Care and Sterilization of Instruments

Carol Olsen

The Arthur Smith Institute for Urology, Zucker School of Medicine at Hofstra/Northwell, Lake Success, NY, USA

History of sterilization

The creation and use of surgical instruments has occurred since prehistoric times. The effects of using instruments that were neither clean nor sterile were not a major concern in past eras. The methods for the care and sterilization of instruments have gone through a huge change and have greatly improved over the last few centuries. It was not until the nineteenth century that the development and recognition of a process for instrument sterilization occurred. During this time the focus on the need to sterilize instruments prior to a surgical procedure developed from the effects of post‐surgery wound management and the need to eliminate the increased infections of these wounds. This recognition led to the evolution and development of the current standard practice of instrument sterilization.

Noted in the nineteenth century, surgeons performed operations in their street clothes, which were often dirty, and they also reused instruments without a standard cleaning process. In 1864, Joseph Lister introduced the use of phenol, or carbolic acid, on inanimate objects and surfaces as well as human tissue, in hospital wards and operating rooms which resulted in a dramatic decrease in the incidence of wound infections. The carbolic acid was used in conjunction with other components to dress wounds in an antiseptic manner which prevented bacteria from entering the wound. This led Lister to introduce other methods of asepsis, such as sterilization of surgical instruments by applying heat and carbolic acid and the frequent cleaning of the surgeon’s hands during an operation. After publication of these findings, in the The Lancet in 1867 the “era of antiseptic surgery” was introduced into the field of medicine and surgery. By the year 1875 Lister’s principles of antiseptic surgery were accepted worldwide [1].

The steam autoclave was derived from a steam digester currently known as a pressure cooker invented by a physicist named Denis Papin in the late 1600s. By 1879, Charles Chamberland, a colleague of Louis Pasteur, made improvements to Papin’s invention and invented a porcelain dish with tiny holes that was able to filter microorganisms from liquid that was poured through this dish. This is known as the Chamberland filter or the Chamberland–Pasteur filter and with his further research in 1884 the autoclave was invented. The use of pressurized steam sterilization of instruments with an autoclave was introduced by Ernst von Bergmann in 1886.

Ethylene oxide (ETO) was first used in 1938 to preserve spices. In the 1950s, ETO was accepted by the medical device industry as a sterilant after a US army researcher investigated the microbicidal effect of ETO and published his findings [2]. This method of sterilization has been used for heat‐sensitive instruments, such as flexible scopes and lenses. In the early 1900s, urological instruments were sterilized in a formalin sterilizer and disinfected with a carbolic acid solution. The formalin sterilizer exposed instruments to heated formalin vapors for 2 hours and remained in the sterilizer until use [3].

Since the late 1980s other methods of sterilization were developed that were less caustic to instruments, required less process time, are noncarcinogenic, and allowed for sterile instrument availability. These methods have replaced some of the older sterilization methods.

Instrument processing

Any item, such as an instrument or medical device that is intended to be reused in a sterile procedure, must be processed in a specific manner, beginning with cleaning and ending with sterilization or high‐level disinfection (HLD). In order for sterilization or HLD of an item to be effective, the following steps must occur in a proper and adequate manner: precleaning, cleaning, decontamination, rinsing, drying, disinfection (includes HLD immersion and rinsing with sterile water) or sterilization, and storage. The necessary type of package or container preparation the item will be placed in is determined by the method of sterilization, such as a paper peel package or metal container. In some instances the item may be placed in storage until reuse, such as those that require, at the minimum, HLD.

Urologic instruments consist of reusable flexible cystoscopes, flexible ureteroscopes, flexing instruments for endoscopes, rigid cystoscopes, semi‐rigid ureteroscopes, transurethral resection instruments, rigid nephroscopes, laparoscopic instruments, metal dilators, various metal surgical instruments, and ultrasound probes, both external and internal (intracavity, endorectal, or prostate biopsy probes).

First the item should be categorized to determine which type of disinfection or sterilization method is recommended for processing. In 1968 Earl H. Spaulding categorized medical instruments and items used for patient care as critical, semicritical, and noncritical based on the degree of risk for infection with the processing and reuse of each item. These categories make up the Spaulding scheme or Spaulding classification system, which is a recognized resource when describing the appropriate disinfection and sterilization process for medical instruments and devices [4, 5]. Critical items are instruments which will come in direct contact with sterile tissue, enter the vascular system, or penetrate the skin. They require sterilization by such methods as steam, ETO, hydrogen peroxide gas plasma, or a liquid chemical sterilant such as peracetic acid [6]. Semicritical items are instruments which will come in contact with mucous membranes and require sterilization or at a minimum HLD. These items have been identified as high risk for transmitting infection [7]. Noncritical items are instruments or medical devices, such as a stethoscope or blood pressure cuff, which will come into contact with intact skin only and require intermediate to low‐level disinfection, such as an impregnated antimicrobial wipe. Neglect of low‐level disinfection can lead to cross‐contamination to the healthcare worker’s hands; reuse of the instrument or medical device with another patient also causes cross‐contamination [5, 8–10].

