Operating Room

Chad J. Smith , ... Luis Melendez , in Clinical Engineering Handbook, 2004

Technical Support Services

Technical support services are vital to the productivity of the OR. Support for operating room technology must be immediately available to ensure the efficiency and safety of the surgical environment. Support groups serving the OR include anesthesia technical support and clinical engineering (see Figure 89-1). Anesthesia technical support is located within, or in the immediate vicinity of, the OR. The anesthesia workroom is primarily used for cleaning, testing, and storing anesthesia equipment. In larger facilities, clinical engineering support workrooms also might be situated within the OR. Later in this chapter, the responsibilities of the clinical engineering department will be discussed in detail.

Figure 89-1. Clinical engineering department engineers and technicians support the OR.

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Medical Biotechnology and Healthcare

J. Liu , ... P. Liu , in Comprehensive Biotechnology (Second Edition), 2011

5.35.2.1.1 Design

Two special operation rooms are included. The cleanliness level operating room is classified in accordance with the National Aeronautics and Space Administration (NASA). The standard of a class 100 laminar-flow operation room is that the number of dust particles larger than 0.5  μm per cubic feet of air should be less than 100, or less than 3.5   l−1 of air, while in China, the criterion is less than 3500   m−3 air. Each operation room should be equipped with independent purification from air-conditioning units. The air-purification systems have more than three filters; and the air supply coverage rate is greater than 0.75, and ventilation is 20–36 times per hour. In the class 100 laminar-flow operation room, the average wind velocity should be 0.25–0.35   m   s−1, and the minimum fresh air requirement for each person is 60   m3  h−1 ( Figure 2 ).

Figure 2. Photographs of the transplant surgery room: (a) internal view of the transplant surgery room; (b) gas supply belt; (c) control panel; (d) air shower; (e) camera operation facilities; and (f) process of operating.

Device configuration includes surgical facilities, cupboard, and writing desk, and a control panel would be in the operation room. A high-quality charge-coupled device (CCD) camera with 360° rotation and zoom lens provides omnidirectional video monitoring of the transplantation operation, for conference viewing, and for teaching purposes.

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Medical protective clothing

O. Troynikov , ... C. Watson , in Protective Clothing, 2014

8.3 Key requirements for surgical gowns: thermophysical comfort

An operating theatre is a critical location in a hospital where invasive procedures are performed and, therefore, strict environmental conditions have to be observed to safeguard the health of a patient. Hence, these environmental conditions are directed mainly towards the patient. As the patient is lying still and often seminude on the operating table and anesthetised, their heat production is at the low basal metabolic rate, in operations involving open body cavities, there may be a considerable heat loss; 31 and so the environmental conditions should be such as to ensure patient's thermophysiological comfort. 32 Lower operating theatre temperatures may lead to hypothermia which may prolong their recovery after the operation. 28

To protect a patient from a risk of hypothermia, it is recommended that the air temperature in an operating theatre remains at 24–26   °C according to Melhado et al. 33 The recommended environmental temperatures and humidity vary between countries, but are also focused on a thermophysiological state of a patient. For example, standards defining air temperatures in operating theatres recommend the optimum range to maintain within as 18–25   °C in Germany, 20–25   °C in France, 22–25   °C in Sweden and 25   °C in Switzerland. 30 , 34 In addition, required operating theatre room design may be covered, including parameters such as air distribution, air change rates, and room pressure.

As far as environmental humidity is concerned, recommendations also vary between 40% RH to 60% RH, 35 , 36 which is considered to be best for operating personnel, worst for the germs such as staphylococcus, and moist enough to minimise the danger from static electricity. Brandt reported that the actual operation room ambient temperature may vary from 15.6 to 25.6   °C and that the relative humidity may vary from 30 to 60%. 37

At the same time as comfort of a patient, the success of the operation closely depends on the performance of the medical personnel present and their comfort, both thermophysiological and psychological. Heat exchange between a human and the environment and, consequently, thermal strain experienced by a human is dependent on a number of factors, such as the type of work performed (metabolic rate), parameters of thermal environment and thermal insulation of worker's clothing. 38

The metabolic rate of a surgeon or medical personnel depends on the surgical procedure and the required body posture. Surgeons perform in a standing position, which often results in a metabolic rate of about 1.5 METs, 39 with orthopaedic operations often involving higher levels of physical activities. In addition, while surgical personnel are carrying out their work, they have little opportunity to move around which adds to their physical fatigue and strain. It is important to note that cognitive workload of a surgeon could well be considered high, 40 where workload is described as a hypothetical construct that represents the cost incurred by the human operator to achieve a particular level of performance. 41 More demanding tasks incur a higher cognitive workload, leaving less spare capacity to deal with new or unexpected events during surgery, and as a result increased errors were seen as a consequence of increased workload. 39 , 42 , 43 It is not difficult to understand the importance of minimising the additional thermophysiological load generated by the protective clothing to the wearer.

