ISSN:1070-5295    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The lung is homogeneously affected by the disease process during the early phase of acute respiratory distress syndrome. This leads to an homogeneous alteration of the vascular permeability. Consequently, the edema accumulates evenly in all lung regions (nongravitational distribution). The increased lung weight, through the transmission of hydrostatic forces, however, causes a collapse of the lung regions along the vertical axes (compression atelectasis). At plateau pressure, the pulmonary units reopen, and during the following expiration they stay open, if the applied positive end-expiratory pressure is adequate. Positive end-expiratory pressure is adequate if it is equal or higher than the hydrostatic forces compressing that unit. Prone position is another maneuver effective in keeping open pulmonary units that were previously collapsed. During late acute respiratory distress syndrome, the compression atelectasis does not exist due to the edema reabsorption, and the lung undergoes structural changes, usually associated with carbon dioxide retention and development of emphysema-like lesions.

ISSN:1070-5295    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

The gastrointestinal tract seems to play a central role in the pathogenesis of pneumonia in critically ill patients. During the past decade, several strategies have been developed that aim to prevent or reduce gastrointestinal colonization and thereby to prevent pneumonia. Acid-independent stress ulcer prophylaxis and selective digestive decontamination are among those most widely discussed. There is strong evidence now that in general, drugs that alter the gastric pH (eg, antacids, H2-antagonists) facilitate respiratory tract infections in patients ventilated for more than 3 days, as compared with sucralfate, which does not. pH-independent stress ulcer prophylaxis can be considered as a physiologic approach, however limited, for the prevention of nosocomial infections, whereas selective digestive decontamination is a much more aggressive approach with potentially greater efficacy, but also clinically relevant side effects. Selective digestive decontamination effectively prevents gram-negative respiratory infections, although the major effect seems to be on tracheobronchitis and not on pneumonia. The implementation of intravenous antibiotics to oropharyngeal and intestinal decontamination seems to be an essential component for achieving full efficacy. Resistance has now become a problem at least in some hospitals, with methicillin-resistantStaphylococcus aureusstrains being the most important problem. The lack of cost-effectiveness in many countries and the growing problem of resistance are significant objections against the widespread use of selective digestive decontamination. If stress ulcer prophylaxis is achieved with sucralfate, only specific subgroups of patients still benefit from selective digestive decontamination. However, intestinal decontamination should be administered 2 hours prior to sucralfate to avoid antibiotic inactivation.

ISSN:1070-5295    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Although nosocomial pneumonia remains a major cause of morbidity and mortality, the diagnosis and treatment of this infection remain controversial. Key questions include: 1) how should an appropriate “gold standard” for diagnosis be defined, 2) is there a role for early treatment in decreasing mortality, 3) is monotherapy effective, and 4) what is the impact of invasive diagnostic testing on outcome? This incomplete knowledge base leads to differing opinions and practice patterns. Several recent key articles have shed light on the controversies in both the diagnosis and treatment of nosocomial pneumonia. In this review, we highlight these new findings and incorporate them into an overall treatment plan for patients with nosocomial pneumonia.

ISSN:1070-5295    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Nitric oxide is a major endogenous mediator of various physiologic processes, including the modulation of the systemic and pulmonary vascular tone. In this article, we review recent papers analyzing the physiologic importance of nitric oxide in modulation of the pulmonary vascular tone, mechanisms of nitric oxide release in the pulmonary circulation, as well as putative mechanisms, consequences, and new therapeutic options of an impaired nitric oxide release in diseases associated with pulmonary hypertension.

ISSN:1070-5295    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

A large body of literature, including six randomized studies, supports applying noninvasive positive-pressure ventilation via mask in patients with chronic obstructive pulmonary disease and acute respiratory failure as an early intervention to prevent deterioration to the point of requiring endotracheal intubation or as an alternative to endotracheal intubation in those with the most severe impairment in gas exchange. Correctly applying noninvasive positive-pressure ventilation results in rapid improvement in the pathophysiology of acute respiratory failure and correction of arterial blood gas abnormalities. A reduction in Pco2or an increase in pH within 1 to 2 hours of noninvasive positive-pressure ventilation predicts a sustained improvement in gas exchange and shorter duration of ventilatory support. Under adequate monitoring, the risk of postponing endotracheal intubation in patients in whom noninvasive positive-pressure ventilation fails (20% to 30%) is minimal.

