Infection control practices in operation theatre: A review

K Senthil Kumar

Senior Consultant & Head, Department of Anaesthesiology, Kauvery Hospital, Trichy

Background

Healthcare organisations (HCO) have the legal responsibility to implement changes to reduce healthcare associated infections (HCAIs) in their hospital environment. Of course, Healthcare providers have responsibilities under the Health and Safety at Work Act 1974

Every HCO should have Infection Control Committee and Infection Control Teams responsible for preparing policies and monitoring compliance, with appropriate standards. A microbiologist should be designated to provide advice on microbiological aspects of decontamination and sterilisation. Users of Operation theatre (Anaesthesiologists, Surgeons, OT nurses, Technicians, etc) play a vital role in taking care of infection control practices in OT environment and during peri-operative period. They should be actively involved in Hospital Infection control (HIC) committee and take the lead in managing infection control practices in OT environment and allied clinical areas.

Definitions

  • Asepsis: the prevention of microbial contamination of living tissues or on sterile materials.
  • Disinfection: the inactivation of non-sporing organisms using thermal or chemical means.
  • Sterilisation: complete destruction of all micro-organisms, including spores
  • Decontamination : It’s a combination of processes including cleaning, disinfection and ⁄ or sterilisation used to make a re-usable item safe to be handled by staff and safe for further use on patients

The sub topics below covers all the aspects of infection control practices in OT environment and allied areas.

Unidirectional flow of patient in OT complex with appropriate zoning

All areas of hospital should be clean and acceptable to patients, visitors and staff. Statutory requirements must be met in relation to safe disposal of clinical waste, laundry and linen.

A Unidirectional pathway of patient movement is effectively designed in operation theatre’s functional layout which will effectively prevent face-to-face movement of incoming and outgoing patients and their bystanders, thereby preventing spread of diseases or infection. That is, a patient coming for surgery will be received in pre-operative holding room and then to OT for surgery and from OT to recovery room/post-operative room or surgical ICU. Hence appropriate zoning shall be followed in OT and its allied areas and label them as Protective or Outer zone, Clean zone, Ssterile zone and Disposal zone

  • Protective or Outer zone – Reception, staff change rooms, waiting bay, electrical rooms
  • Clean zone – Pre-op room, recovery room, doctors and staff lounges, OT store
  • Sterile zone – OT, Anaesthesia induction room, scrub area, instrument area
  • Disposal zone – Dirty utility, Pass box to Dirty corridor, trolley for disposal

Standard precautions

OT users shall follow standard precautions, which incorporate additional safeguards for specificprocedures and patients, including single-use gloves, fluid resistant masks with a transparent face shield and gowns. Precautions are recommended for all patients regardless of their diagnosis or presumed infectious status and must be implemented when there is a possibility of contact with blood, all other body fluids, non-intact skin & mucous membranes

Hand hygiene

Anaesthesiologist, Surgeon and all the OT users must ensure that good hand hygiene becomes an indispensable part of their clinical culture.  Hand-mediated transmission is the major contributing factor to infection associated with healthcare. Effective hand decontamination immediately before every episode of direct patient contact will result in a significantreduction in the transfer of potential pathogens and decrease in the incidence of preventable HCAI. Hand washing steps and Hand hygiene moments should be followed religiously which will have a great impact in infection control.

Theatre suits, protective gears, footwear and gowns

The skin of staff working in the operating theatre is a major source of bacteria that have the potential for being dispersed into the air. Freshly laundered clean theatre suits, gowns and over shoes should be available for all staff in theatre. Special footwear should be worn in the operating department and cleaned if contaminated or after everyuse. Full body, fluid-repellent gowns should be worn where there is a risk of extensive splashing of blood, body fluids, secretions and excretions. Sterile gowns should be worn when invasive procedures are undertaken. Wearing surgical attire outside the theatre and returning to the theatre without changing increases surgical wound infection rates.

