Antiseptic solutions Dr VP Hathila

• Sterilization and asepsis principles were accepted after Joseph Lister (Father of antiseptic surgery) studied prevention of wound infection(1865-1891).

DEFINITIONS

Sepsis- describes real effect of infection, the process of decomposition, putrefaction, poisoning, if not treated can related to fatal outcome.

CLEANING - It is a process which removes visible contamination but does not necessarily destroy micro organisms. It is necessary prerequisite for effective disinfection or sterilization.

ASEPSIS -Term used to describe methods which prevent contamination of wounds and other sites from the microorganism by ensuring that only sterile object and fluids come into contact with them.

ANTISEPSIS – It is the process of destruction of disease causing microorganisms to prevent infection in patient’s body surface. The process may be either bactericidal or bacteriostatic.

DISINFECTION - it is a process of killing pathogenic organisms from inanimate objects such as surgical instruments.

Disinfectant: it is chemical substance used on inanimate objects to kill pathogens.

Antiseptic agent: it is a chemical substance which kills the pathogenic organism or inhibits growth.

STERILIZATION STERILIZATION - - it is the process of destruction or removal of all microorganisms including spores from article, surface or medium.

Sanitization - process that reduces microbial population on object to a safe level.

Decontamination - process that removes pathogenic microorganisms from an object to make it safe to handle.

Bactericidal: antibiotic which kills the pathogens

Bacteriostatic: antibiotic which inhibits the growth of pathogens.

Lysol( Cresol solution)• Dilution in 1 : 100 water • Uses: for sterilization of sharp instruments e.g:

needle, knives, scissors• Time : for 30 mins duration for 100% solution• 1-2 hours for 1: 100 solution• Note: Lysol is an irritant chemical that causes

burns hence instruments should be cleansed with sterile water or normal saline before use

Savlon Composition: Chlorhexidine gluconate -7.5% + Cetrimide -16%

+ Isopropyl alcohol -6.8%• Action--- Germicide and detergent • Uses: cleaning and disinfection of the equipment in the vicinity

of the patient • Storage of previously sterilized instrument• Cleaning and disinfection of postoperative wounds• Scrubbing Soln. changed every weekly.• Prolonged storage of thermometer• Cleaning and disinfection of catheter and appliances• Dilution;; 1:100 Aqueous solution 1ml soln.+100ml

water

Hydrogen peroxide(H2O2)• It is not an antiseptic but a cleansing agent• Uses : destroys anaerobic organisms, and

therefore used for cleaning the wounds.• Produces frothing and brings out debris from

the depth of the wound• Produces heat when it comes in contact with

tissues, thus prevents capillary oozing and hence can be used as hemostatic

• Used to remove blood stains from clothes

Spirit• Composition: alcohol(opt. conc. 70%)• Uses: disinfection of skin before intramuscular and I V

injection• Removal of iodine in preparation of skin for operation• Cleaning the stitched wound• Cleaning the skin of the surrounding ulcer or open

wounds• Can be used for dissolving ear wax in lower conc.• Used along with other disinfectants like iodine-spirit,

cetavlon-spirit for painting the parts before operation

Formalin solution• 30% aldehyde + 10% methane• Preservative for biopsy specimens• Operation theatre sterilization• 2-5% used for sterilization of gloves and

instruments

EUSOL(Edinburgh university solution)

• 1.25 gm Boric acid, 1.25 gm of bleaching powder and sterile water up to 100ml.

• It releases nascent chlorine and becomes useless after 24 hrs

• Uses: to separate slough from infected wounds, ulcers, bed sores, and burn wounds

• Acidic in pH; therefore useful n wounds infected with Pseudomonas bacteria

CIDEX• Glutaraldeyde 2% aqueous solution• Bactericidal, tuberculocidal, pseudomonocidal,

viricidal, fungicidal• Complete disinfection in 10 mins, sporicidal in 4 hrs• Uses: sterilization of large instruments fibre optic

scopes, endoscopes with lenses• Catheter , thermometers, small and sharp

instruments• Best disinfectant with rapid action• To be changed every 15 days.

