Asepsis and antisepsis are important measures in medical practice. An idea of the spread of diseases was vaguely there but the vanity of the idea that a physician "could do no harm to a patient" was even more harmful in the old days. Vienna and Europe during these times were the seats of excellence in medical practice. The renowned practitioners were there together with the best clinics. Still, a considerable number of unaccountable deaths occurred where a real reason could not be found. Interestingly, in ancient India, the later-day well-known physician Sushruta postulated that:
Leprosy, consumption, diseases of the eye, and other infectious diseases spread from one person to another by sexual union, physical contact, eating together, sleeping together, sitting together, and the use of same clothes, garlands and pastes.
Sushruta Samhita,16th century BC.
The Mosaic laws, in the earlier Hebrew bible, mention the spread of diseases. These were the earliest thoughts on this matter. During the early times, of medicine, a veiled theory about an invisible agent was conceived by physicians as a means for transmission of disease. We find the reference of 'semina', animalcules, and various spore-like seeds, which Greeks observed, and this required either inhalation or ingestion for a disease to spread. That Black fever or Plague was contagious was noted by Greeks, and an account of it is found in the works of Thucydides. The Roman poet Lucretius in his poem "De rerum natura" mentions an invisible seed dispersed in the air or environment that must be inhaled or ingested for a disease to happen. The Roman statesman Marcus Terentius Varro in his book on agriculture (de rerum rusticarum libri III) also opined about the need for care when working in swamps. Airborne minuscule invisible seeds may be in contact which can lead to serious diseases. Emphasis was given to this method of spread rather than direct contact.
Galen had similar ideas (On different types of fever, c. AD 175). He speculated that a disease was caused by invisible seeds which resided in the body. The "seeds of fever" may be in the bodies of different types of fever patients and "certain seeds of plague" present in the air were responsible for the plague epidemic (Epidemics, AD 176-178). In explaining recurrences Galen opined on the persistent presence of the seeds of fever in the body. Following a rigid and strict therapeutic regimen was necessary to get rid of these seeds. The term "pestifera semina" or plague-bearing seeds, is also seen in the compilation " On the Nature of things" by Isidore of Seville (c. AD.613). The Italian scholar Tommaso del Garbo, (1345, AD), published a commentary on the works of Galen (Commentaries nonparum utilia in libris Galeni), where the idea of the " seeds of plague is mentioned". A couple of centuries later, the Italian scholar and physician Girolamo Fracastoro in his book, "De Contagione et Contagiosis", suggested that transferable seed-like elements are necessary, and direct or indirect contact was required for the propagation of disease. This came to be known as "seminarian morbi". Long-distance and questionable propagation, however, in non-contacts had not been addressed so far.
The human mind always related bad odor with the disease as we will see in the description. Miasma, or blight an ancient Greek word, and it means pollution. This Miasma theory was afloat during the early times and was accepted by all. It implied "bad air" emanating from rotting organic matter (miasmata -- decomposed matter). Simply said "miasma" was a form of a noxious vapour filled with disease-creating particles that caused propagation. Miasma could always be identified by the putrid offensive smell and those affected were in the miasma environment. Dangerous life-threatening conditions like cholera, chlamydia, and "Black Death" or plague, as it was commonly known then, were spread via miasma. It was a common perception at that time that this illness of plague actually originated in the East and was transmitted therefrom by the drift of the "bad air" from there. This "miasma" theory was so popular that almost all renowned physicians of that time including Galen, believed in it, and endorsed it by writing about it.
The Middle Ages also witnessed a strong belief in this contagion concept. Ibn Sina (known as Avicenna in Europe) tried to explain epidemiological spread by this method (Book IV of El Kanun or The Canon of Medicine). This was in 1025 B.C. There is historical evidence of country-specific attitudes about the spread of disease in ancient times and this period saw several scholars of the Ayyubid Sultanate deliberate about this invisible contagion. They named it the "najasat" or the impure substance.