Considering the number of environmental parameters in an operating theatre, it is clear that, in many instances, there is a conflict between the environmental conditions considered to be comfortable for the medical personnel and those comfortable for a patient. In addition, it is clear that in the majority of the recommended environmental conditions, and also considering the type of protective ensembles worn, a balance between the metabolic heat produced by the wearer and the amount of heat to be released to the environment is not possible and heat strain, resulting in loss of concentration and an increased number of mistakes made. 44 It should also be noted that sometimes surgeons have to wear lead-containing surgical aprons, to protect against x-rays, giving them an additional load of about 3.4   kg. Hence, the role of the protective clothing worn in minimising the generated heat load is vital. This conclusion is in agreement with surgeons themselves, who state that comfort during their work is paramount. 45

However, EN 13795 deals with the comfort of wearers very briefly in Annex A 'Comfort', which is only 'informative'. 29 It states that it is recommended to combine materials and design of medical clothing in a manner that minimises physiological strain related to work in this type of clothing; hence, further extensive investigations are required in this area.

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FACILITIES MANAGEMENT AND DESIGN

In Management of Medical Technology, 1992

Heating, ventilation, and air conditioning

Specifications for general operating rooms include positive pressure in relation to adjacent rooms and corridors; a minimum of three room changes per hour of fresh air and a minimum of 15 room changes per hour of total air with high filtration; no recirculation by room units; relative humidity of 50 to 60 percent; and temperature control of 70 to 75 degrees (F)(a source of consternation for surgeons who say the range is too high, but perhaps correct for patients who have impaired thermoregulation capability). Central monitoring and control of HVAC and temperature systems allow each OR to be independently set up to meet the requirements of the surgeon and procedure. Supply ducts should be located in the ceiling over the surgical field and be constructed with widely dispersed small vent holes to reduce drafts and turbulence. Exhaust or return grilles should be located low to the floor on side walls as far apart from each other as possible, thus producing an air flow pattern in the room that tends to continuously draw contaminants produced by room personnel away from the surgical field.

Laminar flow systems, either vertical or horizontal, are often requested by surgeons who perform procedures, such as total joint replacements, that are subject to increased risk of serious wound infections. Because these systems are very expensive, consume a great deal of energy resources, and must be meticulously maintained, their acquisition and installation must be subjected to careful scrutiny.

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Plant production process, floor plan, and layout of PFAL

Toyoki Kozai , in Plant Factory (Second Edition), 2020

19.5.1 Biological cleanness

The cultivation and operation rooms must be clean biologically as well as physically and chemically. In many industries, the cleanness of room air is expressed as the number of particles (physical objects) with size of 0.1 (or 0.5) μm or larger per unit volume of air. Chemical cleanness of food is often expressed as the concentrations of heavy metals, agrochemicals, and other toxic chemical substances.

In a PFAL, biological cleanness of the room air, harvested produce, or nutrient solution is expressed as CFU (see Chapter 24), which is a measure of the population density of live microorganisms. It is generally considered that fresh vegetables can be eaten without washing if the CFU of the harvest is less than 300 per gram, while the CFU of field-grown lettuce heads ranges from 10,000 to 100,000 if not washed.

Microorganisms can be classified into four groups: (A) potentially harmful to humans but not to plants, (B) potentially harmful to plants but not to humans, (C) potentially harmful neither to humans nor to plants, and (D) potentially harmful to both humans and plants. Thus, in addition to CFU tests, weekly or monthly tests are necessary for measuring the population densities of harmful microorganisms such as the Coliform group and Staphylococcus aureus which may cause human disease (Chapter 24). These pathogens are often brought in by workers having symptoms of diarrhea, so these workers should not be allowed to enter the operation and cultivation rooms.

In order to avoid the dispersion of pathogens that may cause diseases in plants, knives and scissors used for harvesting must be disinfected every time the workers harvest new culture beds or tiers. The propagation of microorganisms (fungi) such as Pythium spp. and Fusarium oxysporum Schlecht. f.sp. occurs mostly in the nutrient solution in the culture beds and wet surfaces where there is food for microorganisms.