Turpentine• Highly irritant mineral oil• Diluted form is used to bring out and kill the maggots

from wounds and ears• Used to remove zinc paste of sticking plaster form the

skin

Ether• It is evaporable, highly inflammable. Makes the

surface cool• Uses: surface and inhalation anaesthesia• Used to clean dirty skin as it removes the greasy

substances by dissolving them

Potassium permanganate (KMnO4)• It has an oxidizing effect, • It is available in crystal form• Concentration: 1:5000 to 1: 10000 solution in

water• Uses: Used as mouth wash Urinary bladder irrigation and wash

Mercurochrome• It is an inhibitor of 5-Hydroxytryptamine• Strong soln. kills WBCs and damages the

granulation tissue. It has astringent action• Uses: bed sore dressing• Diluted soln. applied on wounds with healthy

granulation tissue• Strong soln. for wounds with hyper

granulation tissue• Diluted soln. used as eye drops

Silver nitrate(AgNO3)

• 1:100 to1: 10000 soln. are available• exposure to light cause its destruction hence

Kept in dark container• Uses: chemical cauterization of warts and

hyper granulation tissue• Used for dressing burns• Useful in bladder irrigation in cases of

hematuria, due to its cauterizing effect

Povidone-Iodine (Betadine)• Available as topical solutions(5% & 10%), surgical

scrub(7.5%), mouth wash, ointments, vaginal pessaries

• Germicide, very effective against viruses, bacteria, protozoa, yeast and fungi

• Frequent use contraindicated because of its insolubility, instability, and its staining and irritating properties.

• Uses: mouth rinse and gargle• Local antiseptic and for wound dressing• irrigation of bladder, pyothorax and peritoneal cavity

Silver sulphadizine(SSD)• Mostly used in major burns because of its profound

efficacy and less toxicity• Composition: it is a 1% cream prepared by mixing silver

nitrate with weak acidic sulphadiazine• Action: active agent are sulpha component and slow

release of silver from the cream• Effective against a wide range of G+ve and G –ve

bacteria• Thin layer of 1-2 mm is applied directly to burns• Helps in softening of Eschar• Old cream and loosened Eschar come out with change of

dressings.

Soframycin• Framycetin sulphate cream• Used as 1% cream or powder• Effective against G+ve and G –ve organisms• Does not irritate wound and hence is painless

on application• Sensitivity reactions are uncommon

Neomycin, Polymixin, Bacitracin combination (Neomycin)

• Antibacterial spectrum is mainly gram positive• Eschar penetration is limited• Nephrotoxic if absorbed in large amounts• Used in minor superficial burns especially on

minor superficial burns on face and for small open areas

• In contrast to SSD it does not cause maceration

Gentamycin• Used as 0.1% cream or ointment• Its use as topical agent in burns should be avoided

as it is also used systematically otherwise resistance develop easily

• Can cause ototoxicity and nephrotoxicity• Uses: small wounds colonized with gram-negative

organisms’ resistance to other standard topical agents

• Small superficial burns particularly involving ears or perineum where G-ve infection is common

Care of Antiseptic solutions The Do’s• Always dilute concentrated Antiseptics before

use, as directed• Prepare dilutions in small volumes• Use all diluted solutions within 8 hrs and

discard the remaining• Ensure that the mouth of the bottle is not

touched by hands or materials while pouring

Care of Antiseptic solutions• The Dont’s• Never mix up diluted solutions with

freshly prepared ones• Never leave diluted solutions for more

than 1 working day• Never use corks for sealing the bottles• Never leave bottles open

To achieve sterilization of any instrument three definite stages are to be completed-

Pre sterilization cleaning Sterilization process Aseptic storage

Presterilization cleaning• Objective-

Removal of the organic matters, blood and saliva which provide protective barrier for microorganisms and prevents its destruction.

• There are three methods for cleaning-Manual-Ultrasonic-Mechanical washing

MANUAL CLEANING

• Simplest and the cheapest method, but time consuming and difficult to achieve.

• heavy duty gloves and glasses must be worn to protect needle stick injury and to protect eye.