There were some similarities in the thoughts of Western and Eastern scholars during this period. One thing was evident cleanliness was a pointer to keeping dangerous diseases at bay. However, overcrowding and lack of proper caregivers contributed to the shambled appearance of Hospitals. Also, the then view ventilation (which was not adequate) in the region of the sick was a big factor. The patients were segregated into inadequately ventilated rooms and it was a sheer chance that some of them survived.
Direct visualization of invisible agents causing the disease was elusive. A powerful magnifying glass fabricated into a crude device called a microscope was necessary. The Dutch spectacle maker Zacharias Jansen invented the instrument, and it was Antonie van Leeuwenhoek, who made important contributions to microscopy and was credited with the feat of visualization of microbes for the first time, in1670. There has been a question about whether the German Jesuit and scholar Athanasius Kircher (or Kirchner) beat him to this feat. In one of his books in 1646, there is a reference in Latin, about these seemingly invisible objects. Kircher stated in the book, "
Concerning the wonderful structure of things in nature, investigated by Microscope...who would believe that vinegar and milk abound with an innumerable multitude of worms.
Leeuwenhoek coined the term ‘animalcules’. Kircher examined the blood of plague patients under a microscope and confirmed the presence of these invisible “little” animals. He is the first to document these "worms" in the blood of victims of bubonic plague during an epidemic in the region where he was. Both agreed that these microscopic living objects could be the reason behind the spread of diseases. His conclusion that disease was caused by microorganisms was correct. In his book documenting the event, 'scrutinum physico-medicum', Rome1658, Kircher also proposed hygienic measures to prevent the spread of disease, such as isolation, quarantine, burning clothes worn by the infected, and wearing face-masks to prevent the inhalation of germs.
The "Germ Theory" governing the modern-day belief of the propagation of diseases is evidence-based. It took a long time for people to understand and visualize what is happening. Francisco Redi, an Italian, was the first to experimentally demonstrate that aeration and contamination are essential for growth related to infectious elements. The germs were invisible to the eye and acted as pathogens when they came to invade a new host and multiply in numbers. The collective symptoms were known as infectious diseases. At about the same time a French orthopedician, Nicholas Andry stated that smallpox and other diseases spread via the minuscule agents. Robert Bradley was an academic and botanist at that time. His contention was plague and other fevers with 'all pestilential distempers' were caused by these 'poisonous living insects'. Marcus Antonius von Plenciz was a Viennese physician during the Middle Ages, who tried to advance the germ theory and also held the view that each disease was caused by a different organism that had invaded the body. He also could distinguish between diseases that spread by their contagious nature leading to epidemics and diseases that did not spread by contagion, like rabies and leprosy. His work is documented in the book "Opera Medico-physica". However, these hypotheses were not believed then, and the Miasma theory as proposed by Galen prevailed.
Ignaz Phillip Semmelweis was a young Hungarian physician, working in Vienna in the early 19th century. He observed that the incidence of puerperal fever (or ’child-bed’ fever as it was known then) could be reduced considerably if washing hands with chlorinated water (or lime water) was practised. As a young physician, he observed that the actual number of ‘child-bed’ fevers, which often were lethal and led to unnecessary deaths, was lesser in one of the two Viennese Institutes which was manned by midwives rather than doctors. The more sophisticated obstetric unit where doctors were the primary caregivers, registered a greater number of morbidity and death. The magnitude of the problem was such that even the childbearing ladies with means appealed against admission to the supposedly costlier clinic. Semmelweis was outspoken and bold. But from the time he made this idea public, he faced a backlash from his ilk. Denial made the physicians think that they were immune as carriers of this still ill-understood disease process. One could not conceive that doctors themselves were spreading the disease by performing cadaveric autopsies and examining obstetric patients without changing clothes. Semmelweis's postulations were not realized at that time. They made sure of the ostracization of Semmelweis and mentally tortured him to such an extent that he lost his mind. Subsequently, he lost his mind and was committed to a lunatic asylum, to be beaten to death ultimately.
