Critical care : the official journal of the Critical Care Forum
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The present study aimed to investigate changes of the immune response between sepsis due to ventilator-associated pneumonia (VAP) and sepsis due to other types of infections. ⋯ Decrease of CD4-lymphocytes and immunoparalysis of monocytes are characteristic alterations of sepsis arising in the field of VAP.
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The current debate about the side effects of induction agents, e.g. possible adrenal suppression through etomidate, emphasizes the relevance of choosing the correct induction agent in septic patients. However, cardiovascular depression is still the most prominent adverse effect of these agents, and might be especially hazardous in septic patients presenting with a biventricular cardiac dysfunction--or so-called septic cardiomyopathy. Therefore, we tested the dose-response direct cardiac effects of clinically available induction agents in an isolated septic rat heart model. ⋯ Overall, this study demonstrates that these tested drugs indeed have differential direct cardiac effects in the isolated septic heart. Propofol showed the most pronounced adverse direct cardiac effects. In contrast, S(+)ketamine showed cardiovascular stability over a wide range of concentrations, and might therefore be a beneficial alternative to etomidate.
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Despite the key role of hemodynamic goals, there are few data addressing the question as to which hemodynamic variables are associated with outcome or should be targeted in cardiogenic shock patients. The aim of this study was to investigate the association between hemodynamic variables and cardiogenic shock mortality. ⋯ During the first 24 hours after intensive care unit admission, CI and CPI are the most important hemodynamic variables separately associated with 28-day mortality in patients with cardiogenic shock. A CI of 3 L/min/m2 and a CPI of 0.8 W/m2 were most predictive of 28-day mortality. Since our results must be considered hypothesis-generating, randomized controlled trials are required to evaluate whether targeting these levels as early resuscitation endpoints can improve mortality in cardiogenic shock.
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Comparative Study
Mechanical ventilation using non-injurious ventilation settings causes lung injury in the absence of pre-existing lung injury in healthy mice.
Mechanical ventilation (MV) may cause ventilator-induced lung injury (VILI). Present models of VILI use exceptionally large tidal volumes, causing gross lung injury and haemodynamic shock. In addition, animals are ventilated for a relative short period of time and only after a 'priming' pulmonary insult. Finally, it is uncertain whether metabolic acidosis, which frequently develops in models of VILI, should be prevented. To study VILI in healthy mice, the authors used a MV model with clinically relevant ventilator settings, avoiding massive damage of lung structures and shock, and preventing metabolic acidosis. ⋯ MV induces VILI, in the absence of a priming pulmonary insult and even with use of relevant (least injurious) ventilator settings. This model offers opportunities to study the pathophysiological mechanisms behind VILI and the contribution of MV to lung injury in the absence of pre-existing lung injury.
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Comment
Epinephrine kinetics in septic shock--a means to understand variable catecholamine efficiency?
It is well-established that the hemodynamic response to infusing catecholamines, the most frequently applied drugs for circulatory support during shock states, may vary markedly within and between individuals. In this context it is striking that only scarce data are available on the pharmacokinetics of catecholamines in critically ill patients. ⋯ Abboud and colleagues now report that, in patients with septic shock, epinephrine kinetics are linear and its clearance directly depends on body weight and is inversely related to the severity of the disease. The authors conclude that the endogenous adrenal axis hormones do not assume any additional importance.