In the nutrient solution in cultivation beds, there are many fine roots and algae (some dead and some alive) favored by microorganisms as food. Some microorganisms grow very rapidly under such favorable conditions, so the cultivation panels and cultivation beds must be cleaned by removing the fine roots, algae, and microorganisms every 2–4   weeks.

Continuous sterilization of recirculating nutrient solution is essential, although many microorganisms stay and propagate in the culture beds and do not move with the recirculating nutrient solution, while some pathogens in the nutrient solution move into the roots, propagate in the plants, and cause disease.

Typically, the population density of microorganisms is several hundred times higher in the nutrient solution than in the room air, so the following actions should be avoided: (1) dripping the nutrient solution onto the aerial part of plants, (2) dipping the aerial part of plants into the nutrient solution, (3) harvesting or touching the plants with gloves after touching the roots with gloves, and (4) leaving the roots on the floor, culture beds, and other places in the culture room.

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Lasers in gynecology

J.L. Bacon , in Lasers for Medical Applications, 2013

17.5 Hysteroscopic laser applications

Hysteroscopy allows performance of a variety of minimally invasive procedures performed in an outpatient setting. Removal of intracavitary polyps or fibroids, treatment of sub-mucosal myomas, uterine septae or ablation are the most common procedures with potential laser applications. Endometrial ablation is customarily considered as a treatment for excess menstrual bleeding instead of performing a hysterectomy.

A variety of current techniques for ablation exist. These include cryotherapy, ultrasonic ablation, and several thermal techniques with or without the use of heated water. The laser – principally the Nd:YAG – has been utilized for endometrial ablation. This laser is coupled with a red helium neon laser beam via a 'direct' touch technique with a raw (uncovered) fiber. As mentioned previously, the YAG laser penetrates tissue to a depth of about 4   mm with a raw fiber – excellent for endometrial ablation. A variety of shapes to the fiber tip, including a ball shape, have been developed, and this rounded device is best for ablation. The YAG laser is then placed through a fiber-optic quartz cable within the operating channel of the hysteroscope. All distending media may be used, including glycine and Hyskon.

Ablation should be performed in the early proliferative phase when the endometrium is thin and pregnancy excluded. The depth of tissue penetration also provides hemostasis via coagulation. Endometrial pathology should be excluded pre-operatively, and a hysteroscopic survey of the endometrial cavity performed before employing the laser ablation (Goldrath et al., 1981). Anesthesia is required due to the ablation generating painful uterine contractions.

Strict fluid intake and output are required to prevent electrolyte imbalances. A fluid pump may improve visualization of the endometrial cavity and prevent high pressures of fluid infusion by manual measures. As the surface of the endometrium is treated, the raw tissue enhances fluid absorption. Some hospital protocols call for electrolyte analysis preoperatively and immediately postoperatively, with a mandatory termination of the procedure if a fluid imbalance of 750–1000   ml is noted. Intraoperative electrolyte evaluation may also be performed in cases of large fluid imbalance.

The ablation must be performed systematically, beginning at the top of the fundus and moving from one cornua to the other. The power setting is generally 50–60 watts. Contact versus non-contact with the endometrium may be used in different areas of the endometrial cavity. The cavity may be divided into areas with the laser to ensure complete therapy and prevent disorientation. Ablation is performed in a 'Z' pattern, constantly moving the fiber and always drawing it towards the cervix (never pushing!), to minimize the risk of perforation of the cavity. The outcome of laser ablation is similar to that of other ablative techniques; however, newer techniques require less operating time, and thus have been more utilized.

Adequate education of physicians and operating room staff is imperative for safety and efficiency and proper maintenance of equipment. Many hospitals have a laser safety officer whose job is to assist with laser use and maintenance of equipment as well as assisting the operating room staff in protective measures for themselves and the patient. Standard safety measures for laser therapy in gynecology are as follows:

•

adequate preoperative evaluation (colposcopy, biopsy)

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appropriate anesthetic choice (local, regional, general)

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pre- and intraoperative acetic acid application

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power settings appropriate for patient age and tissue to be treated:

—

adult women 2–3   mm spot size (15–50 watts power setting)

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child 1–3   mm spot size (2–5 watts power setting)

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super pulse or continuous wave setting

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eye protection for patient and staff

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meticulous laser application to appropriate surgical plane

•

removal of char (LGT lesions)

•

complete obliteration of lesions

•

intraoperative and postoperative pain medication (systemic, topical).

