The presence of pathogens or their toxic products in the blood or tissues of the patient, more commonly known as infection [1].
Sterilisation
Total elimination of bacteria or other living microorganisms [2].
11.1 The Principles of Operating Theatre Design and Use
Registered veterinary nurses (RVNs), should aim to create and maintain a clean, safe and effective surgical environment to help to prevent microorganisms and spores from multiplying; this is achieved by using sterilisation and disinfection techniques to eliminate microorganisms and spores. These techniques include autoclaving, cold sterilisation, daily damp dusting, periodic deep cleaning and the use of appropriate disinfection protocols. All equipment, instruments and furnishings used in the theatre or operating suite should be maintained in an aseptic manner. A fresh set of instruments must be used for each patient [3].
The theatre suite must not be a thoroughfare; there should be one way in, and another separate way out. Clearly defined clean and dirty areas of the theatre suite ensure aseptic techniques are easier to manage and have a reduced risk of contamination. When considering design and use, it is also essential to consider the personnel present during surgery; an increased number of personnel will increase the chance of contamination from factors such as skin particles and increased air movement. Operating areas should contain adequate lighting, flooring and wall coverings that are easy to clean, durable and have hygienic protection. It should be possible to control the temperature in these rooms and have positive pressure air ventilation. There should be minimal furniture and no open shelving in the theatre as this will harbour dust; all equipment, including the operating table, should be easy to clean. Standard operating procedures (SOPs) are essential when considering theatre use [4]. Important points relating to SOPs include:
Following written SOPs help to ensure all staff follow the same procedure when cleaning, disinfecting and sterilising to maintain theatre asepsis.
SOPs should be clear and regularly audited to ensure validity.
SOPs should be usable by all members of staff.
SOPs should include the correct dilution rates for cleaning and disinfecting, although not all disinfectants will remove microorganisms and their spores. For this reason, careful consideration must be employed when selecting a disinfectant. It is important to remember that most disinfectants are inactivated by organic material such as blood and faeces, so it is best practice to clean areas before disinfection occurs. Correct dilution of disinfectant is essential in order to reduce disinfectant resistance; manufacturer guidelines should always form part of SOPs.
SOPs detailing daily damp dusting should also be available explaining the importance of daily damp dusting and weekly and monthly deep cleans. It is best practice if working in a busy hospital theatre to do monthly bacterial swabbing of a range of areas within the theatre to identify if cleaning protocols are effective or not. The growth of bacteria of any kind could be detrimental to patient health, and prevention is always preferable over cure [2].
Ideally, every hospital or practice would be purpose‐built, but the buildings used have often been modified and adapted over time due to costs and space requirements. When developing the perfect layout and design, there are many factors to consider, such as the location and flow of patients, staff and materials. In addition to being isolated from the usual traffic of the hospital, communicating with the pharmacy, radiography and emergency access, the surgical area must have the best ambient and operating lighting, the right furniture and a strict and efficient air‐conditioning system. The theatre suite can be broken down into different areas, from the outside spaces to the inner theatre. The objective is to avoid possible contamination and the development of surgical site infections, as the most significant source of infection in postoperative wounds is caused by incorrect handling of the spaces shared by medical staff and patients [5].
Different areas of the surgical suite can be broken up into zones and can even be colour‐coded to ensure that all personnel entering can clearly see where they can and cannot go. An example of this system is as follows:
Black area – this area is considered the most contaminated area and includes all the corridors around the theatre and the horse preparation area before induction. In this area, staff may be dressed in outdoor footwear and clean uniform, but theatre attire is not required.
Grey area – includes the induction and recovery boxes and the anaesthetised patient prep area. In this area, clean clothing should be worn by those entering from the black area, and theatre scrubs with boiler suits over the top should be worn from the yellow area.
Yellow area – this should only be entered through a clean changing room from a black area. Nobody should enter directly from a black area, i.e. from the patient preparation area to the grey area for induction into yellow. Similarly, nobody should exit a yellow area anywhere except via a changing room. Clean theatre scrub suits and theatre hats should be worn when within the yellow area. This area includes the storage areas and scrubbing‐in areas.
White zone – area of maximum restriction, where the operating theatre and sterile storage are located. This should be accessed via a sterile corridor, and a one‐way system should be in place, so the dirty traffic does not go back through the white area. Doors must remain closed at all times, and full theatre attire is required [5].
Regardless of the individual set‐up in a practice, theatres can be separated into different essential areas. These requirements will be specific to the area, including induction and recovery, preparation area, operating theatre, scrubbing‐up area, decontamination and sterilisation area, sterile storage and changing rooms [5].
Induction and Recovery Boxes
Ideally, there would be a separate induction and recovery box; however, this may not be practical or necessary in a smaller practice. The requirements of this area include:
The room size needs to be large enough for the horse but should not be oversized as this will allow the horse to gain momentum that will only increase the chance of injury – typically, the ideal size is between 12 and 16 ft./4–5 m2[6].
Padded walls and doors at least 8–10 ft./2.5–3 m high using robust surface material that can withstand high impacts and can easily be cleaned; this is usually a polyvinyl chloride (PVC) or rubber‐based material; this will also minimise the risk to the patient during induction and recovery [2].
Soft, rubberised floor with a non‐slip surface that provides sufficient traction even when wet, has a drainage system and can readily be cleaned and disinfected [3].
Some practices may opt for a box that has rounded corners and curved borders, while others have a more traditional square room; whichever type is used, there must be no unpadded square edges or protrusions, as these will lead to injury [3].
The doorways should be wide enough for the horse to be safely hoisted through from the theatre and taken back to its stable on the opposing side.
Lockable doors that are secured by transverse bars and/or floor/ceiling bolts [3].
A pulley system is in place to enable rope recovery; this may be used in all recoveries or occasional ones. All bolts, pulleys and mechanisms should be high enough on the walls not to cause injury to the patient during recovery [2, 3].
