Asepsis

 

Asepsis:

Asepsis is the state of being practically free from disease-causing contaminants (such as bacteria, viruses, fungi, and parasites) or, preventing contact with microorganisms.

 The term asepsis often refers to those practices used to promote or induce asepsis in an operative field in surgery or medicine to prevent infection. Ideally, a surgical field is "sterile," meaning it is free of all biological contaminants, that  can cause disease, putrefaction, or fermentation .

The modern concept of asepsis evolved in the 19th century. Ignaz Semmelweis showed that washing the hands prior to delivery reduced puerperal fever.

 Louis Pasteur, Joseph Lister  introduced the use of carbolic acid as an antiseptic and reduced surgical infections rates.

  Ernst von Bergmann introduced the autoclave, a device used for  sterilization of surgical instruments.

Antiseptics (from Greek  anti, '"against" sēptikos, "putrefactive") are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction.

 Antibiotics by the latter's ability to be transported through the lymphatic system to destroy bacteria within the body. Produced from one living organism to kill another organism

Disinfectants, which destroy microorganisms found on non-living objects.

Some antiseptics are true germicides, capable of destroying microbes (bacteriocidal), while others are bacteriostatic and only prevent or inhibit their growth.

Antibacterials are antiseptics that have the proven ability to act against bacteria. Microbicides which destroy virus particles are called viricides or antivirals.

Bacterial growth requires a food supply, moisture, oxygen (if the bacteria are obligate aerobes), and a certain minimum temperature.

The standardization of antiseptics has been implemented in many instances, and a water solution of phenol of a certain fixed strength is now used as the standard to which other antiseptics are compared.

• Alcohols, most commonly ethanol (60–90%), 1-propanol (60–70%) and 2-propanol/isopropanol (70–80%) or mixtures of these alcohols, are commonly referred to as "surgical alcohol", and are used to disinfect the skin before injections are given, often along with iodine (tincture of iodine) or some cationic surfactants (benzalkonium chloride 0.05–0.5% in  QAC, chlorhexidine 0.2–4.0% ).

• The antimicrobial activity of quats is inactivated by anionic surfactants, such as soaps.
• Boric acid is used in suppositories to treat yeast infections of the vagina, in eyewashes, as an antiviral to shorten the duration of cold sore attacks, in creams for burns, and trace amounts in eye contact solutions.

• Brilliant green is efficient against Gram-positive bacteria for wounds and abscess.

• Chlorhexidine gluconate, to treat inflammation of the gums (gingivitis).
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• Hydrogen peroxide is used as a 6% (20 Vols) solution to clean and deodorize wounds and ulcers.
• Iodine is usually used in an alcohol solution (called tincture of iodine) or as Lugol's iodine solution as a pre- and postoperative antiseptic.
• Novel iodine antiseptics containing povidone-iodine (an iodophor, complex of povidone, a water-soluble polymer, with 10% of active iodine) will leave a deposit of active iodine.

•  Phenol is germicidal in strong solution, and inhibitory in weaker ones. It is used as a "scrub" for preoperative hand cleansing

• Sodium chloride (salt) issed as a general cleanser and as an antiseptic mouthwash
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• Sodium hypochlorite was used in the past, diluted, neutralized, and combined with boric acid in Dakin's solution.

• Sodium bicarbonate (NaHCO₃) has antiseptic and disinfectant properties.

 

Sterilisation of Instruments:

Practically making all surgical instruments free of all microbes and spores. The instruments should be used for intended use.Wash the instruments to free them with blood clots, pus, grease with detergent and water,clean with turkey toweland hinges lubricated with instrument milk.

 

Based on the magnitude of risk.

 

Critical	Semi-Critical	Non-Critical
For Surgical pack	For Endotracheal tubes	For Gowns, Masks and caps

 

 

 

 

 

 

 

 

 

 

 

 

Based on methods of sterilisation:

Physical			Chemical	Radiation
Dry Heat (High temp for short time)	Moist Heat (Moist most effective, requires less temp)
Hot air oven at 350 degrees F for 3 hrs. At 120 deg for 8 hrs for clean gowns, drapes, paper wrapped swabs and petri dishes. At 160 deg 60 min for stainless steel and glass wares.	Boiling water with 2% Sod.carbonate to prevent corrosion. Spores are resistant at neutral PH, but by tis they will die.	Autoclave (steam under pressure) 121 deg C for 30 min at 15 PSI, or 250 deg F at 15PSI for 15 min, for sharp cutting instruments, needles all routine instruments. Autoclave test indicator strips are used to know whether sterilization temp are reaches in cooker at field level.	Sharp cutting instruments, guns, elastic or rubber articals  ,dip in 10 % formalin or 1-5 formalin and water for washing and soaking.Absolute alcohol/1 % cetrimide continous immersion. Sod nitrite prevents rusting. Ethylene oxide is used now for Disposables.Ethyl alcohol and isopropyl alcohaol at 70% is having max.germicidal property.For emergency commercial Cidex/sterisol is used instead of autoclave.	UV rays in operation theatre are produced from mercury lamp which is germicidal. X-rays and gamma rays are carcinogenic used  for disposable syringes,catheters, endotracheal tubesand I/V sets.

 

 

 

 

 

 

 

 

Pre-operative considerations:

            Owner ,patient and surgeon are three important components.

 

Owner: Collect the history about the disease, duration of sickness, discuss the        proposed surgical treatment, economic aspects, ethics involved, sentiment of   the owner, date of calving, milk yield , idiosyncracy of earlier general            anaesthesia and possible outcome of the surgery.

 

Patient: Proper identification on animal, its lab reports, its radiographs and particular           site of operation.           

 

Surgeon: 1.General physical exam by palpation of site, auscultation of heart and lungs and percurssion of lungs for different underlying factors like pneumonia, dehydration, debility, sunken eyes, prolonged recumbency.

2.Temp, pulse and respiration, Hb%, PCV%, total plasma proteins, mucous membranes and capillary refill time  to be checked.

3.  Safety to Operate. Very young and very old patients are a surgical risk. Cardiovascular disease, pneumonia, uremia, renal insuffiency and pregnancy will complicate surgery.

4.In fever, debility, heavy bleeding, gastro-intestinal problems, heavy parasitic load, animal in shock and severe dehydration, surgery to be postponed for corrective treatment.

5.Faecal exam for parasites, paracentisis of  any swellings to be done.

6.BUN and creatinine levels for urinary system sufficiency.

7.Radiograph for specified exam like urinary calculi.

8.Purgatives should be given before day and enema on the day of surgery to clear GI contents, but no purgatives for large animals.

9.Better to do surgery in the morning for easy fasting and post operative care and observation.

10.Starvation for 12-18 hours in small  animal and 24-48 hrs in large animal with 12-24 hrs of water withholding.

 

The surgeon:

 

a)Judgement:

The surgeon has to decide when to operate and when not to operate. To treat ventral hernia in late stage of pregnancy is poor judgement and toconduct rumenotomy to remove nails in advanced pregnancy animal is poor. Teat canal obstruction removedin lactation but repair of teat fistula is done in dry period.

The surgeon has to decide choke, haemorrhage from lacerated wound and evisceration by trauma as emergency and castration,rumenotomy and removal of  growths on skin to be planned.

 

b) Planning of surgery:

            1.Through knowledge of surgical regional anatomy is essential.

            2.All required instruments, equipment and drugs to be arranged before hand.

            3.Mental visualisation of surgery.

            4.Getting necessary assistance.

            5.Getting the risk note.

 

 

c)Location of the Surgery:

 

            1.Better to do in operation theatre with routine professional and manual help.

2.For large animal surgery, a square room of 7-8 mts with small anteroom for washing and preoperative medication.

3.Calm location , away from sun rays.

4.Provision for easy cleaning of the room.

5.In open field surgery, clean the area free of dust and dirt and sprinkle it with water.

6.Bullock cart or ready made crush with wooden logs for restraint of the animal.

7.Floor with cushion material like straw covered with gunny bags or tarpaulin.

8.Hand lamp for adequate lightning.

9.Sufficient fresh clean water.

10.No onlookers.

 

 

d)Maintanance of records:

 

1.Record keeping is a must.

2.Note owner name and address, history of case, clinical condition, type of surgery and post operative care and outcome.

3.Record useful in veterolegal or any disputes.

4.Application of time records for knowing the incidence of  a particular case.

 

Operation room:

 

1. Clean, dry, ventilated and illuminated properly.

2.Operation table, instrument table, floor, walls and curtains should be clean and tidy.

3.Wash basin with hot and cold water connection is required with long tap handles.

4.U.V light , wall clock and X-Ray illuminator are other useful equipment.

 

Aseptic technique in conducting operation:

 

1. The skin at the operation site should be Cipped, Shaved with safety razor guard removed , and wash with soap and water with scrubbing.

2.All equipment like instruments, glowns, towels, drapes, curtains should be sterilised.

 3.The hands of the surgeon should be scrubbed clean, sterile gloves ,caps, gowns, masks should be worn.Antiseptic lotion should be applied to hands and hands held high, elbows flexed and dried with clean towels from sterilisation drum.

4.Contamination of the wound from surroundings should be prevented and wound protected until healing.

 

 

 

 

 

Preparation of site of operation(Sterilisation in and around site of operation):

            1.Clipping of hair, shave with guard removed, double the area required.

            2.Wash with soap and water with scrubbing with savlon with centrifugal method.

            3.Wash with fat solvent like turpentine or ether to remove grease.

            4.Repeat soap water washing.

            5.Apply 70% ethyl alcohol.

            6.Apply tinc.Iodine.

            7.Wash iodine by alcohol again.

            8.Apply tinc.Iodine.

            9.Wash iodine with alcohol again.

            10.For birds, pluck the feathers, clean with soap water.

11.For large animals tail is bandaged and drapping is practically not possible and   ruminal contamination is possible, so double area is prepared.

 

 

Post operative care:

1.Animal in cool, comfortable, calm place in comfortable position, not in dorsal recumbency.

2.Tongue pulled out to avoid breathing trouble.

3.In cold wheather cover the body.

4.Prevent struggling in recovery.

5.No water while recovering, can lead to aspiration pneumonia.

6.Check temperature, pulse and respiration periodically.

7.Change the position of the body to prevent hypostatic congestion of lungs.

 

Post-operative complications:

 

1.Pneumonia: By inhalation of foreign body,secretions and vomitus.It can be prevented b fasting, atropine to reduce secretions and antivomiting.

2.Hypostatic congestion of lungs: prevented by periodic change of the position of the animal.

3.Wound infection or stitches getting infected leading to pus and abscess formation, leading to wound dehiscence.

4.Eviseration(protrusion of visera through incision): Intestine protrude by damage of sutures by drying, soiling, infection or injury.

5.Herniation:It is more common by improper suture application and external violence.

6.Peritonitis: By rough handling of visera and by escape of stomach, intestinal, uterus, bladder contents into abdomen. Acute peritonitis can cause sudden death.