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. 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 a patient's own external bacterial flora present in the 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 prophylaxis based on the current clinical evidence is povidone–iodine irrigation.4,5 Patient prophylaxis consists in periocular skin scrubbing with 5% or 10% povidone–iodine ophthalmic solution including eyelashes, eyelids, 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 recommended.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.4 Patient preoperative showering or bathing with chlorhexidine or other wash products has not been found to reduce surgical site infection.11
PERSONNEL DISCIPLINE
Surgical Attire
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.12 Personnel working in the OR should be free from overt, active infection. Surgical attire including scrub clothes, hair coverings, mask, protective eyewear, and other protective 4garments provides a barrier to contamination that may pass from personnel to patients as well as from patients to personnel.13 All persons should change into freshly laundered clothing and must wash their hands thoroughly before entering the OR. The front of the sterile gown is sterile between the shoulders and the waist, and from the sleeves to 2 inches below the elbow.
Home laundering of scrub clothes is a debated issue.14 Head, hair, and beards should be fully covered by caps and masks. Surgical mask should fully cover mouth and nose.15 Other personnel in the operating theater should wear surgical masks if an operation is being performed or if sterile instruments are exposed. Handwashing or hospital-approved disinfectant is required between patients and whenever they become soiled. Fingernails should be kept clean and short. Traditionally, nail polish and 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.16
Surgical Scrubs
The surgical team members 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 bacterial colony-forming units on the hands, are less irritating, and have more persistent effect.17,18 An alternative to traditional hand scrubbing is hand rubbing with alcohol-based hand preparations.19–21 This is approved in some countries as equivalent to traditional hand scrubbing in preventing surgical site infections. The procedure of hand rubbing consists of 1-minute hand and forearms wash with a 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 the forearms, applied twice for 2 minutes 30 seconds (for a total of 5 minutes) without drying.22 Most alcohol-based hand preparations for surgical antisepsis contain either iso-propanol, 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.
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.23 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.24
Donning Gloves
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, the right hand is used to remove the left glove. The left hand is held palm up with fingers straight. The glove is laid on the left wrist, and the cuff is gripped with the left thumb.
- The right thumb is then placed inside the top cuff edge. A fist is made with the right hand and the glove is stretched over the left fingertips.
- The glove is pulled down keeping the left fingers straight.
- The above procedure is repeated to don the other glove, that is, the gloved left hand is used to lay the right glove on the right wrist. The left thumb is slid inside the top of the cuff, a fist is made, and the cuff is stretched over the right fingertips. Sleeve and glove are pulled down together (Figs. 1.1A to P).
Open Donning
- The cuff of the right glove is picked with the left hand. Slide the 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.
- The right fingertips are then slid into the folded cuff of the left glove. The glove is pulled to fit the right hand into it.
- The cuffs are unfolded down the gown sleeves, making sure that gloved fingertips do not touch the bare forearms or wrists (Figs. 1.2A to F).5
OPERATING ROOM COMPLEX
While the most common source of infecting organisms seems to be the patient and the surgical staff,25 environmental contamination plays an important role in surgical infections. The OR complex needs to fulfill the criteria of a cleanroom, 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.
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 the varying degrees of cleanliness through the scientifically planned traffic flow and the 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.26 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 zones. The bacteriological count diminishes progressively from the outer to the inner zone.27
- Outer zone: Reception area with administrative function, waiting room of patients’ relatives, and 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 wash basin. 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 7for 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.28
- Size: Minimum recommended size of 325 square feet (30 m2) and rectangular shape
- Floor: Slip-resistant, suitably hard, nonporous, fire-proof 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
- Walls and ceiling: Nonporous fire-resistant material, seamless, stain resistant, easy to clean, no artificial ceiling and a 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 equipment is 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 mechanical elimination of foreign matters 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, and instrument stands, while OR walls should be cleaned once a week and whenever directly splashed with contaminated material.
Ventilation and Cleaning Procedures
Proper ventilation in and near the OR is fundamental in halting the spread of infection.29 The standards for ventilation ensure good indoor air quality and establish limits for the following aspects: airflow, air filters, rate of air change, temperature, pressure relationship to adjacent areas, and relative humidity.30
The type of ventilation system recommended is the laminar unidirectional vertical airflow with a primary degree of turbulence of less than 5% and a high-efficiency particulate air (HEPA) filter.31 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 pollutant concentration. The minimum requirements for OR air change are 20–25 changes/hour, with 4 changes/hour 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 in order to optimize the comfort of the surgical team. While temperatures below 21°C put the patient at 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, while high relative humidity is related to microbial growth, especially fungal genera.
A bacterial colony count of less than 10 CFU/m3 in air sampling from an empty theater and 35 CFU/m3 in a functioning operation theater with laminar airflow is considered acceptable.