Before Semmelweis, an Italian named Agostino Bassi described a "vegetable parasite" describing the then common affection of silkworms (calcinaccio). This was a micro-organism (later found to be a fungus) and Bassi was able to prove that this was the causative agent. Gideon Mantel, a British physician, famous for the discovery of dinosaurs, stated in his Thoughts on Animalcules (1850) that "many of the most serious maladies which afflict humanity, are produced by peculiar states of invisible animalcular life". John Snow, again a British, was very sceptical about the miasma theory and was able to show a pathway to localize a disease outbreak (cholera in this case). Snow had the right understanding of the germ theory and published his theory of feco-oral transmission of cholera in the essay in 1849 On the Mode of Communication of Cholera. He first recommended that water be filtered and then boiled before consumption. An update with refinements to his theory was published in 1855. It is interesting to know what happened as a follow-up. Though it established a chain of circumstances and identified a culprit and the reason for death from a deadly disease, the authorities only changed the handle of the offending pump and rubbished Snow's observations.
The mid-19th century after these events saw the works of Luis Pasteur in France and Robert Koch in Germany. Pasteur performed a series of experiments and while denouncing the idea of 'spontaneous generation, he showed the world the real nature of puerperal fever, the pus-forming nature of the pyogenic vibrio, and that a solution of boric acid, which is odourless and not an irritant to mucosal surfaces, should be used as an agent to prevent the growth of offending organisms. He devised a method for reducing pébrine in the silkworm industry and promoted the idea of thermal inactivation of micro-organisms. This is better known as Pasteurisation (in his memory) and is extensively used in the dairy industry.
Robert Koch had a different approach. He was more of a theoretician and forwarded the famous Koch's postulates. The beauty of this postulate is the fact that it is even true today and has passed through many a trial and tribulations. Though certain viral and prion-transmitted diseases appear to confound present-day clinicians, Koch's postulates are a basic hypothesis, and still, rule the majority of microorganism related.
The germ theory was gradually gaining credence among the members of the medical community. During this period Lord Lister, as Joseph Lister was known at that time, a surgeon championed the use of phenols or carbolic acid during this time and was able to show lessened infection of open wounds. He even devised several carbolic acid sprays and dispensers to suit surgical purposes. Carbolization of the instruments, theatre, and appliances remains relevant even today and is an important morning ritual by the O.T. personnel even today. It should be added here that there is a common misconception between phenol and phenyle. As said before, phenol is carbolic acid. while phenyl is a compound with cyclic benzene-like rings minus a hydrogen atom with antiseptic properties. Commercially phenyle added with a detergent is available as a bathroom and toilet cleaner.
Cleanliness and maintenance of hygiene became central to reducing infections in medical practice. With time, the increased and new knowledge of infective agents was added and measures were taken accordingly. A universal system governing an invasive procedural room evolved which could be applied to all the establishments involved. Operating room personnel should be aware of :
Proper illumination of the field.
An idea about the transmission of diseases, or vectors.
Clean and sterile attire.
Covering areas able to disperse a disease from the operator.
Regular scrubbing and monitoring of operating areas.
Periodic swab culture of samples taken from different areas of the operating theatre and other procedural areas.
Keep the area shut and out of bounds for at least the prodromal period if a hazardous pathogen is identified or detected in any of the swabs.
The role of each person in the room should be specified and only useful movements by each person advocated.
There should be an idea about the hazardous materials -- both chemical and biological.
Pregnancy is always a special situation and avoiding hazardous materials also includes the non-use of drugs and fumes which may be hazardous for the unborn child as well.
Disinfection has a rich and varied history. Cleanliness and hygienic measures helped in a general reduction of infective probability, In a large area, however, a medical practitioner was more interested in curbing infection in and around an open wound. A surgical wound was a created open wound and hence in the same category. When considering disinfection, the following had to be considered:
Preparation of the persons in the surgical team.
Antiseptic preparation of the skin.
Minimal exposure of the part requiring a procedure.
Disinfecting the instruments.
Transport to a clean, hygienic, and safe area for nursing back to normalcy.
