|Year : 1996 | Volume
| Issue : 3 | Page : 173-177
Asepsis in ophthalmic operating room
Savitri Sharma1, Aashish K Bansal2, Rekha Gyanchand3
1 Devchand Nagardas Jhaveri, Microbiology Centre, Hyderabad, India
2 Slight Savers' Corneal Training Centre, L.V. Prasad Eye Institute, Hyderabad, India
3 Bangalore West Lions Eye Hospital, and Cornea Grafting Centre, Bangalore, India
L.V. Prasad Eye Institue, Road No.2, Banjara Hills, Hyderabad 500 034
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Sharma S, Bansal AK, Gyanchand R. Asepsis in ophthalmic operating room. Indian J Ophthalmol 1996;44:173-7
Surgical techniques in ophthalmology have advanced considerably and in the present time the operating room (OR) has become the most critical point of any hospital set up. The surgical procedure itself is the most important event that happens to a patient. Proper management of this critical act requires a team work. Each member of the team has a key role to play in the overall success of the surgery. The structure of the operating room is as crucial as the functioning team. The central theme of the structure and function of the operating room is infection control. Post operative infection following eye surgery is a serious complication and all measures possible to prevent such an episode need to be undertaken.
We, in this communication, have chosen to discuss the issues that constitute important aspects of maintenance of asepsis in an ophthalmic operating room (OR).
| I. PLANNING THE OR COMPLEX|| |
Most planners of operating room acknowledge that people rather than objects are the chief concern in control of surgical infection. However, design and placement of equipment of a surgical theatre do affect utilization patterns, material handling and traffic in and around the suite. There is a strong relationship between the design, efficiency and the human element. Hence configuration of an OR complex can indirectly affect the incidence of surgical infections. While it is beyond the scope of this article to discuss architectural plans in detail it is attempted to enlist briefly the salient features necessory in planning an OR complex to minimize the nosocomial infection.
(A) Location : The OR complex should always be segregated from the high traffic area of the hospital. Ideally it should be situated either in a separate wing or on the top floor of the building, so that the patients and OR personnel only pass through the passage leading to the surgical suite, thus minimising the chances of infective organisms being carried inside.
(B) Design : The architectural configuration of a surgical suite should aim at separating sterile from non sterile traffic. Various types of configurations have been designed for this purpose.
- i) Central corridor plan - The central core of the complex is the most clean portion. All the sterilized items are stored here and this opens into the ORs.
- ii) Peripheral corridor or race track plan - An encircling peripheral area is the cleanest area that connects the ORs. The dirty traffic accesses the OR from other (inner) side.
- iii) Cluster plan - Each OR with its storage and sterilization area is separated from the other. Thus, each unit is an independent one without any flow of traffic from one to the other.
However, traffic pattern within the surgical suite is probably not important as long as clean internal traffic is efficiently segregated from the potentially infective traffic outside the suite.
Various portions of the OR complex need to be designed thoughtfully to maintain asepsis.
i. Changing room : This room should be located at the entrance of the OR complex. There should always be a separate entrance, through which one enters in street clothes and shoes and exit through that one enters the theatre in OR dress and slippers. Similarly, place for removing and keeping shoes should be earmarked near the entrance and clean slippers near the exit into the OR.
ii. Scrub area : This area should be located just outside the operation room. The areas should be wide enough for two to scrub simultaneously without touching the other's elbow. Taps should be operable by a foot switch and the wash basin should be about waist-high so as to avoid the arms touching the basin.
iii. Transfer area : This is an area, usually a corridor, where the patient is transferred from an outside trolley to an inside trolley. A red line on the floor can demarcate the limit upto which the out side trolley could come from where the patient is shifted to the inside one.
iv. Operation room : This is the most critical area of the OR complex and it is essential to adhere to the specifications while designing this complex. It should be large enough to have enough circulation space. A room no more than 400 square feet, preferably 20 x 20 feet, is required for an ophthalmic surgical suite. The room should have two openings one towards the scrub area and other at the opposite end towards the sterile corridor. The openings need to be fitted with swing doors so that they remain closed at all times. The operating table should be placed in such a way that there is enough circulating space around it. The table should be away from the entrance and the head end should be close to the opening towards the sterile corridor so that the instrument trolley can be taken to the table without having to pass through the entire room. The flooring should be stone (preferably marble) with minimum joints so that they can be efficiently cleaned. Walls should have a smooth finish. Artificial ceilings are not desirable. In general, the harder and less porous the floor, walls and the ceilings, the more dirt resistant the surface will be and easier it will be to clean.
