Sterilizing Your Instruments

Sterilizing Your Instruments

Sterilizing Your Instruments

The delivery of sterile products for use in patient care depends not only on the effectiveness of the sterilization process but also on the unit design, decontamination, disassembling and packaging of the device, loading the sterilizer, monitoring, sterilant quality, and quantity, and the appropriateness of the cycle for the load contents, and other aspects of device reprocessing. 

Midwives should perform most cleaning, disinfecting, and sterilizing of patient-care supplies in a central processing location (either at an office, birth center, or home) in order to more easily control quality. The aim of central processing is the orderly processing of instruments to protect patients from infections while minimizing risks to staff and preserving the value of the items being reprocessed.

Sterilizing Your Instruments

Consistency of Sterilization 

Ensuring consistency of sterilization practices requires a comprehensive program that ensures operator competence and proper methods of cleaning and wrapping instruments, loading the sterilizer, operating the sterilizer, and monitoring of the entire process. Furthermore, care must be consistent from an infection prevention standpoint in all patient-care settings.

All steam, ETO, and other low-temperature sterilizers are tested with biological and chemical indicators upon installation, when the sterilizer is relocated, redesigned, after major repair, and after a sterilization failure has occurred to ensure they are functioning prior to placing them into routine use.

Three consecutive empty steam cycles are run with a biological and chemical indicator in an appropriate test package or tray. Each type of steam cycle used for sterilization (e.g., vacuum-assisted, gravity) is tested separately. In a pre-vacuum steam sterilizer, three consecutive empty cycles are also run with a Bowie-Dick test. The sterilizer is not put back into use until all biological indicators are negative and chemical indicators show a correct end-point response.

Biological and Chemical Indicator 

Biological and chemical indicator testing is also done for ongoing quality assurance testing of representative samples of actual products being sterilized and product testing when major changes are made in packaging, wraps, or load configuration. Biological and chemical indicators are placed in products, which are processed in a full load. 

When three consecutive cycles show negative biological indicators and chemical indicators with a correct end-point response, you can put the change made into routine use. Items processed during the three evaluation cycles should be quarantined until the test results are negative.

The central processing area(s) ideally should be divided into at least three areas: decontamination, packaging, and sterilization and storage. Physical barriers should separate the decontamination area from the other sections to contain contamination on used items. In the decontamination area, reusable contaminated supplies (and possibly disposable items that are reused) are received, sorted, and decontaminated. The recommended airflow pattern should contain contaminates within the decontamination area and minimize the flow of contaminates to the clean areas.

Sterilization Process 

Cleaning reduces the bioburden and removes foreign material (i.e., organic residue and inorganic salts) that interferes with the sterilization process by acting as a barrier to the sterilization agent. Instruments are generally presoaked or pre-rinsed to prevent the drying of blood and tissue. 

Precleaning in a birth room or home setting may be needed on items that are heavily soiled with feces, sputum, blood, or other materials. Items sent to central processing without removing gross soil may be difficult to clean because of dried secretions and excretions. Cleaning and decontamination should be done as soon as possible after items have been used.

Several types of mechanical cleaning machines (e.g., utensil washer-sanitizer, ultrasonic cleaner, washer-sterilizer, dishwasher, and washer-disinfector) may facilitate the cleaning and decontamination of most items. This equipment often is automated and may increase productivity, improve cleaning effectiveness, and decrease worker exposure to blood and body fluids. Delicate and intricate objects and heat- or moisture-sensitive articles may require careful cleaning by hand. 


All used items sent to the central processing area should be considered contaminated (unless decontaminated in the area of origin), handled with gloves (forceps or tongs are sometimes needed to avoid exposure to sharps), and decontaminated by one of the aforementioned methods to render them safer to handle. 

Items composed of more than one removable part should be disassembled. Care should be taken to ensure that all parts are kept together so that reassembly can be accomplished efficiently.

Personnel working in the decontamination area should wear household-cleaning-type rubber or plastic gloves when handling or cleaning contaminated instruments and devices. Face masks, eye protection such as goggles or full-length face shields, and appropriate gowns should be worn when exposure to blood and contaminated fluids may occur (e.g. when manually cleaning contaminated devices). 


Contaminated instruments are a source of microorganisms that could inoculate personnel through non-intact skin on the hands or through contact with the mucous membranes of the eyes, nose, or mouth. Reusable sharps that have been in contact with blood present a special hazard. Employees must not reach with their gloved hands into trays or containers that hold these sharps to retrieve them. Rather, employees should use engineering controls (e.g., forceps) to retrieve these devices.

Once items are cleaned, dried, and inspected, those requiring sterilization must be wrapped or placed in rigid containers and should be arranged in instrument trays/baskets according to the guidelines provided by the AAMI and other professional organizations.


These guidelines state that hinged instruments should be opened; items with removable parts should be disassembled unless the device manufacturer or researchers provide specific instructions or test data to the contrary; complex instruments should be prepared and sterilized according to device manufacturer’s instructions and test data; devices with concave surfaces should be positioned to facilitate drainage of water; heavy items should be positioned not to damage delicate items; and the weight of the instrument set should be based on the design and density of the instruments and the distribution of metal mass.

 While there is no longer a specified sterilization weight limit for surgical sets, heavy metal mass is a cause of wet packs (i.e., moisture inside the case and tray after completion of the sterilization cycle). Other parameters that may influence drying are the density of the wraps and the design of the set.

There are several choices in methods to maintain sterility of surgical instruments, including rigid containers, peel-open pouches (e.g., self-sealed or heat-sealed plastic and paper pouches), roll stock or reels (i.e., paper-plastic combinations of tubing designed to allow the user to cut and seal the ends to form a pouch) and sterilization wraps (woven and nonwoven).