VAP - Lessons Learned from the Canadian VAP Study

The Optimal Management of Ventilator-Associated Pneumonia

Lessons Learned from the Canadian VAP Study

The VAP Study was a multicentered randomized trial of diagnostic tests and empiric antibiotic strategies in patients with suspected Ventilator-associated Pneumonia (VAP). The trial involved over 30 ICUs and randomized 740 patients. The trial was conducted under the auspices of the Canadian Critical Care Trials Group, was funded by the Canadian Institutes of Health Reserach, and was coordinated by the Clinical Evaluation Research Unit at the Kingston General Hospital. The main results from the trial were published in the New England Journal of Medicine and Critical Care Medicine and recently, an additional 12 secondary analyses and related papers were published in the Journal of Critical Care including our national guidelines for the prevention, diagnosis and treatment of VAP.

The main findings from this study, which apply to the average ICU patient with suspected VAP, were:

~To diagnose VAP, it does not matter whether you use standard endotracheal aspirate (ETA) or bronchoscopy with quantitative cultures (BAL). Provided you standardize your response to culture results and tailor therapy accordingly, either BAL or ETA will result in the same outcomes.

Heyland DK, Cook D, Dodek P, Muscedere J, Day A for the Canadian Criticial Care Trials Group. A randomized trial of diagnostic techniques for ventilator-associated pneumonia. N Engl J Med 2006(Dec);355(25):2619-30. Abstract Full text pdf

~Immediately following the diagnostic test, all patients with suspected VAP should receive empiric, broad spectrum antibiotics.

Heyland DK, Dodek P, Muscedere J, Day A, Cook D. Randomized trial of combination versus monotherapy for empiric treatment of suspected ventilator-associated pneumonia. Crit Care Med 2008;36(3):737-744. Abstract Full text pdf

~There is no value to considering the previous ETA culture results, current Gram stain findings, the Clinical Pulmonary Infection Score or physician's pre-test likelihood that the patient has VAP in adjusting or withholding empiric antibiotics. Wait for definitive culture results and then discontinue or de-escalate antibiotics as appropriate.

Muscedere JG, McColl C, Shorr A, Jiang X, Marshall J, Heyland DK. Determinants of outcome in patients with a clinical suspicion of ventilator associated pneumonia. J Crit Care 2008;23:41-49. Abstract Full text pdf

Albert M, Friedrich JO, Adjikari NKJ, Day AG, Verdant C, Heyland DK. Utility of gram stain in the clinical management of suspected ventilator-associated pneumonia: secondary analysis of a multicentre randomized trial. J Crit Care 2008;23:74-81. Abstract Full text pdf

Sanders K, Adhikari NK, Friedrich JO, Day A, Jiang X, Heyland DK. Previous cultures are not clinically useful for guiding empiric antibiotics in suspected ventilator associated pneumonia: secondary analysis from a randomized trial. J Crit Care 2008;23:58-63. Abstract Full text pdf

Lauzier F, Ruest A, Dodek P, Albert M, Shorr AF, Day A, Jiang X, Heyland DK. The value of pretest probability and modified clinical pulmonary infection score to diagnose ventilator-associated pneumonia. J Crit Care 2008;23:50-57. Abstract Full text pdf

~Patients who had their antibiotics discontinued or de-escalated in response to cultures did better or the same than those who remained on broad-spectrum antibiotics without justification (based on culture result).

Joffe AR, Muscedere J, Marshall JC, Su Y, Heyland DK. The safety of targeted antibiotic therapy for ventilatory associated pneumonia: a multicenter observational study. J Crit Care 2008;23:82-90. Abstract Full text pdf

~When prescribing broad-spectrum antibiotics for patients with suspected VAP, monotherapy would be sufficient except when patient has risk factors for Pseudomonas and Multi-Drug Resistant Bacteria. These risk factors include hospitalization (> 48 hours) prior to ICU admission, prior use of antibiotics, and prolonged ICU length of stay (or late VAP). In these cases, two agents with anti-pseudomonal activity prescribed empirically may result in better microbiological and clinical outcomes than one agent.

Parker C, Kutsogiannis J, Muscedere J, Cook D, Dodek P, Day A, Heyland DK. Ventilator-associated pneumonia caused by multidrug-resistant organisms or pseudomonas aeruginosa: prevalence, incidence, risk factors, and outcomes. J Crit Care 2008;23:18-26. Abstract Full text pdf

~Patients who grow a pathogen on their diagnostic culture and are receiving appropriate empiric antibiotics will have the best clinical outcome. Patients who have "no growth" or a "negative culture" actually have the worst outcome (highest mortality rate and longest length of stay). Patients who grow Candida species in their respiratory tract secretions (and nothing else) also have a poor outcome. We hope to conduct a future study to evaluate whether Candida in the respiratory tract secretions requires treatment with anti-fungal agents.

Delisle MS, Williamson DR, Perreault MM, Albert M, Jiang X, Heyland DK. The clinical significance of candida colonization of respiratory tract secretions in critically ill patients. J Crit Care 2008;23:11-17. Abstract Full text pdf

~The failure of the temperature and the oxygen requirements to resolve over the first 3 days are the best indicators to assess how the patient is responding to treatment.

Shorr AF, Cook D, Jiang X, Muscedere J, Heyland DK. Correlates of clinical failure in ventilator-associated pneumonia: insights from a large, randomized trial. J Crit Care 2008;23:64-73. Abstract Full text pdf

As we go forward, we will continue our efforts to generate new knowledge and we look forward to your ongoing support. In addition, we will increasingly focus our efforts on the adoption of new knowledge for patient care. ABATE VAP, which aims to implement clinical practice guidelines for VAP through educational efforts, is the main venue for this. Only through the generation and implementation of new knowledge can we hope to reduce the morbidity and mortality of our patients.

Click here for more information about the ABATE VAP Study.