Expert Techniques in Ophthalmic Surgery Myron Yanoff, Parul Ichhpujani, George L Spaeth
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Section 1
1Basic Principles of Ophthalmic Surgery2
Section Editor Parul Ichhpujani

Asepsis in the Operating RoomCHAPTER 1

Oana Stirbu
 
INTRODUCTION
The chain of asepsis obeys the theory of constraints, ruled by the paradigm stating that a chain is no stronger than its weakest link; therefore, discipline and continuous strive of each team member to reduce the incidence of infection to a minimum are mandatory.1 This systematic effort to prevent infection includes periodic checks, which must be carried out to ensure the continued effectiveness of current practices. Therefore, the Association of peri-Operative Registered Nurses (AORN) have developed standards and recommended practices, which are guidelines to be used by the surgical team to achieve the optimal level of technical and aseptic practice when caring for their patients in the perioperative setting. Pathogenic microorganisms are found in two different reservoirs: the animate environment (infected or colonized personnel and patient) and the inanimate environment [operating room (OR) air and equipment, anesthesia, and surgical instruments].
 
PATIENT CARE
The conjunctiva, contaminated mostly with eyelid margin microbes, constitutes a repository of potentially infectious agents and patient’s own external bacterial flora present in conjunctiva, eyelid or nose represents the main source of postoperative infection.2 Patients with advanced age, local risk factors (chronic use of topical medications, contact lens wear, blepharitis, chronic eyelid or conjunctival inflammation), and systemic risk factors (immunosuppression, diabetes, rosacea, autoimmune conditions, and asthma) present a higher rate of bacterial conjunctival contamination before intraocular surgery.3
The most strongly recommended technique of preoperative patient prophylaxis based on the current clinical evidence consists of povidone-iodine irrigation.4,5 Patient prophylaxis consists in periocular skin scrubbing with 5% or 10% povidone-iodine ophthalmic solution, including eyelashes, eye lids, inner canthus, and surrounding area, allowed to act for a minimum of 3 minutes and one drop of 5% povidone-iodine to the cornea and in the inferior conjunctival sac immediately preoperatively.6-8 Povidone-iodine concentration inferior to 5% and eyelid eversion during conjunctival decontamination are not the recommended agent.9,10
Other prophylactic interventions, such as postoperative subconjunctival antibiotic injection, preoperative lash trimming, preoperative saline irrigation, preoperative topical antibiotics, or antibiotic-containing irrigating solutions are not supported by the available literature.11 Patient preoperative showering or bathing with chlorhexidine or other wash products were not found to reduce surgical site infection.12
 
PERSONNEL DISCIPLINE
Surgical attire is worn to promote cleanliness, surgical consciousness, and professionalism within the surgical environment and personnel entering the OR complex should strictly obey a dress code, as the human body is a major source of microbial contamination.13 Personnel working in the OR should be free from overt, active infection. The surgical team is made up of sterile and nonsterile members. Sterile members or “scrubbed” personnel work directly in the surgical field while the nonsterile members work in the periphery of the sterile surgical field.
 
Surgical Attire
All surgical team members wear scrub attire. Surgical attire, including scrub clothes, hair coverings, mask, protective 4 eyewear, and other protective garments, provide a barrier to contamination that may pass from personnel to patient as well as from patient to personnel.14 All persons should change into freshly laundered clothing and must wash their hands thoroughly before entering the OR. Scrub clothes home laundering is a debated issue.15 Head, hair, and beards should be fully covered by caps and masks. Surgical mask should fully cover mouth and nose.16 Other personnel in the operating theater should wear surgical masks if an operation is being performed or if sterile instruments are exposed. Hand washing or hospital-approved disinfectant is required between patients and whenever they become soiled. Fingernails should be kept clean and short. Traditionally, nail polish, artificial, and long natural fingernails are not permitted for those providing direct patient care. Presently, there is insufficient evidence to determine whether wearing nail polish or finger ring affects the number of bacteria on the skin postscrub.17
 