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An overview of the dynamics of telemedicine and robotics for the benefit of mankind

Swati Sikdar , ... Karabi Ganguly , in Electronic Devices, Circuits, and Systems for Biomedical Applications, 2021

2.2.1 Robots in surgery

A new kind of operating room including robots for local or telesurgery, systems for computer-aided mechanisms, integrated imaging systems, audio-visual telecommunication systems for telemedicine and teleconsultation, and virtual reality simulators with response reaction for haptic dedicated for surgical training are used for robotic surgery. The surgeon, patient, and medium (means for viewing, interaction, and communication with patient) are the cardinal entities for this type of application. Robotic surgery may also comprise an endoscopic camera system, laparoscopic instrument, standard surgical tools, etc. A generalized architecture of surgery with robots encompasses a teleoperation set up with typical master-slave configuration where a surgeon console is the master and the robot is the slave. The master setup has a set of handles, a viewing system, and in some cases, voice control mechanisms, whereas the slave setup includes a minimum of three robotic arms: two for manipulating surgical tools and a third for controlling the endoscopic camera. Robotic arms are manipulated by the surgeon via two handles in the console.

Voice command of the surgeon is needed for controlling the camera. The view is transmitted in the master console. Sometimes force feedback using bilateral (position and force) teleoperation mode can be incorporated, so the surgeons can feel the forces that are generated during interaction of surgical tools with tissues. There are three classes of surgical robot: (a) semiautonomous system or class I, (b) guided system or class II, and (c) teleoperation system or class III. For reducing patient trauma, single-port access, laparo-endoscopic single-site surgery, and natural orifice transluminal endoscopic surgery [25,26] are being explored by surgeons.

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Recycling of textiles used in the operating theatre

M.J. Abreu , ... D. Adolphe , in Recycling in Textiles, 2006

12.4 Products

Although textile materials have been used in medical and surgical applications for many years, until very recently usage has been largely confined to bandages and dressings (mostly of cotton and rayon), hospital textiles including gowns, drapes and bedclothes (largely of woven cotton) and a great quantity of diapers. In recent years, however, there has been an increase in both the size of the market and the variety of products available.

The healthcare and hygiene industry is an important sector in the field of medicine and surgery. Table 12.1 shows the most important fibres and manufacture systems used for these products. 5

Table 12.1. Healthcare and hygiene products

Product application Fibre type Manufacture system
Surgical clothing
Gowns Cotton, polyester, polypropylene, polyethylene Nonwoven, woven
Caps Viscose Nonwoven
Masks Viscose, polyester, glass Nonwoven
Surgical covers
Drapes Polyester, polyethylene Nonwoven, woven
Cloths Polyester, polyethylene Nonwoven, woven
Bedding
Blankets Cotton, polyester Woven, knitted
Sheets Cotton Woven
Pillowcases Cotton Woven
Clothing
Uniforms Cotton, polyester Woven
Protective clothing Polyester, polypropylene Nonwoven
Incontinence
Coverstock sheet Polyester, polypropylene Nonwoven
Absorbent layer Wood fluff, super absorbents Nonwoven
Outer layer Polyethylene Nonwoven

Source: Rigby

The use of protective barrier products is not limited to the operating theatre and is found throughout the healthcare institutions. The range of fibre types is large and goes from natural fibres, (eg. cotton) to regenerated fibres (e.g. viscose) to synthetic fibres (e.g. polyester, polypropylene and polyethylene). The manufactured products are mostly woven, nonwoven or knitted.

The range of products is vast, but this chapter is only about products used in the operating theatre. The products are either used once or laundered and used several times. In the USA, single-use dominates the market, with 90% of drapes and gowns being single-use. In Europe, the situation is very different with single-use accounting less than 50%. These numbers differs throughout Europe. In South Europe and the UK, the penetration of single-use is much lower than in the Scandinavian countries, in which the single-use penetration is over 80%.

The last decade has witnessed a rapid increase in the penetration of single-use drapes and gowns all over the world. The single-use drapes and gowns with superior barrier properties minimise infection transmission, but performance reusable drapes and gowns with good barrier protection as well as surgeon and patient comfort are becoming an emerging force.

12.4.1 Surgical gowns

Surgical gowns are used in the operating theatre to prevent transfer of infective agents. The infective agent can arise from a variety of sources, including airborne bacteria, contact with staff and from the patient's skin bacteria.

12.4.2 Surgical drapes

Surgical drapes are used in the operating theatre to cover the patient and equipment, to protect them from pollutant particles in the air, which carry infective agents. They can include drapes designed for particular surgical procedures and also equipment covers.

