From the Guidelines
Hospital acquired pneumonia (HAP) is defined as a lung infection that develops 48 hours or more after admission to a hospital in patients who did not have pneumonia when they were admitted, characterized by new lung infiltrates on chest imaging along with clinical signs such as fever, purulent sputum, leukocytosis, and declining oxygenation. This definition is based on the most recent guidelines from the Infectious Diseases Society of America and the American Thoracic Society 1. HAP is distinct from ventilator-associated pneumonia (VAP), which specifically occurs in mechanically ventilated patients. The condition typically involves different pathogens than community-acquired pneumonia, often including more resistant organisms like Pseudomonas aeruginosa, Staphylococcus aureus (including MRSA), and various Enterobacteriaceae.
Some key points to consider in the definition and management of HAP include:
- The incidence of HAP ranges from 5 to more than 20 cases per 1000 hospital admissions, with the highest rates in immunocompromised, surgical, and elderly patients 1.
- HAP is associated with increased morbidity, mortality, and healthcare costs, with a mortality rate of approximately 20% in the ICU setting 1.
- Prevention strategies for HAP include good hand hygiene, early mobilization of patients, elevation of the head of the bed, and careful attention to oral hygiene.
- Treatment of HAP typically requires broad-spectrum antibiotics initially, with options including piperacillin-tazobactam, cefepime, or meropenem, often combined with vancomycin or linezolid if MRSA is suspected 1.
- The duration of therapy for HAP is typically 7 days, though this may vary based on clinical response.
It is essential to note that the definition and management of HAP may vary depending on the specific clinical context and the presence of underlying risk factors for infection with multidrug-resistant pathogens. Therefore, it is crucial to consider local microbiologic data and to tailor treatment recommendations to the individual patient's needs 1.
From the Research
Definition of Hospital Acquired Pneumonia
- Hospital acquired pneumonia (HAP) is defined as pneumonia that develops within 48 hours or more of hospital admission and which was not developing at the time of admission 2.
- Alternatively, it is also defined as the form of pneumonia where symptoms present after more than 2 days (> 48 hours) of admission to hospital or as late as 14 days of discharge from hospital 3.
Key Characteristics
- HAP is also known as nosocomial pneumonia (NP) 2.
- It is the second most common hospital infection, with ventilator-associated pneumonia being the most common intensive care unit (ICU) infection 2.
- The microbiology of HAP depends on the timing of onset, with early-onset HAP typically caused by endogenous community-acquired pathogens and late-onset HAP caused by potentially multi-drug-resistant nosocomial organisms 2.
Diagnosis and Treatment
- Accurate diagnosis of HAP is difficult and controversial, and may require the use of invasive quantitative culture techniques 2.
- Empiric antibiotic treatment should be prompt, starting on clinical suspicion, and based on local ICU pathogen epidemiology and antibiotic resistance patterns 2.
- Antibiotic treatment is key to the comprehensive treatment of HAP, and always requires the dosing of antibiotics near the upper limit of the possible range 3.