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.32
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 the delicates from regular instruments, ultrasonic or manual cleaning is performed. The ultrasonic cleaner contains liquids 8through which sound waves disrupt the bonds that hold the particulate matter to surfaces and clean every part of the instrument, including cannula lumen. Dissimilar metals (such as aluminum 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 of the delicate instruments is based on drench, friction, and fluidics. The instruments are soaked for half an hour in a neutral pH 7 detergent, because low-pH detergents cause breakdown of stainless protective surface, and high-pH detergents cause surface deposit of brown stain that interferes with the smooth operation of the instruments. The soiled area is scrubbed afterward 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.
Disinfection: It 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, iodophores), 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).
Sterilization: It can be accomplished by physical or chemical methods. Of all the methods available for sterilization, moist heat under pressure is the most widely used because it is nontoxic, dependable, and inexpensive.
- Physical methods: 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 the 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.33 The process can be hastened by increasing the pressure from 15 to 30 psi.
- Chemical methods: Chemical methods used for the sterilization of heat-labile materials include ethylene oxide (ETO), glutaraldehyde 2%, acetone, and plasma sterilization. ETO is a colorless gas that is flammable and explosive. The four operationals are gas concentration (450–1200 mg/L), temperature (37–63°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.
Sterilization Control
This 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 should be 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 9merely determining whether the physical and chemical conditions necessary for sterilization are met.
Operating Trolley
Before opening packages on operating trolley, check them for sterility by assessing intactness, dryness, and expiry date prior to use. Sterile objects must only be touched by sterile equipment or sterile gloves. Sterile trays/trolley should be set as close to the time of commencing the procedure as possible because sterile objects can become non-sterile by prolonged exposure to airborne microorganisms. All the objects on surgical tray/trolley must be kept inside the sterile field and away from the 1-inch border. No object should be flipped or dropped on the sterile tray as flipping creates air turbulence. Whenever the sterility of an object is doubtful, consider it non-sterile. At all time points, sterile equipment and sterile gloves must be kept above the waist level. Operating and assisting personnel must not sneeze, cough, laugh, or talk over the sterile field. A non-sterile person should not reach over the sterile field. Scrubbed personnel should face the sterile area at all times and should pass back to back or front to front with other scrubbed personnel.
Fluid flows in the direction of gravity. Therefore, the tips of forceps must be directed down during a sterile procedure to prevent fluid traveling over the entire forceps and potentially contaminating the sterile field.
When pouring sterile solutions, the pouring container must not touch any part of the sterile field and splashing must be avoided. The scrubbed assistant must hold the receptacle away from the tray/trolley or place it on the edge of the draped surface thus eliminating the need for the circulating assistant to reach across the sterile field.
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. While 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.34 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 the sterile technique.35
REFERENCES
- Allen HF. Aseptic technique in ophthalmology. Trans Am Ophthalmol Soc. 1959;57:377–472.
- Speaker MG, Milch FA, Shah MK, Eisner W, Kreisworth BN. Role of external bacterial flora in the pathogenesis of acute postoperative endophthalmitis. Ophthalmology. 1991;98:639–49.
- Miño De Kaspar H, Ta CN, Froehlich SJ, et al. Prospective study of risk factors for conjunctival bacterial contamination in patients undergoing intraocular surgery. Eur J Ophthalmol. 2009;19:717–22.
- Ciulla TA, Starr MB, Masket S. Bacterial endophthalmitis prophylaxis for cataract surgery: an evidence-based update. Ophthalmology. 2002;109:13–24.
- Speaker MG, Menikoff JA. Prophylaxis of endophthalmitis with topical povidone-iodine. Ophthalmology. 1991;98:1769–75.
- Endophthalmitis Study Group, European Society of Cataract & Refractive Surgeons. Prophylaxis of postoperative endophthalmitis following cataract surgery: results of the ESCRS multicenter study and identification of risk factors. J Cataract Refract Surg. 2007;33:978–88.
- Wu PC, Li M, Chang SJ, et al. Risk of endophthalmitis after cataract surgery using different protocols for povidone-iodine preoperative disinfection. J Ocul Pharmacol Ther. 2006;22:54–61.
- Isenberg SJ. The ocular application of povidone-iodine. Community Eye Health. 2003;16:30–1.
- Ferguson AW, Scott JA, McGavigan J, et al. Comparison of 5% povidone-iodine solution against 1% povidone-iodine solution in preoperative cataract surgery antisepsis: a prospective randomised double blind study. Br J Ophthalmol. 2003;87:163–7.
- Inagaki K, Yamaguchi T, Ohde S, Deshpande GA, Kakinoki K, Ohkoshi K. Bacterial culture after three sterilization methods for cataract surgery. Jpn J Ophthalmol. 2013;57:74–9.