12.4.3 Clean-air suits

Clean-air suits are intended to minimise contamination of the operating wound by the wearer's skin scales carrying infective agents via the operating room air, thereby reducing the risk for wound infection. 3

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Healthcare technology basics

Samantha Jacques PhD, FACHE , Barbara Christe PhD , in Introduction to Clinical Engineering, 2020

Procedural areas (cardiac catheterization, endoscopy)

Procedural areas are similar to operating rooms, but they are generally more focused on the test/procedure being undertaken. In addition to the general equipment found in an operating room (table, lights/booms, anesthesia machine, crash cart), equipment associated with the specific procedure is included in these areas. In a cardiac catheterization laboratory, minimally invasive tests and procedures are performed to diagnose and treat cardiovascular disease. Specialized equipment required includes single- or multi-plane imaging equipment, patient cooling devices, intravascular ultrasound scanners, and injectors. Endoscopy suites provide non-surgical procedures to view the digestive tract. Specialty equipment includes endoscopes, scope washers, ultrasound scanners, and video systems. Other procedural areas may also include diagnostic/interventional radiology suites and radiation oncology procedure areas, featuring specialized imaging technology.

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Textiles for healthcare and medical applications

S. Rajendran , ... A.J. Rigby , in Handbook of Technical Textiles (Second Edition), 2016

5.5.2 Infection control materials

Infection control is challenging and represents a considerable healthcare burden. With the arrival of high risk multiresistant pathogenic bacteria, healthcare-associated infections are a serious problem, especially in the hospital environment. An expert committee appointed by the UK government predicted recently that drug-resistant infection will kill an extra 10 million people a year worldwide by 2050, which is more than currently die from cancer, unless urgent action is taken to address the problem. There are currently 700,000 deaths each year worldwide due to multiresistant superbugs. Antimicrobial resistance causes at least 50,000 deaths each year in the EU and the US, and the predicted more than 10-fold rise in the death toll by 2050 would severely hit the economy, with a predicted cost of around US$100 trillion. 84

Hospital acquired infection (HAI) costs the UK NHS £1 billion and contributes to the death of an estimated 5000 patients each year. The Department of Health estimates that this infection can cost an extra £4000–£10   000 per patient. Evidence-based guidelines for preventing HAIs in England have been published recently. 85 Controlling wound infection in hospitals is a day-to-day problem for healthcare personnel despite several precautionary measures. Both acute and chronic wounds are vulnerable to bacterial infection. Cross-infection by bacteria through wound dressings and hospital textiles is increasingly common in hospitals and has been a major problem for several years. In the UK, only a small number of patients were infected by MRSA (methicillin-resistant Staphylococcus aureus) in 1992 but this figure rose to 4904 in 2001. According to the Office for National Statistics, the number of deaths in England and Wales involving S. aureus increased from 1212 in 2001 to 2083 in 2005. The death rate due to Clostridium difficile increased by 69%. Elderly people are vulnerable to risk, as evidenced by the fact that the death rate in 2007 involving the 85 years and over age group was 767. It must be pointed out that certain bacteria, for example the MRSA superbug, show resistance even to antibiotics. The bug is contagious and transmitted through skin contact as well as hospital textiles in the hospital environment. It should be noted that the currently available wound dressings are effective against only a few types of bacteria and that no dressing provides a complete shield against a wide spectrum of pathogenic bacteria that includes MRSA and MSSA (methicillin-susceptible Staphylococcus aureus). In a broad sense, an ideal wound dressing should fulfil many major requirements which include high barrier properties against a broad spectrum of pathogenic microorganisms. Highly exudating wounds, macerated, and slough wounds are often at risk of infection. The presence of microorganisms in a wound severely delays wound healing. About 8% of hospital inpatients in England develop infection and in intensive care units the figure increases to 23%. In order to address the problem with particular reference to MRSA and C. difficile, a new £4.2 million consortium has been jointly created by the Biotechnology and Biological Sciences Research Council (BBSRC), the Medical Research Council (MRC), the National Institute for Health Research (NIHR), and the Wellcome Trust in the UK. The projects will range from organising a rapid response, springing into action if a particularly virulent strain of MRSA emerges, and analysing its particular signature so that it can be quickly detected and controlled. Furthermore, the project looks at finding the best ways to change the habits of hospital staff, patients, and visitors to prevent infections from occurring and spreading. The consortium will look at issues such as quick detection and controlling the spread of virulent strains of MRSA, the mode of spreading to hospital equipment such as latex gloves, and identifying the best strategies for preventing such problems.

