Seminars in respiratory and critical care medicine
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Semin Respir Crit Care Med · Feb 2006
ReviewSoluble triggering receptor expressed on myeloid cells and the diagnosis of pneumonia and severe sepsis.
The triggering receptor expressed on myeloid cells (TREM)-1 is a recently identified molecule involved in the inflammatory response. It belongs to the immunoglobulin superfamily and is expressed on the surface of neutrophils, mature monocytes, and macrophages. The engagement of TREM-1 synergizes with the Toll-like receptors signaling pathway in amplifying the inflammatory response mediated by several microbial components. ⋯ Besides its membranous form, a soluble counterpart of TREM-1 exists that is specifically released during several infectious processes. The measurement of that soluble form in biological fluids may be useful as a diagnostic tool, especially during severe sepsis and pneumonia. Moreover, the evolutionary pattern of TREM-1 may be interesting during the follow-up of septic patients.
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Semin Respir Crit Care Med · Feb 2006
ReviewSelective decontamination of the digestive tract: cumulating evidence, at last?
Selective decontamination of the digestive tract (SDD), an infection-control strategy designed to prevent nosocomial pneumonia in mechanically ventilated patients, has been implemented in numerous studies for more than 2 decades, but its role remains controversial. Sentinel studies in the 1960s and 1970s identified a link between colonization of the upper respiratory tract and subsequent increased risk of developing nosocomial pneumonia in critically ill patients. Studies in the 1980s found that prophylaxis with topical and systemic antibiotics to decontamination of the upper respiratory tract and gastrointestinal tract (particularly depleting gram-negative aerobic bacteria) was associated with lower rates of infections. ⋯ Because liberal use of SDD (or any antimicrobial prophylactic strategy) may lead to escalating antimicrobial resistance, the risk of resistance varies according to local pathogens and resistance patterns. This review describes the development of the SDD concept, discusses recently published trials, and develops points for discussion and research. Additional studies are required to further define appropriate indications and limitations of this preventative strategy.
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Semin Respir Crit Care Med · Feb 2006
ReviewTreatment failure in patients with ventilator-associated pneumonia.
Ventilator-associated pneumonia (VAP) is one of the most important infectious diseases in the intensive care unit (ICU). In some series the attributable mortality of VAP may reach 30%, and the adequacy of the initial empirical treatment greatly influences the prognosis. ⋯ Resolution of VAP depends not only on the accuracy of microbial diagnosis but also on comorbidities, the response of the host to the infection, concomitant infections, and the correct clinical diagnosis. Treatment failure can be defined by the pattern of resolution of VAP, which is clearly established in the literature.
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Semin Respir Crit Care Med · Feb 2006
ReviewDiagnosis and treatment of ventilator-associated pneumonia: fiberoptic bronchoscopy with bronchoalveolar lavage is essential.
The management of patients suspected of having ventilator-associated pneumonia (VAP) requires a strategy for diagnosis and treatment that is designated to: (1) identify patients with true lung bacterial infection; (2) determine the pathogen(s) responsible for pneumonia; (3) permit early selection of appropriate antimicrobial therapy; and (4) avoid indiscriminate administration of antibiotics. The use of bronchoscopic techniques to obtain bronchoalveolar lavage (BAL) specimens from the affected area in the lung allows definition of a strategy superior to that based exclusively on clinical evaluation. When BAL is performed before introduction of new antibiotics, it enables physicians to identify patients who need immediate treatment and help to select initial antibiotic therapy (with the results of direct examination of BAL liquid) and to withhold, deescalate, and/or optimize treatment (when the results of quantitative cultures are available), in a manner that is safe and well tolerated by patients. This strategy, based on clinical and bacteriological evaluation, prevents resorting to broad-spectrum drug coverage in all patients who develop signs and symptoms suggestive of pneumonia, thus minimizing the emergence of resistant flora, and redirects the search for another infection site.