INTRODUCTION
The regulations promulgated to implement the amended Animal Welfare Act require that all survival surgery be performed using aseptic procedures. This includes the use of surgical gloves, masks, sterile instruments and aseptic technique.
In this chapter, the Principles of Aseptic Technique will be discussed with the emphasis on the practical application of these principles in the laboratory set ting. In centralized experimental surgeries , a well-trained staff should be available to advise those who use such facilities and oversee its operation to ensure the maintenance of an aseptic environment for survival surgery. When survival surgery is conducted outside such an environment, it is th e principal investigator's responsibility to ensure that appropriate aseptic conditions and practices are maintained. This chapter will provide the necessary information to carry out this responsibility.
Prior to discussing the specific principle s of aseptic surgery a brief review of pertinent terminology is necessary.
TERMINOLOGY
Antimicrobial - An agent or action that kills or inhibits the growth of micro-organisms.
Antiseptic - A chemical agent that is applied topically to inhibit the growth of micro-organisms.
Asepsis - Prevention of microbial contamination of living tissues or sterile materials by excluding, removing or killing micro-organisms.
Autoclave - A steam ste rilizer consisting of a metal chamber constructed to withstand the pressure that is required to raise the temperature of steam to the level required for sterilization. Early models were termed "autoclaves" because they were fitted with a self-closing door .
Bactericide - A chemical or physical agent that kills vegetative (non-spore forming) bacteria.
Bacteriostat - An agent that prevents multiplication of bacteria.
Commensals - Non-pathogenic micro-organisms tha t are living and reproducing as human or animal parasites.
Contamination - Introduction of micro-organisms to sterile articles, materials or tissues.
Disinfectant - An agent that is intended to kill or remove pathogenic micro -organisms, with the exception of bacterial spores.
Pasteurization - A process that kills nonspore-forming micro-organisms by hot water or steam at 65-100oC.
Pathogenic - A species that is capable of causing disease micro-or ganism in a susceptible host.
Sanitization - A process that reduces microbial contamination to a low level by the use of cleaning solutions, hot water or chemical disinfectants.
Sterilant - An agent that kills all types of mi cro-organisms.
Sterile - Free from micro-organisms.
Sterilization - The complete destruction of micro-organisms.
Since the pioneering work of such surgeons as Joseph Lister, who introduced the use of carbolic acid ant iseptics in 1865, and William Halstead, who advocated the use of surgical gloves in 1898, surgeons have strived to eliminate surgical infections through the use of aseptic technique. Potential sources of contamination are well defined. They include the pa tient and the surgical environment: the surgeon and support staff, the instruments, sutures, drapes and all other equipment which can have contact with the surgical field.
FACILITIES
The basis for this discussion about facilities wi ll be the recommendations for Aseptic Surgery contained in the Guide for the Care and Use of Laboratory Animals. The Guide states:
"Functional areas for aseptic surgery should include a separate support area, a preparation area, the operating room or rooms and an area for intensive care and supportive treatment of animals. The interior surfaces of this facility should be constructed of materials that are impervious to moisture and easily cleaned. The surgical support area should be d esigned for storing instruments and supplies for washing and sterilizing instruments. Items that are used on a regular basis, such as anesthetic machines and suture materials, can be stored in the operating room."
"There should be a separate surgi cal preparation area for animals. An area equipped with surgical sinks should be close to, but apart from, the operating room. A dressing area should be provided for personnel to change into surgical attire."
The surgical facility should be locate d outside normal facility traffic patterns. This can help to minimize the potential for surgical suite contamination by the movement of personnel and equipment. Personnel access to these areas should be restricted to essential surgical support staff.
Ideally, the operating room ventilation system should provide a net positive pressure with respect to the surrounding facilities. The system should be regularly monitored. Maintenance work should be performed when the surgery is idle. Ventilation filte rs should be inspected and cleaned or replaced at regular intervals. If explosive anesthetics agents are to be used, the Guide recommends that floors should be conductive and electrical outlets should be explosion-proof and located not less than 5 feet off the floor. Dedicated surgical facilities should be used for aseptic surgeries and the storage of essential surgical equipment, not as general storage space.