Cap and face masks

Should be worn inside the theatre without fail as the air circulation and laminar flow inside the OT may favor dispersion of hair/ skin microorganisms to settle on instruments and surgical field. Hair should be completely covered with a disposable theatre cap or a freshly laundered lint free hat. Masks should neither be worn around the neck nor taken down to speak, and should be changed if they become damp or contaminated. Masks with a face shield should be worn when there is a risk of blood, body fluids, secretions and excretions splashing into the face and eyes.

Gloves

Must be worn as single-use items following strict aseptic method/steps.  They should be put on immediately before an episode of patient contact and removed as soon as the activity is completed, and before contact with fomites, including curtains, pens, clinical notes, keyboards and telephones. Gloves should be changed between patients and between different procedures on the same patient. Gloves must be disposed of as clinical waste and hands should be washed or decontaminated following the removal of gloves. Strictly avoid ornamental rings or bangles or religious threads over wrist and fingers.

Movement within the theatre complex

To reduce airborne contamination, general traffic in and out of the operating theatre itself should be kept to a minimum. Doors should be kept closed to ensure the efficiency of the ventilation system. Opening operating room doors disrupts airflow and pressure differentials within the room, which potentially increases the risk of wound contamination.

Operation theatre Quality assurance& Surveillance, the Engineering controls

The AHU (Air Handling Unit) of each OT, otherwise called as HVAC system, should be dedicated one to that particular OT and should not be linked/shared to air conditioning of any other OT or its surroundings. AHU must be an air purification unit and air filtration unit. The location of outdoor air intake for an AHU must not be located near potential contaminated sources like DG exhaust hoods, lab exhaust vents, and vehicle parking area. Window & split A/c should not be used in any type of OT because they are pure recirculating units and have pockets for microbial growth.

Minimum total air changes per hour should be 20 based on biological load and the location. In that the fresh air component of air change is required to be minimum of 4 air changes out of total minimum 20 air changes per hour

Air Velocity – the airflow from the laminar flow area needs to be unidirectional and downwards on the OT table. An air flow velocity of 25-35 FPM (feet per minute) from non-aspirating unidirectional laminar flow diffuser/ceiling array is recommended.

The minimum positive pressure recommended inside OT is 2.5 Pascal. There is a requirement to maintain positive pressure differential between OT and adjoining areas to prevent outside air entry into OT. Positive pressure should be maintained in OT at all times (operational & non-operational hours).

Air handling in the OT including air Quality: Air is supplied through Terminal HEPA (High-Efficiency Particulate Air) filters in the ceiling. The HEPA can be at AHU level if its not feasible at terminal level inside OT. The minimum size of the filtration area should extend one foot on all sides of the OT table. HEPA filters of efficiency 99.97% down to 0.3 microns or higher efficiency are to be provided

Temperature & Relative Humidity:  Temperature should be maintained at 21°C ± 3°C (except for Joints replacement where it should be 18°C ± 2°C) with corresponding relative humidity (RH) between 20 to 60%, though the ideal humidity recommended is 55%. Appropriate devices to monitor and display these parameters inside OT shall be installed.

Maintenance – Validation of AHU/HEPA system should be done periodically (figure)

  • Temperature and Humidity check – monitor daily
  • Air Change Rate Calculation – validate once in 3 months
  • Air velocity at outlet of terminal filtration unit /filters – validate once in 3 months
  • Pressure Differential levels of the OT with respect to ambient / adjoining areas – monitor daily
  • Validation of HEPA Filters by appropriate tests (air particulate count, filter integrity, air quality, etc) – validate once in 6 months

Microbiological surveillance

Swabs are taken at various locations from OT once in 15 days for culture and randomly at 2 month intervals using settle plate method which will be verified by Infection prevention and control committee

Order of patients (Figure)