v. Sterile corridor : This area is intended to be used for clean activities such as instrument packing and autoclaving (in the attached sterilisation room). It houses the sterilised equipment, linen and instruments, and serves as a supply port to the OR. It is connected to the OR and the sterilisation room also opens into it. All traffic from this area moves in the direction of OR. This area is accessible only to OR personnel in scrub suit and mask and is also used to move from one to other OR by the scrubbed nurse or the surgeon.
vi. Air handling : The air in the entire surgical suite should be well filtered and ventilated. The operating room should be ventilated by an efficient bag filtered or high efficiency particulate air filter (HEPA) system (0.3μ). The environment of such operating room has been shown to be effectively clean. Most bacteria and fungi are in the 0.5 to 5.0μ diameter range. Thus HEPA filtered air is virtually bacteria and fungus free. Air borne organisms assume a significant role in causing infection when an air handling system is contaminated or abused. Abuse of the environment in the form of frequent opening and closing of doors, leaving the door open during surgery, and not covering long hair and beards can lead to contamination of the OR environment. It has to be realised that no matter how particulate free air is blown into the theatre, the particulate biological matter accumulates and circulates in the OR in direct proportion to number and movement of people and amount of exposed skin and hair. Current US Public Health Service minimum requirements for OR air are 25 changes per hour, positive pressure compared with corridors, temperature between 18° C and 24° C, humidity of 50% to 55%, and up to 80% recirculation with effective filtering. Air may be supplied into the OR through ceiling panels at 30-60 feet per minute velocity The filtered air, if delivered by undirectional laminar flow, can lead to reduction in ambient bacterial count. In smaller organisation with resource constraints one could adapt alternative approaches. The use of ultraviolet light in the OR can be considered in such cases. Though the bactericidal effect is undeniable it does not appear to influence an overall incidence of wound infection.
vii. Traffic flow : The figure depicts an ideal OR complex and the traffic flow within it.
| II. CARE OF INSTRUMENTS|| |
Special attention must be given to clean the surgical instrument thoroughly prior to its sterilisation. Instruments should be cleaned as soon as possible after their use. Delicate and regular instruments should be separated. Gloves must be worn while handling the instruments to avoid infective material and cuts.
An ultrasonic cleaner is ideal for cleaning instruments. It thoroughly cleans every part of the instrument, including the depths of the cannulae, tubes and other unreachable parts, with high frequency sound waves generating bubbles and vacuum zones. This vibrating energy dislodges, dissolves and dispenses blood and organic debris. Chrome-plated instruments should not be cleaned in an ultrasonic cleaner. If ultrasonic cleaner is not available, the instruments are to be first soaked in mild detergent (eg. savlon) for half hour and then washed thoroughly under running water using a soft brush.
The instruments are dried completely before reassembling or storing. Instruments will corrode if they are stored with trapped moisture.
Each instrument has to be checked with the microscope or +20D lens blank or loop for its working condition. To avoid electrolysis, it is not advisable to mix instruments made of stainless steel with those made of aluminium, brass or copper.
C. Instrument sets
Instruments must be placed in a tray with perforated bottom to allow steam penetration around the instruments during autoclaving and to prevent air trapping in the tray. Each delicate instruments must be physically separated from adjacent ones to prevent damage, interlocking or crushing. Piling them on top of each other should be avoided. All detachable parts should be disassembled. Sharp or pointed instruments should be carefully spaced in a tray to prevent contact with other instruments that could damage their surface. The size of the instrument pack should not exceed 20" X 20" and weigh not over 5 kgs.
