinical Trial
[Coagulation changes during aortofemoral bifurcation bypass: is volume and plasma substitution possible with hydroxyethyl starch alone?].
The study explored the possibility of eliminating the need for plasma replacement with expensive human albumin (HA) and fresh frozen plasma (FFP) and instead using hydroxyethyl starch (HES). Patients undergoing infrarenal aortofemoral bifurcation grafting were randomly assigned to one group, which received FFP and HA, or another group, which received HES as volume replacement. Blood specimens were collected at five time intervals: preoperatively, prior to cross-clamping of the aorta, prior to declamping, at the end of the operation, and 6 h postoperatively. ⋯ Plasminogen, fibrinogen, antithrombin III, and antiplasmin concentrations fell significantly in both groups; 10% to 20% lower values were determined within the HES group due to the lack of factor substitution. The reduction in the coagulation factors can be explained as a dilution effect, but there are also signs of a consumption reaction taking place at the onset of the operation involving activation of coagulation and fibrinolysis. Restricting the use of FFP and simultaneously increasing HES administration is justifiable in procedures involving the abdominal aorta with moderate blood loss.
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Comparative Study
[The effect of fresh gas flow on the minute volume of anesthesia ventilators with a gas reservoir].
The tidal volume (TV) delivered by conventional anesthesia ventilators is dependent on fresh gas flow rate (FGF). When FGF is reduced, the TV declines; this must be corrected by increasing the ventilator bellows excursion. In addition, the falling bellows produce a negative pressure during the expiratory phase, which may result in positive negative pressure ventilation (PNPV). ⋯ VI-VOLEC (with the relief valve closed) and AV 1 had a loss of less than 10% of the initial TV. Adding a reservoir bag to anesthesia ventilators is an effective method of guaranteeing a TV independent of FGF. The three ventilators tested here proved suitable for minimal-flow anesthesia.
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Forty unpremedicated patients undergoing minor gynecological surgery were anesthetized with 1 mg ketamine and 0.1 mg midazolam per kg bodyweight, if necessary supplemented later with half the initial dose. All patients continued to breathe room air spontaneously with no ventilatory support. There were no incidents of airway obstruction and only 1 case of troublesome airway secretions. ⋯ The median emergence time was 6 min. The side effects of ketamine were well controlled by midazolam, and patient acceptance of the technique was high. We consider that the technique may be suitable for short procedures under primitive conditions, for example after mass casualties, and that it can, if necessary, be applied by specially trained paramedics.
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Case Reports
[Compression of the trachea by a hematoma caused by an internal jugular vein catheter].
In a patient with thrombocytopenia, respiratory obstruction because of a hematoma occurred following internal jugular vein cannulation. This patient recovered completely after surgical intervention. With the following precautions in mind, puncture of the internal jugular vein in patients with coagulopathies has a high success rate and does not result in severe complications: Internal jugular vein cannulation by an experienced physician; optimal conditions for puncture by increasing venous pressure and diameter with slight Trendelenburg position and Valsalva maneuver in patients with spontaneous breathing, or positive end-expiratory pressure in patients with artificial ventilation; catheter insertion by the Seldinger technique; manual compression of the puncture site for 10-15 min; and vein puncture with ultrasonographic aid if possible.