Scrubbing
The surgical team in direct contact with the sterile area should scrub their hands and arms till above the elbows twice for 1–2 minutes each with povidone-iodine or chlorhexidine solution in the scrub area, with sponge or nailbrush. Chlorhexidine-based scrubs seem to be more effective than povidone-iodine scrubs in terms of bacteria colony forming units on the hands, are less irritating, and have more persistent effect.18,19 An option to traditional hand scrubbing is hand rubbing with alcohol-based hand preparations.20-22 Approved in some countries as equivalent to traditional hand scrubbing in preventing surgical site infections, the procedure of hand rubbing consists of 1-min hand and forearms wash with nonantiseptic soap and tap water, rinsed with nonsterile tap water, and wiped carefully with nonsterile paper, followed by 3 or 5 minutes of hand rubbing with enough aqueous alcoholic solution to fully cover the hands and forearm, applied twice for 2 minutes 30 seconds (for a total of 5 minutes) without drying.23 Most alcohol-based hand preparations for surgical antisepsis contain either isopropanol, n-propanol, or ethanol at different concentrations or a combination of these agents, with or without supplements such as quaternary ammonium compounds, octenidine, triclosan, or chlorhexidine.
 
Donning Gloves
After hand rub/scrub, sterile gloves should be donned in a sterile manner. The technique is based on the premise that the skin of the surgical team member must remain exclusively in contact with the inner surface of the glove and any error in the performance of this technique requires a change of gloves.24 Between surgeries, hands should be washed with balanced salt solution or Ringer’s lactate to remove the talc, as inadvertent perforations in the gloves are not infrequent, with the lowest perforation rate found in cataract and intraocular lens surgery and the highest rate in oculoplastic surgery.25
 
Closed donning:
  • Outer pack is peeled open from the corners. The pack is gripped through the gown and opened to display the gloves
  • With the gown covering the fingers, right hand is used. to remove the left glove. Left hand is held palm up with fingers straight. The glove is laid on left wrist, and the cuff is gripped with left thumb.
  • Right thumb is then placed inside the top cuff edge. A fist is made with right hand, and the glove is stretched over left fingertips.
  • The glove is pulled down keeping the left fingers straight.
  • The above procedure is repeated to don the other glove, that is, gloved left hand is used to lay the right glove on the right wrist. Left thumb is slid inside the top of the cuff, a fist is made, and the cuff is stretched over right fingertips. Sleeve and glove are pulled down together (Figs. 1-1A to D).
 
Open donning:
  • The cuff of the right glove is picked with the left hand. Slide right hand into the glove and ensure a snug fit over the thumb joint and knuckles. The bare left hand should only touch the folded cuff.
  • Right fingertips are then slid into the folded cuff of the left glove. The glove is pulled to fit right hand into it.
  • The cuffs are unfolded down the gown sleeves, making sure that gloved fingertips do not touch bare forearms or wrists (Figs. 1-2A to C).
 
Maintaining Sterility of Supplies and Packages
When opening wrapped supplies or packages, the nonsterile person or the circulating nurse should open the top wrapper flap away from them first, then open the flaps to each side. The last wrapper flap is pulled toward the nonsterile person opening the package. All wrapper edges should be secured to prevent flipping the wrapper and contaminating the contents of the sterile package or field. When a package is double wrapped, each institution has its own policies and procedures, which determine if one or both wrappers have to be opened before presentation to the sterile field. When opening a peel package, the nonsterile person opens the package by rolling the wrapper over his or her hands and presenting the inner contents of the package to the scrubbed person.
5
zoom view
Figures 1-1A to D: Closed donning.
When opening a solution container, the nonsterile person should lift the cap straight up and pour the contents of the bottle into a sterile container. When solutions are poured onto the sterile field, they should be poured slowly to prevent contamination and fluid strikethrough from splashing.
 
