Worth a Snot: A pilot study examining bronchoscopy with bronchial alveolar lavage vs quantitative endotracheal aspirates for pneumonia diagnosis in the trauma and acute care surgery population.

Authors:
Hannah Paik, Thomas Schroeppel, Brett Fair, Nathan Schmoekel, Paige Clement, Alyssa Douville

Body of Abstract:
Background:

Bronchoscopy with bronchial alveolar lavage (BAL) is the gold standard for diagnosing pneumonia in acute care surgery patients. The Infectious Disease Society of America as well as the American Thoracic Society recommend against routine bronchoscopy and BAL for diagnosis of pneumonia, as this is considered an invasive and costly procedure. However, both of these organizations represent medical specialties, and the question remains: for the trauma and acute care surgical population, can a quantitative endotracheal tracheal aspirate (ETA) be used to replace bronchoscopy and BAL for both screening and diagnosis of pneumonia? We hypothesized that a quantitative ETA could be used in place of BAL as a less invasive, more cost-effective method of confirmatory diagnosis for pneumonia.

Methods:

A retrospective analysis of prospectively collected data was completed at a level one trauma center where BAL is routinely used to screen for community acquired pneumonia and diagnose ventilator associated pneumonia (VAP). Patients who underwent a BAL for screening or diagnostic reasons had an ETA specimen collected from a new inline suction catheter. Quantitative cultures were performed on both the BAL and ETA samples. Descriptive statistics were performed on the study population. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for ETA using BAL as the gold standard test.

Results

Thirty patients received ETA and BAL quantitative specimens over the four-month study period. The majority of these patients (93%) were trauma patients. The most common reason for ventilation was traumatic brain injury. Most patients were male (66%) with mean age of 42 years (IQR 15,86). Of the thirty specimens compared 90% were concordant. Organisms of the specimens were the same 100% of the time. Patients with VAP had K. aerogenes most commonly, with other organisms including E. coli, MSSA and S. pneumoniae. When diagnosing pneumonia, the ETA was found to have a 100% sensitivity and an 88% specificity. The positive predictive value was 50% and the negative predictive value of 100%. Overall, preliminary data demonstrates a 90% accuracy.

Conclusions

In this pilot study, preliminary data shows quantitative ETA could provide a less invasive and cost-effective alternative to the BAL. More research is needed to validate the ETA and to determine what level of accuracy is clinically acceptable.