Agents used for disinfection are called disinfectants. People did not know what caused disease but the involvement of some sort of living organisms was presumed. The goal was sterilization of infestation with microbial organisms. The idea of disinfectant has been there in the mind from time immemorial and there have been attempts at purifying or detoxifying areas. The use of wine as a surface cleaning agent was documented. Egyptians, from as early as 5000 B.C., knew the use of bleach and they used it to whiten and clean clothes. Bleach or calcium hypochlorite is a powerful oxidizing agent and may be used for detoxifying water as well. The use of bleach in situations where community spread of infection is expected gives a satisfactory result. Bleaching powder is still used now. Any agent having a corrosive effect on organisms will possess disinfectant properties was believed by all. Thus, burning sulfur or mercury and production of toxic fumes was ritually practised before an auspicious entry. This finds a mention in the epic Odyssey as well as in ancient Indian and Chinese practices. The use of mercurial compounds as disinfectants dates back to ancient times in India, China, Europe, and Egypt, likely a direct result of observation of the compound’s corrosive effect. The work of Robert Koch provided evidence of the efficacy of mercurial compounds on in vitro cultures of microorganisms. As a result, some organic mercurials, like Merthiolate and mercurochrome, became widely used in medicine. Acids and alkalis were used for similar corrosive properties; however, alkalis were more effective as they neutralized microorganisms including viruses. Physical disinfection consisted mainly of wiping and scrubbing. A later armamentarium consisted of radiation which needs to be discussed in detail, in an appropriate situation.
Thus disinfection or sterilization from microbes consisted of ----
1. Manual means,
2. Use of chemical agents,
3. Use of physical means like heat, radiation, microwave, etc,
We all know that heat is a powerful tool. The harnessing of the destructive power of heat is well nigh impossible. When not controlled it can cause total annihilation of both the micro-organism together with the tissue of the target area and may even kill the patient if the heat is strong and not properly controlled. So, the heat was only applicable to instruments and appliances that were not perishable and living. Direct heat disinfection was commonly done by flaming. Pre-heated steam, pressurized and supersaturated nowadays, is an example of the transference of heat energy to surgical objects used commonly. This principle is employed in autoclaves now and is common in the central sterilization and disinfection areas of hospitals nowadays. The physicians favour a situation where there is the destruction of the offending microbes while the host is being spared. Indirect transference of energy was thought of and still done, as in autoclaves, to sterilize inanimate objects like the instruments and draping material. The skin in and around the area where an incision is made for access is cleaned with antiseptic chemical agents. Unwanted hair should be removed. Hair not only is dirty and carries pathogens but also may lead to the formation of entrapment lesions later. Earlier it was a norm to shave the important and the other surrounding areas. The knowledge that shaving could lead to unwanted abrasions drawing pathogens from nearby. Also irritating the skin may lead to pouring out and activation of hitherto harmless pathogens from the innumerable skin pores, leading to the more common and hassle-free use of chemical depilatories.
The procedure is performed in a proscribed clean theatre where the temperature and humidity are controlled and the airflow is also laminar and filtered. Sanitation of inanimate objects, e.g., the surgical non-perishable objects can be done by a pressure cooker, but in the actual scenario, a larger scale is required for the volume and size of instruments and the fact that a theatre may house multiple cases. Again, a separate provision is needed for heat-perishable items. A microwave is another alternative, but metals cannot be used in a microwave. A modern operating theatre usually has an anteroom with a large autoclave that can sterilize several objects at a time. A central area or the central sterile services department (CSSD) is more appropriate for a hospital.
Antiquity taught health-care workers about the role of handwashing, especially with a soap-like detergent, and cleanliness with the adoption of hygienic measures was important in preventing infections. Later studies suggested that 80% of offending micro-organisms could be eliminated by hand washing alone. However, the addition of an antiseptic was a psychological ploy to increase antisepsis and may be effective.