Utilization of a reusable instrument or medical device is a major risk due to the potential introduction of pathogenic microorganisms, which can lead to infection. Therefore, adequate cleaning is imperative to successfully eliminate the bioburden or microbes present on an instrument. Cleaning and decontamination of any level of item used in any type of healthcare facility is a mandatory requirement prior to reuse. Each facility must have a policy and procedure manual in place which identifies the process of cleaning or decontamination, followed by the process for disinfection or sterilization of these items when indicated.

Cleaning is the most important step in the process leading to sterilization or HLD and begins with physically removing microbes in preparation for the next step, which is decontamination [8]. There are different accepted methods for cleaning instruments prior to disinfection or sterilization. These are either manual or automated, which can include a washer/sterilizer, ultrasonic cleaner, or washer/decontaminator [11].

Prior to the cleaning process, any healthcare personnel must don personal protective equipment (PPE) to protect their eyes, skin, and clothing from splashing or droplet contact from any angle [12]. PPE includes eye protection (goggles or mask with shield), mask, impervious gown with long sleeves, gloves, hair bonnet or cap, and shoe covers to avoid exposure to microorganisms and for personal safety protection [6, 11]. After the cleaning and decontamination process, the PPE must be removed or doffed followed by hand hygiene practice [12].

Manual cleaning involves three components: a low‐sudsing detergent or enzymatic cleaner, a brush or sponge, and friction [13]. These components will ensure the removal of tissue and debris from an instrument. Manual cleaning of an item begins with immersion in a receptacle or deep sink filled with detergent or enzyme cleaner and warm water solution. Preparation of the detergent or enzymatic cleaner must follow the manufacturer’s instructions to ensure the solution is the correct concentration and temperature to maintain its effectiveness. Many cleaners are designed with a premeasuring pump mechanism; healthcare personnel must make certain a full depression of the pump occurs to ensure appropriate solution concentration. A weak solution may fail to break down proteinaceous tissue or a strong solution may create sudsy bubbles which form air pockets and can prevent surface contact by the cleaner. To accurately fill the receptacle or sink with the correct amount of water, a fluid depth indicator or line should be placed for guidance of accuracy [13, 14]. An example is shown in Figure 1.1. A visible instruction guide should indicate the correct solution amount to be added to the correct measurement of water; for example 1 ounce of detergent to 1 gallon of water (Figure 1.2). To prevent aerosol formation by microorganisms, the item being cleaned should be kept immersed below the solution level [8].

Image described by caption and surrounding text. — **Figure 1.1** Example of the fill line of a cleaning receptacle.

Image described by caption. — **Figure 1.2** Visible instructions for preparing an enzymatic cleaner.

Prior to immersion, if the item has numerous parts it must be disassembled, and hinged instruments must be kept in the open, unlocked position. Gentle scrubbing of the item with a soft‐bristle brush or sponge will assist in removal of bioburden and preservation of the instrument’s functions and effectiveness [11]. The most recent recommendation is to use a disposable, single‐use brush or sponge. The use of disposable brushes or sponges during the cleaning process will help to prevent cross‐contamination to instruments, endoscopes, and medical devices. If a reusable brush is to be used due to cost issues then it must follow undergo HLD between each use [6]. Endoscope manufacturers each have their own select line of various styles and sizes of single‐use brushes, with instructions for use (IFU) guidelines for their specific endoscope models. The correct brush should be used for each instrument; the important components of the brush when selecting which one to use are its length, diameter, design, and material [15]. For example, the proper brush used for a flexible cystoscope should be longer than the scope itself, be the right diameter to easily fit through the internal working channels, be kink‐resistant, and have a plastic tip on the end to protect the scope internal channel(s).

The next step in manual cleaning is to thoroughly rinse the item with cool tap water in a deep sink to allow for ample movement. Following rinsing, sufficient drying time is needed before the item is to be prepared for sterilization or HLD.

In urology, endoscopes, both flexible and rigid, are a frequently used. They are valuable diagnostic tools that are reusable and require healthcare personnel to follow the guidelines for reprocessing to prevent an outbreak of infection due to improper cleaning. These scopes are introduced into the bladder to examine its appearance and anatomy, as well as the lower urinary tract and prostate gland. Other uses are for urine specimen collection, bladder biopsies, removal of small stones, small foreign objects, or an indwelling ureteral stent. An estimated 4 million or more cystoscopies are performed in the United States each year [16].