OR COMPLEX
While most common source of infecting organisms seems to be the patient and the surgical staff,26 environmental contamination plays an important role in surgical infections. The OR complex needs to fulfill the criteria of a clean room, an environment with a controlled level of contamination (dust, airborne microbes, particles, chemical vapors, etc.), ensured by OR complex design and architecture, ventilation and cleaning procedures, and care of instruments.
 
OR Complex Design and Architecture
Asepsis in the OR starts long before the surgery is actually performed, at the moment when the OR is designed by strict regulatory standards of location and architecture. One of the functions of the OR complex modules is to control varying degrees of cleanliness through scientifically planned traffic flow and differential decreasing positive pressure ventilation gradient. The surgical area is isolated from the rest of the hospital, and the OR is further isolated from other parts of the surgical area.27
 
Zoning
The OR complex should be located either on the top or on the bottom floor, preferably in a separate or blind wing and consists of four modules (zones): outer, clean (restricted), aseptic, and disposal zone.
6
zoom view
Figures 1-2A to C: Open donning.
The bacteriological count diminishes progressively from the outer to the inner zone.28
  • Outer zone: Reception area with administrative function, patient relative’s waiting room, toilets, accessible to all persons and supplies.
  • Clean (restricted) zone: Staff changing room, patient transfer area, staff lounge, and anesthetist/recovery room. The changing room, located at the entrance of the OR complex, should have a separate entrance (street clothes) and exit (surgical attire), lockers, and washbasin. Showers are not mandatory in the changing room. The patient transfer area includes the patient changing room and a corridor where the patient is transferred from an outside trolley to an inside trolley.
  • Aseptic zone: Scrub area, OR, and area used for instrument packing and sterilization. The scrub area should be located just outside the OR, wide enough for two to scrub simultaneously without touching the other’s elbow. Taps in the scrub area should be foot/elbow operated or preferably infrared sensor electronically controlled taps. The OR is the most critical area of the OR complex, and all design protocols should be duly observed.29
    • Minimum recommended size of 325 square feet (30 m2) and rectangular shape.
    • Floor: Slip resistant, suitably hard, nonporous, fireproof material, with minimum joints, no floor drains installed.
    • Doors: Minimum width of 1.2 m, hermetically sealed surface sliding doors (not recessed into the walls) that eliminate air turbulence caused by swinging doors, kept closed all the time except for the passage of patients and essential equipment and personnel.
    • Operating table: The head end directed away from the entrance, enough circulating space around all its sides.
    • 7Walls and ceiling: Nonporous fire resistant material, seamless, stain resistant, easy to clean, no artificial ceiling, and minimum of 10 feet high (3.05 m).
    • Lights: General OR lights recessed into the ceiling to prevent dust collection.
  • Disposal zone: Area where used equipments are cleaned and biohazardous waste is disposed.
Cleaning the OR on a regular basis represents an often neglected but fundamental step in environmental asepsis. The process of cleaning consists in mechanic elimination of foreign matter from specific surfaces, by means of water, scrubbing, and detergents. If a surface is not mechanically clean, the following step of disinfection is hindered, as dust, soil, and organic debris prevent thorough contact between the surface to be disinfected and the decontaminating agent. Items recommended to be cleaned after each patient include OR table mat and sides, floor, trash buckets, instrument stands, whereas OR walls should be cleaned once a week and whenever directly splashed with contaminated material.
 
OR Ventilation and Cleaning Procedures
Proper ventilation in and near the OR is fundamental in halting the spread of infection.30 The standards for ventilation ensure good indoor air quality and establish limits for the following aspects: air flow, air filters, rate of air change, temperature, pressure relationship to adjacent areas and relative humidity.31
The type of ventilation system recommended is the laminar unidirectional vertical airflow with a primary degree of turbulence of < 5% and high-efficiency particulate-air filter.32
The air filter, consisting of a mat of randomly arranged glass-reinforced plastic fibers, should be placed in the ceiling and provide a constant vertical stream directed to the floor.
The rate of air change mainly dilutes the pollutants concentration. The minimum requirements for OR air change are 20–25 changes/h, with 4 changes/h of outdoor air. The OR must be maintained at a positive pressure with respect to all adjacent spaces.
The recommended air temperature is 21°C ± 3°C, with the possibility of control to optimize the comfort of the surgical team. While temperatures below 21°C put the patient in risk of becoming hypothermic and increase the chance of a postoperative infection, a temperature above 23°C is usually intolerable for the surgical team.
The relative humidity standards range from 30% to 60%, ideally set at 50–55%, considering the fact that lower relative humidity may result in sensation of dryness and irritation of skin and mucous membranes and increase human electric conductivity, whereas high relative humidity is related to microbial growth, especially fungal genera.
 