Phenol or carbolic acid is an aromatic organic compound, that has been used for mass disinfection for a long period. The slimicidal and disinfectant properties are particularly helpful in cleaning toilets and the typical aroma is quite often associated with hospitals and clinics. Phenyls are cyclic hydrocarbons with a strong smell and disinfectant properties. I today's world the phenyls have replaced the phenols in several situations though both are gastro-intestinal irritants. The active ingredient in lizol or lysol is benzylalkonium chloride and in recent years it has replaced phenols and phenyls as, unlike these, these agents are not irritants and are safe to use. This agent is not new, was discovered by the German chemist Gustav Raupenstrauch in the late 19th century. Since then it was used initially as a medical cleaner, and later the use was extended to industry and households.
Several antiseptic solutions have flooded the market, each claiming superiority over the other. alcohol, halides, aldehydes, triclosan, chlorhexidine, iodophors, and quaternary ammonium compounds constitute the never-exhausting list. The knowledge that the skin harbours a myriad of organisms. The natural pores and hairs make the skin impossible to sterilize, even with the strongest antiseptics, and the goal has been to minimize contact with the infective agents so that transmission of infection is minimized. The agent used should not be an irritant to the skin as well. Techniques have been devised to sterilize skin before making an incision. The real surgery is done in a clean environment without the use of any additional agents in the surgical field and within a reasonable period. The norm is minimal exposure to the operative area and appropriate drapes have to be applied to exclude the other areas. Every establishment or group has its own choice of agents and methods of skin sterilization and barring a few minor modifications, the results have been good so far. The recent generation of antiseptics combines the soapy cleaning property as well and thus are very much liked. Alcohol has always been a choice and disinfection methods always tend to round off with an alcohol wash as alcohol makes the area clean and devoid of the antiseptic and also renders the area dry. The World Health Organization (WHO) suggests that 70% ethyl alcohol is superior to isopropyl alcohol against the influenza virus, however, both provide adequate germicidal properties. It is widely recognized that ethanol in this concentration is effective against many viruses and bacteria. Alcohol, be it ethyl or isopropyl, is bactericidal however, this does not imply that with a higher concentration, the action will be better. Observational studies have shown that 70% is the right strength and isopropyl alcohol though better than ethyl alcohol as a disinfectant, is less effective against the influenza virus. Also, alcohol is not an ideal antiseptic, lacking a sporicidal effect, and breakthrough infections have been reported. After alcohol, iodine and other halides need a mention. Paradoxically the French should be credited with the discovery of almost all the halides, and iodine requires a special mention for its antiseptic properties. Iodine is reactive, takes a shorter time, and is viricidal. Chlorine, slowly liberated by the recent introduction of chloramine-like tablets is better for the sanitation of large water bodies.
The method so far was an iodine application preceded by an alcohol paint and followed by alcohol wash again. Iodine was diluted in alcohol (3% iodine in alcohol was a tincture of iodine) and was widely used so that the intact skin was not irritated. This continued till recently. The present-day surgeons are enamoured with either iodophors or chlorhexidine, and both give good results. Both Povidone-iodine and Betadine are brand names where polyvinyl-pyrrolidine is the vehicle onto which elemental iodine attaches for a slow liberation of nascent iodine for germ destruction at the site of application. Iodophors had the added advantage of less vigorously staining the drapes and other clothing. Paradoxically the lesser the strength (in %) of the iodinated compound, the better the germ-destructing ability. 10% is a viscous stock solution from which the desired % of solution can be made.
Initially introduced as hexachlorophene, which was withdrawn as soon as the ill effects came to light, a reintroduction of chlorhexidine, and other quaternary ammonium compounds, with reasonable time, gives acceptable results. Though microbe count is better reduced with chlorhexidine, the iodophors have the advantage of acting against mycobacterium and are favoured in our and other Asian countries. Also, iodophors are available in different percentages and this makes it more interesting. Another interesting thing is the fact that iodophors liberate iodine, nascent iodine, in very small amounts for the antisepsis, thus ensuring less staining and sustained action. The WHO recommended guidelines for surgical-site antisepsis favoured a combination of chlorhexidine and alcohol. Several meta-analyses support this data of lower organism count, but the points favouring iodophor compounds have to be considered. The addition of soapy detergent to both iodophors and chlorhexidine is possibly helping to clean the local area. One needs to remember that in certain developed countries the use of PVP-Iodine is prohibited as it interferes with thyroid function tests and hence chlorhexidine-based isopropyl alcohol is popular.
