Difference between revisions of "TB Services"
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<div style="color:#00000a;">The National Infection Prevention and Control Policy and Strategy makes specific reference to certain Acts and their relevant regulations, which bear relevance to the development and implementation of these health facility guidelines. These are: | <div style="color:#00000a;">The National Infection Prevention and Control Policy and Strategy makes specific reference to certain Acts and their relevant regulations, which bear relevance to the development and implementation of these health facility guidelines. These are: | ||
− | * <span style="color:#00000a;">Constitution</span><span style="color:#00000a;">'' of the Republic of South Africa, 1996''</span>. <span style="color:#00000a;">s.2,24,27,36&39.</span> | + | *<span style="color:#00000a;">Constitution</span><span style="color:#00000a;">'' of the Republic of South Africa, 1996''</span>. <span style="color:#00000a;">s.2,24,27,36&39.</span> |
− | * <span style="color:#00000a;">''The National Health Act 2003''</span>. <span style="color:#00000a;">(c.61). Cape Town South Africa: Government Gazette.</span> | + | *<span style="color:#00000a;">''The National Health Act 2003''</span>. <span style="color:#00000a;">(c.61). Cape Town South Africa: Government Gazette.</span> |
− | * <span style="color:#00000a;">''The Occupational Health and Safety Act 1993''</span>. <span style="color:#00000a;">s.8(1).</span> <span style="color:#00000a;">Cape Town South Africa: Government Gazette.</span> | + | *<span style="color:#00000a;">''The Occupational Health and Safety Act 1993''</span>. <span style="color:#00000a;">s.8(1).</span> <span style="color:#00000a;">Cape Town South Africa: Government Gazette.</span> |
Department of Labour, 2001. <span style="color:#00000a;">''Regulations for hazardous biological agents''</span>. (Government notice No. R. 1390 of the Occupational Health and Safety Act, 1993. s.43). Pretoria South Africa: Government Gazette | Department of Labour, 2001. <span style="color:#00000a;">''Regulations for hazardous biological agents''</span>. (Government notice No. R. 1390 of the Occupational Health and Safety Act, 1993. s.43). Pretoria South Africa: Government Gazette | ||
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Department of Health, 2003. <span style="color:#00000a;">''Regulations relating to the application of the hazard analysis and critical control point system (HACCP system). ''</span><span style="color:#00000a;">(Government notice No. R. 908 of the Foodstuffs, Cosmetics and Disinfectant Act, 1972. (c.54)). Cape Town South Africa: Government Gazette.</span> | Department of Health, 2003. <span style="color:#00000a;">''Regulations relating to the application of the hazard analysis and critical control point system (HACCP system). ''</span><span style="color:#00000a;">(Government notice No. R. 908 of the Foodstuffs, Cosmetics and Disinfectant Act, 1972. (c.54)). Cape Town South Africa: Government Gazette.</span> | ||
− | * <span style="color:#00000a;">''The Environmental Conservation Act 1989''</span>. <span style="color:#00000a;">(c.73). Cape Town South Africa: Government Gazette.</span> | + | *<span style="color:#00000a;">''The Environmental Conservation Act 1989''</span>. <span style="color:#00000a;">(c.73). Cape Town South Africa: Government Gazette.</span> |
− | * <span style="color:#00000a;">''The Foodstuffs, Cosmetic and Disinfectants Act 1972.''</span> <span style="color:#00000a;">(c.45). Cape Town South Africa: Government Gazette.</span> | + | *<span style="color:#00000a;">''The Foodstuffs, Cosmetic and Disinfectants Act 1972.''</span> <span style="color:#00000a;">(c.45). Cape Town South Africa: Government Gazette.</span> |
</div> | </div> | ||
===Building legislation=== | ===Building legislation=== | ||
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<div style="color:#00000a;">The following legislation and regulations impact and provide guidance on the provision and design of healthcare facilities as above: | <div style="color:#00000a;">The following legislation and regulations impact and provide guidance on the provision and design of healthcare facilities as above: | ||
− | * <span style="color:#00000a;">''The Pharmacy Act 53 of 1974.''</span> <span style="color:#00000a;">(c.53). Cape Town South Africa: Government Gazette.</span> | + | *<span style="color:#00000a;">''The Pharmacy Act 53 of 1974.''</span> <span style="color:#00000a;">(c.53). Cape Town South Africa: Government Gazette.</span> |
− | * <span style="color:#00000a;">''The National Environmental Management Act 1998.''</span> <span style="color:#00000a;">(c.107).</span> <span style="color:#00000a;">Cape Town South Africa: Government Gazette.</span> | + | *<span style="color:#00000a;">''The National Environmental Management Act 1998.''</span> <span style="color:#00000a;">(c.107).</span> <span style="color:#00000a;">Cape Town South Africa: Government Gazette.</span> |
− | * <span style="color:#00000a;">''Building Regulations and Building Standards Act 1977.''</span> <span style="color:#00000a;">(c.103). Cape Town South Africa: Government Gazette.</span> | + | *<span style="color:#00000a;">''Building Regulations and Building Standards Act 1977.''</span> <span style="color:#00000a;">(c.103). Cape Town South Africa: Government Gazette.</span> |
− | * <span style="color:#00000a;">South African Bureau of Standards (SABS), 1990.</span> <span style="color:#00000a;">''SANS 10400:1990 Code of practice for the application of the national building regulations.''</span><span style="color:#00000a;">Pretoria South Africa: SABS Standards Division.</span> | + | *<span style="color:#00000a;">South African Bureau of Standards (SABS), 1990.</span> <span style="color:#00000a;">''SANS 10400:1990 Code of practice for the application of the national building regulations.''</span><span style="color:#00000a;">Pretoria South Africa: SABS Standards Division.</span> |
− | * <span style="color:#00000a;">''Promotion of Equality and Prevention of Unfair Discrimination Act 2000.''</span> <span style="color:#00000a;">(c.4). Cape Town South Africa: Government Gazette.</span> | + | *<span style="color:#00000a;">''Promotion of Equality and Prevention of Unfair Discrimination Act 2000.''</span> <span style="color:#00000a;">(c.4). Cape Town South Africa: Government Gazette.</span> |
</div> | </div> | ||
===Infection prevention and control and TB management policy and guidelines=== | ===Infection prevention and control and TB management policy and guidelines=== | ||
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National Department of Health, 2007. <span style="color:#00000a;">''Management of drug-resistant tuberculosis: Policy guidelines''</span>. [pdf] South Africa: NDoH. Available at: http://www.search.gov.za [Accessed 26 March 2014].<div style="color:#00000a;">National Department of Health, n.d. <span style="color:#00000a;">''Tuberculosis strategic plan for South Africa, 2007-2011.''</span> [pdf] South Africa: NDoH. Available at: http://www.search.gov.za/info/search.jsp. [Accessed 26 March 2014]. | National Department of Health, 2007. <span style="color:#00000a;">''Management of drug-resistant tuberculosis: Policy guidelines''</span>. [pdf] South Africa: NDoH. Available at: http://www.search.gov.za [Accessed 26 March 2014].<div style="color:#00000a;">National Department of Health, n.d. <span style="color:#00000a;">''Tuberculosis strategic plan for South Africa, 2007-2011.''</span> [pdf] South Africa: NDoH. Available at: http://www.search.gov.za/info/search.jsp. [Accessed 26 March 2014]. | ||
− | === South African building practice policy and guidelines === | + | ===South African building practice policy and guidelines=== |
− | * The South African Pharmacy Council, 2004. ''Good pharmacy practice. ''(Board notice 129). Cape Town South Africa: Government Gazette. | + | *The South African Pharmacy Council, 2004. ''Good pharmacy practice. ''(Board notice 129). Cape Town South Africa: Government Gazette. |
</div> | </div> | ||
===International design guidance=== | ===International design guidance=== | ||
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Most TB patients will access services at the primary healthcare level and will require access on site to '''integrated''' services including, but not limited to: | Most TB patients will access services at the primary healthcare level and will require access on site to '''integrated''' services including, but not limited to: | ||
− | * clinical assessment (consulting room with examination facilities, clinical scale); | + | *clinical assessment (consulting room with examination facilities, clinical scale); |
− | * safe facilities for sample (sputum) collection; | + | *safe facilities for sample (sputum) collection; |
− | * nutrition; | + | *nutrition; |
− | * psychosocial services (counselling); and | + | *psychosocial services (counselling); and |
− | * pharmacy dispensary for chronic medication. | + | *pharmacy dispensary for chronic medication. |
</div> | </div> | ||
In addition, on- or off-site access to the following services is required | In addition, on- or off-site access to the following services is required | ||
