Radiology has an important role in imaging patients, and stringent infection control measures need to be implemented to stop the spread of infection. The goal is to reduce the risk of infection to staff, as well as cross-contamination among patients.
Spread of infection within a hospital or health care setting requires three major elements: a source of infecting organisms, a means of passing the organism to someone else (route of transmission), and a person who has no immunity to the disease (susceptible host). In addition, exit and entrance portals and an infectious dose of the infecting organism are required.
Susceptibility to disease can vary greatly. When exposed to an infectious organism, some persons are immune or are able to resist colonization, while others may become infected, yet have no symptoms of infection. Still others will become visibly ill. Standard precautions should be practiced for the care of all patients in the radiology department, regardless of their diagnosis or presumed infection status. This practice is the primary strategy for successful nosocomial (hospital-acquired) infection control.
Routes of transmission
Organisms that cause infection are spread by specific routes of transmission, and some are transmitted by more than one route. The four main routes of disease transmission are:
Contact. This is the most frequent means of transmission of infectious organisms; it can involve direct (physical transfer of organisms between persons) or indirect (with an inanimate object) contact, droplet contact (respiratory or oral secretions), or invasive (blood, injuries with sharps) contact.
Airborne. This occurs when moisture in respiratory droplets evaporates, leaving infectious organisms suspended in the air. Dust particles can also be carriers for airborne microorganisms. Some organisms transmitted by this route are mycobacterium tuberculosis (TB), chickenpox and measles.
Common vehicle transmission. This route, in which disease is spread through contaminated food, water, medications, devices or equipment, is rare in health care facilities.
Vector transmission. This route, in which disease is spread by mosquitoes, ticks, fleas, vermin, is also rare in U.S. health care facilities.
Prevention and control
Hand hygiene is the most important means of preventing the spread of infection. This consists of combining soap, water, friction and rinsing for a minimum of 10 seconds when hands are visibly soiled, or the use of alcohol-based hand sanitizers when hands are not visibly soiled. Hand hygiene should be performed before starting patient care, as needed during the care of the patient, after taking care of patients and after removing gloves. Gloves are not a substitute for hand hygiene, although they play an important role in reducing the risk of transmission.
Gloves are worn to provide a protective barrier and to prevent gross contamination of the hands when touching blood, body fluids, secretions, excretions, mucous membranes and non-intact skin. Wearing gloves in specified circumstances, to reduce the risk of exposure to blood-borne pathogens, is mandated by the Occupational Safety and Hazard Administration (OSHA). Wearing gloves also reduces the likelihood that microorganisms present on the hands of personnel will be transmitted to patients during invasive, or other radiological procedures, that involve touching a patient’s mucous membranes and non-intact skin. It also reduces transmission from patient to staff to patient. Gloves must be changed between patient contacts, and hands washed after gloves are removed. Wearing gloves does not take the place of hand hygiene, because gloves may have small, unapparent defects, or may be torn during use.
Protective face gear (masks and eye protection with side shields) should be worn when necessary, to prevent splash of blood and moist body substances into the eyes, mouth and nose. They should be worn only once and then discarded, not lowered around the neck and re-used.
Gowns should be worn whenever necessary, to prevent soiling of clothing when performing radiological procedures, to reduce the risk of exposures to blood-borne pathogens, when blood or body fluids are present. Gowns should be worn once and then discarded.
Respirator masks approved for use with TB must be worn for care of patients having known or suspected infectious pulmonary TB disease. If the patient has a disease that can be spread via airborne route, the patient should wear a mask while in the radiology department. The patient should be instructed to cover the nose and mouth with a tissue when coughing or sneezing, and be separated as much as possible from other patients.
Sharps should be handled with caution at all times, to prevent needle stick injuries. Needles should never be re-capped, purposely bent or broken, and immediately placed in a designated puncture-resistant sharps disposal container at the point of use by the person who used the sharp.
All waste generated in the radiology department, including patient-generated waste and disposable medical supplies, is considered potentially infectious, and is to be discarded into plastic-lined, biohazard-labeled waste receptacles. Soiled linen is also considered to be potentially infectious and should be placed into a leak-resistant bag.