There was an attempt at introducing triclosan (TCS, the 1960s) into the market and we know that this together with the stronger and more advanced quaternary ammonium compounds like peracetic acid (1988) are the strongest antiseptic agents. However, the use of these agents has been limited to cleaning and sterilizing endoscopes, endo-catheters, arthro-scopes, and related instruments. Peracetic acid is a corrosive agent, but it helps in the removal of proteinaceous materials from the surface of instruments hence its popularity in the sterilization of endoscopes. Triclosan, a chlorinated aromatic product, is a fungicide as well. Triclosan shower was recommended before surgery and was a common additive in several healthcare products such as soaps, shampoos, and toothpaste. However, long-term use may have some medical issues and it was certainly not safe during pregnancy. These issues led to the discontinuance of triclosan.
Peracetic acid, or PAA as it is better known in the industry, is a relatively later introduction. PAA has a high oxygenation potential and the wastes at the end of a process are environmentally friendly, making it very suitable for mass-scale wastewater management. Another good feature is it is not an irritant and can be handled without any Ill effect with a bare hand.
Quaternary ammonium compounds, also known as the quats in the industrial parlour, are strong disinfectants. Most of them feature in the phenolic floor and toilet cleaners as additives, surfactants, and preservatives. Examples include alkyl dimethyl benzyl ammonium chloride, alkyl didecyl dimethyl ammonium chloride, dialkyl dimethyl ammonium chloride, etc. These products can irritate the skin and cause allergic rashes, so should be handled with care. Also, there is some concern about the breakdown products which should not be allowed up to certain levels. In the end, the decision depends upon the establishment to decide on the agent it is going to use and, in our country, the soapy iodophors still find favour among the end-users.
In addition to the usual methods, airflow became an important aspect in today’s design of the operative complex. Environmental air contains numerous microorganisms. A laminar flow ensures the unidirectional flow of air in the room away from the operating area. The use of a filter, a high-efficiency particulate (HEPA) filter, further reduces the offenders and is capable of sanitizing a theatre from dust, moulds, bacteria, and even some viruses.
Fumigation is a process whereby an aerosolized smoke of a chemical is introduced and made to stay in a theatre or similar area with the intent to kill the housed organisms. The area is sanitized thus. Fumigants have also evolved over the years. The usual practice was weekend fumigation with formaldehyde. It was observed that in a sealed and properly humidified room formaldehyde fumigation gave a good result. Time was given for the irritating fume to drift away before the area became usable again. Proper formaldehyde fumigation necessitated several preconditions - a temperature above 13°c, relative humidity around 70% and formaldehyde must be added to a concentrated potassium permanganate solution (40%) for release of formaldehyde fumes. Formaldehyde fumes percolate every nook and corner and as it is a strong irritant to mucus surfaces, entry to a sealed room is prohibited for the period of fumigation and the seals are removed for the diffusion of the product. Formaldehyde fumigation done properly is an effective microbicidal and viricidal as well. However, it is carcinogenic and takes time. Time is also required for drifting away from the pungent residual formaldehyde vapours. Nowadays less irritant and less time-consuming fumigant materials are used for operating room fumigation. The materials include --- 1. Aldekol, a mixture of formaldehyde, glutaraldehyde, and benzalkonium, 2. Bacillocid rasant, a mix of glutaraldehyde and quaternary ammonium compounds, 3. Ecoshield where the active ingredient is hydrogen peroxide. 4. Virkon, a mixture of potassium peroxymonosulfate (an oxidizing agent), sodium dodecylbenzene sulfonate (a detergent), and sulfamic acid (a cleaning agent). These are a few examples and they can both be used as a cleaner or aerosolized with a fogger for fumigation. The time required is about an hour and repeat fumigation of the same room can be done soon after if required.
