Conference Summary: Ventilator-Associated Pneumonia

Abstract

Ventilator-associated pneumonia (VAP), which is usually defined as an infection occurring greater than 48 hours after hospital admission in a patient requiring mechanical ventilation, is an entity that should be viewed as a subcategory of health-care-associated pneumonia, which includes any patient who was hospitalized in an acute care hospital for 2 or more days within 90 days of the infection; resided in a nursing home or long-term care facility; received recent antibiotic therapy, chemotherapy, or wound care within the past 30 days of the current infection; or attended a hospital or hemodialysis clinic. VAP is the most frequent intensive-care-unit (ICU)-acquired infection among patients receiving mechanical ventilation. In contrast to infections of other frequently involved organs (eg, urinary tract and skin), for which mortality is low, the mortality rate for VAP ranges from 20% to 50% and can reach 70% in some specific settings or when lung infection is caused by high-risk pathogens and/or when initial antibiotic therapy is inappropriate. Although the attributable mortality rate for VAP is still debated, it has been shown that these infections prolong both the duration of ventilation and the duration of ICU stay. These prolonged hospitalizations underscore the considerable financial burden imposed by the development of VAP. The causes of VAP are many and may vary by hospital, patient population, and type of ICU, emphasizing the need for timely, local surveillance data. In many cases infection is caused by multiple-drug-resistant pathogens. Risk factors for such resistant microorganisms are the duration of mechanical ventilation, prior antibiotic treatment, and contact with the health care system. Preventive measures should be guided with regard to a full understanding of pathogenesis and epidemiology. Because respiratory-tract colonization of ICU patients is generally very complex, corresponding to a mix of self-colonization and cross-transmission, only a multifaceted and multidisciplinary program can be effective. Antimicrobial therapy of patients with VAP should follow a 2-stage process. The first stage involves administering broad-spectrum antibiotics to avoid inappropriate treatment in patients with true bacterial pneumonia. The second stage focuses on trying to achieve this objective without overusing and abusing antibiotics, combining a number of different steps, such as stopping therapy in patients with a low probability of the disease, streamlining treatment once the etiologic agent is known, switching to monotherapy after days 3–5, and shortening duration of therapy to 7–8 days, as dictated by the patient's clinical response to therapy and information about the bacteriology of the infection.