ISSN:1070-5295    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Tracheostomy is one of the most frequently performed operations in critically ill patients. Indications are relief of airway obstruction, airway protection, provision of long-term positive pressure ventilation, and pulmonary toilet. The appropriate timing of tracheostomies is controversial. Tracheostomy should be performed as soon as it can be determined that the patient will need a long-term artificial airway. However, recent reports suggest that early tracheostomy is beneficial. Bedside percutaneous dilational tracheostomy is a recently described alternative to standard surgical tracheostomy. Percutaneous dilational tracheostomy makes operating room use unnecessary, thereby providing logistic benefits. The risks of patient transport are eliminated, and tracheostomy can be done more expeditiously once the decision is made to perform tracheostomy.Percutaneous dilational tracheostomy is a faster procedure to perform, has lower postoperative complication rates, and costs less than operative tracheostomy. These considerations make percutaneous dilational tracheostomy the procedure of choice in most critically ill patients who require a tracheostomy.

ISSN:1070-5295    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Intensivists need to reevaluate high-frequency ventilation, whether their focus is adult or neonatal and pediatric disease. A recent consensus conference on adult mechanical ventilation recommended the goals of reversing atelectasis while avoiding overdistension. Both extremes of lung volume independently produce ventilator-induced lung injury. Currently these very treatment goals are being achieved in pediatric and neonatal critical care using high-frequency ventilation. The inflammatory process that fuels the acute respiratory distress syndrome can be moderated by achieving alveolar recruitment through the use of high-frequency oscillatory ventilation. Reassuring reports indicate that high-frequency ventilation does not increase the risk of adverse neurologic outcomes even in the very low birth weight infant. Combined therapies show benefit from the use of high-frequency oscillatory ventilation after surfactant and in the infant receiving pulmonary vasodilator therapy with nitric oxide. Complex transport theory is becoming clinically useful as the alveolar distension risks of high-frequency oscillatory ventilation are analyzed in terms of operating frequency and positive end-expiratory pressure levels. The emerging issues are those of timing of institution of high-frequency ventilation within the continuum of care now available.

ISSN:1070-5295    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Total liquid ventilation has been shown to be beneficial in neonatal respiratory distress syndrome and in animal models of acute respiratory failure with respect to reducing barotrauma and improving gas exchange. However, the extra technological requirements do not make total liquid ventilation a practical technique. In this respect the technique of partial liquid ventilation may be promising. Partial liquid ventilation allows ventilation of a lung that is filled only partially with perfluorocarbon with a conventional ventilator. Partial liquid ventilation combines user-friendliness with the same advantages of total liquid ventilation in respiratory failure, including improving lung mechanics and improving gas exchange and minimizing histo-logic abnormalities in comparison to conventional ventilation. Some studies indicate an impairment of the pulmonary surfactant system after partial liquid ventilation. The technique is currently under investigation in clinical trials in neonates and adults with acute respiratory failure.

ISSN:1070-5295    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Lung injury can be produced by mechanical ventilation. Accordingly, ventilatory strategies less likely to cause further injury are currently being investigated. Ventilating patients with acute respiratory distress syndrome in the prone position was first shown to be beneficial in 1977. This review summarizes recent studies concerning the determinants of regional ventilation, regional perfusion, and the gravitational gradient of pleural pressure. These findings, along with physiologic principles that were elucidated more than 20 years ago, provide an explanation for the beneficial effect of the prone position. In theory, ventilator-induced lung injury is least likely to occur when patients receive ventilation in the prone position.

ISSN:1070-5295    

出版商:OVID    

年代:1996

数据来源: OVID