Available online http://ccforum.com/content/12/3/157
Commentary
Ventilator-associated tracheobronchitis (VAT): questions,
answers, and a new paradigm?
Donald E Craven1,2
1Department of Infectious Diseases, Lahey Clinic Medical Center, 41 Mall Road, Burlington, MA 01805, USA
2Tufts University School of Medicine, Boston, MA, USA
Corresponding author: Donald E Craven, donald.e.craven@lahey.org
Published: 18 June 2008 Critical Care 2008, 12:157 (doi:10.1186/cc6912)
This article is online at http://ccforum.com/content/12/3/157
© 2008 BioMed Central Ltd
See related research by Nseir et al., http://ccforum.com/content/12/3/R62
Abstract lower respiratory tract is impeded by the endotracheal tube,
Nosocomial lower respiratory tract infections are a common cause patient sedation, and a reliance on mechanical suctioning
of morbidity and mortality in intensive care unit (ICU) patients. rather than spontaneous coughing. The lower respiratory
Although many studies have investigated the management and tract in the ventilated patient is a continuous ‘battleground’
prevention of ventilator-associated pneumonia (VAP), few have between the numbers, types, and virulence of the incoming
focused on ventilator-associated tracheobronchitis (VAT). In this bacteria versus the lung’s incredible mechanical, cellular, and
issue of Critical Care, Nseir and coworkers present interesting
humoral defenses. The outcome for each patient is either
data from a randomized controlled study of antimicrobial therapy
for VAT. Patients randomly assigned to antibiotic therapy had more lower airway colonization or shades of grey from VAT to VAP.
mechanical ventilation-free days (P < 0.001), fewer episodes of
VAP (13% versus 47%; P < 0.001), and a lower ICU mortality rate Diagnoses of both VAT and VAP rely on clinical and systemic
(18% versus 47%; P = 0.05) than those without antibiotic therapy. signs of infection (fever, leukocytosis, reduced oxygenation)
Although this study has limitations, the data suggest that VAT may plus purulent sputum with high concentrations of bacteria
be an important risk factor for VAP or overlap with early VAP. More
(≥105-6 colony-forming units [cfu]/mL) in the endotracheal
importantly, targeted antibiotic therapy for VAT may improve
patient outcomes and become a new paradigm for prevention or aspirate. Diagnoses of VAP rely on distal samples of bacteria
early therapy for VAP. obtained from bronchoscopic and non-bronchoalveolar
lavage (≥104 cfu/mL) [2] or protected specimen brush (PSB)
In this issue of Critical Care, Nseir and coworkers [1] provide (≥103 cfu/mL). Definitions of VAT and VAP have been based
interesting data from a randomized trial of antibiotic therapy on different sampling techniques and microbiologic
for ventilator-associated tracheobronchitis (VAT). Although thresholds, which may make discrimination between VAT and
ventilator-associated pneumonia (VAP) has been the major VAP difficult. Although VAP requires evidence of a new and
focus of critical care providers, perhaps our focus should also persistent infiltrate on a chest x-ray, the sensitivity and
include VAT, which may be a precursor to VAP or overlap specificity of x-rays are variable and, though improved with
with early VAP [1-5]. Understanding VAT may have important computerized tomographic scans, still have limitations,
implications for the early diagnosis, therapy, and prevention of especially in patients with severe congestive heart failure or
VAP. In comparison with VAP, VAT is plagued by little clinical adult respiratory distress syndrome.
data and several questions: How do we define it? How much
does it overlap with VAP? What level of bacteria in For VAP, and probably VAT, early appropriate antibiotic
endotracheal aspirates is diagnostic? When is antibiotic therapy improves patient outcomes [1,2]. Nseir and co-
therapy indicated and for how long [5]? workers [4] reported an observational cohort of medical and
surgical intensive care unit (ICU) patients who had a 10.6%
Most bacteria enter the lower respiratory tract by leakage of incidence of VAT. VAT was associated with an increased
bacteria and oropharyngeal secretions around the endo- length of stay (LOS) in the ICU and more mechanical
tracheal tube cuff, resulting in colonization, VAT, or VAP [2]. ventilator days, but those receiving antimicrobial therapy had
Furthermore, the primary exit route for bacteria out of the a trend toward decreased LOS, fewer mechanical ventilator
cfu = colony-forming units; ICU = intensive care unit; ITT = intention-to-treat; LOS = length of stay; PSB = protected specimen brush; VAP = venti-
lator-associated pneumonia; VAT = ventilator-associated tracheobronchitis.
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