Operation theatre and intensive care unit fumigation now need a mechanical aerosolizer, better known as a fumigator for such procedures. Effective fumigation in a shorter time is the goal now.
Ethylene oxide sterilization is popular for surgical instruments and perishable products. However, contact time, gas generation, and time required for the gas to diffuse away make it unsuitable for quick use.
Gaseous agents like ozone or hydrogen peroxide are powerful oxidizing agents. They require specific liberators of these gases or generators and are exciting to the medical community. In a lesser time, they can destroy the multi-drug resistant organisms (MDROG) which have till now eluded eradication methods. They are odourless and non-irritant as well and can bring down the possibility of nosocomial infections as well. Plasma sterilization is a method where a saturated environment of hydrogen peroxide is created which permeates through the specially packaged objects and reaches the nooks and corners, to kill the pathogens. Hydrogen peroxide is very reactive and oxidizes the DNA molecules of the organisms. The hydroxyl ion (-OH) is even more reactive and is used nowadays for operating room and ICU fumigations.
Cleaning walls, floors, and spaces meant for the storage of instruments and appliances is a must before preparing an operating area. All exposed surfaces including the ceiling, air-conditioner vents, area around the light attachments, the area adjacent to pendants for a plug-in for appliances, the anaesthesia workstation, etc., need to be wiped with an antiseptic. Restriction of noises and movement of persons in the active area is a part of operating area ethics. Fumigation comes thereafter.
Radiation is a recent addition. Especially ultraviolet radiation (UV) is very useful. It not only kills microbes but also leaves no residual effects. The contact time is low, and it is not irritant at all. UV sterilization of the entire operating theatre personnel can be considered. Ultraviolet Germicidal Irradiation (UVGI) is a proven air purification technology that disinfects the air by emitting UV-C rays at a wavelength of 253.7 nm. These rays kill bacteria, viruses, and fungi by disrupting the DNA of microorganisms, preventing them from reproducing, and thereby killing them. Many corporate offices and homes are using UVGI solutions to sanitize the indoor air by simply installing UV Air Sanitizer for protection against deadly viruses. This is a one-time installation and will eliminate numerous hassles. Even ducts and coils connected to the operative room and intensive care areas may be sterilized with ultraviolet beam installation. surgical and other perishable products may undergo disinfection with gamma rays or other radiation waves, but these are dangerous for human use.
Latex gloves were worn by the members of the surgical team to prevent the transfer of microbes either way and thus lower the possibility of infection in the patient. The operators. in fact, have the advantage of intact skin which the patient does not have making the individual more vulnerable. The story tells that it was more of a romance that led the great Halsted to delve into and involve the Good Year Company to develop a pair of rubber gloves that protected the hands of his lady-love who was an efficient scrub nurse as well. The following period saw the adoption of these rubber gloves to lower the incidence of a different cause, infection. The latex gloves have become thinner over the years and the quality has improved. However, the recent trend is toward institutions becoming latex-free and rubber gloves, used since the days of Halsted, were replaced by new synthetic alternatives that do not incite an infection or an allergic reaction.
One should realize that an operation is a serious matter and requires concentration. Efforts should be made to maintain dignity and only relevant sounds allowed.
A microbial swab examination and surveillance are ideal but not practical. Formalin fumigation, though time-honoured and effective, is time-consuming. The identification of formalin as a carcinogen when the contact time is high, and the irritant nature of the substance makes the use not ideal as a fumigant. Nowadays agents are used with less contact time and are devoid of the bad attributes of formalin. They can be used as cleaning agents as well and do not require the addition of another agent or the time for the irritating fumes to diffuse away.
Cleaning of the operative area does not end with the completion of an operation. Meticulous scrubbing and disposal of material follow. One should have the idea of segregation of wastes, and this is Important in modern-day practice. Designing specialized hospital areas requires skill and knowledge. Operating areas and ICUs are the actual places where most of the activity happens. Thus, waste will be generated accordingly. Segregation and disposal of this medical waste require the placement of sluice gates in a discrete fashion. The wastewater should not flow backwards and methods to be employed so that contamination is minimal. The ultimate disposal goal should be incineration.