Adjustable lighting that enables visualisation of the horse when required, but during recovery, it is sometimes preferable to have lighting dimmed [2].
Heating/Air conditioning (AC) system – recovery should be separately temperature controlled so that heating and cooling can be achieved as required. Cooling may not be necessary, depending on the ambient temperature of the general environment [3].
Hoist – this is a gantry‐mounted hoist that is ideally electrically operated; however, even if an electric one is used, a manual hoist should always be available in case of malfunction. The hoist is essential for moving the horse from the induction box to the operating table and then to the recovery box. In some practices, where there is no preparation room, or the table is not mobile, the hoist will go directly into the theatre. While this may be unavoidable, it is not ideal since the hoist will invariably be contaminated with, for example,. oil and dust. Due to the hoist possibly being over the surgical incision, it is preferable to have a system that avoids the need for the hoist to enter the theatre itself, using a post‐induction preparation area and movable operating bed [2].
There are several ways of monitoring the horse during recovery; the simplest is a spy hole in the door that the person watching the horse can look through; however, the use of closed circuit television (CCTV) that runs to a monitor is preferable as the whole room can be visualised without any blind spots.
Practices with a high surgical caseload typically have two or more recovery boxes; this allows a second horse to be anaesthetised while the first horse is recovering. The practice should have a number of recovery and induction boxes that suit their caseload; if there are more than necessary, this increases the chance of microorganisms growing on surface areas as they are not used and cleaned as often.
Preparation Area
This area is where the horse can be prepared for surgery, and ideally, the area should include the following features [4]:
Situated in close proximity to the theatre suite – ideally, this will be a room that adjoins the induction box, so that once the horse is suitably prepared, it can be taken straight into the induction box.
It needs to be large enough to prepare the horse safely but not too large as this will increase the surface area and encourage further bacterial growth.
Contain equipment required for preparing the horse; this will vary depending on the individual practice but could include the following:
Clippers
Shoe removal kit
Hoof pick, scrubbing brush and bucket
Intravenous (IV) catheter equipment
Hosepipe for cleaning the floor
Large syringe and bucket for rinsing the mouth out
Grooming brushes
Tail bandages
Induction headcollar (ideally made from leather and padded)
Pre‐operative sedation
Sterile gloves and examination gloves
6.2 Operating Theatre
Depending on the caseload of the practice, it may be necessary to have at least two operating theatres. This allows for best practice, ensuring that one theatre is kept for ‘clean’ surgeries, such as elective orthopaedic procedures and fracture repairs. In contrast, the other theatre is used for ‘contaminated’ procedures, such as colic surgery and dental procedures. This approach ensures that procedures already contaminated do not transmit contamination to non‐contaminated, potentially high‐risk surgeries. Many practices do not have the luxury of having multiple theatres; if this is the case, cleaning protocols must ensure effective cleaning has been taken place. The requirements for the operating theatre include:
Size – The theatre needs to be large enough to accommodate a horse positioned in dorsal or lateral recumbency and allow enough room for surgical equipment and a surgical team. Generally, a horse in lateral recumbency will take up double the space of one positioned in the dorsal recumbency. A theatre that is too small will compromise working conditions and make it harder to maintain asepsis; however, in contrast, a theatre that is too large will be difficult to keep clean and has a higher surface area for bacterial growth [7].
Floors – Should be made of smooth, impervious, non‐staining material that is easy to clean, hard‐wearing and non‐slip. Industrial vinyl or rubberised floors can be used. However, they may be damaged by heavy equipment (especially the operating table) and cleaning materials. If this happens, it will allow bacterial colonisation under the surface, making it difficult to keep clean. Screeded concrete can also be used. It is hard‐wearing, non‐slip and easily cleaned; however, the surface can chip away and pit, allowing water to form pools [7].
Walls and ceiling – Should be painted with light‐coloured waterproof paint. Anti‐bacterial coatings are available, but they are expensive and are not long‐lasting, so a re‐painting schedule should be implemented. Other options for walls within the operating theatre include:
Epoxy Resin Coatings: Durable and resistant to chemicals and stains.
Vinyl Wall Coverings: Seamless, hygienic, and easy to clean.
Ceramic Tiles: Smooth, non‐porous, and easy to disinfect, though grout lines must be minimised.
Stainless Steel Panels: Highly durable, easy to clean, and resistant to microbial growth. [7].
Operating table – This should be adjustable to facilitate the needs of the patient and the surgeon. It should ideally be able to be raised, lowered and tilted as necessary, and this is typically achieved by using a hydraulic or electric pump system. The table may have wheels to allow it to be moved around easily in the room, or it could remain in a fixed position. It is essential to consider that the typical equine patient will be large, heavy and difficult to move. The choice of operating table will depend on the size of the operating theatre, the amount and type of surgeries performed, and financial and personal considerations. There are a range of equine operating tables available:
Mobile – These are typically beds that are on wheels and can be manoeuvred around the theatre suite and into the preparation area as required. Some beds have to remain attached to a power supply to be able to adjust but can be disconnected while the horse is being prepped. Others have a chargeable battery system that allows for completely unrestricted movement.
Fixed hydraulics – These tend not to be as commonly used; as the name suggests, they are fixed, and therefore, there is no way to change the position in the room. They often have a pit under them so the bed can go right to the floor without damaging the hydraulics underneath, but this also creates an area that can build with debris and harbour microorganisms.
Inflatable – These are ideal in a smaller practice with a minimal theatre caseload. They have layers of inflatable mattresses that build up height and are adjustable by removing air from the valves. These do have limitations and can be unstable in certain surgeries [2].
Ideally, the operating theatre should have minimal equipment in it. It should not have any shelving or unnecessary furniture, as this will harbour dust and microorganisms. Any shelving should be behind doors or in a separate area, such as sterile storage. Other important points to consider are as follows:
Drains – Although they are a potential source of bacteria, drains are essential in an equine operating theatre if a good standard of asepsis is to be maintained. A good SOP should be in place detailing how to clean the drains to minimise the risk of bacterial growth. Floors should be gently sloped towards the drains to facilitate drying and prevent the pooling of water [4].
