ISSN:1070-5295    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Because occult tissue hypoxia may contribute to the development of multisystem organ failure, monitoring of tissue oxygenation is an important goal of critical care. This has been accomplished most commonly by assessment of global (whole body) oxygenation. However, no global parameter provides a sufficient, reliable assessment of adequacy of global oxygenation for routine clinical application. In addition, such measurements do not reflect local oxygenation. A number of regional techniques have been devised, but none is well enough developed to be recommended. Finally, no method of tissue oxygenation assessment has been tested in a randomized, controlled trial to determine its effects on patient outcome.

ISSN:1070-5295    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Positive-pressure breaths can be categorized by three variables: the trigger, the limit, and the cycle. They interface the ventilator with the three variables of the breathing pattern: ventilatory drive, ventilatory requirements, and duration and ratio of inspiratory time to total breath cycle duration. The inspiratory effort necessary to trigger a breath is a significant part of the total inspiratory effort; optimization of the triggering mechanisms may improve patient to ventilator interaction. Setting ventilator flow as close as possible to patient's flow by appropriate setting of peak value and waveform profile will also improve patient to ventilator interactions. During pressure support ventilation, ineffective efforts and uncoupling between effort and ventilator output are due to the asynchrony between ventilator and patient's inspiratory time. They may be counterbalanced by adequate peak flow and flow threshold values. Proportional assist ventilation may optimize patient to ventilator interactions, but continuous monitoring of respiratory mechanics should be performed along with its definitive technologic implementation. Its clinical use should be continuously adapted to resistance and elastance measurements.

ISSN:1070-5295    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Adjunctive ventilatory strategies have been developed to improve oxygenation or CO2removal during mechanical ventilation of critically ill patients. These techniques allow the clinician to attain clinical goals at lower levels of ventilatory support. These innovative techniques accomplish gas exchange external to the lungs (extracorporeal and intravenacaval gas exchange), augment alveolar ventilation by decreasing the physiologic dead space fraction of each tidal breath (tracheal gas insufflation), or administer therapeutic agents designed to improve the ventilation-perfusion matching of the lung (nitric oxide, surfactant replacement therapy, perflu-orocarbon-associated gas exchange, and prone positioning). At the current state of development, each of these adjuncts is promising. However, most lack solid clinical data defining their role in the care of critically ill patients.

ISSN:1070-5295    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

The use of selective pulmonary vasodilators or vasoconstrictors is a new therapeutic option to improve arterial oxygenation in patients with ARDS. The objective of such a therapy is to reduce the need for high 02 concentrations and airway pressures, thereby decreasing ventilator-induced lung injury. Nitric oxide (NO) is one part of this approach. It is administered through the inhalation route in mechanically ventilated patients. It reduces the vasomotor tone of pulmonary vessels from the ventilated part of the lung. It also reduces pulmonary arterial pressure and alveolar deadspace. Aerosolized prostacyclin in doses as low as 2ng/kg/1/min is another means to improve arterial oxygenation, through a dilation of the vessels located in the ventilated part of the lung. Conversely, almitrine improves arterial oxygenation by reinforcing hypoxic pulmonary vasocon-striction. When combined with inhaled NO, the benefical effect of almitrine on arterial oxygenation is potentiated while its detrimental effects on the pulmonary circulation are blunted. Cyclooxygenase inhibitors also improve arterial oxygenation byr einforcing hypoxic pulmonary vasoconstriction. All these new treatments have profoundly changed the therapeutic strategy aimed at correcting life-threatening hypoxemia in patients with severe acute respiratory distress syndrome.

ISSN:1070-5295    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Respiratory muscle dysfunction has been implicated in the pathogenesis of ventilatory failure resulting from various diseases. Apart from its life-saving potential, positive-pressure mechanical ventilation has long been regarded as a therapeutic intervention that spares the respiratory muscles from an undue breathing workload. Over the past several years, increasing attention has been paid to patients' work of breathing during assisted forms of mechanical ventilation. Although ventilatory support has been used for more than two decades, only recently has clear insight been gained into the factors governing patient effort during its use. In this review, we focus on recent progress in this area and its relevance in the day-today management of critically ill patients requiring ventilatory support.

ISSN:1070-5295    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Acute lung injury is the end result of common pathways initiated by a variety of local or systemic insults leading to diffuse damage to the pulmonary parenchyma. Despite the accumulation of abundant information regarding the physiological and cellular basis of lung injury and increasingly sophisticated intensive care, an improvement in prognosis has lagged behind. It has become clear that there is not one mediator responsible for acute lung injury but rather a complex interplay exists between diverse proinflammatory (eg, lipopolysaccharide, complement products, cytokines, chemokines, reactive oxygen species, and eicosanoids) and anti-inflammatory (inter-leukin-10, interleukin-1-RA1PGI2) mediators. It is essential that we obtain a better understanding of the complexities of the acute inflammatory response if we are to successfully intervene to prevent or ameliorate tissue injury. The purpose of this review is to summarize recent developments that have contributed to our understanding of the basic mechanisms of lung injury. We focus on the persistence of the inflammatory response on a local and systemic level, including local mechanisms acting within the alveolar space regulating synthesis, release, and activation of inflammatory mediators; the balance of proteinases and antiproteinases; the abnormalities of surfactant; and the potential importance of endogenously released anti-inflammatory mediators. It is hoped that the results of these studies will provide insights into the pathogenesis of lung injury and lead to novel therapeutic strategies to prevent or ameliorate lung injury.

ISSN:1070-5295    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Numerous methods are commonly used to monitor lung function in the critically ill. Gas exchange is usually assessed from arterial blood gas pressures, whereas determination of the pressure-volume relation in the lungs permits the optimal adjustment of mechanical ventilatory support. Several indices have been designed to assist in predicting successful weaning from mechanical ventilation, but clinical assessment is still the most sensitive predictor.

ISSN:1070-5295    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Despite many advances in the treatment of ventilator-dependent patients cared for in ICUs, ventilator-associated pneumonia remains a frequent complication leading to mortality and morbidity. Over the past year, many important articles have been published dealing with the critical question of the relationship between the severity of underlying disease and the occurrence of ventilator-associated pneumonia and death. Pneumonia is the ICU-acquired infection that most frequently leads to mortality and has a poorer prognosis when it is caused by multiresistant bacteria, including gram-negative microorganisms such asPseudomonas aeruginosaorAcinetobacterspp or methicillin-resistantStaphylococcus aureus. This pejorative prognostic effect is stronger in patients with an intermediate level of severity of illness, and this risk increases with prolongation of the ICU stay.

ISSN:1070-5295    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Investigators are extending the scope of feasible therapeutic approaches to patients with acute pulmonary edema or acute respiratory distress syndrome. With the recognition of the complex pathophysiology of acute respiratory distress syndrome and the identification of numerous mediators, avenues of research have opened up leading to the exploration of potential therapies. Neutrophil elastase and arachidonic acid metabolites are mediators that, if effectively inhibited, could mitigate acute injury. Repletion of antioxidants and surfactant might also be of benefit. We continue to understand more fully the potential of inhaled nitric oxide to improve the detrimental vascular response seen in acute respiratory distress syndrome, and newer approaches to mechanical ventilation continue to be studied as we become cognizant of volutrauma. Other studies are identifying means to increase lung edema clearance. We provide here a synopsis of the research in these areas occurring in the past year.

ISSN:1070-5295    

出版商:OVID    

年代:1997

数据来源: OVID