OR Sterilization
Floor of the OR should be cleaned after each operative session with a phenolic solution. After contamination with material/fluids from an infected patient, wet mopping with phenolic detergent may be followed by wiping all equipment surfaces with 70% alcohol. Daily cleaning of shelves, ledges, and lights should be carried out. Anesthetic equipment must be disinfected after each use. Walls should be washed 3–6 monthly.
OR sterilization can be effectively done by using formaldehyde. About 10–15 oz of 40% formalin diluted with equal amount of water is added to 5 ounces of potassium permanganate for every 1000 ft3 of space placed in a jar. The contact of reagents results in violent effervescence and release of formaldehyde. A vaporizer can also be used with 1:20 dilution of 40% formalin is vaporized over an hour.
 
Care of Instruments
Instruments pass through a chain of procedures directed to ensure surgical asepsis, consisting of cleaning, disinfection, and sterilization performed within strict guidelines.33
 
Cleaning
Thorough cleaning is an obligatory step before high-level disinfection and sterilization because inorganic and organic remains on the surfaces of instruments interfere with the effectiveness of these processes. Cleaning is also a good time to inspect each instrument for proper function and condition. Surgical instruments should be cleaned as soon as possible after their use. After separating delicate from regular instruments, ultrasonic or manual cleaning is performed.
Ultrasonic cleaning: The ultrasonic cleaner contains liquids through which sound waves disrupt the bonds that hold particulate matter to surfaces and clean every part of the instrument, including cannulae lumen. Dissimilar metals (such as aluminium and stainless) should not be mixed in the same cycle to prevent cross-plating. Chrome-plated instruments should not be cleaned in an ultrasonic cleaner. Upon completion of the cycle, instruments should be immediately removed, rinsed, and thoroughly dried, as trapped moisture produces corrosion.
Manual cleaning: Manual cleaning of delicate instruments is based on drench, friction, and fluidics. The instruments are 8 soaked for half an hour in a neutral pH7 detergent, because low pH detergents cause breakdown of stainless protective surface and high pH detergent causes surface deposit of brown stain, which interferes with smooth operation of the instruments. The soiled area is afterward scrubbed with a soft brush and finally, fluids under pressure remove the debris. Gloves must be worn while handling the instruments to avoid infective material and cuts. Other forms of cleaning include washer/decontaminators, washer/disinfectors, and washer/sterilizers.
 