It should be stated that the currently available wound dressings are effective against only a few types of bacteria and no such dressings provide a complete shield against a wide spectrum of pathogenic bacteria that include MRSA, VRE (vancomycin-resistant enterococci), and other superbugs. Silver dressing is normally used for controlling infection, but it is not effective against a wide range of bacteria that include superbugs. Besides, some patients are sensitive to silver ion products and prolonged use can lead to the absorption of silver ion and this can have a major effect on their kidneys in eliminating silver from the body. 86 Silver products have been linked with low white blood cell counts and the use of silver dressing should be discontinued if this occurs. 86

With an aim to develop such textile materials, considerable research has been carried out by making use of organic and inorganic compounds, antibiotics, heterocyclics, quaternary ammonium compounds, and so on. Some recent developments in antibacterial products include a process involving the preparation of combined antibacterial and flame retardant cotton fabrics. 87 The treated fabrics exhibited higher antibacterial activity against Escherichia coli and S. aureus, which were 97% and 96% respectively. Similarly, Ibanescu et al. discussed the combined photocatalytic and antimicrobial Ag/ZnO treatment on cotton and cotton/polyester blended fabrics. 88 Fabrics made from viscose fibres containing polysilicic acid (Visil®) and aluminium silicate (Visil AP®) have been given urea peroxide treatment to make them antibacterial as well as deodorant. 89 The cellulose has been modified chemically with biocides accompanied by redox reaction to achieve durable and regenerable antibacterial activity on cotton and other cellulosic fabrics. The finish poly(hexamethylene biguanide hydrochloride) (Reputex 20®) imparts an antimicrobial property to cotton and cotton blended materials that is effective against a broad spectrum of bacteria, fungi, and yeasts and is also durable to 50 launderings. The antimicrobial effect of 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (Si-QAC) has been studied on different fibre types, such as cotton, silk, and wool, and it was found that the activity of Si-QAC was most effective for cotton fibres, less effective for wool fibres, and least effective for silk fibres. 90 The chitosan treatment on cotton fabrics imparts antibacterial activity against S. aureus and E. coli. 91 It should be mentioned that the synthetic fabrics, such as polyester, polyamide, and acrylic can also be made antimicrobial by treating them with antimicrobial agents. 92 A recent review highlights the application of principal antibacterial agents such as quaternary ammonium compounds, N-halamines, chitosan, polybiguanides, triclosan, nanoparticles of noble metals and metal oxides, and bioactive plant-based products on fabrics. 93

In the last few decades, the research has been carried out in developing novel technologies to produce enhanced antimicrobial activity on textiles, by using different synthetic antimicrobial agents such as triclosan, metal and their salts, organometallics, phenols, and quaternary ammonium compounds. 94 Although the synthetic antimicrobial agents are very effective against a range of microbes and provide a durable effect on textiles, they are a cause of concern due to the associated side effects and ecological problems such as water pollution. Hence, there is a need and demand for antimicrobial textiles based on eco-friendly agents, which not only help to reduce the ill effects associated due to microbial growth on textile materials but also comply with the statutory requirements imposed by the regulating agencies. There is a vast resource of natural products with active antimicrobial ingredients, amongst which are a major range of plant-based products. 95 The healing power of some plant materials has been well known and utilised since ancient times, worldwide. A systematic study on integrating antimicrobial neem seed and bark extracts to cotton 96 and cotton/polyester blend 97 has been reported. One of the major challenges in the application of natural products for textiles is that most of these plant materials are complex mixtures of several compounds and also the composition varies between different species of the same plant. Durability, shelf life, and antimicrobial efficiency of natural products are other areas of concern. In order to address these issues, further research should be carried out in the area of bioactive textiles made from natural products, with a view to making them viable alternatives to synthetic product-based antimicrobial textiles.

Bioactive fibres and polymers are high molecular weight natural and synthetic macromolecules and their complexes. Biomaterials research is focused on wound healing and antimicrobial materials, where the design and mechanism of the biologically active molecule plays a key role in the textile fibre function. By achieving more insight into the actual activity of the molecule on the textile surface, it is possible to develop novel wound healing and antimicrobial materials. The mechanism of fibre activity is directly related to the complex biological environment surrounding the fibre. Hence, this interdisciplinary subject area has brought together physical science disciplines from textile synthetic, analytical and polymer chemistry, and life science disciplines of medicine, biochemistry, biophysics, and microbiology.