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Since 2010 the SA National Department of Health has adopted a policy of decentralised management of Multi Drug-resistant TB<ref name="ftn2">2 Prior to 2010, the National policy was for centralised management of drug-resistant TB. All confirmed DR patients were to be referred to a DR TB facility for a period of about six months being subject to two consecutive negative TB cultures taken 30 days apart as identified by the supporting diagnostic laboratory service (NDoH, 2010a, p.8). But whilst this minimum period of six months was sometimes met in practice, and despite high demand for beds, national average length of stay is reportedly closer to 183 days for MDR TB and in excess of 199 days (occasionally over two years) for XDR TB. Following the two consecutive negative TB cultures, the policy stipulated that the patient was to be discharged for ambulatory care at the nearest health facility with ongoing treatment and psychosocial support. Given the total stock of 1 854 for dedicated specialised TB beds (NDoH, 2010a, p.8); the national DR TB bed capacity is ill-matched to fulfil a hospitalisation policy. As only under one third of patients could be accommodated, either other patients are displaced, are treated in their communities, or alternatively remain untreated. The available DR TB dedicated beds have in most instances been established either within existing hospital wards or from reinstated old TB-sanatoria</ref>. In addition to outpatient services, there is a requirement for inpatient hospital facilities: | Since 2010 the SA National Department of Health has adopted a policy of decentralised management of Multi Drug-resistant TB<ref name="ftn2">2 Prior to 2010, the National policy was for centralised management of drug-resistant TB. All confirmed DR patients were to be referred to a DR TB facility for a period of about six months being subject to two consecutive negative TB cultures taken 30 days apart as identified by the supporting diagnostic laboratory service (NDoH, 2010a, p.8). But whilst this minimum period of six months was sometimes met in practice, and despite high demand for beds, national average length of stay is reportedly closer to 183 days for MDR TB and in excess of 199 days (occasionally over two years) for XDR TB. Following the two consecutive negative TB cultures, the policy stipulated that the patient was to be discharged for ambulatory care at the nearest health facility with ongoing treatment and psychosocial support. Given the total stock of 1 854 for dedicated specialised TB beds (NDoH, 2010a, p.8); the national DR TB bed capacity is ill-matched to fulfil a hospitalisation policy. As only under one third of patients could be accommodated, either other patients are displaced, are treated in their communities, or alternatively remain untreated. The available DR TB dedicated beds have in most instances been established either within existing hospital wards or from reinstated old TB-sanatoria</ref>. In addition to outpatient services, there is a requirement for inpatient hospital facilities: | ||
− | * for all types of TB patients (pulmonary, extra-pulmonary, etc.) requiring acute treatment for TB or other comorbidities | + | *for all types of TB patients (pulmonary, extra-pulmonary, etc.) requiring acute treatment for TB or other comorbidities |
− | ** within patient populations of general hospitals, | + | **within patient populations of general hospitals, |
− | ** In dedicated wards at general hospitals for acute episodes, and | + | **In dedicated wards at general hospitals for acute episodes, and |
− | ** at specialised hospitals (long-term accommodation) for sub-acute and palliative care for patients who are not best served by community-based care, for various reasons. | + | **at specialised hospitals (long-term accommodation) for sub-acute and palliative care for patients who are not best served by community-based care, for various reasons. |
</div> | </div> | ||
Inpatient beds for TB services have frequently been provided by converting old wards and sanatoria as a quick solution to address at least part of the pressing need. In many instances building infrastructure has been modified or retrofitted with the intention of making it suitable. However, because beds are provided in this reactive way, the infrastructure is frequently poorly aligned with current best infection-prevention and ‑control practice and patient-centred care.<div style="color:#00000a;">South African healthcare workers are increasingly becoming aware of the need to implement and manage infection-control measures for preventing the spread of infectious diseases in healthcare settings; however, due to lack of resources, inadequate facility design and the lack of environmental controls, the means for achieving adequate infection-prevention and -control are not always found. | Inpatient beds for TB services have frequently been provided by converting old wards and sanatoria as a quick solution to address at least part of the pressing need. In many instances building infrastructure has been modified or retrofitted with the intention of making it suitable. However, because beds are provided in this reactive way, the infrastructure is frequently poorly aligned with current best infection-prevention and ‑control practice and patient-centred care.<div style="color:#00000a;">South African healthcare workers are increasingly becoming aware of the need to implement and manage infection-control measures for preventing the spread of infectious diseases in healthcare settings; however, due to lack of resources, inadequate facility design and the lack of environmental controls, the means for achieving adequate infection-prevention and -control are not always found. | ||
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These policy requirements will go some way to addressing the twin objectives of patient-centred care and effective infection prevention and control in the emerging pandemic. However, there are additional planning, design, management and maintenance considerations to reach best practice standards and these are discussed in detail below. | These policy requirements will go some way to addressing the twin objectives of patient-centred care and effective infection prevention and control in the emerging pandemic. However, there are additional planning, design, management and maintenance considerations to reach best practice standards and these are discussed in detail below. | ||
− | = Understanding transmission to manage risk = | + | =Understanding transmission to manage risk= |
==Transmission of M. Tuberculosis== | ==Transmission of M. Tuberculosis== | ||
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</div> | </div> | ||
− | === Disease status === | + | ===Disease status=== |
<div style="color:#00000a;">TB patient status could at any point: | <div style="color:#00000a;">TB patient status could at any point: | ||
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<div style="color:#00000a;">Children can contract any of the strains that adults can and manifest TB in all forms that adults present. There is consensus that whilst small children may have less lung capacity to develop velocities required for aerosolisation this has not been proven and is not universally true. Older, larger children are more likely to have transmission patterns like adults. </div> | <div style="color:#00000a;">Children can contract any of the strains that adults can and manifest TB in all forms that adults present. There is consensus that whilst small children may have less lung capacity to develop velocities required for aerosolisation this has not been proven and is not universally true. Older, larger children are more likely to have transmission patterns like adults. </div> | ||
− | === Origin of airborne infection === | + | ===Origin of airborne infection=== |
− | <div style="color:#00000a;">Organism-bearing particles are liberated into the air primarily from activities involving the respiratory tract such as sneezing and coughing. In quiet breathing, very few organisms are liberated, but in talking, coughing and especially in sneezing, large numbers of droplets, many of which contain organisms, are ejected. The high velocity of air passing over the respiratory tract shears off a profusion of small droplets which are forcibly ejected into the air. | + | <div style="color:#00000a;">Organism-bearing particles are liberated into the air primarily from activities involving the respiratory tract such as sneezing and coughing. In quiet breathing, very few organisms are liberated, but in talking, coughing and especially in sneezing, large numbers of droplets, many of which contain organisms, are ejected. The high velocity of air passing over the respiratory tract shears off a profusion of small droplets which are forcibly ejected into the air. |
+ | The size of the droplets swept by an air current from the surface of a liquid is determined principally by the velocity of the air and the surface tension of the liquid. As the air velocity increases, the size of the droplets decreases until above 100 m/s where the diameter of the water droplets approaches at least 10 microns (μm). In sneezing and coughing, the peak air flow in the bronchi approaches 300 m/s and the droplets are in the order of six μm in diameter. | ||
− | < | + | After being expelled from the TB patient’s mouth and nose, even the smallest droplets begin to fall. Generally, the large particle droplets<ref name="ftn5"> greater than 5 μm</ref> fall to the ground where they become mixed with dust (see Figure 11). The fate of the smaller droplets is however, quite different. Droplets below a certain aerodynamic diameter fall slowly and lose water rapidly and evaporate almost instantaneously. In this way the droplet diminishes in size until the concentration of dissolved substances is such that the vapour pressure which the droplet exerts equals that of the atmosphere. |
− | + | The residue of the droplet after evaporation, which may contain the micro-organism(s) from the respiratory tract, has been called the droplet nucleus. Droplet nuclei are so light that they may not settle in the gentlest of moving air of occupied spaces and may remain suspended for extended periods of time. This poses risk to building occupants until the particles are removed by ventilation or through other air disinfection. | |
− | + | Tubercle bacilli cannot be cultured from the air because of their low concentration and slow growth rate relative to other micro-organisms. The slow growth of tubercle bacilli and low concentrations in air require long sampling periods during which culture media, even with selective antibiotics to suppress microbial growth, become overgrown with fungi and other bacteria. Molecular amplification methods can detect nucleic acid from tubercle bacilli in the air, but cannot distinguish living from dead organisms<ref name="ftn6"> Although emerging research indicates that this may soon be possible.</ref> nor quantify those with infectious potential. It is therefore not possible to measure infectiousness of TB or DR TB directly, nor can the efficacy of environmental infection control interventions to reduce or prevent transmission be measured directly. | |
− | + | Also, when considering airborne contagion, it is not well understood is how many infectious particles, or droplet nuclei, are required to infect. Compounding this uncertainty there are marked differences in the numbers of organisms liberated by coughing and sneezing of individual infectors. Despite these limiting factors, which are the subject of on-going speculation, investigation and scientific research, the general principles of contagious potential applies. | |
− | + | In any form of contagion the probability of infection increases with the degree of exposure to the infection (see Figure 3: Contagion). The factors implicated in the potential to be contagious are: | |
− | <div style="color:#00000a;"> | + | * the presence of susceptible members of the community |