Electrical sockets/network interfaces – There should be a good supply around the room, either recessed into the wall or suspended from the ceiling, and they should have protective covers. Care must be taken that these are out of reach from water and that they do not get wet during the cleaning process [8].
Lighting – This is essential in the operating theatre; ideally, lighting should be flush with the ceiling to prevent dust from building up on surfaces; strip lighting is a good source of light in a theatre. There should also be an adjustable ceiling‐mounted spotlight to allow illumination of the surgical site; these can come with single or multiple heads and have removable autoclavable handles to enable the surgeon to have the correct placement of light during a procedure [8].
Ventilation – There should be a positive pressure ventilation system that allows frequent air changes in the operating theatre to remove airborne microorganisms and help maintain asepsis. This, however, is expensive and may not be feasible in smaller practices [4].
Windows – Operating theatres are generally windowless, although windows are becoming more prevalent in newly built theatres, to provide clinical teams with natural light and may improve surgeons’ mental well‐being and consequently improve surgeon occupational health [9]. However, they should be airtight and soundproof, and the use of tinted glass will mean that blinds are not necessary as they will allow dust to build up on them. Some procedures may require them to be blocked off, i.e. the use of a laser, as this may be detrimental to the health of others.
Heating – The ambient temperature should be 15–20 °C, so some form of heating is required. Airconditioning units may be used as part of the ventilation system, but these should not include a fan; fan heaters must be avoided as they will cause movement of dust and debris. Panel heating within walls is desirable but expensive. Modern wall‐mounted radiators are often the most practical method but must be easily cleanable to prevent dust and debris from accumulating [10].
Wall clock – For anaesthetic monitoring and timing of the surgery; if possible, this should be behind a see‐through panel to avoid dust accumulation.
Other fixtures and equipment include:
Anaesthetic machines, scavenging systems, storage for emergency drugs, and items needed in case of a cardiopulmonary arrest are also required. See Chapter 10 for more details.
A dry wipe board – where details such as swab numbers and sutures used are recorded.
Theatre trolley – For holding instruments during surgery. This should be made of stainless steel and, ideally, have two shelves with a guard rim around the edge to prevent instruments from falling on the floor. The mayo trolley is a type of theatre trolley with a removable tray for cleaning. These are adjustable in height and designed to sit over the patient; some also feature a pivot system to assist with placement over the operating table. These are not regularly used in equine practice as they would not easily fit over the equine patient [10].
Fittings for piped gases – oxygen and occasionally nitrous oxide, and medical air for power tools – and scavenging systems may be wall‐mounted or dropped from the ceiling.
X‐ray viewers – Tend to be portable now that digital imaging systems are mainly used, but this could be built into the wall, so the panel is flush with the wall surface.
Wall fittings ‐ rings in the wall or hoist systems may be used for positioning limbs for surgery [4].
Scrubbing‐up Area
Ideally, this should be an adjoining room to the operating theatre, which can be reached via swing doors. Desirable features are as follows:
Stainless steel scrub sinks at an appropriate height for staff; these should have either elbow‐ or foot‐operated taps.
Storage for sterile gowns, gloves and hand towels.
The room should be large enough for the trolley to be laid out and for staff to gown and glove without contamination [7].
Decontamination and Sterilisation Area
A designated area within the theatre suite should allow for the decontamination of used equipment and sterilisation. This should be separate from the sterile storage area to prevent cross‐contamination from dirty instruments and include the following features:
A double sink – this will allow contaminated instruments to be submerged in instrument cleaner and then a sink of clean water to rinse off residual cleaning products [5].
A range of brushes and cleaning tools to ensure kits are cleaned effectively.
An ultrasonic cleaner to ensure that all organic matter is removed from instruments before sterilisation.
A washing machine and tumble dryer to launder all drapes and clothing used in surgery.
Packing materials required for re‐packing clean instruments ready for sterilisation.
An autoclave for the sterilisation of packed and clean materials.
An ethylene oxide steriliser to sterilise materials that cannot be processed using an autoclave [11].
Sterile Storage
The sterile storage area should be accessible from all operating theatres and is where all sterilised equipment should be located. It should have the following features:
There should be limited access to sterile storage, and it should be a temperature‐controlled environment – temperature should be 18–23 °C, and humidity should be maintained at between 30% and 60% and not exceed 70% [5].
The floors, walls and surfaces should be made of materials that are non‐porous and able to withstand chemical agents used in cleaning and disinfection [12].
Shelves used for storage of clean and sterile equipment are at least:
25 cm (10 in.) off the floor
45 cm (18 in.) from the ceiling and sprinkler heads
Changing rooms should be located at the entrance to the theatre and should be marked as sterile areas; they should include the following features:
External hooks for outdoor coats and jumpers
Exterior shelving for footwear worn outside of the theatre
Suitable changing facilities to cater for the individual needs of staff and visitors
Labelled shelving for staff scrubs and visitor scrubs
Contain theatre‐use boiler suits that are clearly labelled, so that staff can carry out daily jobs inside without getting entirely changed if there is no surgery happening
Contain theatre footwear that is clearly labelled
Contain hats and masks
Contain a written SOP for appropriate theatre attire [2].
11.2 Maintenance and Cleaning of the Theatre Suite
Theatre suite cleaning protocols must be strictly adhered to in order to maintain a clean environment with a low risk of contamination. All areas within the theatre suite must be easy to clean, preferably made of hard plastic or stainless steel and be anti‐static. RVNs must understand the importance of maintaining this environment, the schedule for which can be broken down into daily tasks and periodic deep cleans which should typically be carried out on a monthly basis [10].