Scientists have been working on the issues that underpin making more efficient wound dressings and antiseptic textiles for more than a century. The molecular bases of disease processes are better understood now, and our basic understanding of the structure and function of biologically active molecules does enable the creation of bioactive fibres that can selectively interact with their biological environment. Some scientists have coined the term 'smart fabrics' to describe the targeted functions that these types of textiles have and their ability to perform a specific function in wound healing, arterial implants, or antimicrobial activity.

Many types of wound dressings have been developed, both non-medicated and medicated. Commercially available synthetic wound dressings consisting of a polyurethane membrane are capable of minimising evaporative water loss from the wound and preventing bacterial invasion and thus are useful in the management of superficial second-degree burns. The ideal structure of an illuminate dressing consists of an outer membrane and an inner three-dimensional matrix of fabric or sponge. The outer membrane prevents body fluid loss, controls water evaporation, and protects the wound from bacterial invasion. On the other hand, the inner matrix encourages wound adherence by tissue growth into the matrix. Silver/nanosilver is mostly incorporated in the wound dressing which provides an antimicrobial shield against a wide range of bacteria. The antibacterial effect of silver was already known in ancient times. Silver tools and containers were used around 4000 bc for storing and transporting water, to prevent the formation of germs and ensure high water quality. A number of wound dressings containing silver have recently been developed. Thomas and McCubbin 98 critically discussed the role of silver in wound dressing. These dressings function by the sustained release of low concentrations of silver ions over time and generally appear to stimulate healing as well as inhibiting microorganisms. The evaluation of silver-impregnated dressings, as with other topical therapies, includes in vitro antibacterial studies, animal models, and clinical testing.

It has been argued that the antimicrobial efficacy alone is of insufficient benefit in modern wound dressings and that additional properties promoting wound healing are required. Based on this, the ability to remove any undesirable bacterial products in the wound environment that impinge on healing would be a bonus, for example binding bacterial endotoxin (toxins released on cell death) to a silver dressing would be of benefit. Materials incorporated into modern silver-based dressings such as hydrocolloids, charcoal, and polymers are included as an aid to wound management but also modulate the release of silver ion. Silver exhibits a selective toxicity in bacterial cells and yeasts through its action on cell membranes, respiratory enzymes, and DNA. Silver-impregnated polyamide cloths are effective antibiotics and are designed to deliver silver ions to wound sites without potential side effects; the silver is rendered harmless as it is lost naturally as the wound heals. The systemic toxicity of silver is not well documented, but silver sulphadiazine used in the treatment of burn wounds is implicated as a cause of leucopenia and renal damage. In addition to silver, natural products such as honey, aloe vera, and neem are potential antibacterial agents for modern wound dressing. A systematic review of the use of honey in wound dressings has been published elsewhere. 99

5.5.2.1 Hospital protective garments

Textile materials used in the operating theatre include surgeons' gowns, caps and masks, patient drapes, and cover cloths of various sizes (Fig. 5.7). It is essential that the environment of the operating theatre is clean and a strict control of infection is maintained. A possible source of infection to the patient is the pollutant particles shed by the nursing staff, which carry bacteria. Surgical gowns should act as a barrier to prevent the release of pollutant particles into the air. Traditionally, surgical gowns are woven cotton goods that not only allow the release of particles from the surgeon but are also a source of contamination, generating high levels of dust (lint). Disposable nonwoven surgical gowns have been adopted to prevent these sources of contamination to the patient and are often composite materials comprising nonwoven and polyethylene films. 19

Fig. 5.7. Surgical garments.

Protective garments protect both patients and medical professionals from cross- infection in hospitals. Typically, these garments are used as gowns, laboratory coats, coveralls, headwear, footwear, and facial protection. The gowns are designed either single layer or reinforced double and multilayer, depending on the level of protection required in hospital environments such as operating rooms, postoperative blocks, and bedding areas. A single layer gown could be a highly repellent fabric intended for use where minimal fluid is present. Reinforced and multilayer gowns are intended for use in the areas where a high level of protection is required. A highly protective three layer gown consists of a tough outer layer that resists abrasion and puncture, a middle layer provides resistance to fluid penetration, and the inner layer is a soft layer which adds comfort in addition to protection. The pore size of the gowns is designed to prevent the penetration of microorganisms but allows gaseous exchange. Impervious gowns prevent strike-through during fluid intensive procedures. Protective gowns are generally heavy compared to conventional cotton or blended fabrics, mainly because the gowns contain appropriate finishes/laminates. Drapes are designed to prevent hospital-acquired infections and are for single or multiple uses. Single use and reusable gowns and drapes are usually made from cotton, polyester, polypropylene, and their blends and are widely available in Europe. A good source of references for further reading can be found elsewhere. 100–102