• Material used for manual cleaning-Soaps-Detergents

ULTRASONIC CLEANING

Principle- conversion of electrical energy into vibratory sound waves which pass through a soap solution containing the instrument.

Used mainly for burs, bone files, bone cutter, artery forceps, saw etc.

MECHANICAL WASHING

Principle- High-pressure jets of water with or without a detergent which removes debris from instrument. Small instrument like burs, blade are not suitable for this type of cleaning.

Classification of the method of sterilization/Disinfection

A. PHYSICAL

1- Sun Light

2- Drying

3- Heat i- Dry

                    ii-Moist

4- Filtration

5- Gas

6- Irradiation

7- Ultra sonic cleaning

B. CHEMICAL

1. Phenol Derivatives : Phenol, Cresol, resorcinol, chloroxylenol

2. Oxidizing agents :Pot.Permanganate, Hydrogen Peroxide,Benzoyol Peroxide

3. Halogens : Iodine, chlorine

4. Biguanide : Chlorhexidine

5. Quarternary Ammonium (Cationic) : Cetrimide, Zephiran

6. Alcohols : Ethanol, Isopropanol.

7. Aldehydes : Formaldehyde, Glutaraldehyde

8. Acids : Boric acid, acetic acid

9. Metallic salts ; Silver Nitrate, Zince Sulfate, Zinc Oxide, calamine,

10. Dyes : Gentian violet, proflamine, Acriflamine

11. Furan derivatives : Nitro flurazone  

HEATMost common and one of the most effective methods of sterilization. Factors influencing sterilization by heat are : -

i. Nature of heat

a.        Dry

b.       Moist

ii.Temperature & time

iii. No. of organism present

iv.Whether organism has sporing capacity

v. Type of material from which organism is to be eradicated

A. DRY HEAT

Killing is due to :

- Dehydration and oxidation of organisms

- Protein denaturation

- Toxic effects of elevated levels of electrolytes

1. Red Heat : It is used to sterilize metallic objects by holding them in flame till they are red hot. Example : inoculating wires, needles, forceps etc.

2. Flaming : The article is passed over flame without allowing it to become red hot. Example : Glass plates, Cotton wool plays and glass slides.

3. Hot air oven :It is used to sterilize items, which do not get damaged by high temp. such as laboratory glass, flasks, instruments with sharp cutting edges, B.P. handles, Powders, Dapen dishes, mouth mirrors.

Temp. & Time: The sterilization is complete if these two factors are achieved throughout the load.

Temperature Time(Min)

140oC 180

150oC 150

160oC 60

170oC 45

180oC 18

190oC 7.5

Sterilization Control of Hot Air Oven

• The spores of non-toxigenic strain of Bacillus subtilis and Clostridium tetani are used as a microbiological test of dry heat.

• Browne’s test strip available that contain a chemical indicator.

AUTOCLAVE1. Steam is the effective means of sterilization, because of its

2. High penetrating capacity.

3. It gives of large amount of heat to surface with which it comes in contact.

4. Principle: Sterilization is done by steam under pressure. It kills vegetative bacteria, myco. Tb, viruses such as Hep B, C, A, HIV etc.

5. Heat resistant spores including Cl. Tetani and cl. Welchii

Autoclaves, or steam sterilizers essentially consist of following: i) A cylindrical or rectangular chamber, with capacities ranging from 400 to 800 liters. ii) Water heating system or steam generating system iii) Steam outlet and inlet valves iv) Single or double doors with locking mechanism. v) Thermometer or temperature gauge vi) Pressure gauges

• To achieve sterility, a holding time of at least 30 minutes at 121 °C (250 °F) at 15 psi(pounds per square inch) (100 kPa) above atmospheric pressure is required.

• Autoclave is used for sterilization of – - All Surgical instruments except sharps - Syringes,- Needles, - Linen including gown, mask - Abdominal swabs- Dressing material including cotton

Sterilization control of the moist heat Physical Indicator- an alloy designed to melt only after being subjected to relevant holding time.

