Critical care : the official journal of the Critical Care Forum
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Comment Review
Noninvasive ventilation for acute lung injury: how often should we try, how often should we fail?
The selection of patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS) to receive noninvasive ventilation (NIV) is challenging, partly because there are few reliable selection criteria. The study by Rana and colleagues in the previous issue of Critical Care identifies metabolic acidosis and a lower oxygenation index as predictors of NIV failure, although it is unable to identify threshold values. It also demonstrates that treating patients with NIV for ALI/ARDS and shock is an exercise in futility. Future studies need to focus on criteria that will enable selection of patients for whom NIV will have a high likelihood of success.
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There is growing acceptance within the medical community of induced (therapeutic) hypothermia as a tool to achieve neuroprotection and/or cardioprotection. Although much work remains to be done in identifying those clinical situations in which hypothermia can be effective, there is now sufficient evidence to regard it as a standard of care, at least for some indications such as selected patients with postanoxic encephalopathy. ⋯ General aspects and advantages/disadvantages of surface versus core cooling are discussed, as are potential side effects, device-specific pros and cons, and cost-effectiveness issues. In addition, the current state of the evidence for use of induced hypothermia for various indications is briefly reviewed.
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Comparative Study
Use of an integrated clinical trial database to evaluate the effect of timing of drotrecogin alfa (activated) treatment in severe sepsis.
Several studies have indicated that early identification and treatment of patients with severe sepsis using standard supportive care improves outcomes. Earlier treatment with drotrecogin alfa (activated) (DrotAA) may also improve outcomes in severe sepsis. Using a recently constructed integrated severe sepsis database, our objectives in this study were to describe the influence of baseline clinical characteristics on timing of DrotAA treatment in patients with severe sepsis, to evaluate the efficacy of DrotAA with respect to timing of administration, and to examine the association between early intervention with DrotAA and patient outcomes, using adjustments for imbalances. ⋯ Using an integrated database of five severe sepsis trials and appropriate statistical adjustments to reduce sources of potential bias, earlier treatment with DrotAA seemed to be associated with a lower risk-adjusted mortality than later treatment. These data suggest that earlier treatment with DrotAA may provide most benefit for appropriate patients.
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Comparative Study
Oxidative stress is increased in critically ill patients according to antioxidant vitamins intake, independent of severity: a cohort study.
Critically ill patients suffer from oxidative stress caused by reactive oxygen species (ROS) and reactive nitrogen species (RNS). Although ROS/RNS are constantly produced under normal circumstances, critical illness can drastically increase their production. These patients have reduced plasma and intracellular levels of antioxidants and free electron scavengers or cofactors, and decreased activity of the enzymatic system involved in ROS detoxification. The pro-oxidant/antioxidant balance is of functional relevance during critical illness because it is involved in the pathogenesis of multiple organ failure. In this study the objective was to evaluate the relation between oxidative stress in critically ill patients and antioxidant vitamin intake and severity of illness. ⋯ The critical condition of patients admitted to the ICU is associated with worsening oxidative stress. Intake of antioxidant vitamins below 66% of RDA and alteration in endogenous levels of substances with antioxidant capacity are related to redox imbalance in critical ill patients. Therefore, intake of antioxidant vitamins should be carefully monitored so that it is as close as possible to RDA.
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From the report by Connors and coworkers in 1996 until now, much effort has been directed at demonstrating the safety and/or effectiveness of strategies based on pulmonary artery catheter (PAC) data. Although studies have failed to demonstrate a clear benefit of PAC use, neither have any corroborated the initial report of PAC-induced mortality. ⋯ The PAC has evolved since its initial presentation, and it now offers numerous parameters in addition to cardiac output and pressure measurement, such as mixed oxygen saturation and right ventricular ejection fraction. Because many techniques may be used to measure cardiac output, the indications for PAC use have become founded on other parameters that are useful in more specific situations, essentially involving the right circulation.