Ventilator-associated Pneumonia

Diagnosis
Fagon J, Chastre J, Wolff M, et al. Invasive and noninvasive strategies for management of suspected ventilator-associated pneumonia. Ann Intern Med 2000;132:621-30. Randomized study found use of BAL or PSB to dictate antibiotic treatment in suspected VAP resulted in lower mortality at 14 days and less antibiotic use compared to standard approach of clinical impression coupled with endotracheal aspirates. Initiation of antibiotic treatment for VAP was withheld until after obtaining specimens and antibiotics were stopped if cultures were negative. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=10766680

Chastre J, Fagon J, Bornet-Lesco M, et al. Evaluation of bronchoscopic techniques for the diagnosis of nosocomial pneumonia. Am J Respir Crit Care Med 1995; 152:231-240. Study compared immediate post-mortem BAL and PSB to lung biopsy histology and culture and found bronchoscopic specimens had a sensitivity of 82-91% and specificity of 78-89% compared to the gold standard of lung biopsy cultures, provided patients had no recent antibiotic changes prior to death and had not developed pneumonia prior to the terminal phase of their disease. Pertinent in that the above study by Fagon et al is predicated on the belief that BAL and PSB accurately diagnose VAP. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=7599829

Kirtland SH, Corley DE, Winterbauer RH, et al. The diagnosis of VAP: a comparison of histologic, microbiologic, and clinical criteria. Chest 1997;112:445-57. Study with a similar design to the Chastre study but without restrictions on use of antibiotics or recent pneumonia. Authors found poor correlation between histologic findings and quantitative cultures from bronch specimens. Tracheal aspirates were 87% sensitive but 31% specific compared to biopsy culture. A sterile BAL had a PPV of 91% for sterile lung parenchyma. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9266883

Canadian Critical Care Trials Group. A randomized trial of diagnostic techniques for ventilator-associated pneumonia.  N Engl J Med. 2006; 355:2619-30.Randomized trial (N= 740) found the use of bronchoalveolar-lavage with quantitative culture vs. routine culture of endotracheal-aspiration resulted in similar clinical outcomes and antibiotic use when used for the diagnosis of ventilator-associated pneumonia. The exclusion of immunocompromised patients and those infected or colonized with MRSA or Pseudomonas, the format for empiric antibiotic use, and the criterion for a positive BAL culture are concerns raised about the applicability of the findings. http://www.ncbi.nlm.nih.gov/pubmed/17182987?ordinalpos=6&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum  

Prevention and treatment
Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia: Official statement of ATS and IDSA 2004. Am J Respir Crit Care Med 2005; 171:388-416. This in-depth evidence-based guideline on the management of nosocomial pneumonia emphasizes early collection of lower respiratory tract samples, early institution of antibiotics, a shorter duration of antibiotics for uncomplicated pneumonia, and use of linezolid, colistin, inhaled antibiotics, and combination therapy. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15699079                                                                                                               

Chastre J, Wolff M, Fagon J et al. Comparison of 8 vs. 15 days of antibiotic therapy for ventilator-associated pneumonia in adults. JAMA 2003;290:2588-98. RCT comparing 8 vs. 15 days of antibiotic in 401 immunocompetent patients with VAP (diagnosed by bronchoscopic quantitative cultures) found no difference in pulmonary infection recurrence, 28-day mortality, ventilator free-days, organ failure-free days, and length of ICU stay between groups. The 8-day group had a higher recurrence of pulmonary infections due to non-lactose fermenting gram negative rods, including Pseudomonas aeruginosa (41% vs. 25%).  This article constitutes the main evidence supporting shorter duration of VAP treatment in the above IDSA/ATS guidelines. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=14625336