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Query: UMLS:C0010200 (cough)
 23,843 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nosocomial pneumonia remains a common complication in patients treated with endotracheal intubation and mechanical ventilation and continues to have a significant impact on the mortality rate of these patients. Epidemiologic studies have shown that the risk of pneumonia increases with the duration of intubation but that the period of highest risk is the first 2 weeks of therapy. Gram-negative bacteria account for most nosocomial pneumonias in intubated patients, but Staphylococcus aureus may also play a role in what may be a polymicrobial infection. In the most seriously ill individuals, and in those treated with long-term mechanical ventilation, Pseudomonas aeruginosa is a common pathogen. Endotracheal intubation and mechanical ventilation predispose to pneumonia for a variety of reasons (see Fig. 1). The endotracheal tube can have direct effects on the airway that result in a reduction in local host defenses. Thus, mucosal injury can reduce mucociliary function, while upper airway defenses are bypassed and the effectiveness of cough is reduced. Indirectly, intubation can result in an enhanced capacity of tracheobronchial cells to bind gram-negative bacteria, an effect that favors airway colonization and pneumonia. The injury to the airway can create binding sites for bacteria in the basement membrane of the bronchial tree and the stimulation of the secretion of mucus, which then stagnates and can create potential sites for bacterial adherence. The endotracheal tube also enhances bacterial entry to the lung by serving as a reservoir for bacteria to remain sequestered, safe from host defenses. Respiratory therapy devices can allow bacteria to proliferate and can then introduce them into the patient if not handled properly. Finally, patients who are ill enough to require intubation also have disease-associated impairments in systemic host defense, which add to the impairments caused by the use of an artificial airway. The host defense impairments that occur in mechanically ventilated patients can lead to respiratory tract infection in the form of either febrile tracheobronchitis or pneumonia. The diagnosis of pneumonia in intubated patients is difficult and controversial. It can be made by either clinical criteria or microbiologic criteria, the latter by using a bronchoscopically directed protected specimen brush. Therapy of pneumonia in mechanically ventilated patients is not always successful, and systemic antibiotics may need to be supplemented by topical antimicrobials. No clearly effective prophylactic strategy currently exists, but our understanding of pneumonia pathogenesis has led to some promising directions. As more data are collected, inhaled antibiotics, selective digestive decontamination, and enhancement of host defenses by cytokines and pre-formed antibodies may emerge as useful approaches.
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PMID:The impact of tracheal intubation on host defenses and risks for nosocomial pneumonia. 193 53

Nosocomial pneumonia occurs in 0.6% of hospitalized patients. The usual causative agents are gram-negative bacilli, Staphylococcus aureus, Streptococcus pneumoniae, and anaerobic bacteria. In immunocompromised hosts, the differential diagnosis also includes fungi, mycobacteria, viruses, Nocardia, and Pneumocystis carinii. Important risk factors for the development of nosocomial pneumonia include prolonged mechanical ventilation, thoracic or upper abdominal surgery, altered mental status, underlying immunosuppression, chronic obstructive pulmonary disease, and the use of antacids or histamine type 2 blockers. Colonization of the oropharynx and tracheal secretions with gram-negative aerobic bacteria is common in hospitalized patients with or without pneumonia. The diagnosis of nosocomial pneumonia is usually based on the clinical features of dyspnea, cough, fever, purulent sputum production, new pulmonary infiltrates, hypoxemia, and leukocytosis. However, the clinician must recognize that the presence of these features is neither sensitive nor specific in the diagnosis of nosocomial pneumonia. Microbiologic diagnosis is also difficult because blood cultures are usually negative, and cultures of tracheal secretions, although usually sensitive, are not specific. Invasive procedures may prove useful, but most have yet to be studied in large groups of patients with nosocomial pneumonia.
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PMID:Diagnosis of nosocomial pneumonia. 304 15

Nosocomial pneumonia remains an important problem in patients undergoing mechanical ventilation, being associated with high mortality and morbidity and considerable expenditure. In the past respiratory equipment has been implicated in the development of nosocomial pneumonia and strict recommendations for cleaning and maintenance have been practiced. It is now known that the circuit and other equipment rapidly become contaminated with microorganisms originating from the patient's upper airway flora. These organisms access the circuit through suctioning and coughing, and may contaminate distant sites by traveling in association with aerosols or condensate. Current evidence suggests that circuit contamination usually is a result rather than a cause of airway colonization and does not have an important role in the pathogenesis of nosocomial pneumonia. Provided that reasonable infection control measures are taken, circuit contamination does not pose a risk to the ventilated patient. Although bacterial filters placed in the circuit effectively prevent circuit contamination they do not significantly reduce the incidence of nosocomial pneumonia in patients receiving mechanical ventilation.
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PMID:The role of filtration during humidification. 964 91

The second most common nosocomial infection in the United States is pneumonia, with the highest rates seen in patients requiring mechanical ventilation. Nosocomial pneumonia is a serious disease associated with significant morbidity and mortality; crude mortality rates have been estimated at 20% to 50%. The rapid institution of appropriate antimicrobial therapy has been shown to improve mortality in patients with ventilator associated nosocomial pneumonia. Thus, the identification of nosocomial pneumonia with a timely microbiologic diagnosis is important for the management of these patients. However, the accurate diagnosis of nosocomial pneumonia, along with identification of the responsible organism(s), can be challenging. This task becomes even more difficult in patients who are mechanically ventilated. The presence of new pulmonary infiltrates along with clinical criteria including fever, cough, and purulent secretions are neither sensitive nor specific for the diagnosis of nosocomial pneumonia. The laboratory can enhance the accuracy of pneumonia diagnosis, as well as provide the identification of an etiologic organism(s). There are, however, many challenges which confront the laboratory including: the ability to identify organisms from an extensive microbiologic spectrum; distinguishing colonization from infection of predominately gram-negative oropharyngeal flora; and providing timely results. This article reviews the various diagnostic tests available for nosocomial lung infections, and in particular, ventilator associated pneumonia including: blood cultures; pleural fluid; expectorated sputum; endotracheal aspirates; and respiratory specimens obtained by more invasive techniques using bronchoscopy and transthoracic needle aspiration. Emphasis is placed on optimal specimen collection, the processing of samples in the laboratory, and on the evaluation of potential risks and benefits associated with the varying techniques.
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PMID:Laboratory diagnosis of nosocomial pneumonia. 1098 30