When indicated by the manufacturer a leak test should be performed on flexible endoscopes after precleaning and prior to full immersion of the scope in the cleaning solution. This test is done to check the integrity of the outer covering and the internal lining of the scope shaft for any leaks. Before the shaft of the scope is submerged in water, the scope manufacturer leak testing device (which may be manual/hand‐operated or automated) is connected to the flexible scope to allow pressurized air to fill the internal channel. The purpose of this test is to determine if there are any microscopic holes from continued use and reprocessing, which would be a source of contamination due to fluid accumulation. The presence of a leak will be identified if the pressurized scope produces a flow of bubbles when inserted in water. Careful inspection of the flexible endoscope for any visible cracks, tears in the sheath material, or malfunctions of its performance is another vital step in reprocessing [6, 7].

External surfaces should be washed with a soft brush or sponge to remove any visible debris. Careful attention should be focused on the lumens and working channels of all endoscopes. Lumens and working channels should be irrigated with a large syringe or a manufacturer‐specific irrigating device. This is done first with detergent or enzymatic solution to help remove any residue, followed by a water rinse until it appears clear. Using the appropriate‐size flexible brush will allow for proper cleaning of the lumens and working channels. Once the brush exits the tip of the scope, the bristles should be cleaned before pulling the brush back into the internal channel [6]. Brushes are available in a variety of sizes and shapes to accommodate any manufacturer’s endoscopes, and proper selection is essential for prevention of damage to the endoscope (Figure 1.3). Use of newly prepared cleaning solution prior to cleaning of each endoscope is most effective and helps prevent cross‐contamination [13, 14].

A washer/sterilizer is designed to have several cycles, starting with a cold water pre‐rinse, followed by a high‐temperature wash cycle with an alkaline low‐sudsing detergent, a neutralizing cycle, and then by a final rinse, steam sterilization, and a drying cycle [9, 11]. An ultrasonic cleaner functions by cavitation. Ultrasonic energy is passed through a water bath, creating microscopic bubbles that implode. The implosion process creates a suction action that pulls soil and foreign body matter away from instrument surfaces [9, 11]. Instruments that contain plastic or rubber should not be placed in an ultrasonic cleaner. The washer/decontaminator is a single or multi‐chamber unit that cleans using an alkaline low‐sudsing detergent with a spray force action and heat during the drying cycle. Multi‐chamber units allow multiple single tasks to be performed simultaneously including a cool‐water rinse, pre‐wash with an enzymatic cleaner, wash cycle with detergent, ultrasonic cleaning, pure hot water rinse, and high‐temperature drying [9, 11].

Protection, handling, and maintenance of instruments

Protection, proper handling, and maintenance of instruments are vital in maintaining the efficacy of instruments as well as keeping instrument replacement costs down [17]. During and immediately following a procedure, heavily soiled instruments should be immersed in warm water to prevent the onset of corrosion, pitting, and rusting [11, 17]. Precleaning helps to remove debris or bioburden and prevent it from drying on the instrument. If not removed completely debris could cause an obstacle in the next steps of reprocessing and be a potential source of cross‐contamination. When using flexible or rigid endoscopes, the working channel should be flushed immediately after use to prevent bioburden from drying inside and the external part should be wiped down to remove visible debris [6].

Proper handling of instruments is a crucial part of maintaining an instrument’s function, especially when setting up a procedure and during reprocessing. This step is often overlooked in a careless manner due to one’s haste in preparing for the next procedure. Any delicate instruments such as telescopes, flexible scopes, light cables, and fine instruments such as microinstruments must be handled in a specific manner. During a procedure these instruments should be kept in a separate location on the sterile field/setup to avoid other instruments from being placed on top of them and causing potential damage. When transporting delicate instruments to the soiled processing room they should be placed in a specific labeled biohazard container designed for instrument transport [12]. Flexible scopes and light cables must not be over‐coiled while on the sterile field/setup or during transport; this will help prevent the internal fiber optics from becoming cracked or broken.

After cleaning, instruments should be checked for their function and lubricated when recommended by the manufacturer with a water‐soluble lubricant [4]. Lubrication also helps prevent rusting and maintains the function of any movable piece, such as a Leur Lock part.

Methods of sterilization

Sterilization can be achieved by way of several approved methods. These methods include using steam, ETO gas, peracetic acid, or hydrogen peroxide gas plasma. Each method has its advantages and disadvantages along with specific indications for use. The manufacturer’s guidelines and IFU for any instrument must be followed when selecting which method to use to ensure instrument viability and appropriate sterilization [18]. The healthcare setting will determine which method is suitable for the facility’s operational workflow. Monitoring and documentation of the effectiveness of any sterilization method is a mandatory requirement and must be followed according to your facility’s policy and procedure guidelines.