Passive Layer Surgical Instrument Corrosion
Stainless steel surgery instruments are made of corrosion resistant high-grade specialty steels. Corrosion resistant does not mean corrosion proof. One of the special characteristics of these steels is that the manufacturer forms a passive oxide layer on the surface, which protects them against corrosion. This makes surgery instruments as corrosion resistant as possible. It is imperative that you maintain the passive oxide layer to prevent corrosion and maintain your surgery instruments in optimal condition. If this is not done the stainless steel will be more susceptible to corrosion, pitting and stains.This will reduce the life of the surgery instruments and/or render it useless. Initially, all stainless steel surgical instruments have the same corrosion resistance. When strength and hardness requirements are important factors for instrument function, corrosion resistance is generally lower. Increasing the corrosion resistance would soften the stainless steel. Manufacturers of surgery instruments and surgical instrument containers recommend the use of neutral pH cleaning concentrates. Neutral pH all-in-one or combination detergent cleaning concentrates have been shown to be effective in optimizing the efficacy of the Surgical Instrument Passive Layer. This will provide a longer life for stainless steel surgery instruments. Cleaning concentrates with a high or low ph have been shown to erode the passive layer. The most common of these cleaning concentrates utilize an alkaline detergent with an acid neutralizer. Virtually all manufacturers of surgical instruments and surgical instrument containers recommend against using these detergents and recommend using a neutral ph detergent. Mechanical surgical instrument cleaning treatments for cleaning surgical instruments and chemical surgical instrument cleaning treatments are necessary prior to sterilization. Yellow-brown to dark-brown stains or spots on surgical stainless steel instruments are frequently mistaken for rust. These residue deposits (stains or spots arranged in groups or along edges or in crevices) are usually the instrument being exposed to result of high chloride content. They will lead to pitting of the surgical instrument surface if not removed. Excessively hard water can contain high levels of salt sufficient to cause stains or spots that appear as rust. Boilers used to generate the steam for steam sterilizers, if not cleaned properly, will produce contaminated steam which can deposit minerals onto instruments during the sterilization process. To maintain moving parts and protect instruments from staining and rusting during sterilization and storage, they should be lubricated with a water-soluble, preserved lubricant after each cleaning. The ONEcleaner enzyme detergent cleaning concentrates provides lubrication.
Prevent Staining and Corrosion of Surgical Instruments
Staining and spotting may result if residual chemicals are not completely rinsed from surgery instruments that are subjected to steam sterilization. The proper sequence of treatments (cold water pre-wash, enzyme-detergent wash, purified water rinse/lubrication, and drying) is critical to prevent stains and spots. Cleaning Concentrates that will avoid spotting are free-rinsing and rinse clean. Studies regarding the passive oxide layer of Surgical Instruments of the stainless steel passive layer to prevent corrosion have revealed a reduction in corrosion prevention with the use of cleaning concentrates that are not neutral ph. The use of cleaning concentrates that deliver an acid rinse will release nickel from the stainless steel and decrease the efficacy of the passive layer. This is most critical on initial reprocessing events of stainless steel surgical instruments. Measurable levels of nickel have been detected. It was also shown that, as the number of subsequent uses increased, the level of nickel release diminished and reached a steady state These observations reflect the changes that occur in the passive oxide layer on first immersion of stainless steels in aqueous media.
What is a Stainless Steel Surgical Instrument?
The passive layer or stainless steel is intended to prevent or resist corrosion. The process is called Passivation. Passivation and Polishing eliminate the carbon molecules form the instrument surface. This forms a layer which acts as a corrosive resistant seal. Passivation is a chemical process that removes carbon molecules from the surface of the instrument. This chemical process can also occur through repeated exposure to oxidizing agents in chemicals, soaps, and the atmosphere. Proper cleaning, handling, and sterilization will build up the passive layer of chromium oxide and protect the surgical instrument from corrosion and pitting. In some circumstances older instruments have higher resistance to corrosion than new ones. The newer instruments have not had the time to build up the chromium oxide layer. Improper cleaning and sterilization can cause the layer of chromium oxide to disappear or become damaged thus increasing the possibility of corrosion and/or pitting. Proper cleaning and sterilization can cause the passive layer of chromium oxide to improve over time thus increasing the protection against corrosion and pitting.