LEARNING OBJECTIVE: Recall the principles and guidelines for surgical aseptic technique, and determine the correct sterilization process for different types of materials.
As used in this discussion, surgical aseptic technique is the term used to describe the sterilization, storage, and handling of articles to keep them free of pathogenic organisms. The following discussion will address the preparation and sterilization of surgical equipment and supplies, and the preparation of the operating room for performing a surgical procedure. It should be noted that specific methods of preparation will vary from place to place, but the basic principles of surgical aseptic technique will remain the same. This discussion will present general guidelines, and individual providers are advised to refer to local instructions regarding the particular routines of a specific facility.
Before an operation, it is necessary to sterilize and keep sterile all instruments, materials, and supplies that come in contact with the surgical site. Every item handled by the surgeon and the surgeon’s assistants must be sterile. The patient’s skin and the hands of the members of the surgical team must be thoroughly scrubbed, prepared, and kept as aseptic as possible.
During the operation, the surgeon, surgeon’s assistants, and the scrub medical technician must wear sterile gowns and gloves and must not touch anything that is not sterile. Maintaining sterile technique is a cooperative responsibility of the entire surgical team. Each member must develop a surgical conscience, a willingness to supervise and be supervised by others regarding the adherence to standards. Without this cooperative and vigilant effort, a break in sterile technique may go unnoticed or not be corrected, and an otherwise successful surgical procedure may result in complete failure.
To assist in maintaining the aseptic technique, all members of the surgical team must adhere to the following principles:
Methods of Sterilization
Sterilization refers to the complete destruction of all living organisms, including bacterial spores and viruses. The word “sterile” means free from or the absence of all living organisms. Any item to be sterilized must be thoroughly cleaned mechanically or by hand, using soap or detergent and water. When cleaning by hand, apply friction to the item using a brush. After cleaning, thoroughly rinse the item with clean, running water before sterilization. The appropriate sterilization method is determined according to how the item will be used, the material from which the item is made, and the sterilization methods available. The physical methods of sterilization are moist heat and dry heat. Chemical methods include gas and liquid solutions.
PHYSICAL METHODS.—Steam under pressure (autoclave) is the most dependable and economical method of sterilization. It is the method of choice for metalware, glassware, most rubber goods, and dry goods. All articles must be correctly wrapped or packaged so that the steam will come in contact with all surfaces of the article. Similar items should be sterilized together, especially those requiring the same time and temperature exposure. Articles that will collect water must be placed so that the water will drain out of the article during the sterilization cycle. A sterilizer should be loaded in a manner that will allow the free flow of steam in and around all articles. Each item sterilized must be dated with the expiration of sterility. Sterilization indicators must be used in each load that is put through the sterilization process. This verifies proper steam and temperature penetration.
The operating procedures for a steam sterilizer will vary according to the type and manufacturer. There are a number of manufacturers, but there are only two types of steam-under-pressure sterilizers. They are the
downward displacement and the pre-vacuum, high-temperature autoclaves.
Downward Displacement Autoclave.—In the downward (gravity) displacement autoclave, air in the chamber is forced downward from the top of the chamber. The temperature in the sterilizer gradually increases as the steam heats the chamber and its contents. The actual timing does not begin until the temperature is above 245°F (118°C).
Pre-vacuum, High-temperature Autoclave.— The pre-vacuum, high-temperature autoclave is the most modern and economical to operate and requires the least time to sterilize a single load. By use of a vacuum pump, air is extracted from the chamber before admitting steam. This pre-vacuum process permits instant steam penetration to all articles and through all cotton or linen dry goods. The sterilization time is reduced to 4 minutes. The temperature of the chamber is rapidly raised and held at 274°F (134°C). The cycle is timed automatically.
Sterilizing Times.—If the temperature is increased, the sterilization time may be decreased. The following are some practical sterilization time periods.
All operating rooms are equipped with high-speed (flash) sterilizers. Wrapped, covered, opened instruments placed in perforated trays are “flash” sterilized for 3 minutes at 270°F (132°C). Sterilization timing begins when the above temperature is reached, not before.
Dry-Heat Sterilization.—The use of dry heat as a sterilizing agent has limitations. It should be restricted to items that are unsuitable for exposure to moist heat. High temperatures and extended time periods are required when using dry heat. In most instances, this method often proves impractical. The temperature must be 320°F (160°C), and the time period must be at least 2 hours.
CHEMICAL STERILIZATION.—Only one liquid chemical, if properly used, is capable of rendering an item sterile. That chemical is glutaraldehyde. The item to be sterilized must be totally submerged in the glutaraldehyde solution for 10 hours. Before immersion, the item must be thoroughly cleansed and rinsed with sterile water or sterile normal saline. It should be noted that this chemical is extremely caustic to skin, mucous membranes, and other tissues.
The most effective method of gas chemical sterilization presently available is the use of ethylene oxide (ETO) gas. ETO gas sterilization should be used only for material and supplies that will not withstand sterilization by steam under pressure. Never gas-sterilize any item that can be steam-sterilized. The concentration of the gas and the temperature and humidity inside the sterilizer are vital factors that affect the gas-sterilization process.
ETO gas-sterilization periods range from 3 to 7 hours. All items gas-sterilized must be allowed an aeration (airing out) period. During this period, the ETO gas is expelled from the surface of the item. It is not practical here to present all exposure times, gas concentrations, and aeration times for various items to be gas-sterilized. When using an ETO gas-sterilizer, you must be extremely cautious and follow the manufacturer’s instructions carefully.
Preparation of Supplies for Autoclaving
Comply with the following guidelines in preparing supplies that are to be autoclaved.
The following are specific guidelines for sterilizing instruments, glassware, suture materials, and rubber latex materials.
Suture Material: Suture materials are available in two major categories: absorbable and non-absorbable. Absorbable suture materials can be digested by the tissues during the healing process. Absorbable sutures are made from collagen (an animal protein derived from healthy animals) or from synthetic polymers. Non-absorbable suture materials are those that effectively resist the enzymatic digestion process in living tissue. These sutures are made of metal or other inorganic materials. In both types, each strand of specifically sized suture material is uniform in diameter and is predictable in performance.
Modern manufacturing processes make all suture materials available in individual packages, presterilized, with or without a surgical needle attached. Once opened, do not resterilize either the individual package or an individual strand of suture material.
Rubber Latex Materials: