General surgery: Aseptic and Antiseptic techniques

General surgery: Aseptic and Antiseptic techniques

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Aseptic and Antiseptic techniques

The most important cause of impaired wound healing is infection. Microorganisms reach the tissues during an operation or during changes of dressings or any other minor interference with the surgical wound. They are carried and transmitted by people (including the patient and anyone else who touches the wound or sheds organisms into the surrounding air), inanimate objects (including instruments, sutures, linen, swabs, solutions, mattresses, and blankets), and the air around a wound (which can be contaminated by dust and droplets of moisture from anyone assisting at the operation or caring for the wound).

The aseptic treatment of a wound is an attempt to prevent contamination by bacteria from all these sources, during the operation and throughout the first week or so of healing. Modem methods of preventing infection in “clean” wounds also include the use of surgical techniques designed to make the wound less receptive to bacterial growth: gentle handling, sharp dissection, good haemostasis, and accurate apposition of the wound edges without tension when the wound is being closed. Bacteria can never be absolutely eliminated from the operating field, but practicable aseptic measures can reduce the risk of contamination to an acceptable level.

Definitions

Aseptic technique: the prevention of microbial contamination of tissues and sterile materials by excluding, removing or killing microorganisms

Disinfection: involves the killing or removal of sufficient microbes to render an inanimate object safe for its intended purpose

Antiseptics: Chemicals which can be applied to living tissues to kill or inhibit the growth of microbes.

Cross infection: the transfer of microbes in hospitalized patients to other patients.

Auto infection: infection caused by organisms already colonizing the patient’s body or in septic lesions.

Choice of antiseptic

The ideal antiseptic will have the following four properties

  • The spectrum of activity would be broad
  • It would be resistant to inactivation by organic materials, such as blood & feces
  • There would be no toxicity or allergic reaction, and the antiseptic should be non – staining
  • It would be inexpensive.

Preparation for surgery

The patient’s stay in hospital before an operation should be as short as possible. Therefore, any tests and treatment that could prolong the preoperative stay beyond 24 hours should be carried out as outpatient services, if possible. Before the operation, correct gross malnutrition, treat serious bacterial infection, investigate and correct gross anaemia, and control diabetes. As a routine, measure the patient’s haemoglobin level and test the urine for sugar and protein.

The patient’s stay in hospital before an operation should be as short as possible. Therefore, any tests and treatment that could prolong the preoperative stay beyond 24 hours should be carried out as outpatient services, if possible. Before the operation, correct gross malnutrition, treat serious bacterial infection, investigate and correct gross anaemia, and control diabetes. As a routine, measure the patient’s haemoglobin level and test the urine for sugar and protein.

Just before the operation, wash the area around and including the operative site, and prepare the skin with antiseptic solution, starting in the centre and moving out to the periphery. This area should be large enough to include the entire incision and an adjacent working area, so that you can manoeuvre during the operation without touching unprepared skin. Ethanol 70% (by volume) is recommended as an antiseptic, except for delicate skin, such as that of the genitalia and near the eye, and for children; 1% cetrimide (10 g/litre) is an alternative, as is 2.5% iodine in ethanol (25 g/litre).

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The surgical team

Anyone entering the operating room, for whatever reason, should first put on clean clothes, an impermeable mask to cover the mouth and nose, a cap or hood to cover all the hair on the head and face, and a clean pair of shoes or clean shoe-covers.

Before each operation, all members of the surgical team – that is those who will touch the sterile surgical field, sterile instruments, or the wound – should cleanse their hands and arms to the elbows, using soap, a brush (on the nails and finger tips), and running water. The team should scrub up for at least 5 min before the first procedure of the day, but between consecutive clean operations a minimum of at least 3 min is acceptable.

After scrubbing their hands and drying them with sterile towels, the members of the surgical team should put on sterile gowns and sterile gloves. A glove punctured during the operation should be promptly changed.

The operating room

Operating Room There are few bacteria in the air of an empty theatre but every individual liberates about 10,000 organisms per minute into the air. Therefore, to decrease airborne infections, keep the number of personnel reduced to a minimum. Unnecessary movement should also be discouraged.

There should be adequate ventilation for most procedures. If there is no system to provide this, windows should be open to allow ingress of fresh outside air and escape of anesthetic gases.

Keep all doors closed except as needed for passage of equipment and personnel.

Clean operating rooms between operations. At regular intervals, conduct a more thorough cleaning by mopping the floor and washing the walls with detergents.

All instruments and garments to be used in surgical procedures must be sterile and this is attained by sterilization.

Sterilization: is a process by which inanimate objects are made free of all microorganisms. Widely used methods of sterilization in a hospital are.

Autoclaving: This is the preferred method of sterilization. It uses steam at a pressure of 750 mmHg above atmospheric pressure and temperature of 1200 C for 15-30 minutes. The steam is helpful for penetration even into spores. Appropriate indicators must be used each time to show that the sterilization is accomplished.

Properties of commonly used antiseptics

Alcohols (e.g. ethyl, isopropyl): Broad spectrum, rapid action, moderately expensive, most active against bacteria at 70% concentration

Chlorhexidine: Good activity against staphylococci and streptococci, moderate activity against gram-negative bacteria, persistent action, moderately expensive, non-toxic, unpleasant taste

Iodine (lugols solution): Broad spectrum, cheap, stains, hypersensitive

Povidone iodine: Broad spectrum, moderately expensive, some hypersensitivity, rapid inactivation by blood

Hexachlorophane: Slow, but cumulative action against staphylococci and streptococci, systemic toxicity for neonates, moderately expensive

Triclosan: Similar activity but less toxic than hexachlorophene

Chlorine (chlorinated lime and Boric acid (Easol): Broad spectrum, locally toxic, expensive

Dilute sodium hypochlorite solution: Broad spectrum, cheap, locally toxic

Quaternary ammonium compounds 🙁 e.g. cetrimide in benzalkonium chloride) Poor gram-negative activity, readily contaminated, detergent, cheap, non-toxic.

Noxythiolin: Releases formaldehyde in contact with tissues, broad spectrum, expensive, weak and slowly bactericidal

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