Chemical indicator- Strips or tapes that change color once the correct conditions have been met. Signolac autoclave labels –

light green changes to dark grey/black on sterilization

Biological indicator- Spores of Geobacillus stearothermophilus are used as the test organisms as it is toughest organism for an autoclave to destroy. Its spores require an exposure of 15 mins at 1210 c to be destroyed.

Paper strips impregnated with 106 spores are dried and placed in paper envelopes. These envelopes are inserted in different parts of the load and after sterilizing the strips are inoculated for test of efficacy.

Boiling method of sterilization

• Heat at 100 degree C for 30 mins• All surgical instruments except sharp

instruments• Boiling is only done when autoclave is not

available• Disadvantage: spore bearing organisms are

not killed.

IRRADIATION Radiation used for sterilization is of two types

1. Ionizing radiation, e.g., X-rays, gamma rays, and high speed electrons .

2. Non-ionizing radiation, e.g. ultraviolet light, and infrared light.

These forms of radiation can be used to kill or inactivate microorganisms.

1. Ionizing Radiation

X-rays, gamma rays and cosmic rays are highly lethal to DNA and other vital constituents.

They have high penetration power.

There is no appreciable increase in temperature, thus referred to as cold sterilization.

Commercial plants use gamma radiation for sterilizing plastics, syringes, swabs, catheters, suture materials and surgical instruments, infusion sets, prosthesis etc.

.

2. Non-ionizing radiation

Two types of non-ionizing radiations are used for sterilization:-

• A. Ultraviolet -Short range UV(UVC) is considered “germicidal UV”.UV waves destroys micro-organismal DNA.Used mainly for air purification and water purification AND WARDS AND O. T in hospitals.

• B. Infrared –It is most commonly used to purify air, such as in the operating room, syringes. Infrared is effective, however, it has no penetrating ability.

Ethylene Oxide Sterilization (ETO)

• Used almost exclusively to sterilize medical products that cannot be steam sterilized or sensitive to radiation.

• Mechanism of action: It destroys micro-organisms by alkylation and cause denaturation of nucleic acids of micro-organisms.

• Ethylene oxide is a colorless liquid with a boiling point of 10.7 °C.

• Highly penetrating gas with sweet ethereal smell.• Plastics, rubber & photographic equipments can be

sterilized by this method. • Also used for mass sterilization of disposable items,

plasticsyringes,needles,catheters,blades optical lenses, endoscopes etc.

• Disadvantages– Lengthy cycle time– Cost– Potential hazards to patients & staff

• Advantage: Can sterilize heat or moisture sensitive medical equipments.

Aseptic storageThe maintenance of sterility during transportation and storage is of utmost importance.

• Instruments are kept wrapped until ready for use .

• To reduce the risk of contamination, sterile packs must be handled as little as possible.

• Sterilized packs should be allowed to cool before storage; otherwise condensation will occur inside the packs.

• To prevent contamination from rodents, ants, and cockroaches, the store must be subjected to adequate pest control .

• Materials should be stored at least 8” off the floor and 18” from the ceiling

• Sterile packs must be stored and issued in correct date order. The packs, preferably, are stored in drums which can be locked. Preset trays and cassettes, are useful as, the instruments can be organized as per the procedure

    

Operation Theatre Sterilization by Fumigation

• Formaldehyde fumigation is the accepted method of sterilization. Formaldehyde vapor is an extremely effective biocidal agent.

• Surgical site infections (SSIs) are the second most common cause of hospital acquired (Nosocomial) infections

• By maintaining sterile environment in surgical theater we can control major part of exogenous infections.

Preparation for sterilization • Thoroughly clean windows, doors, floor, walls, surgery

table and all washable equipments with soap and water.• Close windows and ventilators tightly. If any openings

found seal it with cellophane tape or other material to avoid the leak of fume.

• Switch off all lights, A/C and other electrical & electronical items.

• Calculate the room size (surgical theater only) in cubic feet (L×B×H) and calculate the required amount of formaldehyde as given in step 3.