+ | * the presence of infectious cases | ||
+ | * the effective contact rate (opportunities for transmission) influenced by variables which in the airborne example are factors such as: | ||
+ | ** exposure time | ||
+ | ** breathing rates of infector and susceptible | ||
+ | ** virulence (strength) of bacteria | ||
+ | ** environment (qualities of the room, such as humidity, air volume) | ||
+ | </div> | ||
+ | Figure 3: Contagion<span style="color:#ff0000;"> </span><div style="color:#00000a;">The probability of infection (1- e -Iqpt/Q) as a function of degree of exposure to infection Iqpt/Q (The point where Iqpt/Q =1 is identified by the co-ordinates). | ||
+ | The number of new cases occurring in an epidemic is directly related to the number of susceptible persons, the number of infectors and the effective contact rate. Respiratory droplets (for example flu), with their limited flight, range and dependence on the simultaneous presence of source and subject, behave as a form of effective contact. Droplet nuclei, with their prolonged suspension and rapid dispersion may provide an enhanced exposure and effective contact rate. It was for this reason that Wells called droplet-nucleus-borne infection, airborne contagion. | ||
− | + | DR TB can be acquired in two different ways: primary and secondary modes. Primary transmission is caused by person-to-person transmission of a drug-resistant strain of the TB bacilli. Secondary infection develops during TB treatment, either because the patient was not treated with the appropriate treatment regimen or because the patient did not follow the treatment regimen as prescribed. Approximately 1.8% of new TB and 6.7% of retreatment cases results in MDR. DR TB can be transmitted in the same way as drug-susceptible TB. | |
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+ | Evidence suggests virulence of DR TB is the same as for drug-susceptible strains. However, DR TB is more difficult to treat because it can survive in a patient’s body even after treatment with the first-line drugs is started. A key challenge with current tuberculosis diagnosis technique is the delay in culturing this slow-growing organism in the laboratory. Blood or sputum culture results can take between four and twelve weeks. Because there has historically been a delay in diagnosing drug-resistant TB, these patients may be infectious for a longer period of time. Rapid screening tools for drug-resistance (GeneXpert) have been approved by the WHO, and are now in widespread use in South Africa. | ||
− | + | The infectious droplet-nuclei which may remain suspended in air for prolonged periods of time and the respiratory droplets leads to a high risk of infection in shared spaces. This risk cannot be eliminated. However, expert consensus, based on strong circumstantial evidence, is that with adequate planning, design, management and maintenance, this risk can be reduced or managed. International best practice indicates that patients with drug-resistant TB should be closely monitored when commencing treatment and they should remain in isolation until they are no longer infectious. | |
− | + | </div> | |
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− | + | The following invasive procedures should be regarded as high risk situations for transmission (Culver, Gordon and Mehta, 2003): | |
− | + | * bronchoscopy, | |
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*sputum collection and induction, and | *sputum collection and induction, and | ||
*administration of aerosolized medications | *administration of aerosolized medications | ||
− | === | + | ===Infection prevention and control hierarchy=== |
− | <div style="color:#00000a;">The emergence of DR TB has highlighted the need for strengthened infection prevention and control (IPC) measures to interrupt the transmission of TB in healthcare settings. There is has been no observed difference between the speed of transmission of susceptible TB and resistant MDR or XDR TB. For this reason, infection control measures apply to all TB strains irrespective of the resistant pattern. | + | <div style="color:#00000a;">The emergence of DR TB has highlighted the need for strengthened infection prevention and control (IPC) measures to interrupt the transmission of TB in healthcare settings. There is has been no observed difference between the speed of transmission of susceptible TB and resistant MDR or XDR TB. For this reason, infection control measures apply to all TB strains irrespective of the resistant pattern. |
+ | The requirement for controls to minimise the risk of spreading this airborne disease is legislated in the ''OHS Act'' (Act 85 of 1993). ''The National Department of Health Tuberculosis Strategic Plan for South Africa, 2007-2011'', in the ''Decentralised Management of Multi Drug Resistant TB – a Policy Framework for South Africa'' and various international agencies such as the WHO, Centers for Disease Control and Prevention in the USA provide policy guidance for infection control practices. Common to the last two is the need to base these practices on the hierarchy of control measures. These are arranged from most to least important as follows: | ||
− | + | Administrative measures such as work practices, policies and procedures, education and training, TB screening of healthcare workers, and appropriate utilisation of existing facilities, the implementation of environmental (engineering) controls, and the use of personal respiratory protection in specified areas where there is a high risk of exposure. | |
+ | </div> | ||
− | <div style="color:#00000a;"> | + | === Administrative IPC measures === |
+ | <div style="color:#00000a;">Appropriate architectural design to support the functional and operational processes required for the first level of the hierarchy of control, namely the administrative measures, must be investigated and ensured via the design and layout of the facility as a priority. The first and most important level of control is the use of administrative control measures is to prevent conditions for the spread of contagion, by limiting number and duration of encounters between susceptible members of the community and infectious air. Ideally, if the risk of exposure can be eliminated, no further controls are needed. Unfortunately, the risk usually cannot be eliminated, but it can be significantly reduced with proper administrative control measures. In any healthcare setting, important administrative control measures include: | ||
− | + | * early diagnosis of potentially infectious TB patients, | |
*prompt separation or isolation of infectious TB patients, and | *prompt separation or isolation of infectious TB patients, and | ||
− | *the prompt initiation of appropriate anti-tuberculosis treatment. | + | *the prompt initiation of appropriate anti-tuberculosis treatment.</div> |
− | + | Other important administrative control measures include an assessment of the risk of transmission in the facility, the development of a TB infection control plan that details in writing the measures that should be taken in a given facility, and adequate training of healthcare workers to implement the plan. | |
− | + | Figure 4: CSIR generic model illustrating functional separation | |
+ | <div style="color:#00000a;">From a facility planning and design perspective, administrative control measures can be addressed through the spatial separation techniques of functional separation, respiratory isolation, and separation for patient management. Functional separation (see Figure 4) provides for the physical separation of functionally discrete parts of the facility. Administrative functions and clinical support (admissions and discharge, accounts and finance, information services, medical records) should be substantially or exclusively reserved for staff use, and zoned separately. Nursing services, outpatient facilities, allied health services (radiology, pharmacy, rehabilitation) and visitors’ spaces may be used by both patients, staff and visitors, but should be laid out and managed so that the appropriate infection control measures are ensured. Finally patient support facilities, recreation facilities, and patient wards should be accessible to patients, but not necessarily all patients at all times, because of risk of cross-infection. | ||
+ | The following situations and design features have been identified as presenting the potential for increased risk of TB transmission in healthcare settings, so that when allocations of spaces are made in existing infrastructure systems the following should be borne in mind: | ||
− | + | * Congregate settings - any setting (usually waiting areas) where large groups of patients are kept in close proximity to each other are potentially high risk areas. The highest risks are usually in admission, main outpatient, emergency or pharmacy waiting areas where undiagnosed or untreated patients congregate. Smaller waiting areas or other functional areas, such as in x-ray departments or even multi-bed patient rooms can equally pose a risk. | |
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*Restricted / inadequate ventilation - appropriate ventilation is important, especially in congregate settings or other direct contact areas, such as dining facilities, occupational therapy areas etc. Waiting areas need to be adequately ventilated at all times in order to dilute concentrations of infectious airborne bacteria. Areas such as consulting, examination, counselling or treatment areas where staff spend long times in relatively small areas in close proximity to patients should be considered high risk areas. Minimum opening window areas are prescribed but often not complied with. The WHO guidelines (WHO, 2009a) indicate a target of 20% open window area to space floor area. The design of the window is also important to promote natural ventilation. However improved ventilation alone is usually not enough to reduce risk in that the directional flow of air to and from adjacent areas needs to be addressed. | *Restricted / inadequate ventilation - appropriate ventilation is important, especially in congregate settings or other direct contact areas, such as dining facilities, occupational therapy areas etc. Waiting areas need to be adequately ventilated at all times in order to dilute concentrations of infectious airborne bacteria. Areas such as consulting, examination, counselling or treatment areas where staff spend long times in relatively small areas in close proximity to patients should be considered high risk areas. Minimum opening window areas are prescribed but often not complied with. The WHO guidelines (WHO, 2009a) indicate a target of 20% open window area to space floor area. The design of the window is also important to promote natural ventilation. However improved ventilation alone is usually not enough to reduce risk in that the directional flow of air to and from adjacent areas needs to be addressed. | ||
