STERILISATION AND DISINFECTION.pptx

Microorganisms are the agents of contamination, infection and decay. Hence it becomes necessary to remove them.

1. STERILISATION AND DISINFECTION SREEVIDYA V S NURSING TUTOR/ CLINICAL INSTRUCTOR CENER, AIIMS RISHIKESH

2. INTRODUCTION HOW CAN YOU SAY SOMETHING IS DIRTY OR NOT CLEAN? HOW WILL YOU CLEAN DIRTY OBJECTS?

3. INTRODUCTION Microorganisms are the agents of contamination, infection and decay. Hence it becomes necessary to remove them.

4. Terminologies Unclean/dirty: not clean or visibly soiled Contaminated/Infected : affected by an organism that can cause disease

5. Terminologies Cleaning :  the act of removing visible dirt/ soil from the surface of floor, utensils, glass, metals etc. Decontamination : it removes or destroys contamination so that infectious agents cannot reach a susceptible site in sufficient quantities to initiate infection, or other harmful response Physical cleaning Water purification Ultrasonic cleaning Antisepsis Disinfection Sterilization

6. Terminologies Antiseptic:   antiseptic prevent the growth and development of microorganisms in the body surface. Antibiotic : chemical substances usually kill and prevent the growth of microorganisms

7. Terminologies Disinfection : The process of killing (inactivating) harmful and objectionable bacteria, cysts and other microorganisms (pathogenic) by various agents. Sterilization : It is the removal of all forms of microorganisms from the surface of an object. It includes both spore and vegetative forms. 

8. WHO AM I?

9. HIGH RISK ITEMS

10. CLEANING

11. DISINFECTION

12. CONCURRENT DISINFECTION Concurrent disinfection is the immediate disinfection of all contaminated articles and bodily discharges during the course of the disease Concurrent disinfection of the contaminated articles immediately, then and there during the course of illness. It includes cleaning the isolation unit daily with effective disinfectant.

13. TERMINAL DISINFECTION Terminal disinfection means disinfection of the patients unit and all the articles used after the discharge, transfer or death of the patient who was suffering from the contagious disease It means after the patient has recovered from a communicable disease, the disinfection of the room and articles used by him is done after his discharge from the unit or transfer or death

14. PRE-CURRENT/ PROPHYLACTIC DISINFECTION Before any disease condition As a prophylactic measure.

15. DISINFECTANT- TYPES Alcohols Aldehydes Halogens Oxidising agents Quaternary ammonium compounds

16. Alcohols Alcohols, usually ethanol or isopropanol, are wiped over benches and skin and allowed to evaporate for quick disinfection. They have wide microbiocidal activity, are non corrosive, but can be a fire hazard. They also have limited residual activity due to evaporation, and have a limited activity in the presence of organic material. Alcohols are more effective combined with water—70% alcohol is more effective than 95% alcohol. Alcohol is not effective against fungal or bacterial spores.

17. Aldehydes Aldehydes, such as Glutaraldehyde (2%) , have a wide microbiocidal activity and are sporocidal and fungicidal. They are partly inactivated by organic matter and have slight residual activity . CONTACT TIME – 20MIN IN 20 DEGREE CELSIUS

18. Halogens Chlorine is used to disinfect swimming pools, and is added in small quantities to drinking water to reduce waterborne diseases. Hypochlorites (Sodium hypochlorite), often in the form of common household bleach, are used in the home to disinfect drains, and toilets. I odine has been used as an antiseptic for skin cuts and scrapes.

19. HYPOCHLORITE 1% SODIUM HYPOCHLORITE AVAILABLE FORM = 5% Used for spillage management - HIV , HEP B

20. Oxidising agents Hydrogen peroxide is used in hospitals to disinfect surfaces. A 3% solution is also used as an antiseptic. When hydrogen peroxide comes into contact with the catalase enzyme in cells it is broken down into water and a hydroxyl free radical . It is the damage caused by the oxygen free radical that kills bacteria. However , recent studies have shown hydrogen peroxide to be toxic to growing cells as well as bacteria; its use as an antiseptic is no longer recommended .

21. Phenol Phenolics are the active ingredient in most bottles of "household disinfectant". They are also found in some mouthwashes and in disinfectant soap and handwashes. Phenol is probably the oldest known disinfectant as it was first used by Lister, when it was called carbolic acid. It is rather corrosive to the skin and sometimes toxic to sensitive people, so the somewhat less corrosive phenolic o -phenylphenol is often used in favour.

22. Quaternary ammonium compounds Quaternary ammonium compounds (Quats), such as benzalkoniu M chloride, are a large group of related compounds. Some have been used as low level disinfectants.

23. Air disinfection/fumigation Fumigation is  the process of using chemical smoke to kill pests like insects or rodents .  Also be used as disinfection technique in hospital. The unit must be closed before fumigation.

24. Factors influencing activity of disinfectants Activity directly proportional to temperature. Directly proportional to concentration up to a point – optimum concentration. After this level no advantage in further increases in concentration.

25. Factors influencing activity of disinfectants Disinfectants may be inactivated by : Dirt Organic matter : Proteins, Pus, Blood, Mucus and Feces. Non organic: Cork, Hard water and Some plastics. Time : Disinfectants need time to work. Range of Action : Disinfectants not equally effective against the whole spectrum of microbes. e.g. Chlorhexidine less active against Gram negative bacteria than Gram positive cocci . Hypochlorites and Gluteraldehyde are more active against hepatitis viruses than most other disinfectants .

