Critical care medicine
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Critical care medicine · Mar 2005
Review Comparative StudyProtocols for lung protective ventilation.
Protocols have a well-established role in clinical research and are increasingly being used to direct routine clinical care. In this article, we review the differing goals of research and clinical protocols and outline the similar process for their development. We use the mechanical ventilation protocol of the ARDS Network trial comparing small with traditional tidal volumes as an example. As a starting point for debate, we also suggest guiding principles and specific components of a protocol for high-frequency oscillatory ventilation.
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Critical care medicine · Mar 2005
ReviewHigh-frequency oscillatory ventilation: lessons learned from mechanical test lung models.
Review data obtained from high-frequency oscillatory ventilation (HFOV) and mechanical test lung models with respect to delivered tidal volume, distal pressure transmission, endotracheal tube cuff leaks, and simulated clinical conditions. ⋯ Mechanical test lung and artificial trachea simulations may provide useful information on the interaction of HFOV with altered lung mechanics and may contribute to the formulation of HFOV clinical strategies. Important limitations of these models include absence of gas exchange, histologic and biologic markers, or hemodynamic data.
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Critical care medicine · Mar 2005
Calpain inhibition decreases endothelin-1 levels and pulmonary hypertension after cardiopulmonary bypass with deep hypothermic circulatory arrest.
Cardiopulmonary bypass in infants and children can result in cardiopulmonary dysfunction through ischemia and reperfusion injury. Pulmonary hypertension and injury are particularly common and morbid complications of neonatal cardiac surgery. Inhibition of calpain, a cysteine protease, has been shown to inhibit reperfusion injury in adult organ systems. The hypothesis is that calpain inhibition can alleviate the cardiopulmonary dysfunction seen in immature animals following ischemia and reperfusion with cardiopulmonary bypass. ⋯ The reduction in plasma endothelin-1 and maintenance of lung endothelial nitric oxide levels after cardiopulmonary bypass and deep hypothermic circulatory arrest with calpain inhibition were associated with reduced pulmonary vascular resistance. Improved gas exchange and higher systemic oxygen delivery suggest that calpain inhibition may be advantageous for reducing postoperative cardiopulmonary dysfunction commonly associated with pediatric heart surgery and cardiopulmonary bypass.
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Critical care medicine · Mar 2005
Characteristics and outcomes of cancer patients requiring mechanical ventilatory support for >24 hrs.
To describe the characteristics of a large cohort of cancer patients receiving mechanical ventilation for >24 hrs and to identify clinical features predictive of in-hospital death. ⋯ Severity of acute organ failures, poor performance status, cancer status, and older age were the main determinants of mortality. The appropriate use of such easily available clinical characteristics may avoid forgoing intensive care for patients with a chance of survival.
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Critical care medicine · Mar 2005
ReviewClinical use of high-frequency oscillatory ventilation in adult patients with acute respiratory distress syndrome.
High-frequency oscillatory ventilation (HFOV) is an emerging ventilatory strategy for adults that has been used successfully in the neonatal and pediatric population. This modality utilizes high mean airway pressures to maintain an open lung and low tidal volumes at a high frequency that allow for adequate ventilation while at the same time preventing alveolar overdistension. With the current understanding that excessive lung stretch and inadequate end-expiratory ventilatory volume may be injurious to the lungs, HFOV seems to be the ideal lung-protective ventilatory mode. During the past 8 yrs, there have been increasing numbers of studies describing its use in adult patients with acute respiratory distress syndrome. This article aims to review the published studies of HFOV in adults with acute respiratory distress syndrome with regard to its safety and efficacy. ⋯ HFOV seems to be safe and effective for adults with severe acute respiratory distress syndrome who have failed conventional ventilation. Further research is needed to determine the ideal patients, timing, and optimal technique with which to provide HFOV. When considering HFOV as an early, lung-protective mode of ventilation, there is still a need to perform an adequately powered, randomized, controlled trial comparing it with the best available form of conventional ventilation. However, we believe that such a trial should wait until we have a better understanding of HFOV in adults.