Daily Care
At the beginning of each day, before the daily operating list commences, all surfaces must be damp dusted; this includes overhead lights, the top of the hoist and anaesthetic monitoring equipment. Damp dusting involves the use of clean or new cloths with a suitable cleaning agent for theatre, to remove all dust particles which may have built up. Traditional dusting moves the dust particles around; therefore the cloth used must be regularly changed to prevent a build‐up of bacteria [3].
Between surgeries, all areas within the operating room, including the operating table, any mattresses or stands, equipment and adjoining rooms, must be cleaned and disinfected with an appropriate disinfectant designed to kill microorganisms and their spores. All surfaces and equipment must first be cleaned with water +/− a detergent to remove all organic material before disinfection. Failure to do this may mean that the disinfection process is not achieved due to inactivation or partial inactivation of the active ingredient in the disinfectant by organic materials.
The cleaning process for the theatre suite should begin in the operating room, where the walls should be washed first, working down to the floor and towards the drain. The room should slope slightly towards the drain to prevent water pooling, which may encourage the growth of bacteria. Then, a cleaner safe for all surfaces can be used, using a scrubbing brush marked for theatre use only. Once all areas have been scrubbed, they must be rinsed with clean water. Finally, a disinfectant used at the correct dilution rate, following the manufacturer’s guidelines, can be used and left to dry for more prolonged residual activity. The rest of the theatre suite can be cleaned following this same protocol, working from back to front and top to bottom. All surfaces must be wiped down with a disinfectant at the correct dilution at the end of each day, and if using reusable cloths, have a regular rotation of clean ones. All bins must be emptied between each surgery, including general, offensive, clinical and anatomical waste [10].
Other daily tasks may include:
Care of clippers – clippers should be cleaned and sprayed with a hygiene spray. This will ensure that they are not contaminated when used on other patients.
If a hoover is used in the theatre to clean any loose hair before scrubbing takes place, this will need regular cleaning and emptying.
Putting away sterile supplies and ensuring the sterilisation process is complete.
Stocking consumables and used items required for operating.
Ensuring all items are in date.
Changing over any equipment that may be required for emergency surgery out of hours [2].
Periodic Deep Cleaning
Methicillin‐resistant Staphylococcus aureus (MRSA) is a bacteria that is resistant to commonly used antimicrobials in both animals and humans. It is paramount that the effective use of disinfectants in practice is adhered to. Regular swabbing should be carried out to ensure correct usage. MRSA is a nosocomial (hospital‐acquired) bacteria that is one of the top causes of post‐operative complications in hospitalised patients. Because of this, regular deep cleans must be factored into the running of a theatre suite; this should ideally be carried out every month along with monthly swabbing of a range of areas to ensure no bacterial growth has occurred, and that the disinfectant solutions and cleaning protocols used are effective. Deep cleaning the theatre suite means all areas, including drains, windows and coving are thoroughly cleaned. A wet vacuum could help reduce the amount of standing water (with regular filter changes required) or an industrial floor scrubber could be used [13].
All cleaning utensils and equipment used in the theatre must be colour‐coded or marked ‘Theatre use only’. This prevents contamination from other parts of the practice, which would be classed as ‘dirty’.
Electrical Equipment Cleaning and Maintenance
Modern operating theatres contain a range of electrical equipment that will require special considerations when it comes to maintenance; these include:
Clippers – These are essential items in theatre; they will be used to touch up any surgical site clipping and clip areas for arterial lines and emergency catheter placement. Clippers used in theatre must be ‘Theatre‐only’ clippers and serviced annually. New clipper blades are recommended for each surgery ensuring the blades sharp and free from contamination; if this is not possible, they should be appropriately cleaned and sprayed with hygiene spray to prevent cross‐contamination. Clippers should undergo portable appliance testing (PAT) annually.
Lighting – Strip lighting and spotlights require annual servicing.
Operating table – Annual servicing and PAT testing if there are electrical components, so the table is safe for use; if using hydraulic arms on the table, having spares is essential to allow for them to be replaced if they break during surgery.
Hoists – Electric/manual, annual service by the manufacturer, keep well‐oiled unless not required by the manufacturer. PAT testing is required for electric hoists.
Stretchers – These are made out of fabric or plastic with handles to lift a patient. Due to the size of the horse, they are not commonly used but are helpful for foals; these need to be checked for cracks.
Hobbles – These are required to go around the patient’s pasterns to lift the horse onto and off the surgical table. These need a weight certificate to be issued annually to ensure they are safe to use.
Autoclave – Depending on usage, this will require either bi‐annual or annual servicing and also require a boiler test done annually – this will require the manufacturer and a boiler inspector to be present at the same time, and the autoclave must be cold to carry this out, it is advised that it is switched off overnight to ensure that this is the case.
Ethylene oxide steriliser – Annual service by the manufacturer and PAT testing.
Suction unit – This is an essential item in the operating theatre for many reasons. It can be used for removing blood and fluid from the surgical field and occasionally for the aspiration of fluids from the oropharynx and nasopharynx during or after surgery, or for suctioning fluids and blood during surgical procedures. Various suction machines are available, and size should be considered – units range from one to four canisters depending on usage required, with a preference being for two canisters, to allow one to be quickly emptied while the other is in use (Figure 11.1). Fluid accumulation should be disposed of appropriately, and some suction units have liners containing the fluid rather than pouring it down a sluice drain. Most suction units have manufacturers’ guidelines for disposal and safe use and local and national waste disposal legislation. These must be thoroughly cleaned after use and disinfected, especially if a reusable canister is being used. These units must be sent off for servicing annually, so there is no drop in suction performance. They will also require an annual PAT test [4].