Precaution for sterilization

• Adequate care must be taken by wearing cap, mask, foot cover, spectacle etc.,

• Formaldehyde is irritant to eye & nose; and it has also been recognized as a potential carcinogen.

• So the fumigating person must be provided with the personal protective equipments (PPE).

• Paste a warning notice on the front door indicating fumigation is in progress

FUMIGATION OF OPERATION THEATRE

- Fumigation of the operation theatre is achieved by formaldehyde(40%) and potassium permanganate reaction technique.

- 500 ml formaldehyde(Formalin)+ 450gm KMnO4

for a 10 X 10 X 10 room .

procedure of fumigation Potassium Permanganate Method:

Here the heat generation is induced by an oxidizer - Potassium permanganate (KMnO4), which results in auto boiling and generates fume from formaldehyde. Take 500 ml of formaldehyde (40% solution) in 1000 ml of water in a heat resistant/steel bucket and then add 450gm of KMnO4 for 1000 cubic feet of theatre volume.

Eg: Surgical Theater Volume = L×B×H = 20 × 15 × 10=3000 cubic feet Formaldehyde required for fumigation = 500 ml for 1000 cubic feet = So, 1500 ml of formaldehyde required (to be diluted in 3000 ml of

distilled water)

• After the initiation of formaldehyde vapor, immediately leave the room and seal it for at least 12 to 24 hours.

Neutralization after fumigation• Before neutralization, remove fumigating apparatus

from the surgical theatre. • Then the toxicity of formaldehyde vapor should be

neutralized with ammonia solution.• Place a cotton ball and pour 300 ml of 10% ammonia

(for each 500 ml of formaldehyde used) on the floor of surgical theater, at least 4 hours before (07 a.m.) the “Sterility Test”.

• Formaldehyde gas reacts with ammonia gas and produce Hexamine which is considered a harmless substance.

Factors influencing the fumigation of the theatre :

1. Relative humidity

Relative humidity plays a major role in fumigation. A minimum of 70% is essential. Water used in fumigator with fumigant helps to achieve and maintain humidity.

2. Temperature

temperature for effective fumigation is 300-400C.

3. Formaldehyde levels in the Air in the operation theatre

The dose of formaline is usually decided by the size of the room. As a rule, 280 ml is used for a room of the size 1000 cubic feet.

Emerging Compounds in use for Sterilization of Operation theatres:

BACILLOCIDRASANT:

• A newer and effective compound in environmental decontamination with very good cost/benefit ratio, good material compatibility, excellent cleaning properties and virtually no residues. It has the advantage of being a Formaldehyde-free disinfectant cleaner with low use concentration.

Advantages• - Provides complete asepsis within 30 to 60 minutes.• - Cleaning with detergent or carbolic acid not required.• - Formalin fumigation not required.• - Shutdown of O.T for 24 hrs. not required.

CHEMICAL METHODS

No available chemical solution will sterilize instruments immersed in it.

Secondly, there is a risk of producing tissue damage if residual solution is carried over into the wound while it is being used.  

Mechanism of action of chemical disinfectants :

The mechanism of action of most of the chemicals are nonspecific and complex but most of them effect microorganisms by one of the following mechanisms.

1. Cell membrane injury.

2. Coagulation and Denaturation.

3. Interactions with functional groups of proteins.

1. ALDEHYDE COMPOUNDS

a. Formaldehyde:

A broad-spectrum antimicrobial agent, used for disinfection, has limited sporicidal activity.

Hazardous substance, inflammable and irritant to the eye, skin and respiratory tract.

a. Glutaraldehyde:

It is a high level disinfectant

A solution of 2% glutaraldehyde (Cidex), requires immersion of 20 minutes for disinfection; and 6 to 10 hours of

immersion for sterilization.

 

2. ALCOHOLS

Act by denaturing bacterial proteins.

Solutions of 70% ethanol are more effective than higher concentrations, as the presence of water speeds up the process of protein denaturation as reported by Lawrence and Block (1968).

Frequently used for skin antisepsis prior to needle puncture.

Isopropyl alcohol is preferred as it is a better fat solvent, more bactericidal and less volatile. Used for disinfection of clinical thermometer .