Radiology treatment rooms require standardized, thorough cleaning of all rooms, including disinfecting equipment and environmental surfaces. X-ray tables, film cassettes and portable X-ray machines should be wiped down with EPA-approved disinfectant after each patient use.
Rooms used for invasive procedures should have traffic restricted to authorized personnel only. Procedures must be performed using strict aseptic technique. Physicians performing the procedure are required to wear sterile gowns, gloves, masks, and should practice barrier technique and precautions. The surgical site is prepped with a surgical scrub, and sterile sheets and drapes are utilized. Clean/sterile supplies are stored in dry, clean areas away from contaminated areas. These supplies should never be stored in boxes on the floor.
Radiological staff having signs/symptoms of infection must report to their supervisor, who will refer them to the employee health department, where appropriate action will be determined.
Staff in radiology departments must participate in in-service education, and be trained in OSHA and the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) requirements. They must also be familiar, and comply with, policies set forth in their department’s infection control manual. Darren Daigle, assistant director of medical imaging at Charlotte Regional Medical Center, Punta Gorda, Fla., insists on quality care, which he says, means meticulous infection control.
Know your infectious diseases
SARS-In Hong Kong, radiologists have developed protocols for examining patients suspected of having SARS, and minimize the risk of infection between patients, and to staff. The American Roentgen Ray Society (ARRS) recommends a list of useful tips, which can be found at: http://www.arrs.org/air/sars/sarssynopsis.html. Some of those tips include:
Facilities imaging patients with SARS should be situated outside the main department, if possible. If not, patients with SARS should be segregated
Specific rooms in the emergency room should be available for examining persons suspected of having SARS
Minimize congestion in the waiting room
Identify a department infection control team to draw up guidelines and insure they are enforced
Rotate staff to reduce viral load to individuals in high-risk areas
Restrict outpatient visitors
MRSA-All people carry bacteria on their skin and other body areas, but they do not cause illness in healthy people. People whose immune systems are compromised by illness or drugs, though, can get ill this way.
Methicillin Resistant Staphylococcus Aureus (MRSA) is an antibiotic resistant organism, a bacteria or germ that is not killed by the usual medicines. If an infection results from such an organism, a stronger drug must be used for treatment. The patient, visitors, and staff must use isolation precautions to prevent the spread of this infection. The patient is usually confined to his or her room, except when transported for tests or procedures. People entering or leaving the room (including visitors) should wear gloves, and wash their hands.
An article in the November 2002 issue of American Journal of Infection Control reports, “Health care workers who do not follow appropriate precautions are often responsible for nosocomial infections that are transmitted from one patient to another. Infection control guidelines recommend contact precautions for patients colonized or infected with multi-drug resistant organisms. They include the use of gloves, gowns and hand hygiene for each patient contact.”
VRE-Enterococci are bacteria typically found in the human bowel and normally do not cause disease. In recent years, due partly to overuse of antibiotics, strains of this organism have developed a resistance to Vancomycin, hence the name, Vancomycin Resistant Enterococci (VRE). It is not harmful to healthy individuals, but can cause problems for patients who are seriously ill and who have weakened immune systems.
Patients carrying VRE are usually not sick, but occasionally serious illness develops, such as a wound or blood infection. VRE is often discovered when a patient develops diarrhea caused by another bacteria. At risk for VRE are those patients:
Who have had therapy with Vancomycin or multiple antibiotics;
With serious medical or surgical conditions and weakened immune systems;
Who have had a prolonged hospital stay;
With in-dwelling devices (catheters).
VRE is found in large quantities in the bowel, and when outside the body, it can survive in the environment for long periods of time. It is spread by direct contact by a person with VRE, or with contaminated equipment or articles. Patients with known VRE are placed in isolation-a private room with a private bathroom is essential, and dedicated equipment is used to control the spread. Gloves and gowns should be worn by all persons entering the room, and scrupulous hand washing is extremely important.
Generally, VRE does not cause problems in the individual in whom it is discovered, but acts only as normal flora in the bowel. But, as it can be transmitted from one patient to another, it can lead to serious complications in those at risk.
In many hospitals across the nation, the medical imaging department is the hub of the facility. Inpatients and outpatients, alike, are the recipients of millions of imaging procedures a year. It behooves the imaging staff to contain, and stop the spread of infection for everyone’s sake.