*Shape and volume - the shape and volume of a space can also be a risk indicator. Occupied spaces with minimal floor to ceiling height (often found in multi-storey buildings) are generally higher risk areas than those with a shaped ceiling to high level clear storey windows. Shape and volume usually is linked to ventilation flow patterns and rates. The position and ease of opening of both high and low level windows is important. Staff awareness of the need to keep windows open to allow unobstructed ventilation is needed. “Open window” stickers are frequently used to provide visible reminders of open window policy. | *Shape and volume - the shape and volume of a space can also be a risk indicator. Occupied spaces with minimal floor to ceiling height (often found in multi-storey buildings) are generally higher risk areas than those with a shaped ceiling to high level clear storey windows. Shape and volume usually is linked to ventilation flow patterns and rates. The position and ease of opening of both high and low level windows is important. Staff awareness of the need to keep windows open to allow unobstructed ventilation is needed. “Open window” stickers are frequently used to provide visible reminders of open window policy. | ||
*Adjacency - the distance between carriers and staff or other patients is a risk factor. Congregate areas where patients are sitting close together is an obvious situation and settings where close contact occurs such as during consultation, examination and treatment are risk situations. Narrow bed spacing (less than 1.2 m) presents risk for both fine droplet and droplet nuclei contamination. Multi-bed wards configurations are risk situations. | *Adjacency - the distance between carriers and staff or other patients is a risk factor. Congregate areas where patients are sitting close together is an obvious situation and settings where close contact occurs such as during consultation, examination and treatment are risk situations. Narrow bed spacing (less than 1.2 m) presents risk for both fine droplet and droplet nuclei contamination. Multi-bed wards configurations are risk situations. | ||
− | *Places where aerosol-generating procedures are undertaken- These are defined as high-risk procedures that may increase the potential of generating droplet nuclei because of the mechanical force of the procedure (e.g. intubation, cardiopulmonary resuscitation, bronchoscopy, autopsy, and surgery where high-speed devices are used) (WHO, 2007) | + | *Places where aerosol-generating procedures are undertaken- These are defined as high-risk procedures that may increase the potential of generating droplet nuclei because of the mechanical force of the procedure (e.g. intubation, cardiopulmonary resuscitation, bronchoscopy, autopsy, and surgery where high-speed devices are used) (WHO, 2007)</div> |
− | + | Total respiratory isolation for TB treatment would be ideal from an infection prevention and control point of view. Several factors make this both impractical and undesirable. First there are negative social and psychological impacts to strict separation including isolation and stigmatisation of patients. Second, nursing requirements, acuity and management dictate that patients must be visible to healthcare workers and accessible to them.<div style="color:#00000a;">Whilst provision of single bed wards is advisable as far as possible, shared spaces for joint activities are required. Estate legacy constraints (the size and shape of existing rooms), affordability (single-bed wards require a higher capital investment, higher operational and maintenance costs) and nursing acuity constraints (compact configurations allow for improved nursing efficiency) mean that single-bed configurations are not always possible, and it therefore is common practice at facilities in South Africa to provide rooms with two, four, six or more patients. | |
− | + | TB facilities generally experience highly fluctuating patient demographics and needs. Given resource constraints and high demand, it is frequently useful to provide configurations which allow for flexible arrangements which can be administered according to prevailing needs. | |
− | <div | + | </div> |
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− | <div style="color:#00000a;">Whilst provision of single bed wards is advisable as far as possible, shared spaces for joint activities are required. Estate legacy constraints (the size and shape of existing rooms), affordability (single-bed wards require a higher capital investment, higher operational and maintenance costs) and nursing acuity constraints (compact configurations allow for improved nursing efficiency) mean that single-bed configurations are not always possible, and it therefore is common practice at facilities in South Africa to provide rooms with two, four, six or more patients. </div> | ||
− | + | Management of patients may require spatial and/ or physical separation in accordance with facility policy: according to gender | |
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− | Management of patients may require spatial and/ or physical separation in accordance with facility policy: | ||
+ | *according to gender | ||
*ostensibly drug susceptible TB – retreatment (treatment failure) | *ostensibly drug susceptible TB – retreatment (treatment failure) | ||
*Mono-resistant TB (suspected-MDR) | *Mono-resistant TB (suspected-MDR) | ||
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*patients requiring isolation ( for additional infectious diseases, psychological disturbance, prisoners) | *patients requiring isolation ( for additional infectious diseases, psychological disturbance, prisoners) | ||
+ | Occasionally facility policy may allow for or require additional accommodation for outpatients, visitors or patients awaiting transfer. This may be applicable to specialised facilities (Centres of Excellence), where family and patients are likely to travel great distances but will not be applicable to Satellite Facilities on the decentralised scheme.<div style="color:#00000a;">Separation of each of the cohorts described above, especially at long-term care facilities is highly desirable. Generally, at a minimum, separation of gender, paediatrics and XDR patients is required. It is highly preferable to have some accommodation for patients requiring isolation and patients with first culture negative result (suspected cured). Further refinement will be dependent on individual facility policy, size of facility (larger facilities being more complex in nature) and whether it is primarily aimed at acute or sub-acute care. | ||
+ | Administrative control measures must also ensure optimal operation of environmental control measures (see below). This may include assignment of a person to oversee environmental controls, to open and close windows as appropriate, change filters, test environmental control measures periodically, clean UVGI lamps if installed, perform preventative maintenance measures, etc. Whatever environmental control measures are in place, their adequate operation and maintenance should be included in the administrative control measures through the TB Infection Control Plan and their operational parameters and proper function should be evaluated regularly. | ||
+ | </div> | ||
− | + | === Environmental IPC measures === | |
− | |||
− | |||
− | |||
− | |||
− | |||
<div style="color:#00000a;">Environmental IPC protection methods should be the second- most prioritised approach, after administrative IPC measures and before personal protection measures (which should be used as measure of last resort). Two broad environmental strategies can be identified: dilution, which results in the reduction in concentration of contaminated particles in a volume of air and disinfection, which is the partial or complete destruction (sterilisation) of micro-organisms in air. Disinfection substances/ processes may be harmful to humans.</div> | <div style="color:#00000a;">Environmental IPC protection methods should be the second- most prioritised approach, after administrative IPC measures and before personal protection measures (which should be used as measure of last resort). Two broad environmental strategies can be identified: dilution, which results in the reduction in concentration of contaminated particles in a volume of air and disinfection, which is the partial or complete destruction (sterilisation) of micro-organisms in air. Disinfection substances/ processes may be harmful to humans.</div> | ||
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Revision as of 10:35, 27 July 2020
Contents
- 1 Policy and service context
- 2 Understanding transmission to manage risk
- 3 Planning and design principles
- 4 Operational narrative and user room requirements
- 4.1 Daily Schedule
- 4.2 User room requirements
- 4.2.1 Consulting room
- 4.2.2 Counselling room
- 4.2.3 Diagnostic radiology services
- 4.2.4 Sputum collection and induction
- 4.2.5 Pharmacy
- 4.2.6 Laboratory services
- 4.2.7 Clinical support services for inpatient care
- 4.2.7.1 Duty station/ nurse’s station
- 4.2.7.2 Clean linen area
- 4.2.7.3 Dirty utility room
- 4.2.7.4 Sluice room
- 4.2.7.5 Surgery services (operating theatre)
- 4.2.7.6 Staff facilities
- 4.2.7.7 Procedure room
- 4.2.7.8 Store rooms
- 4.2.7.9 Medical store
- 4.2.7.10 Matron’s office
- 4.2.7.11 Mortuary
- 4.2.7.12 Visitor’s area
- 4.2.7.13 Visitor’s ablution
- 4.2.7.14 Dining facilities
- 4.2.7.15 Business centre
- 4.2.7.16 Resource centre/ media room/ library
- 4.2.7.17 Games room
- 4.2.7.18 TV room
- 4.2.7.19 Kitchenette
- 4.2.7.20 Patient laundry
- 4.2.7.21 Other recreation
- 4.2.7.22 Occupational therapy
- 4.2.7.23 Audiology
- 4.2.7.24 Physiotherapy
- 4.2.7.25 Clinical psychology
- 4.2.7.26 Social services
- 4.2.7.27 School
- 4.2.7.28 Kitchen
- 4.2.7.29 Laundry
- 4.2.7.30 Waste management
- 4.2.7.31 Maintenance services - building
- 4.2.7.32 Clinical engineering
- 4.2.7.33 Gardening services
- 4.2.7.34 Cleaning services
- 4.2.7.35 Co-located institutions/ activities
- 4.2.7.36 Overnight stay
- 4.2.7.37 Commercial support (tuck shop, ATM)
- 4.2.7.38 Staff accommodation
- 4.3 List of case studies
- 5 BIBLIOGRAPHY
- 6 Abbreviations
Policy and service context
Legislation, policies and international guidance
Infection Prevention and Control Legislation
- Constitution of the Republic of South Africa, 1996. s.2,24,27,36&39.