There should be a written hospital policy requiring accurate printed theatre lists to be available prior to the scheduled date. ‘Dirty cases’, i.e. patients likely to disperse microbes of particular risk to other patients, should be identified before surgery and theatre staff should benotified. These patients should be scheduled last in the operating list to minimise risk. The most probable routes for transmission of infection between successive patients are airborne or on items andsurfaces that have been in contact with the previous patient. Appropriate cleaning of the operating theatres betweenall patients should be undertaken with help of a check list. Whenever there is visible contamination with blood or other body materials, the area must be disinfected with sodium hypochlorite (according to local protocols) and then cleaned with detergent and water. Floors of the operating room should be disinfected at the end of each session. The surgical area of the patient should be prepared with hair clippers only and not to be shaved with razors, as shaving with razor can cause microscopic cuts and scrapes favouring bacterial colonization over raw areas in the skin, a nidus for infection

Safe use and disposal of sharps

Accidental injury has long been recognised as an occupational hazard in the healthcare setting. Accidental inoculation with infected blood, however small in amount, presents a significant risk to. Overall, 16% of occupational injuries occurring in hospitals are attributed to sharps injuries. These should be preventable by adhering to standard guidelines

  • Sharps must not be transferred between personnel and handling should be kept to a minimum.
  • Needles must not be bent or broken prior to use or disposal.
  • Needles and syringes must not be disassembled by hand prior to disposal.
  • Needles should not be recapped or re-sheathed.
  • Used sharps must be discarded into an approved sharps container at the point of use.
  • The sharps container should be sealed and disposed of safely by incineration when two-thirds of the container is full or in use for more than four weeks, whichever is sooner.
  • Blunt aspirating needles should be used for drawing up drugs

Preventing contamination of drugs

Syringes and needles are sterile, single-use items and, after entry or connection to a patient’s vascular system or attachment to infusions, a syringe and needle shouldbe considered contaminated and used only for that patient. In other words, all infusions, administration sets or items in contact with the vascular system or other sterile body compartments are for single-patient use. Injection ports should be maintained with a sterile technique, kept freeof blood and covered with a cap when not in use. Connections and injection ports in intravenous lines should be kept to a minimum. Three-way taps should be avoided if possible. Needle-free Luer injection devices should be used to cover exposed female Luer injection ports. These are easily cleaned before and after drug administration, do not harbour blood in crevices and also reduce the need for needles, resulting in a reduction of needle stick injuries. Single use ampoules should be discarded after the required amountof drug is drawn up and not re-used for subsequentpatients.

Antibiotic chemoprophylaxis

Timely antibiotic chemoprophylaxis is an important strategy to reduce surgical site infections and is the responsibility of the whole surgical team. Usually a prophylactic antibiotic for surgery is given within 60 minutes of skin incision as we ensure the same during WHO surgical safety check list “Sign in & Time out” session.  Indication and agent choice should be in accordance with local surgical prophylaxis guidelines and antibiogram. Antibiotics are repeated if surgery exceeds 4 hours from the first dose of antibiotic and also earlier second dose if there is a major blood loss or hypovolemia during surgery

Maintenance of Normothermia, euvolemia, euglycemia and avoidance of hypotension

It is very vital in reducing infections and SSI. A restrictive blood transfusion strategy will also play a vital role in infection control

Anaesthetic equipment and Infection control

Items of anaesthetic equipment may become contaminated either by direct contact with patients, indirectly via splashing by secretions or from handling by staff. Contamination is not always visible and all used piecesof equipment must be assumed to be contaminated and disposed of or, if reusable, undergo a thorough process of decontamination.

Single use item / Re use item -Where appropriate, single-use disposable equipment (ETTs, Airways, Oxygen mask, etc) will remove the difficulties of re-use and decontaminationprocedures. The use of such equipment is to be encouraged.  If single use devices are re used they should be properly decontaminated, checked for its functional integrity, proper mechanism to know the number of times it is re-used and the same to be mentioned in consent form approved by patient.

Decontamination

Decontamination is a combination of processes including cleaning, disinfection and ⁄ or sterilisation used to make a re-usable item safe to be handled by staff and safe for further use on patients. Effective decontamination of re-usable devices is essential in reducing the risk of infection.

Cleaning – removal of foreign material from an item. This usually involves washing with a detergent to remove contamination followed by rinsing and drying. All organic debris, e.g. blood, tissue or body fluids, must be removed before disinfection or sterilisation, as its presence will inhibit disinfectant or sterilant from contacting microbial cells. Cleaning before sterilisation is of the utmost importance in the effectiveness of decontamination procedures in reducing the risk of transmission of prions.

