Critical care medicine
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Critical care medicine · Apr 2003
ReviewSelective pulmonary vasodilation in acute respiratory distress syndrome.
Acute respiratory distress syndrome (ARDS) is characterized by a marked maldistribution of pulmonary perfusion in favor of nonventilated, atelectatic areas of the lungs, and it is the main cause of pulmonary right-to-left shunting and hypoxemia. Therapeutic interventions to selectively influence pulmonary perfusion in ARDS became feasible with the introduction of inhaled nitric oxide, which provided a means not only to reduce pulmonary hypertension, but also to improve matching of ventilation to perfusion and, thus, hypoxemia. Clinical studies in ARDS subsequently demonstrated that the combination of inhaled nitric oxide with other interventions, such as positive end-expiratory pressure and prone positioning, yielded beneficial and additive effects on arterial oxygenation. ⋯ Ongoing research aims to augment the effectiveness of vasodilators with specific inhibitors of phosphodiesterases or by combination with intravenous vasoconstrictors. Consequently, several alternative ways to selectively modulate pulmonary vascular tone in patients with ARDS may be available in the near future. Cost-benefit analysis of these therapeutic options will largely determine their future perspective.
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Critical care medicine · Apr 2003
ReviewLung-protective ventilation strategies in acute lung injury.
To review the challenges of providing mechanical ventilatory support for respiratory failure while avoiding ventilator-associated lung injury in patients with acute lung injury. To review the results of several randomized clinical trials of lung-protective ventilation strategies using conventional mechanical ventilators. ⋯ Evidence supports the use of a volume- and pressure-limited approach to mechanical ventilation in patients with acute lung injury. It is not yet clear whether the open-lung approach will further reduce mortality in patients receiving volume- and pressure-limited ventilation support.
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Critical care medicine · Apr 2003
Review2001 SCCM/ESICM/ACCP/ATS/SIS International Sepsis Definitions Conference.
In 1991, the American College of Chest Physicians (ACCP) and the Society of Critical Care Medicine (SCCM) convened a "Consensus Conference," the goals of which were "to provide a conceptual and a practical framework to define the systemic inflammatory response to infection, which is a progressive injurious process that falls under the generalized term 'sepsis' and includes sepsis-associated organ dysfunction as well." The general definitions introduced as a result of that conference have been widely used in practice and have served as the foundation for inclusion criteria for numerous clinical trials of therapeutic interventions. Nevertheless, there has been an impetus from experts in the field to modify these definitions to reflect our current understanding of the pathophysiology of these syndromes. ⋯ This document reflects a process whereby a group of experts and opinion leaders revisited the 1992 sepsis guidelines and found that apart from expanding the list of signs and symptoms of sepsis to reflect clinical bedside experience, no evidence exists to support a change to the definitions. This lack of evidence serves to underscore the challenge still present in diagnosing sepsis in 2003 for clinicians and researchers and also provides the basis for introducing PIRO as a hypothesis-generating model for future research.
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Critical care medicine · Apr 2003
ReviewHigh-frequency oscillatory ventilation for acute respiratory distress syndrome in adult patients.
High-frequency oscillatory ventilation (HFOV) using an open-lung strategy has been demonstrated to improve oxygenation in neonatal and pediatric respiratory failure, without increasing barotrauma. Animal studies using small (<4 mm) endotracheal tubes have shown reduced histopathologic evidence of lung injury and inflammatory mediator release, suggesting reduced ventilator-induced lung injury. ⋯ Future studies should compare different algorithms of applying HFOV to determine the optimal techniques for achieving oxygenation and ventilation, while minimizing ventilator-associated lung injury. The potential role of adjunctive therapies used with HFOV (e.g., prone ventilation, inhaled nitric oxide, aerosolized vasodilators, liquid ventilation) will require further research.
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Critical care medicine · Apr 2003
Case Reports Multicenter Study Clinical TrialDetecting life-threatening lactic acidosis related to nucleoside-analog treatment of human immunodeficiency virus-infected patients, and treatment with L-carnitine.
Our first objective was to determine a blood lactate threshold predictive of survival in human immunodeficiency virus patients experiencing lactic acidosis related to nucleoside analogs, and second, to test l-carnitine for the treatment of patients exceeding that threshold. ⋯ The blood lactate levels in human immunodeficiency virus patients receiving nucleoside-analog therapy can predict mortality in these patients. The preliminary data from this pilot study suggest that l-carnitine may be helpful for patients who have nucleoside-analog-related lactic acidosis with blood lactate levels >10 mmol/L. Further studies will be necessary to affirm the therapeutic efficacy of l-carnitine in this setting.