- The National Health Act 2003. (c.61). Cape Town South Africa: Government Gazette.
- The Occupational Health and Safety Act 1993. s.8(1). Cape Town South Africa: Government Gazette.
Department of Labour, 2001. Regulations for hazardous biological agents. (Government notice No. R. 1390 of the Occupational Health and Safety Act, 1993. s.43). Pretoria South Africa: Government Gazette
Department of Health, 2003. Regulations relating to the application of the hazard analysis and critical control point system (HACCP system). (Government notice No. R. 908 of the Foodstuffs, Cosmetics and Disinfectant Act, 1972. (c.54)). Cape Town South Africa: Government Gazette.
- The Environmental Conservation Act 1989. (c.73). Cape Town South Africa: Government Gazette.
- The Foodstuffs, Cosmetic and Disinfectants Act 1972. (c.45). Cape Town South Africa: Government Gazette.
Building legislation
- The Pharmacy Act 53 of 1974. (c.53). Cape Town South Africa: Government Gazette.
- The National Environmental Management Act 1998. (c.107). Cape Town South Africa: Government Gazette.
- Building Regulations and Building Standards Act 1977. (c.103). Cape Town South Africa: Government Gazette.
- South African Bureau of Standards (SABS), 1990. SANS 10400:1990 Code of practice for the application of the national building regulations.Pretoria South Africa: SABS Standards Division.
- Promotion of Equality and Prevention of Unfair Discrimination Act 2000. (c.4). Cape Town South Africa: Government Gazette.
Infection prevention and control and TB management policy and guidelines
- National Department of Health (NDoH), 2007. The draft national infection prevention and control policy for TB, MDRTB and XDRTB. South Africa: NDoH.
National Department of Health, 2007. Management of drug-resistant tuberculosis: Policy guidelines. [pdf] South Africa: NDoH. Available at: http://www.search.gov.za [Accessed 26 March 2014].
South African building practice policy and guidelines
- The South African Pharmacy Council, 2004. Good pharmacy practice. (Board notice 129). Cape Town South Africa: Government Gazette.
International design guidance
South Africa faces one of the most devastating TB epidemics in the world. TB – with TB/HIV/Aids – is the leading cause of death
- American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), 1999. ANSI/ASHRAE standard 52.2-1999 Method of testing general ventilation air cleaning devices for removal efficiency by particle size. Atlanta USA: ASHRAE.
- American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), 1989. ASHRAE standard 62 Ventilation for acceptable indoor air quality. Atlanta USA: ASHRAE.
- American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), 2003. HVAC design manual for hospitals and clinics. Atlanta USA: ASHRAE.
Chartered Institution of Building Services Engineers (CIBSE), 1997. CIBSE applications manual AM10 natural ventilation in non-domestic buildings. London: CIBSE.
American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE),
- American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), 2009. ANSI/ASHRAE/ASHE standard 170-2008 ventilation of health care facilities. Atlanta USA: ASHRAE.
- QASA, “Know Your Rights” [Accessibility & the Built Environment]
- Department of Health and Human Services (Centre for Disease Control and Prevention), 2003. Environmental control for tuberculosis: Basic upper-room ultraviolet germicidal irradiation guidelines for healthcare setting. USA: DHHS.
- World Health Organisation (WHO), 2009a. Natural ventilation for infection control in health-care settings. Geneva Switzerland: WHO
- World Health Organisation (WHO), 2009b. WHO policy on TB infection control in health-care facilities, congregate settings and households. Geneva Switzerland: WHO
Service context
The WHO reports that TB treatment success is low[1] and treatment default rates and mortality are high. The high default from TB treatment by patients represents a major problem which, in conjunction with other factors, has led to the emergence of drug-resistant TB (DR TB). Transmission of TB, multi-drug-resistant TB (MDR TB) and extreme (or extensively) drug-resistant TB (XDR TB) in communities and congregate settings has been documented in several studies, frequently linked to HIV infection and affecting vulnerable groups such as children. MDR and XDR TB linked with HIV therefore have the potential to result in an uncontrollable epidemic with devastating economic and social consequences. The epidemiological burden co-infection in South Africa is currently estimated to be in excess of 70% of TB and HIV (WHO, 2009b). Provision of poorly designed, maintained and operated infrastructure can exacerbate transmission. Well-designed and well-maintained facilities can reduce the risk of TB infection.
M. tuberculosis is an infectious disease, and is transmitted from person to person exclusively by the airborne route, usually through coughing by a patient with active pulmonary TB. MDR TB is a consequence of human error resulting from combinations of the management of drug supply, patient management, chemotherapy prescription and patient adherence. Treating MDR TB takes longer and requires drugs that are more toxic, more expensive (up to 100 times the cost of treating a drug-susceptible TB patient) and generally less effective, particularly in persons with HIV infection.
The problem of drug resistance in TB has been compounded by the emergence of XDR TB. Patients with XDR TB are extremely difficult and expensive to treat, with mortality rates between 50 and 70% (CDC, undated). In XDR TB patients with HIV co-infection, mortality rates, though improving, remain at about 90% (Neel, et al., 2010).
Owing to the District Health system, patients are intended to, and generally do, enter the healthcare system via primary healthcare services - namely the clinics and community health centres (CHCs) and private general practitioners (GPs). It is in these settings that untreated, undiagnosed infectious individuals will inevitably come into contact with susceptible individuals and the risk of transmission is produced. With the introduction of the NHI, the profile of risk in former “private” facilities may change as demographic shifts in access to these services occur. It is therefore in the interest of public health that private-sector facilities are designed, constructed and operated to meet airborne infection control requirements.
The National Department of Health (NDoH) Primary Healthcare Directorate advocates the WHO-endorsed approach in the public sector to integrated service provision (WHO, 2011). In the context of this document, this means that individuals seeking care are to receive all appropriate services and interventions at a “one-stop shop”. The common practice of provision of service by diagnosis within a facility (e.g. separation of TB, HIV/Aids, diabetes) or by vertical programmes (different clinical activities on different days) does not support integration of services. This implies that, as far as it is safe and reasonable, most services should be available in most patient/client contact spaces. The integration of services should not subject healthcare workers, clients or the public to undue exposure to airborne pathogens. In particular, when reconfiguring services in existing facilities, due diligence must be paid in ensuring that designs meet required standards for TB infection control.
