Sterilization and Disinfection

Online Crash Course for Infection Control Professionals STERILIZATION & DISINFECTION Learning Objectives………… • Definitions • Spaulding’s classification • Methods • CSSD work flow • Validation • Reprocessing of SUD 2 Definitions ▪ Disinfection is a process where most microbes except bacterial endospores are removed from a defined object or surface. ▪ Sterilization is a process by which an article, surface or medium is made free from all micro-organisms including spores. 3 Spaulding’s classification Spaulding outlined three categories of risk from medical instruments based on its potential to transmit infection if the instrument is microbiologically contaminated. Non-critical Semi-critical Critical 4 Spaulding’s Classification Device classification Minimum inactivation level Intact skin Non-critical Low level or intermediate level disinfection Mucous membranes or non-intact skin Semi-critical High level disinfection Sterile areas of the body including blood contact Critical Sterilisation Patient contact Example 5 Resistance of Microorganisms to Disinfection & Sterilisation Resistant Level Prions (Creutzfield-Jacob Disease) Prion Reprocessing Bacterial Spores (Bacillus atrophaeus) D i s i n f e c t i o n Coccidia (Cryptosporidium) Mycobacteria (M. tuberculosis, M. terrae) Nonlipid or small viruses (polio, coxsackie) Fungi (Aspergillus, Candida) Vegetative bacteria (S. aureus, P. aeruginosa) High Intermediate Low Lipid or medium-sized viruses (HIV, herpes, hepatitis B) Susceptible 6 Disinfection 7 Types of Disinfectants Intermediate level High level disinfectants (HLD) ▪ Glutaraldehyde (2.45%) (> 20 mins) ▪ Ortho-phthalaldehyde (OPA) (0.55%) ▪ Peracetic Acid (0.2%) ▪ Hydrogen Peroxide(7.35%)/ Peracetic Acid (0.23%) disinfectants (ILD) ▪ ▪ ▪ ▪ ▪ Sodium Hypochlorite Povidone Iodine Chlorhexidine Phenols Glutaraldehyde (Short Exposure Time) Low level disinfectants (LLD) • Alcohols • Benzalkonium chloride • Soaps 8 Hospital Disinfection 1. Disinfection of the hands. 2. Disinfection of the patient’s skin 3. Disinfection of Instruments and Equipment. 4. Linen. 5. Environmental Hygiene ( surfaces ) and Sanitation. How to select a disinfectant? A disinfection agent should be selected based on the following criterion: ▪Intended use and appropriateness. ▪Degree of disinfection required. ▪Spaulding’s classification. ▪Safety. ▪Turn-around-time (TAT). 10 In-use Testing of Disinfectants • Quality Control of disinfectants. • Human Error. • Lack of supervision. • Adequate knowledge of disinfectants. • Unexpected Conditions. ▪ Mop solutions / solution from discard jars. ▪ 1 :10 dilution. ▪ 10µl – 10 drops. ▪ Growth in more than 5 drops inoculated. ATP Bioluminescence Assay Systems Step 1 Use special swab to sample surface units. Step 2 Place swab in reaction tube. Step 3 Place tube in luminometer. Results: Relative Light. Testing of Glutaraldehyde - Inuse STERILIZATION 14 Central Sterile Supplies Department • The CSSD is the service within the hospital, catering for the sterile supplies to all departments such as specialized units as well as general wards and OPDs. 15 Functions of CSSD Cleaning Distribution Disinfection Drying Storage Inspection and assembly Sterilisation Labelling Packaging 16 CSSD- Central sterile supply department Unidirectional Flow - CSSD Cleaning Area Drying Area Sterilisation Area Clean Zone Barrier Barrier Soiled Zone Packaging Area Storage Issue Counter Sterile Zone Controlled air flow Soiled Zone - Negative Clean Zone – positive (+) Sterile Zone – positive (++) 18 CSSD Essentials ▪ Zoning ▪ Uninterrupted power supply. ▪ Packing material – Woven / Non-woven/ Peel pouches/ Paper/ Plastic/ Closed containers. ▪ Compressed air. ▪ Appropriate PPE - Utility gloves and eye wear. ▪ Water with low TDS. (RO water is ▪ Availability of SDS. preferred for final rinse) ▪ Environmental controls: ▪ Periodic checks: ▪ Equipment monitoring. ▪ Temp – 18 - 25 0 C. ▪ Audits. ▪ Humidity – 40-60 %. ▪ Periodic training. ▪ Pressure Gradient. ▪ Documentation. 19 Types of Sterilisation ▪ Steam sterilisation or autoclave ▪ ETO sterilisation ▪ Plasma gas ▪ Peracetic acid ▪ Ozone ▪ Chlorine dioxide ▪ Hot air oven 20 Autoclave – Steam Sterilisation ▪ Requires exposure to direct steam contact at: ▪ Temperature: 121° C. ▪ Pressure: 15 psi. ▪ Time: 30 mins. ▪ Sterilising only heat stable items. ▪ Sterilising discards - 60 mins 21 Types of Steam Sterilisation Gravity air displacement Pre-vacuum dynamic air removal Flash autoclave or Immediate Use Steam Steriliser (IUSS) 22 Performance Qualification/Batch Process Record • The following information should be recorded in the steam sterilisation batch record: ▪ Sterilizer identification. ▪ Cycle number. ▪ Batch number. ▪ Date of sterilization. ▪ Reference number of the master process record. ▪ Temperature (chamber temperature). ▪ The pressure (chamber pressure). ▪ A signature of the CSSD Technician/ Staff in charge confirming whether the cycle was satisfactory or not. • Note: The batch record should be verified and the load authorized. 