- Webster J, Osborne S. Preoperative bathing or showering with skin antiseptics to prevent surgical site infection. Cochrane Database of Systematic Reviews 2015, Issue 2. Art. No.: CD004985. DOI: 10.1002/14651858.CD004985.pub5.
- Ritter MA, Eitzen H, French ML, Hart JB. The operating room environment as affected by people and the surgical face mask. Clin Orthop Relat Res. 1975;111:147–50.
- Bell RM. Surgical procedures, techniques and skills. In: Lawrence PF, Bell RM, Dayton MT (Eds). Essentials of General Surgery, 4th edn. Philadelphia, PA: Lippincott Williams & Wilkins; 2006.
- Doshi RR, Leng T, Fung AE. Reducing oral flora contamination of intravitreal injections with face mask or silence. Retina. 2012;32:473–6.
- Arrowsmith VA, Taylor R. Removal of nail polish and finger rings to prevent surgical infection. Cochrane Database of Systematic Reviews 2014, Issue 8. Art. No.: CD003325. DOI: 10.1002/14651858.CD003325.pub3
- Jarral OA, McCormack DJ, Ibrahim S, Shipolini AR. Should surgeons scrub with chlorhexidine or iodine prior to surgery? Interact Cardiovasc Thorac Surg. 2011;12:1017–21.
- Tanner J, Dumville JC, Norman G, Fortnam M. Surgical hand antisepsis to reduce surgical site infection. Cochrane Database of Systematic Reviews 2016, Issue 1. Art. No.: CD004288. DOI: 10.1002/14651858.CD004288.pub3
- Boyce JM, Pittet D. Guideline for hand hygiene in health-care settings. Recommendations of the healthcare infection control practices advisory committee and the HICPAC/SHEA/APIC/IDSA hand hygiene task force. MMWR. 2002;51:1–45.
- Lai KW, Foo TL, Low W, Naidu G. Surgical hand antisepsis—a pilot study comparing povidone iodine hand scrub and alcohol-based chlorhexidine gluconate hand rub. Ann Acad Med Singapore. 2012;41:12–6.
- Widmer AF. Surgical hand hygiene: scrub or rub? J Hosp Infect. 2013;83:S35–9.
- Parienti JJ, Thibon P, Heller R, et al. Hand-rubbing with an aqueous alcoholic solution vs traditional surgical hand-scrubbing and 30-day surgical site infection rates: a randomized equivalence study. JAMA. 2002;288:722–7.
- Pittet D, Allegranzi B, Boyce J. The World Health Organization guidelines on hand hygiene in health care and their consensus recommendations. Infect Control Hosp Epidemiol. 2009;30:611–22.
- Miller KM, Apt L. Unsuspected glove perforation during ophthalmic surgery. Arch Ophthalmol. 1993;111:186–93.
- Drake CT, Goldman E, Nichols RL, Piatriszka K, Nyhus LM. Environmental air and airborne infections. Ann Surg. 1977;185:219–23.
- Ram J, Kaushik S, Brar GS, Taneja N, Gupta A. Prevention of postoperative infections in ophthalmic surgery. Indian J Ophthalmol. 2001;49:59–69.
- Harsoor SS, Bashkar SB. Designing an ideal operating room complex. Indian J Anaesth. 2007;51:193–9.
- Sharma S, Bansal AK, Gyanchand R. Asepsis in ophthalmic operating room. Indian J Ophthalmol. 1996;44:173–7.
- Allo MD, Tedesco M. Operating room management: operative suite considerations, infection control. Surg Clin North Am. 2005;85:1291–7.
- Melhado MA, Jensen JLM, Loomans M, Forejt L. Review of operating room ventilation standards. Proceedings of the 17th International Air-conditioning and Ventilation Conference. Prague 2006.
- Center for Disease Control (CDC) and the Healthcare Infection Control Practices Advisory Committee (HICPAC). Guidelines for Environmental Infection Control in Health-Care Facilities. Atlanta, GA; 2003. http://www.cdc.gov/hicpac/pubs.html.
- Recommended practices for the care and cleaning of surgical instruments and powered equipment. AORN J. 1997;6:124–8.
- Rutala WA, Weber DJ, Healthcare Infection Control Practices Advisory Committee (HICPAC). Guideline for Disinfection and Sterilization in Healthcare Facilities. Atlanta, GA; 2008. http://www.cdc.gov/hicpac/pubs.html.
- McWilliams RM. Divided responsibilities for operating room asepsis: the dilemma of technology. Med Instrum. 1976;10:300–1.
- Roesler R, Halowell CC, Elias G, Peters J. Chasing zero: our journey to preventing surgical site infection. AORN J. 2010;91:224–35.