Most TB patients will access services at the primary healthcare level and will require access on site to integrated services including, but not limited to:
- clinical assessment (consulting room with examination facilities, clinical scale);
- safe facilities for sample (sputum) collection;
- nutrition;
- psychosocial services (counselling); and
- pharmacy dispensary for chronic medication.
In addition, on- or off-site access to the following services is required
- laboratory services (microscopy, culture, GeneXpert, for drug sensitivity), and
- radiology.
For a quick reference to primary healthcare services for uncomplicated building projects consult IUSS:GNS Primary Healthcare.
Evidence suggests that drug-susceptible TB and MDR TB, when diagnosed and under treatment, become rapidly less infectious (Dharmadhikari, forthcoming). This means that, after as little as 24 hours on appropriate treatment, TB patients - and even MDR patients - can be regarded as and accommodated with the non-infectious population. No special facilities are required for these patients (if they are short-term patients) and they can be accommodated in accordance with IUSS norms and standards (Refer to IUSS:GNS Adult inpatient services).
Patients recently enrolled on treatment (<24hours) who are suspected of having XDR, confirmed XDR patients, patients who interrupt treatment, and complicated cases may be considered infectious and negative-pressure isolation is strongly recommended - or, if not possible, at least patient management by respiratory isolation or, if that is not possible, by patient cohorting (patient management by clustering patients with most similar diagnoses).
The number of DR TB cases in South Africa increased from 10 085 in 2011 to 15 419 in 2012 (WHO, 2013, p.52). This is largely due to intensified case finding and investment in laboratory services. However, it represents only a portion of the estimated cases (WHO, 2013).
Since 2010 the SA National Department of Health has adopted a policy of decentralised management of Multi Drug-resistant TB[2]. In addition to outpatient services, there is a requirement for inpatient hospital facilities:
- for all types of TB patients (pulmonary, extra-pulmonary, etc.) requiring acute treatment for TB or other comorbidities
- within patient populations of general hospitals,
- In dedicated wards at general hospitals for acute episodes, and
- at specialised hospitals (long-term accommodation) for sub-acute and palliative care for patients who are not best served by community-based care, for various reasons.
Inpatient beds for TB services have frequently been provided by converting old wards and sanatoria as a quick solution to address at least part of the pressing need. In many instances building infrastructure has been modified or retrofitted with the intention of making it suitable. However, because beds are provided in this reactive way, the infrastructure is frequently poorly aligned with current best infection-prevention and ‑control practice and patient-centred care.
There have been both legal and ethical challenges posed to TB hospitalisation (Singh, Upshur and Padayatchi, 2007; London, 2009). Media have reported incidents of patients rioting and absconding (Dugger) which attested to the unpopularity of the policy and the unsuitability of the arrangements, including - though by no means limited to – the building infrastructure provided.
The NDoH has subsequently recognised the need to provide recreational, occupational and educational facilities for patients that require specialised long-term DR TB treatment (NDoH, 2007b, p.25). Social support should also be provided for all patients and their families whilst hospitalised. In the past TB facilities were simply not designed or built to address these needs. This must be recognised when assessing precedent or in identifying case study examples.
Figure 1: Centralised management of MDR TB
Consequently the National Department of Health expanded its approach in adopting a multi-faceted decentralisation policy in future according to the following health framework for DR TB management (see Decentralised Management of Multi Drug Resistant TB – a Policy Framework for South Africa). According to this framework (see Figure 3), for a successful decentralised MDR TB programme, the following should be provided in inpatient care facilities in order to ensure adequate infrastructure and infection control measures:
- Well ventilated consulting roomWell ventilated waiting area
- Well ventilated rooms that can accommodate from one to six patients
- Distance between beds not less than 1.2 m
- Administration control measures of infection control in place
- UVGI lights and extractors fans where possible[3]
- Respiratory protection tools available: surgical masks, N95 respirators
These policy requirements will go some way to addressing the twin objectives of patient-centred care and effective infection prevention and control in the emerging pandemic. However, there are additional planning, design, management and maintenance considerations to reach best practice standards and these are discussed in detail below.
Understanding transmission to manage risk
Transmission of M. Tuberculosis
When the droplets produced by an infected person are inhaled by a susceptible person, TB may be contracted. However, this alone does not seem to account for observable instances of transmission. There is a widely accepted theory - the droplet-nucleus hypothesis - that infectious droplet nuclei containing tubercle bacilli may remain suspended in air for prolonged periods of time, potentially long after the infector has left the room. This leads to a high risk of infection in congregate settings (shared spaces). This risk cannot be eliminated. However, expert consensus is that with adequate ventilation or air purification the risk can be reduced. Here is a brief explanation for the transmission theory (Riley and O’Grady, 1961).
The bacterium, M. tuberculosis, becomes aerosolised in small droplets of water or bodily fluid when a person with the disease of the lung coughs, sneezes, laughs or sings. Many of the smallest respiratory droplets dry into “droplet nuclei” and become airborne following room air currents is described. Infection can occur when the droplet nuclei containing the bacterium are inhaled.
Figure 2: Coughing generating aerosols - Source Jennison 1942
The infection turns to disease when the body can no longer contain the infectious material in the lung. The infection then spreads, usually within the lung (where it is called pulmonary TB) and possibly to other areas of the body. This spread usually shows up as chronic respiratory symptoms such as cough and fever. People with TB disease of the lungs can therefore transmit the infectious bacterium.
Disease status
- be actively diseased and infectious;
- be simultaneously infected by more than one strain;
- be diseased and undergoing treatment;
- be recovered after undergoing therapy;
- be developing resistance while undergoing therapy;
- have latent disease;
- have relapsed into disease;
- be re-infected;
- be immune; or
- have additional related/ unrelated medical conditions (co-morbidity)
Determining the current status of any given patient or transition times between statuses is problematic (given lags in diagnosis, individual patient responses etc.).
Table 2: Drug resistance TB (CDC, 2010[4], slide number 28)
Mono-resistant | Resistant to any one TB treatment drug |
Poly-resistant | Resistant to at least any 2 TB drugs (but not both isoniazid and rifampin) |
Multidrug-resistant
(MDR TB) |
Resistant to at least isoniazid and rifampin, the 2 best first-line TB treatment drugs |
Extensively
drug-resistant (XDR TB) |
Resistant to isoniazid and rifampin, PLUS resistant to any fluoroquinolone AND at least 1 of the 3 injectable second-line drugs (e.g., amikacin, kanamycin, or capreomycin) |
Manifestations of TB
Drug-susceptible TB
Pre-MDR TB
Drug resistance (see can only be defined through laboratory confirmation of in-vitro resistance to one or more anti-TB drugs. Results are defined as follows:
- Mono-resistant TB: in patients whose infection isolates of M. tuberculosis are confirmed to be resistant to one first line anti-TB drug.
- Poly-resistant TB: TB in patients whose infection isolates are resistant in vitro to more than one first line drug, other than isoniazid and rifampicin.
MDR TB
Pre-XDR TB
XDR TB
Paediatric patients
Origin of airborne infection
The size of the droplets swept by an air current from the surface of a liquid is determined principally by the velocity of the air and the surface tension of the liquid. As the air velocity increases, the size of the droplets decreases until above 100 m/s where the diameter of the water droplets approaches at least 10 microns (μm). In sneezing and coughing, the peak air flow in the bronchi approaches 300 m/s and the droplets are in the order of six μm in diameter.
After being expelled from the TB patient’s mouth and nose, even the smallest droplets begin to fall. Generally, the large particle droplets[5] fall to the ground where they become mixed with dust (see Figure 11). The fate of the smaller droplets is however, quite different. Droplets below a certain aerodynamic diameter fall slowly and lose water rapidly and evaporate almost instantaneously. In this way the droplet diminishes in size until the concentration of dissolved substances is such that the vapour pressure which the droplet exerts equals that of the atmosphere.
The residue of the droplet after evaporation, which may contain the micro-organism(s) from the respiratory tract, has been called the droplet nucleus. Droplet nuclei are so light that they may not settle in the gentlest of moving air of occupied spaces and may remain suspended for extended periods of time. This poses risk to building occupants until the particles are removed by ventilation or through other air disinfection.
