Sterilization Techniques Health Article

Definition

Sterilization techniques include all the means used to completely eliminate or destroy living microorganisms on any object, including tools used to test or treat patients.

Purpose

The term microorganism, or microbe, refers to any single-celled living organism, including bacteria, viruses, and fungi. (Though viruses are not true single-celled organisms, medical science still usually classifies them as microorganisms.) Microbes can be transferred by direct contact or indirectly through a vehicle (like a surgical tool) or via the air the patient breathes. If favorable conditions for growth exist in the new host, microbes reproduce and establish colonies. Many of these microscopic organisms are normal inhabitants of the human body (called microflora). For example, varieties of the bacterium Staphylococcus are normal inhabitants of the skin and nasal passages, and many different species of bacteria live in the small and large intestine, aiding in the process of digestion.

However, many types of microorganisms are pathogenic (considered foreign to the host body) and, upon entering the body, cause infection when they either damage cells directly or release toxins that will eventually cause damage. The prevention of disease-causing microbes in a patient-care environment is generally accomplished through aseptic or sterile techniques. The goal is to create as germ-free an environment as possible, primarily through sterilization and the maintenance of sterile/nonsterile barriers.

Precautions

Like foods sold in the grocery store, sterile medical and surgical solutions and some other equipment have expiration dates indicating when the product is no longer considered sterile. Although many hospitals consider sterile, prepackaged disposable materials to be sterile indefinitely if the packaging is undamaged, sterile goods must be examined carefully to ensure that there are no breaks in the integrity of the packaging or that the package has not gotten wet. Microbes are able to enter sterile goods through either breaks in the wrapping (the sterile barrier) or moisture. If the wrapper is no longer intact, or has been wet, sterile goods must be repackaged and resterilized.

Description

Patients having invasive medical or surgical procedures are at risk for infection primarily from four sources:

• Infection is transferred from other people, including patients and health care providers. Such infection is called direct transmission, which usually occurs as a result of direct contact with skin or bodily fluids, including saliva, coughing, and spitting.
• Infection results from equipment or other objects that come in contact with the patient. This is called vehicle-borne infection because the microbe is transported from another place on some object or vehicle and introduced through a break in the skin or mucosal membranes. Primary examples are food poisoning caused by contaminated food items or infection caused by the use of non-sterile equipment in an invasive pro cedure like bronchoscopy or phlebotomy.
• Infection arises from the patient's own body, such as the possible contamination of a surgical site during intestinal resection if the patient's own fecal material contaminates the abdominal cavity contents.
• The air transports microbes. An example of air-borne infection is tuberculosis, in which bacteria are transmitted on air currents to others through coughing or spitting.

Managing as germ-free an environment as possible is necessary for surgical procedures and even minor medical treatments normally done in a doctor's office, such as suturing a laceration. Patients with conditions or under treatments that cause the immune system to be compromised are sometimes treated in an artificially created environment called reverse isolation. Leukemia patients, especially those on aggressive chemotherapy who receive bone marrow transplants and people with immunodeficiency disorders (which can lead to little or no natural defense against infection), are all potential candidates for reverse isolation procedures. Patients with AIDS (acquired immune deficiency syndrome) may be treated in an environment of isolation, both direct and reverse isolation for their protection, as well as the protection of caregivers. An extreme example of reverse isolation is the use of a sterilized plastic tent with filtered air circulation called an isolator. (Premature infants may be placed in special sterile plastic bassinets called an isolette.)