1. Prevention of Hospital Infection Exogenous infection
2. Hospital Infection
3. Surgical wards
Should be well ventilated and cleaned
The floor should be scrub washed once a week
Preop. Ptsshould not be mixed with postop. Pts.
Severely infected cases should be isolated
Immuno suppressed pts also isolated
4. Operation Theaters
Height 3M. Floor area 10 sqM.
Anaesthetic room -10 Sqm.
Minimise bacterial contamination
The concept Site away from the wards of zones : a) outer zone reception area. b) clean zone between the reception and OR. C) asceptic zone OR . D) dirty zone disposal area and space for cleaning of instruments
5. Air flow of OR
Filtered air directed vertically or horizontally
Ideal laminar flow
Restrictentry of nonessential personnel & their movements
Temperature 20 - 22 C
6. Other Measures
Wearing of disposable nonwoven fabric
Head & beard cover
Preparation of the surgical team
Preparation of the patient
Preoperative hospitalisation minimised
Skin infection treated
Skin preparation, Drapes
The process that reduces the no. of viable microorganisms, but does not affect the spores
Three levels of disinfection
1. Low: reduces the overall no. of vegetative microorganisms. Does not destroy TB bacilli or bacterial spores .Application environmental surfaces
2. Intermediate :kills TB bacilli, most viruses,and some fungi but only some spores. Application horizontal surfaces,floors
3. High: kills most forms of microbial life including TB bacilli but not some spores. Application flexible endoscopes
3)Low temperature steam disinfection
10. Chemical disinfection
Chemical disinfectants are used to reduce the pathogenic microbes of inanimate objects, which are heavily contaminated.
Alcohols, aldehydes, halogens, phenolics and quaternary ammonium compounds
11. Chemical disinfectants
Alcohol isopropyl alcohol & ethyl alcohol kills most vegetative bacteria in less than 30 seconds , relatively inactive against spores and fungi. 70% alcohol is usually used.
Aldehydes glutaraldehyde & formaldehyde good activity against spores, bacteria, virus and fungi . 2% glutaraldehyde rapidly inactivates HIV and hepatitis B after exposure for 10 minutes.
12. Chemical disinfection
Diguanides e.g. chlorhexidine good activity against gm + ve organisms , moderate activity against gm- ve organisms, poor activity > TB bacilli, spores , fungi & viruses . Used as an antiseptic for skin & mucous memb.
Halogens e.g. hypochlorites and chlorine active against bacteria including spores ,fungi, hepatitis B & HIV virus
13. Chemical disinfection
Iodophores -1% availableIodine mixed with alcohol excellent skin preparation
Quaternary ammonium compounds good detergent properties savlon when mixed with chlorhexidine
Complete removal of all microbes including spores
Methods :Heat method dry or moist
Ethylene oxide gas
15. Heat Methods
Dry heat Hot air ovens which have controlled cycles, such as 160 C for 1 hour suitable for killing bacteria on materials which are not penetrable by steam e.g. glassware, powder such as talc, oils & petroleum jelly.
Moist heat Steam under pressure simplest is domestic pressure
High pressure vacuum autoclaves
Low temp. steam(73C) & formaldehyde suitable for heat sensitive materials and equipment with plastic component
16. Ionising Radiation
Gamma rays lethal, noncharged, ultrashort, wavelength rays with great penetrating power from a radioactive isotope such asCobalt-60 e.g.Disposable syringes, sutures and rubber gloves
The radiation dose 2.5 mrad kills bacteria by ionising their DNA.
It should be used with suitable humidity at the correct temp. for sufficient time
CO2 is mixed with ethylene oxide to reduce Highly toxic inflammable gas kills all types of microbes including spores.
the risk of explosion
It diffuses well through items such as plastic materials, swabs and paper.