Update on the diagnosis and treatment of hospital-acquired pneumonia

Key Points

Abstract

Hospital-acquired pneumonia (HAP) is a frequently occurring complication of endotracheal intubation and hospitalization that is associated with a significant increase in morbidity, mortality, and cost of care. Diagnosis is difficult because of the reliance on clinical parameters and noninvasive methods for microbial diagnosis. The most recent published guidelines for the diagnosis and treatment of HAP, as well as ventilator-associated pneumonia (VAP) and healthcare-associated pneumonia (HCAP), highlight the use of invasive techniques for microbial identification and the importance of appropriate stratification of patients at risk of infection caused by drug-resistant pathogens. The importance of appropriate empirical antimicrobial selection and antimicrobial de-escalation based on culture data and the use of shorter treatment courses are key recommendations. Newly approved antibacterials have marginally expanded the current antibiotic armamentarium for treatment of HAP and VAP. Development of antibiotics with unique mechanisms of actions and in vitro activity against extremely drug-resistant gram-negative pathogens is of the utmost importance. (Formulary. 2008;43:250–258.)

HAP is defined as pneumonia occurring ≥48 hours after hospital admission that was not incubating at the time of admission.⁴ Rates of pneumonia are higher for patients in the ICU than for those on hospital wards, and the risk for developing pneumonia is 3- to 10-fold higher for intubated patients.^1,2,4,7 VAP is defined as pneumonia occurring 48 to 72 hours after intubation.⁴ HCAP occurs in patients from the community who reside in long-term care facilities or nursing homes; visit hemodialysis clinics or hospitals; were hospitalized for ≥2 days within the last 90 days; or received intravenous (IV) antibiotic therapy, chemotherapy, or wound care within the past 30 days.⁴

VAP is described as either early onset or late onset, depending on whether the pneumonia occurred within or after the first 4 days of endotracheal intubation, respectively. This distinction is significant, as causative bacteria, and therefore empiric antimicrobial selection and disease prognosis, differ.² The primary risk factor for VAP is endotracheal intubation. Rates of crude mortality for VAP range from 24% to 76%, with higher rates for patients infected with pathogens such as Acinetobacter species, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA).^6,8,9 Advanced age, prolonged intubation, underlying cardiopulmonary compromise, and immunosuppression are established risk factors for increased mortality due to VAP.^2,10,11