Disinfection and Sterilization
Disinfection implies elimination of most pathogenic microorganisms (excluding bacterial spores) on surfaces and objects and sterilization refers to destruction of all living microorganisms, including spores. The effective use of disinfectants and sterilization procedures in the OR is critical for the prevention of postoperative infections. Medical devices that have contact with sterile body tissues or fluids are considered critical items and should be sterile when used because any microbial contamination could result in disease transmission.
Sterilization can be accomplished by physical or chemical methods.
  • Physical methods: Of all the methods available for sterilization, moist heat under pressure (autoclaving) is the most widely used because it is nontoxic, dependable, and inexpensive. Saturated steam at a required temperature and pressure for a specified time in an autoclave is microbicidal and sporicidal, producing irreversible coagulation and denaturation of enzymes and structural proteins. The two common steam-sterilizing temperatures are 121°C (250°F) and 132°C (270°F). Recognized minimum exposure periods for sterilization of heat stable critical items are 30 minutes and 121°C in a gravity displacement sterilizer or 4 minutes at 132°C in a prevacuum sterilizer.34 The process can be hastened by increasing the pressure from 15 psi to 30 psi.
  • Flash sterilization: It is a method of emergency sterilization. The equipments to be decontaminated are kept at 132°C at 30 lbs of pressure for 3 minutes.
  • Chemical methods: These are used for the sterilization of heat labile materials, include ethylene oxide (ETO), glutaraldehyde 2%, acetone, and plasma sterilization.
  • ETO: ETO is a colorless gas that is flammable and explosive. The four operationals are gas concentration (450–1200 mg/L); temperature (37°C–63°C), relative humidity (40–80%), and exposure time (1–6 hours). The main disadvantages associated with ETO are the lengthy cycle time, the cost, and its potential hazards to patients and staff.
  • Glutaraldehyde 2%: It is suitable for instruments that cannot be autoclaved like sharp cutting instruments, plastic and rubber items, and endoscopes. It is effective against vegetative pathogens in 15 minutes and resistant pathogenic spores in 3 hours. It is not recommended for lumen containing instruments such as irrigating cannulae as the residual glutaraldehyde, even after rinsing, causes corneal edema, endothelial cell damage, and uveitis. The recommended time period for effective sterilization is 8–10 hours. Articles can then be stored in a covered sterile container for up to 7 days.
  • Radiation: Gamma irradiation is a method for cold sterilization with high penetrating power, which is lethal to DNA.
    • Sterilization control can be performed using physical, chemical, or biological methods.
      • Physical monitoring involves independent temperature, pressure, and vacuum, measurements performed automatically by the sterilizer by gauges and data loggers, throughout its cycle. Temperature and pressure readings should be taken at least three or four times during the sterilizing cycle, and the records kept until all tests are completed. Gauges and recorders should be calibrated at regular intervals against standard instruments.
      • Chemical indicators for steam sterilization are printed inks on packaging materials, or paper strips on which the chemical indicator is printed, placed inside packs being sterilized.
      • Biological indicators are the most accepted means of monitoring the sterilization process because they directly determine whether the most resistant microorganisms (e.g. spores of Bacillus stearothermophilus in autoclave and spores of Bacillus subtilis in ETO sterilization) are present rather than merely determine whether the physical and chemical conditions necessary for sterilization are met.
Disinfection is achieved using alcohols (ethyl alcohol, isopropyl alcohol, and methyl alcohol), aldehydes (formaldehyde, glutaraldehyde), phenols (5% phenol, hexachlorophene, chlorhexidine, chloroxylenol), halogens (chlorine, bleach, hypochlorite, tincture iodine, iodophors), heavy metals (mercuric chloride, silver nitrate, copper sulfate, organic mercury salts), surface active agents (anionic and cationic detergents), hydrogen peroxide, and dyes (aniline and acridine dyes).9
 
Microbiological Monitoring of an OR
Microbiology department plays a pivotal role in identifying the pathogens and monitoring the antibiotic regimen used. They should be updated with information on the antibiogram patterns from time to time. Swabs are collected from various locations in the OT and cultured for aerobic (chocolate agar) and anaerobic (Robertson’s cooked meat medium) growth.
The areas swabbed include:
  • Operation table at the head end
  • Over head lamp
  • Four Walls
  • Floor below the head end of the table
  • Instrument trolley
  • AC duct
  • Microscope handles
Asepsis in the OR complex is an issue regulated by local health authorities, and there might be slight differences between countries or even regions within the same country. Although OR complex design and architecture observe general guidelines, ventilation standards present different values in different countries; therefore, it is difficult to know the ideal limits of the individual requirements.
Asepsis in the OR is not a static concept.35 It starts with constant following the recommended local regulations, passes through a relentless team effort involving nurses, surgeons, and anesthesiologists and continues with conscientious periodic monitoring and educational sessions to reinforce sterile technique.36
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