Moist heat, or steam heat, is the most effective method of sterilization, or eliminating microorganisms. An autoclave uses moist heat within a cylinder to sterilize medical instruments. The autoclave is also used to sterilize biological waste before it is disposed of; the level of steam produced within the autoclave causes coagulation of protein materials and results in irreversible damage to cells.
Using Paper Bags
Steam-permeable paper bags are used inside the autoclave to enclose reusable items. Before steaming, the bags are folded and taped closed. After sterilization, items remain in the bags until their next use.
Sterilizing Without Bags
Sometimes reusable instruments are sterilized in the autoclave without a bag. When this occurs, any tubular or conical instruments must be plugged with cotton wool to keep the interior of the instrument sterile after the process. Mesh baskets are used for small instruments. All lids are loosened to prevent explosion.
If steam does not reach all items in the autoclave, the sterilization process will be incomplete. Personnel must be careful to fill the autoclave only with the recommended number of instruments so that moist heat permeates throughout the cylinder. When using the autoclave, wear a lab coat, safety glasses and gloves that resist heat. The autoclave must be opened slowly after the steam cycle to prevent burns and glass breakage, allowing steam to escape before you attempt to completely open the cylinder. An autoclave is not intended for solvents, radioactive material or any volatile or corrosive chemicals. Do not attempt to clean a spill inside the autoclave before the cylinder is completely cooled. Never use your bare hands to retrieve broken glass. Sharp objects can poke through an autoclave bag and cause a needle-stick injury. For this reason, all sharps should be placed not in the autoclave but in an appropriate disposal container. Autoclave bags should be lifted out of the cylinder by the tops of the bags. Steam sterilization can make sharp edges blunt. Steam does not penetrate oil, grease or powder materials.