The contact at ACCP is Kimberly Lynch who can be reached at (847) 498-8341 or at [email protected].
For Immediate Release
NEW RECOMMENDATIONS ISSUED FOR DIAGNOSING VENTILATOR-ASSOCIATED PNEUMONIA
The American College of Chest Physicians (ACCP) has issued new recommendations to assist physicians in the diagnosis of a serious and often fatal condition, ventilator-associated pneumonia.
The report assesses a number of diagnostic tools, procedures, and approaches. It includes a diagnostic algorithm to guide physicians through a series of steps in order to reach a basis for efficacious and focused treatment. It was published as a recent supplement to CHEST, the peer-reviewed journal of the ACCP.
Difficult to diagnose, ventilator-associated pneumonia (VAP) is a common disorder among patients in intensive care units (ICU) and long-term care facilities. It is associated with complications of intubation (insertion of a breathing tube into the mouth, nose, or trachea) and mechanical ventilator support. Depending on the population studied, the prevalence of VAP may range from as low as 6 per 100 patients (6%) to 52 per 100 patients (52%). Early-onset VAP occurs during the first 4 days of mechanical ventilation and often is caused by Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis. Each day the patient receives endotracheal intubation and mechanical ventilation, the crude rate of VAP increases by 1 to 3% and the risk of death increases twofold to 10-fold.
The new report, entitled "Evidence-Based Assessment of Diagnostic Tests for Ventilator-Associated Pneumonia," was prepared by the ACCP's Clinical Practice Guideline Panel.
Prior to the issuance of the panel report, there were few recommendations to guide physicians. This, according to Ronald F. Grossman, M.D., FCCP, the panel Chair, was largely due to concerns over diagnostic accuracy, reproducibility of results, diagnostic thresholds, nonstandardized methodology, and lack of data on clinical outcome.
The panel conducted an exhaustive literature search and solicited expert input. Studies were analyzed on the basis of scientific rigor and the applicability of findings outside the study settings.
The synthesis of the results of the studies provided the basis for developing recommendations. Recommendations were given a grade weight based on the scientific depth and merit. For example, an "A" was given to a recommendation based on direct scientific evidence. A "C" was given to a recommendation that was based on expert opinion alone.
The panel cautioned against undue reliance on radiologic diagnosis. "Chest radiographs," it said, "are not a reliable diagnostic tool, as there is only marginal reproducibility of the findings obtained from two readers." It also noted that the precise role of invasive testing in diagnosing VAP is controversial. It said that clinicians are increasingly turning to the protected specimen brush (PSB) and bronchoscopic BAL as two such invasive techniques.
The report said more studies are needed to determine the quality of these techniques even though both have been in use for several years. As part of its conclusions, the report said that an associated pneumonia should be suspected in patients receiving mechanical ventilatory support if two or more of the following clinical features are present: temperature of >38EC (>100.4EF) or <36EC (<96.8EF); leukopenia (an abnormal decrease in white blood cells) or leukocytosis (an abnormal increase in the number of circulating white blood cells); prurulent tracheal secretions; and decreased Pao2 (partial pressure of oxygen in arterial blood). In the absence of such findings, the report said, no further investigations are required, and observation will suffice. If two or more of the stated abnormalities are present, a chest radiograph should be evaluated, according to the report. If the findings from it are normal, other causes of the abnormal clinical features should be investigated. If the radiograph shows alveolar infiltrates or an air bronchogram sign, or if the findings have worsened, the panel recommends two options, one involving quantitative testing and the other empirical treatment and nonquantitative testing as outlined in the algorithm.
Despite the literature search and the intensive analysis, more research was seen as crucial by the panel. "Substantial gaps exist in the scientific knowledge of all of these (diagnostic) techniques," said Dr. Grossman. "The best example," he added, "is the lack of data from chest radiographs. Because many diagnostic techniques have not been standardized, reported data on sensitivity and specificity vary, and it is difficult to compare results between medical centers. We recommend formal outcome research with randomized controlled trials to assess various diagnostic and management strategies. This approach," he said, "would provide the opportunity to evaluate economic outcomes using cost-benefit, cost-effectiveness, and cost-utility analyses."
CHEST is published by the American College of Chest Physicians, which represents 15,000 members who provide clinical, respiratory, and cardiothoracic patient care in the U.S. and throughout the world.
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Reporters may wish to contact Kimberly Lynch of the ACCP at (847) 498-8341 for a copy of the supplement. She can also be reached by fax at (847) 498-5460 or by email at [email protected]. Dr. Grossman can be reached by phone at (416) 586-5168 or by email at [email protected].
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