Tubercle bacilli cannot be cultured from the air because of their low concentration and slow growth rate relative to other micro-organisms. The slow growth of tubercle bacilli and low concentrations in air require long sampling periods during which culture media, even with selective antibiotics to suppress microbial growth, become overgrown with fungi and other bacteria. Molecular amplification methods can detect nucleic acid from tubercle bacilli in the air, but cannot distinguish living from dead organisms[6] nor quantify those with infectious potential. It is therefore not possible to measure infectiousness of TB or DR TB directly, nor can the efficacy of environmental infection control interventions to reduce or prevent transmission be measured directly.
Also, when considering airborne contagion, it is not well understood is how many infectious particles, or droplet nuclei, are required to infect. Compounding this uncertainty there are marked differences in the numbers of organisms liberated by coughing and sneezing of individual infectors. Despite these limiting factors, which are the subject of on-going speculation, investigation and scientific research, the general principles of contagious potential applies.
In any form of contagion the probability of infection increases with the degree of exposure to the infection (see Figure 3: Contagion). The factors implicated in the potential to be contagious are:
- the presence of susceptible members of the community
- the presence of infectious cases
- the effective contact rate (opportunities for transmission) influenced by variables which in the airborne example are factors such as:
- exposure time
- breathing rates of infector and susceptible
- virulence (strength) of bacteria
- environment (qualities of the room, such as humidity, air volume)
Figure 3: Contagion
The number of new cases occurring in an epidemic is directly related to the number of susceptible persons, the number of infectors and the effective contact rate. Respiratory droplets (for example flu), with their limited flight, range and dependence on the simultaneous presence of source and subject, behave as a form of effective contact. Droplet nuclei, with their prolonged suspension and rapid dispersion may provide an enhanced exposure and effective contact rate. It was for this reason that Wells called droplet-nucleus-borne infection, airborne contagion.
DR TB can be acquired in two different ways: primary and secondary modes. Primary transmission is caused by person-to-person transmission of a drug-resistant strain of the TB bacilli. Secondary infection develops during TB treatment, either because the patient was not treated with the appropriate treatment regimen or because the patient did not follow the treatment regimen as prescribed. Approximately 1.8% of new TB and 6.7% of retreatment cases results in MDR. DR TB can be transmitted in the same way as drug-susceptible TB.
Evidence suggests virulence of DR TB is the same as for drug-susceptible strains. However, DR TB is more difficult to treat because it can survive in a patient’s body even after treatment with the first-line drugs is started. A key challenge with current tuberculosis diagnosis technique is the delay in culturing this slow-growing organism in the laboratory. Blood or sputum culture results can take between four and twelve weeks. Because there has historically been a delay in diagnosing drug-resistant TB, these patients may be infectious for a longer period of time. Rapid screening tools for drug-resistance (GeneXpert) have been approved by the WHO, and are now in widespread use in South Africa.
The infectious droplet-nuclei which may remain suspended in air for prolonged periods of time and the respiratory droplets leads to a high risk of infection in shared spaces. This risk cannot be eliminated. However, expert consensus, based on strong circumstantial evidence, is that with adequate planning, design, management and maintenance, this risk can be reduced or managed. International best practice indicates that patients with drug-resistant TB should be closely monitored when commencing treatment and they should remain in isolation until they are no longer infectious.
The following invasive procedures should be regarded as high risk situations for transmission (Culver, Gordon and Mehta, 2003):
- bronchoscopy,
- sputum collection and induction, and
- administration of aerosolized medications
Infection prevention and control hierarchy
The requirement for controls to minimise the risk of spreading this airborne disease is legislated in the OHS Act (Act 85 of 1993). The National Department of Health Tuberculosis Strategic Plan for South Africa, 2007-2011, in the Decentralised Management of Multi Drug Resistant TB – a Policy Framework for South Africa and various international agencies such as the WHO, Centers for Disease Control and Prevention in the USA provide policy guidance for infection control practices. Common to the last two is the need to base these practices on the hierarchy of control measures. These are arranged from most to least important as follows:
Administrative measures such as work practices, policies and procedures, education and training, TB screening of healthcare workers, and appropriate utilisation of existing facilities, the implementation of environmental (engineering) controls, and the use of personal respiratory protection in specified areas where there is a high risk of exposure.
Administrative IPC measures
- early diagnosis of potentially infectious TB patients,
- prompt separation or isolation of infectious TB patients, and
- the prompt initiation of appropriate anti-tuberculosis treatment.
Other important administrative control measures include an assessment of the risk of transmission in the facility, the development of a TB infection control plan that details in writing the measures that should be taken in a given facility, and adequate training of healthcare workers to implement the plan.
Figure 4: CSIR generic model illustrating functional separation
The following situations and design features have been identified as presenting the potential for increased risk of TB transmission in healthcare settings, so that when allocations of spaces are made in existing infrastructure systems the following should be borne in mind:
- Congregate settings - any setting (usually waiting areas) where large groups of patients are kept in close proximity to each other are potentially high risk areas. The highest risks are usually in admission, main outpatient, emergency or pharmacy waiting areas where undiagnosed or untreated patients congregate. Smaller waiting areas or other functional areas, such as in x-ray departments or even multi-bed patient rooms can equally pose a risk.
- Restricted / inadequate ventilation - appropriate ventilation is important, especially in congregate settings or other direct contact areas, such as dining facilities, occupational therapy areas etc. Waiting areas need to be adequately ventilated at all times in order to dilute concentrations of infectious airborne bacteria. Areas such as consulting, examination, counselling or treatment areas where staff spend long times in relatively small areas in close proximity to patients should be considered high risk areas. Minimum opening window areas are prescribed but often not complied with. The WHO guidelines (WHO, 2009a) indicate a target of 20% open window area to space floor area. The design of the window is also important to promote natural ventilation. However improved ventilation alone is usually not enough to reduce risk in that the directional flow of air to and from adjacent areas needs to be addressed.
- Shape and volume - the shape and volume of a space can also be a risk indicator. Occupied spaces with minimal floor to ceiling height (often found in multi-storey buildings) are generally higher risk areas than those with a shaped ceiling to high level clear storey windows. Shape and volume usually is linked to ventilation flow patterns and rates. The position and ease of opening of both high and low level windows is important. Staff awareness of the need to keep windows open to allow unobstructed ventilation is needed. “Open window” stickers are frequently used to provide visible reminders of open window policy.
- Adjacency - the distance between carriers and staff or other patients is a risk factor. Congregate areas where patients are sitting close together is an obvious situation and settings where close contact occurs such as during consultation, examination and treatment are risk situations. Narrow bed spacing (less than 1.2 m) presents risk for both fine droplet and droplet nuclei contamination. Multi-bed wards configurations are risk situations.
- Places where aerosol-generating procedures are undertaken- These are defined as high-risk procedures that may increase the potential of generating droplet nuclei because of the mechanical force of the procedure (e.g. intubation, cardiopulmonary resuscitation, bronchoscopy, autopsy, and surgery where high-speed devices are used) (WHO, 2007)
Total respiratory isolation for TB treatment would be ideal from an infection prevention and control point of view. Several factors make this both impractical and undesirable. First there are negative social and psychological impacts to strict separation including isolation and stigmatisation of patients. Second, nursing requirements, acuity and management dictate that patients must be visible to healthcare workers and accessible to them.
TB facilities generally experience highly fluctuating patient demographics and needs. Given resource constraints and high demand, it is frequently useful to provide configurations which allow for flexible arrangements which can be administered according to prevailing needs.
Management of patients may require spatial and/ or physical separation in accordance with facility policy: according to gender
- according to gender
- ostensibly drug susceptible TB – retreatment (treatment failure)
- Mono-resistant TB (suspected-MDR)
- Poly-resistant TB (suspected-MDR)
- MDR TB
- MDR treatment failure
- Pre XDR TB
- XDR TB
- XDR treatment failure
- First sputum culture negative result, pending second result (suspected cured)
- children (with or without boarding parents)
- patients requiring isolation ( for additional infectious diseases, psychological disturbance, prisoners)
Occasionally facility policy may allow for or require additional accommodation for outpatients, visitors or patients awaiting transfer. This may be applicable to specialised facilities (Centres of Excellence), where family and patients are likely to travel great distances but will not be applicable to Satellite Facilities on the decentralised scheme.
