Diagnostic techniques for ventilator-associated pneumonia: Conflicting results from two trials
Bibliographic record
Abstract
Expanded AbstractCitationA randomized trial of diagnostic techniques for ventilator-associated pneumonia. N Engl J Med 2006, 355:2619–2630 [1].BackgroundCritically ill patients who require mechanical ventilation are at risk for ventilator-associated pneumonia. Current data are conflicting as to the optimal diagnostic approach in patients who have suspected ventilator-associated pneumonia.MethodsObjectiveTo compare the quantitative culture of bronchoalveolar-lavage fluid and nonquantitative culture of endotracheal aspirate in critically ill patients with suspected ventilator-associated pneumonia, testing the hypothesis that bronchoscopy with quantitative culture would be associated with lower mortality rates and less use of antibiotics.DesignMulti-center non-blinded randomized controlled trial.Setting28 intensive care units (ICUs) across Canada and the United States.Subjects740 immunocompetent critically ill adult patients with suspected ventilator-associated pneumonia after 4 days in the ICU. Patients known to be colonized or infected with Pseudomonas species or methicillin-resistant Staphylococcus aureus were excluded.InterventionUsing a 2-by-2 factorial design, subjects were randomly assigned to a) undergo bronchoalveolar lavage with quantitative culture of the bronchoalveolar-lavage fluid or endotracheal aspiration with nonquantitative culture of the aspirate, and to b) receive empirical combination antibiotic therapy or monotherapy. Empirical antibiotic therapy was initiated in all patients until culture results were available, at which point a protocol of targeted therapy was used for discontinuing or reducing the dose or number of antibiotics, or for resuming antibiotic therapy to treat a pre-enrollment condition if the culture was negative.OutcomeThe primary outcome was 28-day mortality. Secondary outcomes included ICU and hospital survival, duration of mechanical ventilation, response to clinical and microbiologic treatment, discontinuation of antibiotics after culture results known, and other measures of antibiotic use.ResultsThere was no significant difference in 28-day mortality rate between the bronchoalveolar-lavage group and the endotracheal-aspiration group (18.9% and 18.4%, respectively; P = 0.94). The bronchoalveolar-lavage group and the endotracheal-aspiration group also had similar rates of targeted therapy (74.2% and 74.6%, respectively; P = 0.90), days alive without antibiotics (10.4 +/- 7.5 and 10.6 +/- 7.9, P = 0.86), and maximum organ-dysfunction scores (mean [+/- SD], 8.3 +/- 3.6 and 8.6 +/- 4.0; P = 0.26). The two groups did not differ significantly in the length of stay in the ICU or hospital.ConclusionTwo diagnostic strategies for ventilator-associated pneumonia – bronchoalveolar lavage with quantitative culture of the bronchoalveolar-lavage fluid and endotracheal aspiration with nonquantitative culture of the aspirate – are associated with similar clinical outcomes and similar overall use of antibiotics.Trial Registration(Current Controlled Trials number, ISRCTN51767272.)
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.028 | 0.077 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.011 | 0.013 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.006 | 0.005 |
| Insufficient payload (model declined to judge) | 0.011 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".