23 ETO Sterilisation • Ethylene oxide (EO) is released at an ambient temperature and pressure. ▪ Temp - 37⁰C to 55⁰C & pressure: 1.0-1.5 kg/cm2. ▪ Exposure time: 60 to 120 minutes and 8-12 hrs- Aeration. ▪ EO kills by alkylation of macromolecules (nucleic acids, proteins). ▪ It is highly penetrating with minimal material interaction. ▪ BI - Bacillus atrophaeus 24 Plasma sterilization • Plasma sterilizer is used to create the plasma state - ions, photons, free electrons and free radicals • Kills by oxidizing macromolecules • H2O2 is vaporized (50 mins) @ temperature - 37-44◦ C • 24-55mins • Linen or paper or cellulose or liquid cannot be processed • Not useful for long lumens • BI - Bacillus stearothermophilus Storage of Sterile Supplies • The sterilized packages must be stored only on stainless steel racks. • Sterilized materials placed at a distance of: ▪ 45 cms from the roof. ▪ 20-25 cms from the floor. ▪ 5 cms from the wall. ▪ The shelf life of the sterilized items depends on the method of sterilization and package. ▪ It is date and event related. ▪ The sterilized items are dispatched - first in first out (FIFO) basis. 26 Validation of Sterilisation Process Physical indicators Chemical indicators Biological indicators 27 Physical Indicators • Each sterilization cycle gives the printout of time , temperature and pressure under which the cycle is processed. 28 Chemical Indicators ▪ Type 1: Process indicators ▪ Type 2 :Indicators for use in specific test (BD test) ▪ Type 3: Single-parameter indicators (not routinely used). ▪ Type 4: Multi-parameter indicators ▪ Type 5: Integrating indicators ▪ Type 6: Emulating indicators 29 Biological Indicators • They contain live bacterial spores which are difficult to kill. This helps in finding out whether the sterilization process is efficient enough to kill the bacterial spores 30 Monitoring Sterilization Process Releasing an Implant • Only biological indicator results can be used to release implants. • “Every sterilization load containing implants should be monitored with a PCD containing a BI (a BI challenge test pack). A Class 5 integrating CI should be included in this PCD. Implants should be quarantined until the results of the BI testing are available.” (CDC, 2008) • “Releasing implants before the BI results are known is unacceptable and should be the exception, not the rule.” 32 Reprocessing – Single use devices - DIN EN ISO 13485:2007 • A single use device (SUD) is a device that is marketed or labeled for single patient use or single procedure use. • It is not marketed or labeled with the intent of reusing the device on another patient. 33 Principles of Reprocessing Reusable Devices ▪ Identification of reprocessing times of SUD. ▪ Labelling of SUD with the name of the device, size specifications, original manufacturer, number of times the device has been used, date of last use and date of reprocessing. ▪ Non-repeatable batch number to the device to facilitate recall of the device. ▪ Not reusing original packaging materials from the manufacturer. ▪ Obtaining consent for use on patients. ▪ Documentation. 34 Sterilisation Failure - Recall • Conditions when instruments or equipment are returned to CSSD: ▪ When the biological indicator shows bacterial growth. ▪ When it is wet inside the sterilised package. ▪ When there is no colour change in the chemical indicator. ▪ If the SUD is found unsafe to use due to repetitive incidents or due to a report by Microbiology department or from its manufacturer. 35 To Summarize …………….. • Spaulding’s classification • High- Intermediate - Low-level disinfectant • Sterilizers – function • Methods of Efficacy testing – Sterilizers / Disinfectants • Reprocessing of SUDs 36 References • Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008 • Comprehensive guide to steam sterilization and sterility assurance in health care facilities, ANSI/AAMI ST79:2017 & A1:2017, A2:2017, A3:2017 & A4:2017 • Perioperative Standards and Recommended Practices (AORN -2020) • APSIC – Sterilization guidelines for disinfection & Sterilization of Instruments in Health care facilities , 2017 37 38