Diathermy unit – This machine uses a high‐frequency electrical current, which produces heat within the tissues at the point of application. The nature of the waveform of the applied current used in diathermy can vary in effect from continuous waveforms for cutting tissues and interrupted waveforms for coagulation. It is a valuable piece of equipment that allows rapid control of haemorrhages, minimising blood loss, and allows for clear visualisation of the surgical field. The electrical box should be damp dusted daily, ensuring that dust and debris do not build up. After each use of the diathermy, the earth plate should be cleaned and disinfected (if reusable). The cable and leads should be inspected for patency and then washed; the electrical ends should not be submerged in water unless the manufacturer’s guidelines state that this is appropriate. The unit should be maintained according to ‘the manufacturers guidelines and serviced and maintained regularly by a qualified engineer. PAT testing should be carried out annually. There are several types of diathermy machines available for surgical use. The two most common types are:
Monopolar diathermy – this typically uses a finger‐switch pencil used for cutting and coagulation. This diathermy requires the patient to be ‘earthed’ or ‘grounded’ using a diathermy pad. In monopolar action, the electrical current oscillates between the surgeon’s electrode through the patient’s body until it meets the ‘diathermy pad’ (typically positioned on the patient’s spine) to complete the circuit. If this is not present, the electricity will pass along the line of least resistance, which may be the patient or the surgeon leading to a severe electric shock or burning. The earth plate may be disposable or reusable.
Bipolar diathermy – does not require a ground or earth plate as the current passes through the tips of the forceps across the tissue. The current is usually activated using a foot pedal connected to the machine. Coagulation is achieved by applying the forceps directly to the source of the bleeding, by touching or clamping the vessel [4].
Cryosurgery equipment – Uses extreme cold to destroy living tissue and aims to kill diseased cells in a target area, whilst causing minimal damage to the surrounding healthy tissue. Liquid nitrogen is most commonly used, and after application to the area, the intracellular and extracellular water begins to freeze with its reduced temperature causing the formation of ice crystals, eventually leading to cell denaturation and death. Liquid nitrogen is a harmful substance, so many precautions are associated with its storage and use. To comply with Control of Substances Hazardous to Health (COSHH) regulations, a SOP should be in place to prevent accidents when storing and handling liquid nitrogen. All personnel involved in the use of liquid nitrogen should be trained and familiar with the SOP. Liquid nitrogen should be transported and stored only in containers supplied by the liquid nitrogen provider or a cryosurgical equipment manufacturer. These are insulated metal containers of varying sizes. The correct personal protective equipment (PPE) should always be worn when handling liquid nitrogen; this should include protective goggles, an apron and insulated gloves. Contact with the skin should be avoided as this will cause severe thermal burning. In veterinary practice, small specially developed thermos canisters are used as they are easy to handle and manipulate. The liquid nitrogen can be applied via a probe attachment that adheres to the tissue surface or from a more diffuse spray. Once the probe or spray attachment has been used, it will be frozen, so it should be left to thaw before being washed and disinfected. The remaining liquid nitrogen should be poured back into the main container [4].
Laser – Laser stands for ‘light amplification by stimulated emission of radiation’ . Laser is used to seal small blood vessels and lymph vessels as it cuts, reducing bleeding and post‐op swelling. It also allows the surgeon to be more precise in their actions since the tissues appear cleaner and more apparent. Laser seals off nerve endings as it cuts, reducing post‐operative pain [14]. It kills bacteria instantly, effectively sterilising the operating area. It is helpful in minor procedures such as sarcoid removals and hobday surgeries. The laser machine requires an annual service by the manufacturer; the goggles must be regularly checked for defects to ensure they are safe for their intended use. It will also require PAT testing [4].
11.3 Roles in the Operating Theatre
The procedure for setting up the operating theatre varies slightly depending on the individual surgery and the patient. A foal will require a slightly higher ambient temperature than an adult horse, as foals cannot regulate their body temperature as efficiently. A colic surgery will require different equipment compared to a fracture repair. It is essential to be aware of the differences in surgical techniques, hospital or practice protocols and surgeon preferences. RVNs should be involved in the planning that goes into creating a surgical plan; a good plan should consider the needs of the patient, surgeon, anaesthetist and nursing team to minimise risk factors and increase the chances of success.
The correct order of surgeries is essential to reduce the risk of surgical site contamination. If space allows, two theatres are necessary for gold standard practice allowing for clean and dirty procedures to be separated into different theatres. However, if this is not possible, then the operating list should follow the stated order below from first to last:
Clean – Elective orthopaedic procedure, implants may be used.
Clean contaminated – Controlled entry into the gastrointestinal or respiratory tract.
Contaminated – Open, fresh wound <6 hours old, small intestinal resections with no excess contamination.
Dirty – Infected wounds >6 hours old, anal surgery, colon dump as these have an increased risk of MRSA due to the nature of the wound or area of the surgical site [10].
Theatre Attire
Good personal hygiene and general cleanliness are essential to maintaining asepsis within the theatre suite; before entering, all personnel should wash their hands; hand washing should occur regularly while working in the theatre suite. If clothing becomes contaminated at any stage, scrubs must also be changed, ideally personnel should shower before returning to the theatre. All jewellery, including watches, rings and earrings, must be removed before entering the theatre suite, as they harbour bacteria and risk contaminating the surgical site. If jewellery cannot be removed, it must be covered with tape. Finger nails must be kept short, and the use of nail varnish, including gel and acrylic, is much debated. The latest studies show that there is not an increase in the number of microorganisms if nail varnish is on and undamaged. However, if there is damage to the surface of the nail varnish, this can facilitate an increase in microorganisms. Therefore, current advice is to avoid wearing nail varnish or acrylics in the operating theatre.
No outdoor clothing or footwear should be worn inside the theatre suite. It is best practice for all personnel entering a theatre suite to either change into a two‐piece scrub suit or cover their outerwear with a boiler suit. Theatre clothing should be made from cotton or polyester and worn inside the suite. It should be washed at the end of the day and changed between surgeries if necessary or thought to be contaminated; all laundering should be done within the theatre suite.
Footwear for theatre is typically croc‐type shoes or wellingtons with non‐slip, antistatic soles, which are easy to clean either in a washing machine or wiped over.