The need for a reusable surgical gown that meets the necessary criteria, such as barrier against pathogenic bacteria, blood, and liquid repellency, has resulted in the application of fabric technology adopted for clean room environments, particularly those used for semiconductor manufacture. Single use materials are highly preferred rather than reusable products mainly because they reduce the risk of cross-infection to a greater extent. Nonwoven medical products are being increasingly used in hospitals, although disposability of single use products poses environmental concerns. Both spunlaced and spunlaid composites are used to produce surgical gowns and drapes. Spunlaced material provides enhanced comfort and aesthetic properties but spunlaid materials offer superior barrier properties. Spunlaid-meltblown spunlaid (SMS) products possess the highest level of protection, and their softness and comfort have been improved considerably. A typical isolation and cover gown consists of a single layer spunlaid basic cover or a three layer SMS fabric for increased barrier properties, softness, and comfort. SMS fabrics are also used to produce laboratory coats, jackets, and coveralls. Nonwoven surgical gowns that contain polyethylene films are composed in the mass range of 30–45   g/m2. 103 Nonwoven gowns and drapes are produced at the different levels (level 1 to level 4) of barrier protection that are warranted in different wards in hospitals. For instance, level 1 represents a light-weight material and is used in an environment where there is little or no contact with blood or body fluid, whereas level 4 is a strong barrier material for use in areas prone to high contact with blood and body fluid. Surgical masks consist of a very fine middle layer of extra-fine glass fibres or synthetic microfibres covered on both sides by either an acrylic bonded dry-laid or wet-laid nonwoven. The application requirements of such masks demand that they have a high filter capacity, a high level of air permeability, and are lightweight and non-allergenic. Disposable surgical caps are usually dry-laid or spunlaid nonwoven materials based on cellulosic fibres. Operating room disposable products and clothing are increasingly being made from hydroentangled nonwovens. Surgical drapes and cover cloths are used in the operating theatre either to cover the patient (drapes) or to cover the working areas around the patient (cover cloths). The construction of level 1 to level 4 nonwoven surgical gowns is discussed elsewhere. 103 High levels of antibacterial and blood and fluid repellency can be imparted to protect textiles by treating/coating them with antibiotics and fluorochemical derivatives respectively.

Nonwoven materials are used extensively for drapes and cover cloths and are composed of films backed on either one side or both sides with nonwoven fabrics. The film is completely impermeable to bacteria while the nonwoven backing is highly absorbent to both body perspiration and secretions from the wound. Hydrophobic finishes may also be applied to the material in order to achieve the required bacteria barrier characteristics. The developments in surgical drapes have led to the use of loop-raised, warp-knitted polyester fabrics that are laminated back to back and contain microporous PTFE films in the middle for permeability, comfort, and resistance to microbiological contaminants.

The second category of textile materials used for healthcare and hygiene products is those commonly used on hospital wards for the care and hygiene of the patient; this group includes bedding, clothing, mattress covers, incontinence products, cloths, and wipes. Traditional woollen blankets have been replaced with cotton leno woven blankets, which reduce the risk of cross-infection and are made from soft-spun twofold yarns which possess the desirable thermal qualities, are durable, and can be easily washed and sterilised. The clothing products, which include articles worn by both nursing staff and patients, have no specific requirements other than comfort and durability and are therefore made from conventional fabrics. In isolation wards and intensive care units, disposable protective clothing is worn to minimise cross-infection. These articles are made from composite fabrics that consist of tissue reinforced with a polyester or polypropylene spunlaid web. 19

Incontinence products for the patient are available in both diaper and flat sheet forms, with the latter being used as bedding. The disposable diaper is a composite article consisting of an inner covering layer (coverstock), an absorbent layer, and an outer layer. The inner covering layer is either a longitudinally orientated polyester web treated with a hydrophilic finish or a spunlaid polypropylene nonwoven material. A number of weft- and warp-knitted pile or fleece fabrics made of polyester are also used as part of a composite material which includes foam as well as PVC sheets for use as incontinence mats. Cloths and wipes are made from tissue paper or nonwoven bonded fabrics, which may be soaked with an antiseptic finish. The cloth or wipe may be used to clean wounds or the skin prior to wound dressing application or to treat rashes or burns. 63

Surgical hosiery with graduated compression characteristics is used for a number of purposes, ranging from a light support for the limb to the treatment of venous disorders. Knee and elbow caps, which are normally shaped during knitting on circular machines and may also contain elastomeric threads, are worn for support and compression during physically active sports or for protection.

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