Critical care medicine
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Critical care medicine · Mar 2005
ReviewHigh-frequency oscillatory ventilation and ventilator-induced lung injury.
Although mechanical ventilation is lifesaving for patients with acute respiratory distress syndrome, it can cause ventilator-induced lung injury. To minimize ventilator-induced lung injury, different ventilatory strategies have been developed. One of the strategies is the use of high-frequency oscillatory ventilation (HFOV). THEORETICAL BACKGROUNDS OF VENTILATOR-INDUCED LUNG INJURY AND HFOV: Because of the novel gas exchange mechanisms, HFOV can provide adequate gas exchange using extremely small tidal volumes and maintain high end-expiratory lung volume without inducing overdistension, which should result in minimization of ventilator-induced lung injury. ⋯ A recent clinical trial demonstrated early (<16 hrs) improvement in oxygenation with HFOV and a 30-day mortality of 37% with HFOV vs. 52% with pressure-controlled ventilation (p = .102), suggesting that HFOV is as effective and safe as the conventional strategy in adult acute respiratory distress syndrome. Future studies examining optimal algorithms of HFOV using clinically relevant animal models, and patients with acute respiratory distress syndrome, are imperative to determine whether the wide-spread application of HFOV is warranted in adult acute respiratory distress syndrome.
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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.
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Critical care medicine · Mar 2005
ReviewSedation, analgesia, and neuromuscular blockade for high-frequency oscillatory ventilation.
To provide a comprehensive review of the issue related to the administration of sedative, analgesic, and neuromuscular blocking agents (NMBA) to patients who are receiving ventilatory support for acute respiratory distress syndrome (ARDS) with high-frequency oscillatory ventilation. ⋯ A multidisciplinary, structured approach that is based on the considerations described should help achieve optimal results in this challenging patient population.
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Critical care medicine · Mar 2005
Comparative StudyPersistent elevation of high mobility group box-1 protein (HMGB1) in patients with severe sepsis and septic shock.
To study the systemic release and kinetics of high mobility group box-1 protein (HMGB1) in relation to clinical features in a population of patients with severe sepsis or septic shock and to compare these with the kinetics of the cytokines interleukin-6, interleukin-8, interleukin-10, and tumor necrosis factor-alpha. ⋯ This is the first prospective study assessing the release over time of HMGB1 in a population of patients with sepsis, severe sepsis, or septic shock. Levels remained high in the majority of patients up to 1 wk after admittance, indicating that the cytokine indeed is a downstream and late mediator of inflammation. Further studies are required to fully define the relationship of HMGB1 to severity of disease.
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Critical care medicine · Mar 2005
ReviewNoninvasive assessment of lung volume: respiratory inductance plethysmography and electrical impedance tomography.
Respiratory inductance plethysmography (RIP) and electrical impedance tomography (EIT) are two monitoring techniques that have been used to assess lung volume noninvasively. ⋯ The promise of monitoring techniques such as RIP and EIT is that they will guide lung protective ventilation strategies and allow the clinician to optimize lung recruitment, maintain an open lung, and limit overdistension. EIT is the only bedside method that allows repeated, noninvasive measurements of regional lung volumes. In the future, it will be important to standardize the definitions of alveolar recruitment and ultimately demonstrate the superiority of EIT-guided ventilator management in providing lung protective ventilation.