Scrub hats are required to ensure that hair and skin flakes do not contaminate the theatre; these can either be made from reusable cotton or be disposable. Using cotton hats has less environmental impact over disposable hats, especially in large practices that typically use large quantities of these items. Different designs cover long hair, short hair and beards [4].
There is currently mixed evidence on the use of surgical masks in the operating theatre and the reduction in post‐operative site infections. There is not yet enough data to say that they should not be worn, so it is still believed to be best practice to wear a surgical mask during procedures; however, these should be changed between procedures or during if it is a lengthy procedure to minimise the chance of the mask losing efficacy [15].
Conduct
Effective and clear communication is critical to ensure the smooth, efficient running of the theatre suite; and minimise the chance of error due to human factors. Although all personnel within the operating theatre should understand where they can and cannot go, sometimes situations can occur where there is a break in sterility. If this situation occurs, an environment should be created that allows personnel to speak up without fear of retribution, allowing for immediate resolution.
As an RVN in theatre, there are three main roles, a circulating nurse, a scrubbed RVN, or an anaesthetist; these roles are equally crucial to the smooth running of an operating suite and have independent functions, but form part of the team that is crucial to enable surgery to happen [8]. The role of the RVN as an anaesthetist is covered in Chapter 10.
The Circulating Nurse
As the circulating nurse, it is essential to ensure that any ancillary and powered equipment is checked before the procedure starts and that any equipment relating to the procedure, including relevant gowns and gloves, are out and ready to open, maintaining sterility throughout.
The circulating nurse is responsible for positioning the patient correctly for surgery, preparing the patient and ensuring the correct site has been clipped and then prepared for surgery. Clipping, where possible, should be done before the patient enters the theatre to prevent contamination and reduce surgical time. In a gold‐standard environment, clipping would be done in a preparation area outside the main theatre, so that the horse can be fully prepared on the theatre bed and then wheeled into the theatre. If this is not possible within the set‐up, a hoover can be used to remove all hair and debris post‐clipping, minimising the chance of contamination.
Applying a tourniquet or an Esmarch bandage may be a role for the circulating nurse and therefore needs to be understood. Esmarch bandage tourniquets are commonly used in theatre and are typically applied by the RVN before the surgical scrub has started. Esmarch tourniquets used during surgery can aid the surgeon in providing a bloodless surgical field which assists with the identification of anatomical structures. In turn, this helps to reduce operating time and therefore reduce surgical complications. Care is needed for prolonged use, as this could lead to ischemic damage or neuropathy of the limb depending on the location and time the tourniquet is in place. Tourniquets are commonly reusable and do not need to be sterile as the application occurs before the sterile scrub takes place, but will still need to be cleaned and disinfected between patients [4].
Esmarch bandage or Esmarch tourniquet is a typically 10 cm wide soft rubber bandage used to expel blood from a limb (exsanguinate). The bandage is applied to the distal end of the limb and extends proximally up the limb. The remaining bandage is used as a traditional tourniquet to cut off the blood supply. Once secured in place, the distal portion can be unravelled and tied around the tourniquet portion of the bandage. The limb is often elevated as the elastic pressure is applied. The exsanguination is necessary to enable some arthroscopic procedures to take place, as having blood in the surgical field would cause difficulty navigating the surgical area [16].
Once the horse has been correctly positioned and prepared for surgery, the circulating nurse can assist with dressing the surgeon, scrub nurse and opening sterile supplies. When passing sterile instruments to a scrubbed operator, it is essential to maintain asepsis at all times ensuring that the instrument handle is being passed first and directly into the hands or the surgeon or assistant. It is vital to know how to open all sterile packaging and to ensure that none comes in contact with the sterile field. Instruments should be opened in the order in which they will be used (e.g. trolley drape first followed by the surgical kit). It is also essential to stand in a position that avoids leaning over the sterile field and ensure that the surgeons’ view is not obstructed. When passing sterile instruments, it is vital to take care and not damage any equipment when passing it to the surgeon [13].
The circulating nurse may be required to assist with draping the patient; it is essential to listen to the surgeon and act on their instructions to maintain sterility at all times.
During the surgery, the circulating nurse can clear away used materials, prepare cleaning products and pass any equipment or consumables that the surgeon may require during surgery. Recording of instruments and swab counts during surgery is essential for patient safety. Many practices will have kits made up of pre‐counted swabs and a certain number of instruments included per kit. This should be the same number every time, but all equipment must be counted prior to the surgery start time. During surgery, the number of swabs or instruments removed from the sterile field must be accounted for; a whiteboard is helpful in theatre. A regular count during surgery is useful, with another count performed before closing. A final count of all instruments, needles and swabs should also be performed at the end of surgery. This is also an excellent time to invoice the materials used during the surgery to ensure the clients’ billing is kept up to date and this prevent items from being forgotten.
Monitoring blood loss during equine surgery is complex, although swabs can be weighed and an estimate can be made if able to contain the blood in a bowl or bucket. If this is not possible, the circulating nurse should be vigilant with how often blood is washed away and communicate with the surgeon if at all concerned. However, a horse’s large blood volume means that they seldom have a blood loss issue [4].
After the surgery, the circulating nurse may be required to place a bandage on the patient if they have had surgery on a limb and assist with transporting the horse to the recovery box. If not needed to assist with the recovery, the circulating nurse can clean the theatre and prepare for the next patient [2].
The Scrub Nurse
The role of the scrub nurse is to assist the surgeon with the sterile procedure by scrubbing into the surgery and passing instruments and consumables as required [4]. They must systematically scrub the skin on their arms and hands (see method below). Once they have achieved this, they can don a gown and gloves and assist with laying out the instruments on the trolley. Maintaining sterility is paramount, so an awareness of surroundings whilst acting as a scrubbed assistant is essential. When not required to pass instruments or assist, the scrub nurse should place their hands together or keep them on the trolly. This prevents the temptation of touching somewhere inadvertently.