3. IODOPHOR COMPOUNDS

Many studies have shown, that, iodophor compounds are the most effective antiseptics,. Iodine is complexed with organic surface-active agents, such as, polyvinylpyrrolidone (Betadine, Isodine). Their activity is dependent on the release of iodine from the complex.

These compounds are effective against most bacteria, spores, viruses, and fungi. These are the most commonly used surface disinfectants along with hypochlorite.

4. Biguanide :Most commonly used biguanide compound is chlorhexidine.

It is a powerful non-irritating antiseptic that disrupts bacterial cell membrane.

It persists on skin for longer period of time and that is why it is extensively used for surgical scrubbing, neonatal bath, mouth wash and a general skin anti-septic.

5.Hydrogen peroxide

• Strong oxidant.

• Oxidizing properties allow it to destroy wide range of pathogens.

• Biggest advantage is short cycle time.

• Used in 35% to 90% concentration.

Operation theatre procedure :

Antiseptic environment :

The principle is to minimize bacterial contamination,especially, in the vicinity of operating table;the concept of zones is useful,and must be employed.

Outer and general access zone- patient reception area and general office.

Clean or limited access zone- the area between reception & general office and corridors & staff room.

Restricted access zone-f or those properly clothed personnel engaged in operating theatre activities,anesthetic room.

Aseptic or operating zone- the operation theatre.

HAND WASHING

• Three types of hand washing-

– Social hand washing– Clinical hand washing– Surgical hand washing

Social hand washing

• Recommended following social-type contact with clients, after going to the toilet and after covering a cough or sneeze.

• A plain liquid soap is often used.

Clinical hand washing

• A clinical hand wash is used before clinical procedures on clients, when a client is being managed in isolation, or in outbreak situations.

• An anti-microbial soap, containing an antiseptic agent, is used.

Surgical hand washing

• A surgical hand wash is required before any invasive or surgical procedure requiring the use of sterile gloves.

• An antimicrobial skin cleanser, usually containing chlorhexidine or detergent-based povidone-iodine, is used.

Surgical Scrubbing :The purpose is to reduce resident and transient skin flora (bacteria) to a minimum.

Proper hand scrubbing and the wearing of sterile gloves and a sterile gown provide the patient with the best possible barrier against pathogenic bacteria in the environment and against bacteria from the surgical team.

The following steps comprise the generally accepted method for the surgical hand scrub-

1. Disinfection is : a. removal of visible contamination but does not

necessarily destroy micro organisms b. reduction of number of viable microorganisms

but may not inactive some viruses and bacterial spores.

c. destruction or removal of all microorganisms including spores.

d. destruction or removal of all microorganisms excluding spores.

2. Sterility assurance level (SAL) acceptable for critical item is :

a. 4 b. 5 c. 6 d. 7

3. Which of the following is semicritical ? a. mucous membrane b. intact skin c. tissue space d. vascular space

4. Minimum Relative humidity essential in fumigation is : a. 50% b. 70% c. 90% d. 100 %

5. Cidex consist of a. 2% glutaraldehyde b. 4% glutaraldehyde c. 2% chlorhexidine d. 4% chlorhexidine

6. Tyndallisation is : a. Exposure of 100 C for 20 min for 3 successive day. b. Exposure of 100 C for 10 min for 3 successive day c. Exposure of 100 C for 30 min for 2 successive day d. Exposure of 100 C for 10 min for 2 successive day

7. Which of these is an appropriate sterilizing cycle? a. 121 degree centigrade for 15 min b. 134 degree centigrade for 3 min c. 109 degree centigrade for 10 min d. A or B e. all of these

8. Which of these is used for gas sterilization ? a. Glutaraldehyde b. Liquid Nitrogen c. Ethylene oxide d. All of these

9. Which of these is used for liquid sterilization ? a. Ethylene oxide b. Liquid Nitrogen c. Glutaraldehyde d. All of these

10. What would you use to clean a flexible endoscope after use ? a. Sterilization b. Paracetic acid c. Alcohol d. Autoclave