Chapter 129: Healthcare-Acquired Pneumonia, Including Ventilator-Associated Pneumonia

Introduction

Healthcare-associated infections (HAIs) impose a significant economic and clinical burden on healthcare systems. The burden is magnified by increasing infection rates due to multi-drug resistant (MDR) pathogens. Nosocomial pneumonia remains an important etiology of HAIs and consists of three distinct entities: healthcare-associated pneumonia (HCAP), hospital-acquired pneumonia (HAP), and ventilator-associated pneumonia (VAP).¹ Definitions for each of these conditions can be seen in Table 129-1. Three device-associated HAIs are reported to the National Safety Healthcare Network (NHSN), the surveillance branch of the Centers for Disease Control and Prevention (CDC). These include central line–associated blood stream infection (CLABSI), catheter-associated urinary tract infection (CAUTI), and VAP. According to an annual summary by the NHSN published in 2008, VAP accounted for 15.9% of all the reported HAIs, placing third among device-associated HAIs.² Nosocomial pneumonia results in excess healthcare utilization and leads to greater mortality. This chapter focuses on the microorganisms responsible for infection, the complexities surrounding the diagnosis, and the preventive and therapeutic management strategies used to combat nosocomial pneumonia.

Epidemiology

HAP, although not a reportable infection, is thought to occur at a rate of 5 to 10 cases per 1000 hospital admissions, and numerous studies indicate that VAP occurs in 9% to 27% of all intubated patients.¹ In a 1-day prevalence study involving critically ill patients across Western Europe, pneumonia was the most common ICU-acquired infection occurring in 10% of patients and accounting for 47% of all ICU-acquired infections.³ An additional large study conducted in Europe revealed a similar pneumonia rate of 9%.⁴ These two studies, in addition to others,⁵ demonstrated that mechanical ventilation served as the most important risk factor for nosocomial pneumonia. Therefore, the CDC now reports the incidence of nosocomial pneumonia as cases per 1000 ventilator days.

The NHSN functions as the CDC's surveillance system for HAIs and collects data from more than 5000 participating healthcare facilities. The NHSN data summary report from 2010 categorized rates of VAP based on ICU location.⁶ Rates of VAP ...