As the scrubbed nurse, it is essential to have all instruments laid out on the instrument trolley and easily visible, making them easier to find when asked for them. The order they are laid out in will be similar for all types of surgery, although there will be some key differences. Instruments on the trolley must be laid out in order of use and, depending on preference, left to right or right to left [10].
Towel clamps
Drape scissors
Scalpel blade
The instruments used next will depend on the surgery; the final instruments will always be the same
Needle holders, also sometimes known as needle drivers
Rat tooth forceps
Using the correct method to pass instruments to the surgeon is vital for ease, speed and safety; they must be given with the blade facing away from the surgeon and the handle placed into a finger grip. Ringed instruments must be passed into the surgeons’ palms with points outwards and curves upwards. All instruments with ratchets must not have these engaged. A theatre nurse may open needles and syringes, and both the needle and cap must always be taken; the cap must remain in place until the syringe is ready for use.
When mounting and demounting a blade, the blade must face forward, down and away from the operator. This will help to prevent injury during the removal process.
Maintaining sterility of the trolley during procedures must be strictly adhered to; this is managed by an acute awareness of surroundings, ensuring all sharps are kept facing away with the blade laid on a clean, sterile swab so as not to pierce the trolley drape accidentally. Fluids must be kept to one end in case of strikethrough. All tissues removed should be placed onto a clean swab or metal dish to be dealt with at the end of surgery.
At the end of the surgery, the scrub nurse is responsible for performing a final count of swabs and instruments before closure; they can then take the surgical kit to be cleaned and decontaminated, ready for re‐sterilisation [13].
Scrubbing into Surgery
The technique for scrubbing into surgery should follow a systematic method, starting with a skin antiseptic. This removes all organic material and microorganisms from the elbows down to the hands, as it is impossible to sterilise the skin. There are two typical scrub solutions commonly used in practice for traditional scrubbing techniques:
Chlorhexidine gluconate 4% – Has broad‐spectrum antimicrobial qualities, is effective against organic matter, is virucidal and fungicidal, and has sporicidal properties. It has an improved residual effect compared to povidone‐iodine. It is harmful to mucous membranes and has been proven to irritate tissues and be ulcerative to the eyes, so care should be taken in these areas [4].
Povidone‐Iodine 10% – This also has broad‐spectrum antimicrobial qualities, ineffective against organic matter, has virucidal and fungicidal properties and has a relatively short period of efficacy. Also found to be an irritant to tissues and should be used at the correct dilution if used around mucous membranes [10].
The Traditional Method of Hand Scrubbing
Research has shown that significant numbers of common skin bacteria continue to be removed after 5 minutes of scrubbing, but at 10 minutes, no more significant benefit ensues. Therefore, it is logical to adopt a scrubbing technique that takes 5–10 minutes, allowing time for rinsing between stages. The method for using both chlorhexidine gluconate and povidone iodine is as follows [17]:
Remove jewellery and watches, and ensure fingernails are short.
Adjust the water supply to a safe flow and temperature – this is usually elbow or foot operated, although no‐touch sensors may also be used. Once the scrubbing has begun, the hands should not touch the taps, sink or soap dispenser; only use elbows or feet should be used. If they are inadvertently touched, repeat the last stage of the procedure.
Wash the hands thoroughly using a plain soap or surgical scrub solution and clean under the nails with a sterile nail pick – pre‐prepared scrub brushes that contain a nail pick can be used.
After hand washing, the arms are washed up to and including the elbows. Always keep the hands above the elbows so that water drains down towards the unscrubbed arms to avoid recontamination – this phase aims to remove organic matter and grease from the skin.
Rinse both hands and arms by allowing water to wash away the soap from the hands to the elbows (avoid using the opposite hand to assist with the rinsing, which could lead to recontamination).
Repeat this procedure, beginning with the hands, using a surgical scrub solution such as chlorhexidine or povidone‐iodine. Use minimal water to produce a lather so the scrub solution does not get diluted, reducing its bacterial properties. Correct contact times for the product used should be used.
Excessive amounts of water will rinse away the scrub solution before it has destroyed sufficient bacteria.
Rinse off the scrub solution from the hands but leave the arms coated.
Take a sterile scrubbing brush and scrub solution and systematically scrub the hands. Scrub the palms of the hand, wrist and four surfaces of each finger and thumb, nails and nailbed. Either rinse the brush, add more scrub solution and scrub the other hand, or discard it and take a second brush. It is advisable to avoid scrubbing the backs of the hands and arms as the skin here tends to be sensitive and scrubbing with a brush may damage the surface, increasing surface microorganisms. Some commercially available disposable scrub brushes have very soft bristles and a sponge back which may be less traumatic to this sensitive skin and allow scrubbing of this area without leading to excoriation. If a brush is used on the arms, then both hands and arms should be rinsed during stage 7.
Rinse the hands and arms as in stage 5.
Wash the hands and arms in surgical scrub solution, but this time finish just below the elbow, so there is no danger of contact with a previously unscrubbed area.
Rinse the hands and arms as before, and then turn off the tap using an elbow or foot.
Allow excess water to drip from the elbows before leaving the sink.
Take a sterile hand towel, holding it at arm’s length, so it does not touch the scrub suit. Use a different section to dry each hand and arm. Discard the towel. It is a good idea to check the clock at the start and again before the final stage to ensure that the procedure has taken the allotted time [4].
Sterillium® Surgical Hand Preparation
This method is now widely replacing the traditional hand scrubbing technique in many practices. There are multiple benefits of using Sterillium®, which is fast‐acting and has long‐lasting efficacy with broad‐spectrum antimicrobial qualities. It has virucidal, fungicidal and sporicidal properties with a long residual effect. Sterillium® is non irritating to tissues and can increase the skin’s moisture levels with regular use [18].
The use of Sterillium® should start with a hand wash; any can be used; however, the manufacturer of Sterillium® makes a product called Baktolin®, which is a cleanser only and has no antimicrobial ingredients, it has a neutral pH, so it is much kinder to the skin. The hand wash only needs to occur before the first surgery of the day and does not need to be repeated, unless the hands get soiled between patients [18].
