Chapter 19: Healthcare-Acquired Infections

INTRODUCTION

A healthcare-associated infection (HAI), or nosocomial infection, is defined as a localized or systemic condition resulting from the presence of an infectious agent(s) or its toxin(s) that develop in a hospital or other healthcare facility that were not present or incubating at the time of admission.¹ Healthcare-associated infections increase healthcare costs and contribute to extended intensive care unit (ICU) length of stay and increased morbidities. Mortality rates associated with healthcare-associated infections are significantly higher than those associated with community-acquired infections. While reports vary, recent data suggests that on a given day, 1 of every 25 inpatients at US acute care hospitals had at least 1 HAI.² Recent estimates suggest that the annual direct cost of HAIs to the healthcare system is approximately $6.65 billion.³ Risk factors for development of an HAI include length of hospital stay, the presence of a central catheter, presence in a critical care unit, and mechanical ventilation. The leading causes of HAIs include pneumonias, surgical-site infections (SSIs), gastrointestinal infections (including those caused by Clostridium difficile), catheter-associated urinary tract infections, and bloodstream infections.²

INFECTION CONTROL

The mode of infection that develops in the hospital is thought to be due to either (1) autoinfection or an infection that was present with the patient on admission but without signs or symptoms of infection or (2) cross-contamination or the patient acquires an infective agent in the hospital and subsequently becomes infected. Controlling the infection also requires separating the source and cutting the modes of transmission. There are standard, droplet, airborne, contact, neutropenic, and bone marrow transplant precautions.

Standard precautions include the use of handwashing, gloves, mask, eye protection and/or face shield, gown, patient care equipment, environmental control, and occupational health to prevent injuries from needles, scalpels, and other sharp devices. Controlling the infection also requires separating the source and cutting the modes of transmission.

Droplet precautions prevent the transmission of respiratory particles larger than 5 microns in size, and can travel up to 3 feet away.⁴ Transmission can occur when healthcare workers’ (HCWs) mucosal membranes (eyes, nose, and mouth) come in contact with the patient’s respiratory secretions. Patients should be in private rooms, although cohorting of patients with the same infection is appropriate. Surgical masks are advised for healthcare workers who come in direct contact with the patient. Because of the closed circuit and ventilator filters, transmission of organisms from patients who are intubated is unlikely. However, a surgical mask should still be worn, particularly when the patient is being transported, because the endotracheal tube can get disconnected.

Airborne precautions address respiratory particles smaller than 5 microns that can remain suspended in the air. Patients should be in private rooms with negative pressure and a minimum of 6 to 12 air changes per hour.⁴ Healthcare workers must wear respirators with 95% filtering efficiency. In order to function ...