D. Pappert

Dopamine, dopexamine and dobutamine in liver transplant recipients : a comparison of their effects on hemodynamics, oxygen transport and hepatic venous oxygen saturation

The purpose of this study was to determine the effects of vasoactive treatment with dopamine (DO), dopexamine (DX), and dobutamine (DOB) on hemodynamics, oxygen transport and hepatic venous oxygen saturation (SvhO2) after orthotopic liver transplantation (OLT). A pulmonary artery catheter was inserted into the right hepatic vein of 17 OLT patients. Timed infusion of DO, DX, and DOB was performed at the following rates: DO at 4 and 8 μg/kg per minute, and DOB at 5 and 10 μg/kg per minute. Hemodynamics, oxygen transport variables, and SvhO2 were assessed. Each catecholamine induced a significant increase in cardiac index, oxygen delivery, and SvhO2. Mean arterial pressure was increased during DO and DOB, but significantly reduced during DX. Each inotrope increased oxygen delivery in parallel with SvhO2, suggesting a corresponding increase in hepatic oxygen supply. Therefore, it appears that each vasoactive drug may be utilized in OLT patients to provide oxgen delivery without impairment of splanchnic oxygenation.

Klinische Aspekte des akuten Lungenversagens des Erwachsenen (ARDS)

ZusammenfassungDas akute Lungenversagen des Erwachsenen ist selten, aber auch heute noch mit einer sehr hohen Letalität belastet, wenngleich sich in den letzten Jahren ein Trend zu verbesserten Überlebensraten abzuzeichnen beginnt. Neuere Studien haben gezeigt, daß die bis vor kurzem noch in der Behandlung des ARDS angewendete Beatmungstherapie mit großen Atemzugvolumina, hohen Beatmungsdrücken und hohen inspiratorischen Sauerstoffkonzentrationen die erkrankte Lunge weiter schädigen kann. Diese Erkenntnisse haben zu einem Umdenken in der Behandlung geführt. Vorrangiges Ziel ist heute nicht mehr, die Wiederherstellung und Aufrechterhaltung physiologischer Normwerte für Sauerstoff- und Kohlendioxidpartialdrücke sowie arteriellen pH zu erreichen, sondern die Lunge vor beatmungsinduzierten Schäden zu schützen.Hierzu hat sich ein erweitertes Behandlungskonzept, bestehend aus verschiedenen Formen der drucklimitierten Beatmung mit PEEP und permissiver Hyperkapnie, Lagerungsmaßnahmen, Inhalation von Stickstoffmonoxid und – zumindest in Europa – extrakorporaler Membranoxygenierung als erfolgreich erwiesen, ohne daß die Effizienz jeder einzelnen Methode in kontrollierten randomisierten Studien bewiesen worden wäre. In dem vorliegenden Übersichtsartikel werden die neuesten Entwicklungen aufgezeigt, diskutiert und im Hinblick auf ihre klinische Effizienz bewertet.AbstractAcute respiratory distress syndrome (ARDS) is rare but beset with a high mortality rate. In recent years, however, a trend towards higher survival rates has been observed. High inspiratory oxygen concentrations, large tidal volumes, and high peak inspiratory airway pressures applied during mechanical ventilation have been identified as harmful to the lung and can contribute to the progression of ARDS. This had led to reconsideration of the sequelae of ventilatory therapy. Mechanical ventilation and other adjunctive strategies in ARDS have changed from the conventional approach aiming at normalisation of physiological ventilatory parameters to an elaborated approach that intends to protect the ventilated lung, prevent oxygen toxicity, recruit the infiltrated atelectatic and consolidated lung and reduce the anatomical and alveolar dead space. This new approach consists of various forms of pressure-controlled mechanical ventilation with PEEP and permissive hypercapnia, body position changes, and inhalation of nitric oxide. Should these procedures fail to improve impaired gas exchange, extracorporeal membrane oxygenation is an additional therapeutic option. None of these therapeutic procedures, however, has been tested against traditional standard treatment in a classical randomised controlled trial. The following review focuses on the latest insights into the pathophysiology, diagnosis, and treatment of ARDS.

Treatment of ARDS with nitric oxide and ECMO.

Important contributing factors to the high mortality of severe acute respiratory distress syndrome (ARDS) are the aggressive therapies required, such as mechanical ventilation with high inspiratory oxygen concentrations and airway pressures. As specific therapies for reducing or preventing the general inflammatory reaction of the lungs resulting in severe hypoxemia are unknown, todays therapy is limited to procedures which predominantly support or maintain pulmonary function, i.e. pressure limited ventilation with PEEP and permissive hypercapnea, avoiding prevention treatment of fluid overload, and positional maneuvers. New approaches seek a reduction in peak airway pressure and application of less enriched oxygen mixtures. Recently, inhalation of low concentrations of nitric oxide (NO) has been described to cause selective pulmonary vasodilation and an increased arterial oxygenation in patients with severe ARDS.