Once the hand wash has been completed, the following steps should be completed with Sterillium®; the process takes 90 seconds, using a timer and the hands must remain moist all this time. Immediately before starting, the Sterillium® timer is set and starts counting down [18].
A minimum of 1.2 ml of Sterillium® is dispensed into the palm of one hand.
The fingers of the opposite hand are dipped into the solution, working it under the nails.
The solution is spread onto the palm, fingers and back of the first hand.
This is repeated with the other hand, using another 1.2 ml Sterillium®.
Another 1.2 ml Sterillium® is dispensed into the palm of one hand and spread onto the forearm.
This step is repeated with the other forearm.
Finally, another 1.2 ml Sterillium® is dispensed into the hands, which are rubbed until the 90‐second timer sounds and the hands are dry.
The hands are kept in a vertical position and are ready for gloving [17].
Closed Gloving
Most surgical gloves are made of latex, but it is now becoming more popular to have latex‐free gloves available, as latex can cause a skin reaction in some people. Having non‐powdered gloves is preferable for surgeries to prevent contamination from the powder when they are donned and during surgery. Still, powdered options, which tend to be cheaper, are suitable for minor procedures. All sterile gloves create an effective barrier and increase asepsis; depending on which technique is used, the asepsis is increased [3].
Disposable surgical gowns are commonly used and ensure asepsis is maintained; they are pre‐packaged, pre‐sterilised and water resistant. Reusable gowns are not as common in practice, but their use may increase due to their environmental benefits; however, they need to be washed, dried and packed, which some feel outweighs the cost of purchasing disposable gowns. Reusable gowns also lose their sterility rapidly when wet, as they are not typically water resistant, so ‘strike‐through’ (fluid leaking through the gown) occurs. Most gowns come with side ties, providing better coverage and this means that the whole gown remains sterile.
The transition away from surgical gowns with ties at the back is driven by a focus on maintaining sterility and enhancing the safety of surgical procedures. Traditional gowns with back ties present several issues:
Sterility compromise: The back of the gown becomes non‐sterile once the ties are fastened, as this process typically involves touching the gown’s exterior, potentially introducing contaminants. This non‐sterile area increases the risk of contamination during surgery.
Enhanced design features: Modern surgical gowns have front closures or wrap‐around styles that ensure the entire gown remains sterile. These designs allow for a more straightforward and reliable process for maintaining sterility.
Infection control: The transition to gowns without back ties is crucial in reducing hospital‐acquired infections (HAIs). This design shift helps minimise contamination, thereby protecting both patients and employees.
Ease of use: Gowns with front closures or Velcro straps are easier to secure and adjust, improving the surgical team’s overall efficiency and effectiveness.[13].
The closed gloving technique should be used if preparing for surgery with a gown and gloves. Using this technique means the hands should not come out the end of the gown and contact the outside or the outside of the gloves. It is essential to realise that the hands can never truly be sterile, whereas the gown and gloves are [16]. The correct technique for closed gloving is as follows:
Ask the assistant to open the gown for you, take out the gown and place it on the sterile trolley (Figure 11.2); if using a disposable gown, carefully open the lining around the gown; care should be taken when opening not to touch your hands on the table surface and keep your hands on the inside of the lining.
Pick the gown up and face the inside towards you with the arm holes visible, then gently slide arms into the arm holes while allowing the gown to drop towards the floor (Figures 11.3 and 11.4). *Make sure you are not standing near any surfaces that you may touch*
You then need to ask your assistant to carefully, without touching the outside of the gown, fasten the top fastening at the neck and the tie in the back that has an external and internal tie that tie together, closing the back portion of the gown (Figures 11.5 and 11.6).
Ask the assistant to pass you a pair of gloves, take the inner packet without touching the outside packaging or allowing your fingers to leave the gown.
Place the glove packet on the trolley (Figure 11.7), ensuring that the fingers are pointing towards you, then open the glove packet, ensuring that you don’t touch the surface, keeping your hands on the inside of the packet and within your gown at all times – the right glove is on the left, and the left glove is on the right (Figure 11.8).
Using the right hand, pick up the right glove by the rim of the glove’s cuff. The hand is then turned upside down, so the fingers face the body and the glove is lying flat on the palm/wrist of the hand (Figures 11.9 and 11.10).
Next, with the left hand, grasp the rim of the glove on the right hand and pull the glove over the hand. At the same time, push your fingers out of the gown into the glove (Figures 11.11 and 11.12).
When the glove is on, repeat the process on the left hand and try to make final adjustments to the gown until both hands are in the gown.
Once both hands are safely inside the gloves, adjustments can be made; you should aim for the gown to be at knuckle height inside the gloves to ensure a good overlap between the two (Figure 11.13).
If using a side‐tying gown, you now need to remove the cardboard tab from the short section of the tie and pass the tab to an assistant, informing them only to hold the end of the cardboard (most modern gowns are colour‐coded to help with this). Figure 11.14.
Once they have hold of the tab, you need to spin around carefully. Once back to the front, pull out the tie from the tab and tie it to the side of the gown (Figure 11.15).
You are now sterile, provided your hands have not been on the outside of the gown at any point and have not touched any surfaces. Once gowned and gloved, stand with hands clasped in front of you to minimise the risk of contaminating yourself (Figure 11.16) [4].
Open Gloving
Open gloving is a technique used when a gown is not required; this would include minor procedures and sterile scrubbing [10].
The glove packet is opened so the fingers can point away from the body.
Using the left hand, the right glove is picked up at the bottom of the folded back cuff and holding only the inner surface of the glove; it is pulled onto the right hand; the right thumb must hook under the cuff.
This is repeated on the left hand, but using the right hand, the free fingers tuck under the cuff to pull the glove onto the hand, only touching the glove’s outer surface.