Low Level Disinfection – kills most vegetative bacteria (except TB and endospores), some fungi and some viruses using disinfectants such as sodium hypochlorite, 70% alcohol and chlorhexidine.

High Level Disinfection – kills vegetative bacteria (not all endospores), fungi and viruses. With sufficient contact time (often several hours), these high level disinfectants may produce sterilisation, e.g. the use of aldehydes, per-acetic acid and chlorine dioxide.

Sterilisation – A process used to render an object free from viable micro-organisms, including all bacteria, spores, fungi and viruses, with techniques such as autoclaving.

The choice of equipment and ⁄ or the level of cleanliness⁄ disinfection ⁄ sterility required for re-usable items may be assessed against the risk posed to patients with degree of transmission of infection during that that procedure in which the equipment is employed. The risks posed are mentioned below

High Risk – the device will penetrate skin or mucous membranes, enter the vascular system or asterile space – these devices require sterilisation.

Intermediate Risk – the device will be in contactwith intact mucous membranes or may becomecontaminated with readily transmissible organisms –these devices require high level disinfection o sterilisation

Low Risk – the device contacts intact skin or does not contact patient directly – these devices require low level disinfection or cleaning.

Anaesthetic face masks and anaesthesia related devices

although normally in contact with intact skin, these items are frequently contaminated by secretions frompatients and have been implicated in causing crossinfection, local disinfection is not normally effective. These items should be single-use items or should be sterilised between patients as per local guidelines, preferably using Ehtylene Oxide

Oral airways, Nasal airways, tracheal tubes, catheter mounts, anaesthesia breathing circuits with HME, Oxygen masks, suction catheters and tubes, etc are of single use only.The breathing bag is easily contaminated by hand contact during induction and emergence from anaesthesia. Breathing bags should be cleaned with detergent and water between each patient use or replaced if single use.

Anaesthetic machines & equipment

Routine daily sterilisation or disinfection of internal components of the anaesthetic machine is not necessary if a bacterial/viral filter is used between patient and circuit. However, cleaning and maintenance policies should be followed. Bellows, unidirectional valves and carbon dioxide absorbers should be cleaned and disinfected periodically. Laryngoscope blades are considered critical equipment because they may penetrate skin or mucous membranes with invisible breaches, and hence require sterilisation by ETO. Laryngoscope handles, being non-critical devices, should be cleaned with detergent and water between each patient use.The surface of the anaesthetic machine and monitoring equipment should be cleaned between each patient with detergent and water. This includes non-invasive blood pressure cuffs and tubing, pulse oximeter probes and cables, stethoscopes, electrocardiographic cables, blood warmers etc, and the exterior of anaesthetic machines and monitors. Items such as temperature probes should be single patient use.

Regarding the usage of USG for Nerve block & vascular access

The USG probe and cable should be protected from contamination by use of a sterile cover and be prepared in such a way as to maintain the sterility of the procedural region. The skin area of needle entry should be thoroughly prepared with antiseptics and nerve block needle should be of single use only. The performer should follow all etiquettes and full sterile attire like, cap, mask, sterile gown, gloves and thorough hand hygiene.

Key performance indicators

In OT like SSI, adherence to prophylactic antibiotic administration, hand hygiene compliance rates, etc should be monitored and discussed in OT users committee and Hospital infection control committee in specified periodic intervals so that corrective action and preventive action are implemented then and there.

In summary, all OT users must comply with local theatre infection control policies and ensure that appropriate infection control precautions should be established for each surgical procedure.

References

  • Association of Anaesthetists of Great Britain and Ireland. Infection control in anaesthesia. Anaesthesia. 2008 Sep;63(9):1027-36
  • PG28(A) Guideline on infection control in anaesthesia 2015; Australia and New Zealand college of anaesthetists and the Faculty of pain medicine
  • Revised guidelines forair conditioningin operation theatres(2018); NABH

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