D. Disinfection And Sterilisation
The effective use of disinfectants and sterilisation procedures in the OR is critical for the prevention of post operative infections. The choice of agents and procedures to be used in OR depends on a variety of factors, such as, degree of microbial killing required, the nature of the item or surface to be treated and the cost and ease of using the available agents. Because it is unnecessary to sterilise all items in the OR, policies must be formulated regarding indications for cleaning, disinfection or sterilisation on the basis of the intended use. Spaulding described three categories of items such as critical, semi-critical and non-critical when determining the methods of disinfection or sterilisation. [Table - 1] shows the classification of devices with the corresponding process of disinfection.
A variety of disinfectants are available in the market [Table - 2]. The manufacturer's instructions should be adhered to while using any of the disinfectants.The role of acetone in the sterilisation of ophthalmic instruments is questionable and is not advisable. Several factors may affect the efficacy of a disinfectant, such as prior cleaning of the object, the organic load on the object, the concentration of and exposure time to the disinfectant, the physical configuration of the object (e.g, crevices, hinges, lumens), and the temperature and pH of the disinfection process.
Moist heat such as autoclaving at 121 °C for 15 minutes at 15 lb of pressure is the most efficient method of sterilisation for all heat stable critical items. The process can be hastened (3 minutes) by increasing the pressure to 30 lb, when a temperature of 134°C would be achieved. Regular usage of biological indicators (spores of Bacillus stearothermophilus) is recommended to ensure proper functioning of autoclaves. Improper sterilisation could result from incorrect wrapping, careless loading, time and temperature failure and tendency to short-cuts or irresponsibility. Every pack that goes through autoclaving must be labelled with colour indicator which mentions date of autoclaving. Regular servicing of the autoclave is mandatory.
Gas sterilisation using ethylene oxide has simplified the sterilisation of heat labile materials. Manufacturer's instructions must be adhered to while using such equipment. Spores of Bacillus subtilis can be used periodically to ensure proper functioning.
| III. ENVIRONMENTAL DECONTAMINATION|| |
The OR environment consists of a variety of items that does not come in direct contact with the patient. Although the chances of such items being related to post operative infections are remote, every effort must be made to keep them as germ free as possible. A totally sterile environment is neither feasible nor is it advisable to direct all resources to achieve that. However, policies must be made and adhered to, to keep the environment clean. The frequency of environmental decontamination is outlined in [Table - 3]. Frequent wet-mopping of all hard surfaces using a phenolic solution is an unsurpassed method of keeping the environment clean.
The technique of cleaning a "contaminated" operating room, especially after a "dirty" operation, consists of wet mopping or flooding with a good phenolic detergent, wiping down all metal furniture and plastic surfaces with germicidal detergent or 70% alcohol, and changing all rubber or plastic sheets and tubings in the room. It is not necessary to clean the walls unless direct splashing has occurred. One of the common errors in cleaning procedures is to clean walls and neglect anaesthesia equipment or operating table.
Routine culture testing of specimens from the nasopharynx or other sites of personnel, and from the OR environment is not considered mandatory. However, microbiologic evaluation of all possible samples, to track down possiblé sources in the event of an infection, and evaluation of cleaning methods to set policies, is recommended. Cleaning, disinfection and sterilisation methods should be checked for efficacy at regular intervals. "Fogging", the nebulization of a disinfectant, especially formalin, is employed by most hospitals in India to decontaminate the ORs. The origins of fogging can be traced to the 19th century when Lister aerosolized carbolic acid (phenol) to improve asepsis in operative practice. The popularity of formalin fogging has declined in the recent years, especially in the west. Formaldehyde is a high level disinfectant and its decontaminating value is undeniable. However, various objections have been raised against the practice of fogging. It is generally agreed upon that fogging cannot replace manual cleaning and may in fact cause a false sense of security leading to the abandonment of more effective infection control measures. Most hospitals in the United States do not use formalin fogging for any purpose because of its toxic (carcinogenic) nature and the fact that other methods of cleaning and disinfection can be as good if not better. Whether formalin fogging can be given up in Indian situation is a matter of controversy. The quality of the cleaning methods followed and the level of confidence in the OR personnel to carry out set policies would determine whether an age old practice of fogging can be done away with.
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[Figure - 1]
[Table - 1], [Table - 2], [Table - 3]