Bacterial Pulmonary Infection in PICU
Condition: Bacterial Infection
MeSH terms: Infections; Communicable Diseases; Bacterial Infections
Study type: Observational

Summary: 
      The purpose of this study is to develop a scoring system to allow doctors to accurately
      identify children on a mechanical ventilator who have bacterial pneumonia. Currently this
      diagnosis is very difficult to make, resulting in the overuse of antibiotics and the
      promotion of antibiotic-resistant bacteria in the pediatric intensive care unit (ICU). Four
      ICUs at 3 children's hospitals will participate. Study participants will include 150
      children, ages 2 months to 17 years old who require mechanical ventilation, and in whom the
      bedside health care providers suspect bacterial pneumonia. Bacteria will be studied by
      sampling lung fluid through the breathing tube less than 12 hours after starting antibiotics,
      using a procedure known as "non-bronchoscopic-bronchoalveolar lavage (NB-BAL)." Participants
      may be involved in study related procedures for up to 31 days.
    

Detailed description: 
      The primary objective of this prospective cohort study is to derive a clinical score for
      predicting the absence of bacterial pulmonary infection in children requiring mechanical
      ventilation. This study is in preparation for designing an interventional trial whose aim
      will be to reduce antibiotic use in the pediatric intensive care unit (ICU) and thereby
      reduce the incidence of acquisition of antibiotic resistant bacteria. Secondary study
      objectives are to: define key characteristics of bacterial pulmonary infection in children
      requiring mechanical ventilation: demographics, microbiology, and predisposing factors; and
      assess the duration and number of antibiotics used for the treatment of pneumonia in this
      study population and to further assess the amount of antimicrobial therapy that could
      potentially be avoided in patients with a low probability of bacterial pneumonia as
      determined by the scoring system. The study hypothesis is that a non-invasive clinical
      scoring system can be devised for bacterial pulmonary infection in children requiring
      mechanical ventilation, to identify a threshold score below which the probability of
      bacterial pulmonary infection is sufficiently low that the clinician can safely withhold or
      stop antibiotics. The primary outcome (bacterial pneumonia) will be defined as meeting the
      following 2 criteria: the presence of greater than 10,000 organisms/mL of one or more
      pathogenic bacterial species obtained by blind non-bronchoscopic bronchoalveolar lavage
      (NB-BAL) on Day 0 or the isolation of a pathogenic organism from pleural fluid culture
      obtained between Day -1 through Day 3, in a patient with a pulmonary infiltrate; and
      persistence of Day 0 pulmonary infiltrate on Day 3 based on a comparison of results of chest
      x-rays from Days 0 and 3. The secondary endpoint is the duration and number of antibiotics
      used, for the treatment of pneumonia in the study population and separately in subgroups
      defined by the threshold score for bacterial pneumonia. Potential predictive parameters for
      bacterial pulmonary infection will be calculated at the initiation of antibiotics and 3 days
      later. These parameters will include factors in the Clinical Pulmonary Infection Score (CPIS)
      developed for adult patients. Additional potential predictors of bacterial pulmonary
      infection that may be relevant in children also will be recorded and added to the model in an
      attempt to improve its predictive accuracy. Study outcome will be microbiologically defined
      bacterial infection, using quantitative lower respiratory tract specimens collected by blind
      NB-BAL at entry and persistence of infiltrate on chest x-ray at Day 3. The study population
      will include children, age greater than 48 weeks post-conception and less than 18 years,
      requiring mechanical ventilation in the pediatric ICU, presence of an abnormal chest x-ray,
      and initiation of antibiotics less than or equal to 12 hours prior to NB-BAL by the assigned
      health care providers for suspected bacterial pulmonary infection.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Children, ages > 48 weeks post-conception and < 18 years, requiring mechanical ventilation
        in pediatric ICU, presence of abnormal chest x-ray, and initiation of antibiotics (less
        than or equal to 12 hours prior to NB-BAL).
      
Biospecimen description: 
      Nasal aspirate, tracheal aspirate, and non bronchoscopic bronchoalveolar lavage.
    
Keywords: bacterial infection, pneumonia, ventilation, children