In general, physicians should have a detailed knowledge of anti-sepsis and asepsis and conduct themselves in a manner so that he has little chance of introducing infecting microbes into the system.
We all know about Harpic, Lysol, Dettol, Vanish, and similar other substances as the aggressively advertised and marketed antiseptic scrubbing products available. Each one is better than the other and, advertisements make even the newer generation of the same product with a higher price tag superior to the one that we were using. The active ingredients, courtesy of the internet, are known even by intelligent common people -- 10% hydrochloric acid is the active ingredient of Harpic, benzalkonium chloride as the microbiocidal in an alkaline medium is available in Lysol, chloroxylenol is the antiseptic principle of Dettol, and Vanish is a product for the removal of stains mainly. Also, these
products are available in catchy colours and solid, liquid, and spray forms. With the recent pandemic, the advertising trend for enticing common people is to educate the effectiveness of viruses.
The present trend of endoscopic surgery and the use of long-handled instruments has created certain problems. These scopes and the instruments are costly and, though reusable, need gentle handling and cannot be subjected to the rigours of autoclaving. Gas sterilization with EtO2 is an option but allowing the gas to blow away completely and setting up a separate unit for gas sterilization is not often an option. Sterilization by radiation is costly. The long-term chemical disinfectants and reduction of the time taken for sterilization have allowed repetitive use of the same instruments in consecutive procedures. Gluteraldehyde has been known as a chemical sterilizing agent for a long time and either its alkalinization with sodium bicarbonate or novel glutaraldehyde formulations (e.g., glutaraldehyde-phenol-sodium phenate, potentiated acid glutaraldehyde, stabilized alkaline glutaraldehyde) produced in the past 50 years have overcome the problem of rapid loss of activity. The activity against mycobacteria and fungi has been documented by numerous workers. An increase in the contact time with the material also kills the spores. Gluteraldehyde is used as a biocide in the concentration of 0.1 to 1%. Additionally, it may be used as a tanning agent and a fracking material. The endoscopes and accessory perishables should be deproteinized (with peracetic acid), cleaned, and washed thoroughly with demineralized water before soaking them in a tray of Cidex.
Johnson & Johson came out with Cidex OPA which contains ortho-phthalaldehyde as the active ingredient. It is said to be more effective than glutaraldehyde and further reduces contact time. The recommended strength of this chemical is 2.45% with a contact time varying from 10 to 20 minutes at 20-25 degrees Celcius for anti-mycobacterial and fungicidal effects. Though a contact time as low as 5 minutes is enough for the biocidal effect, it is better to be on the safe side, and soaking the perishable products for 10 hours or more kills the endospores as well. The preparation of materials to be soaked is the same as described. The scopes and other materials soaked in the sterilant-containing tray should be washed thrice with sterile water and all the openings and channels flushed similarly before use.
The disinfectants used for healthcare-associated infections can be classed as having a high level, intermediate level, and low disinfectant level and they are as follows:
Formaldehyde is carcinogenic in prolonged use.
Glutaraldehyde, in a stable and activated form, is used for disinfection and preservation of prostheses like valves. Orthopthalaldeyde (OPA) or CidexOPA (Johnson & Johnson), used for sterilization of heat-perishable O.T. instruments and short-term sterilization of non-sterile agents used in the O.T.
Hydrogen peroxide,
Peracetic acid,
Hydrogen peroxide and Peracetic acid combination is even better as the action is complimentary.
Sodium hypochlorite or similar chlorine-releasing agents,
Iodophores like povidone-iodine and betadine,
Phenols and phenyle,
Quaternary ammonium compounds or (QACs)
Although aggressive marketing has penetrated almost all countries, every region is driven by its preferences and aseptic procedures may vary. Aerosolised disinfection of rooms and confined spaces is the new fad.
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