26. Hospital disinfection methods Article Disinfectant Floors, walls Phenolics fluids 1-2% Surfaces tables Hypochlorite, Alcohol Skin Surgeons ’ hands Chlorhexidine, Iodin , alcohol Patient skin 70% Alcohol, Iodine Endoscopes Gluteraldehyde 2% ( Cidex ), steam Thermometers 70% Alcohol

27. STERILIZATION

28. STERILIZATION The Central Sterile Services Department ( CSSD) Also called Sterile Processing Department (SPD ) or Central Supply Department (CSD)

29. Methods of Sterilization Physical methods : Heat ( dry heat & moist heat) U.V. Light Ionizing Radiation Filtration 2. Chemical method : (used for heat sensitive equipments) Ethylene Oxide Gluteraldehyde .

30. PHYSICAL METHODS HEAT : Most important should be used whenever possible Types: Dry heat at temperature of 160˚C for one hour Moist heat eg . Autoclave at 121 or 134 C for 10 or 15 minute

31. Sterilization by Heat - Common methods Dry Heat Dry Heat- kills microorganisms by destroying their oxidative processes. Simplest method is exposing item to be sterilized to the naked flame e.g. Bunsen burner- for sterilizing bacteriological loops, knives, blades. Hot air oven expose items to 160 °C for 1 hour. Has electric element in chamber as source of heat plus a fan to circulate air for even distribution of heat in chamber. Oven without fan is dangerous. Used for items that are lacking water such as: -Metals -Glassware -Ointment / Oils/ Waxes /Powder

32. Moist Heat Uses hot water. Moist heat kills microorganisms by denaturating proteins. Autoclaving – standard sterilization method in hospitals. The equipment is called Autoclave and it works under the same principle as the pressure cooker where water boils at increased atmosphere pressure i.e. because of increase pressure the boiling point of water is >100 °C. The autoclave is a tough double walled chamber in which air is replaced by pure saturated steam under pressure.

33. The air in the chamber is evacuated and filled with saturated steam. The chamber is closed tightly the steam keeps on filling into it and the pressure gradually increases. The items to be sterilized get completely surrounded by saturated steam (moist heat) which on contact with the surface of material to be sterilized condenses to release its latent heat of condensation which adds to already raised temperature of steam so that eventually all the microorganisms in what ever form are killed. The usual temperature achieved is 121 °C , exposure time of only 15 mins .

34. Advantages of Autoclave Temp. > 100 C therefore spores killed. Condensation of steam generates extra heat. The condensation also allows the steam to penetrate rapidly into porous materials. Note: for all invasive procedures at operating room or clinics, autoclavable equipments should be used.

35. Monitoring of Autoclaves 1 . Physical method: use of thermocouple to measure accurately the temperature. 2. Chemical method: it consists of heat sensitive chemical that changes color at the right temperature and exposure time. e.g. a)- Autoclave tape b)- Browne ’ s tube. 3. Biological method : where a spore-bearing organism is added during the sterilization process and then cultured later to ensure that it has been killed .   pores from  B. stearothermophilus , a microorganism that is inactivated when exposed to 121.1 o C

36. Moist heat: Other Applications Pasteurization Used heat at temperatures sufficient to inactivate harmful organism in milk. The temperatures of sterilization is not achieved . Temperature may be 74°C, for 3-5 seconds. ( Flash methods or 62°C for 30 minutes. ( Conventional method ). Boiling – quite common especially in domestic circumstances.

37. Other physical methods : Radiation U.V. light Has limited sterilizing power because of poor penetration into most materials. Generally used in irradiation of air in certain areas such as operating rooms and tuberculosis labs. Ionizing radiation- e.g. Gamma radiation: has greater energy than U.V. light, therefore more effective. Used mainly in industrial facilities e.g. sterilization of disposable plastic syringes, gloves, specimens containers and Petri dishes.

38. Sterilization by Chemical Methods Useful for heat sensitive materials e.g. plastics and lensed endoscopes). 1. Ethylene Oxide Chamber Ethylene oxide alkylates DNA molecules and thereby inactivates microorganisms. Ethylenes oxide may cause explosion if used pure so it is mixed with an inert gas .Requires high humidity (50-60% ) .Temperature : 55-60°C and exposure period 4-6 hours. 2. Activated alkaline Gluteraldehyde 2% Immerse item in solution for about 20 mins . If Mycobacterium tuberculosis or spores present then immersion period 2-3 hou rs.

39. Other physical methods : Filtration May be done under either negative or positive pressure. Example ; membrane filter made of cellulose acetate. Generally removes most bacteria but viruses and some small bacteria e.g. Chlamydia & Mycoplasma may pass through. Thus filtration does not technically sterilize items but is adequate for circumstances under which is used. Main use: for heat labile substances e.g. sera, antibiotics.

40. Chemical Methods Some strong chemical substances may be used to achieve sterilization ( kill spores) e.g . Gluteraldehyde and Ethylene oxide. Used for heat sensitive equipments . CONTACT TIME 10HRS

41. High-touch areas H igh-touch areas are surfaces that are frequently touched by healthcare providers and clients. Examples of high-touch areas include: Door handles Light switches Alcohol-based solution dispensers Sink taps Call bells Bed rails

42. Important points Any instrument or item used for sterile body site should be sterile. Any instrument or item used for non-sterile body site can be disinfected. Hand washing is the most important to prevent hospital acquired infection.