Administrative control measures must also ensure optimal operation of environmental control measures (see below). This may include assignment of a person to oversee environmental controls, to open and close windows as appropriate, change filters, test environmental control measures periodically, clean UVGI lamps if installed, perform preventative maintenance measures, etc. Whatever environmental control measures are in place, their adequate operation and maintenance should be included in the administrative control measures through the TB Infection Control Plan and their operational parameters and proper function should be evaluated regularly.
Environmental IPC measures
* Wind direction and profile;
- Building geometry;
- Interior obstructions and flow paths;
- Inner and outer temperature (buoyancy);
- Type and degree of envelope and building permeability;
- Adjacent structures and building location;
- Terrain; and
- Complimentary ventilation systems.
* Definition of performance and functional requirements as identified during the project definition stage
- Ensuring that the performance and functional requirements are met by the design and specification
- Validating that the ventilation system performs and functions as intended. An independent authority shall validate the performance and functioning of the ventilation system.
=== Dilution systems ===
Mechanical ventilation | Natural ventilation | Hybrid (mixed-mode) ventilation | |
Advantages | Suitable for all climates and weather with air-conditioning as climate dictates | Suitable for warm and temperate climates – moderately useful with natural ventilation possible 50% of the time | Suitable for most climates and weather |
More controlled and comfortable environment | Lower capital, operational and maintenance costs for simple natural ventilation | Energy saving | |
Capable of achieving high ventilation rate | |||
Smaller range of control of environment by occupants | Large range of control of environment by occupants | More flexible | |
Disadvantages | Expensive to install and maintain. | Easily affected by outdoor climate and/or occupants’ behaviour | May be expensive |
Reported failure rate in delivering the required outdoor ventilation rate | Reduces occupants comfort level when hot, cold or humid | May be more difficult to design | |
Potential for noised from the equipment | Inability to establish negative pressure in isolation areas, but may be provided by proper design; depends on situation | ||
Potential for noise intrusion | |||
High tech natural ventilation shares some of the disadvantages and limitations of mechanical ventilation |
Table 3: Summary of the advantages and disadvantages of mechanical, natural and mixed-mode ventilation systems (WHO, 2009a).=== Natural ventilation systems ===
#
- The principal driving forces, which enable the desired airflow patterns and ventilation rates (air changes) to be achieved, must be defined and quantified. Certain strategies tend to be wind-driven; others stack-driven. In successful designs, the principal airflow drivers are complementary to the intended flow rate and distribution.
- Size and locate the openings (windows) so that the minimum and average required flow rates can be delivered under all operating regimes.
# In new healthcare facilities or renovated spaces, an hourly average of 160 l/s/patient in airborne precaution rooms, with a minimum of 80/l/s per patient.
- In general wards and outpatient departments (OPD), 60 l/s/patient. The occupancy of general wards and OPDs vary, and this should be considered in the design phase.
- In corridors and other transient spaces, a minimum of 2.5 l/s/m3 is required. When emergency medical procedure are performed in these areas , an hourly average of 160 l/s/patient is required for high risk procedures, and 60 l/s/patient for all other procedures.
# the fluctuation rates due to changes in weather in the design of natural ventilation systems (including extremes of wind speed);
- building performance in inclement weather;
- patient comfort; and
- control of drafts in the occupied zone- Air currents in excess of 0.8 m/s in the occupied zone can cause disturbance and discomfort.
Mixed-mode systems
# Complementary mixed-mode ventilation
- Zoned mixed-mode ventilation
Mechanical ventilation systems
# A ventilation rate of 12 ACH, or
- A ventilation rate of 80 l/s/patient of outside or sterilised air.
=== Disinfection systems ===
Upper-room air UVGI
* include the sensitivity of the microorganisms to UVGI
- and the dose of UVGI received by a microorganism
- the room occupancy levels
- or population of microorganisms.
Personal protection measures
* SANS 50149 FFP2/3 respirators
- CDC - NIOSH N95 respirators
* protective eyewear (for UV device maintenance)
- respiratory protection (typically respirators for healthcare workers, cleaning and maintenance staff, visitors), and
- surgical masks (for patient use).
Planning and design principles
* a safe, secure and functional environment for patients and staff;
- optimal accommodation and support for long term patient stay;
- low capital and on-going operating costs (service, staffing and maintenance);
- an environmentally appropriate design solution; and
- a fully accessible, inclusive environment.
Patient profile
[[Image:|top]]
Figure 5: Changes in the number of TB notifications in a sample South African community, stratified by age, 1996 - 2004 (Lawn, et al., 2006, p.1043)
[[Image:|top]]
Figure 6: Total number of TB notifications between 1996 - 2004 in a sample South African community, stratified by age and sex (Lawn, et al., 2006, p.1043)
== Patient-centred care ==
=== Safety ===
=== Isolation ===
* Separation – patients are housed in single room accommodation though they may not be self-harming or violent.
- Negative pressure room applied to infectious patients, with airlock ante-chamber (e.g. TB patients).
- Positive pressure isolation room applied to immuno-compromised/ susceptible patients, with airlock (e.g. burns patients).
- Duel-function isolation – with controls to convert from positive to negative pressure according to current room occupancy, with airlock. This is discouraged due to complexities in designing and operating these and due to increase risk in accidental incorrect use.
- Seclusion (Social isolation) – for patients who are self-harming or violent. A room with high level of security which complies with national norms and standards for psychiatric care facilities. Airlock not required.
- Barrier isolation – patients are housed within a chamber constructed of an impermeable barrier and typically ventilated through HEPA filters. Decontamination airlocks and material transfer chambers are included in the system. These types of systems are exclusively used for suspected P4 level pathogens, and are not indicated for use with TB patients.
=== Infection prevention and control ===
=== Slips, trips and falls ===
=== Alarms and fire alarms ===
=== UV exposure risk ===
=== Safe Exposure Limit ===
=== Reflections into the Lower Room ===
=== Security ===
=== Inclusive design ===
=== Holistic care ===
=== Balanced service provision ===
=== Healing environments ===
=== Occupant comfort ===
* Proportion of hours where the targeted ACH rate is achieved (currently 160 l/s per person for naturally ventilated areas)
- Proportion of hours where either:
- PMV levels between -1.0 and 1.0 are achieved; or
- Acceptability limits of ASHRAE Standard 55, 2004 are achieved within 80% of acceptability limit 1
- Predicted operational costs (energy use and maintenance)
== Staff: patient ratios ==
Doctor1/40 beds
Professional nurse / Staff nurse or Nursing Assistant4/ 11 per 40 beds
Pharmacist1 per 100- 200 beds
Social worker 1 for > 40 beds
Dietician1 for > 40 beds
Clinical Psychologist 1 for > 40 beds
OT1 for > 40 beds
Audiologist1 for > 40 beds
Physiotherapist1 for > 40 beds
Data Capturer/ Admin Clerk1 for 100- 200 beds
Driver1 for > 40 beds
Table 4: Sample Organisational Development Investigation the following staffing complement per 30 bed functional unit (courtesy Brooklyn Chest Hospital).
OFFICE: ADMINISTRATION | NUMBER OF POSTS | COMMENTS |
Administration clerk | 1 | |
CLINICAL SERVICES | ||
Medical officer | 1 | |
MEDICAL AUXILLARY SERVICES | ||
Physiotherapist | Central services | |
Occupational therapist | Central services | |
Social work | Central services | |
Dietician | Central services | |
Audio/speech therapist | Central services | |
Clinical Psychologist | Central services | |
Radiographer | Central services | |
Pharmacist | Central services | |
Counsellor | Central services | |
NURSING SERVICES | ||
ASD nursing area | Central services | |
Operational manager nursing | 1 | |
Professional nurse | 4 | |
Staff nurse | 4 | |
Auxiliary nurse | 8 | |
Housekeeping supervisor | 1 | |
Household aid | 6 | |
NIGHT DUTY MANAGEMENT | ||
Night duty manager | 1 | Central services |
Professional nurse | 1 | |
Staff nurse | 3 | |
Auxiliary nurse | 2 | |
Household aid | 1 |
Supporting the caregiver
Recruitment, retention and productivity in staff
* which address risk from an IPC perspective in a way which is explicit and reassuring;
- which provides for physical safety against violent/ disturbed patients; and
- which allow adequate safe storage for personal belongings.
=== Additional personnel considerations ===
== Site appraisal ==
=== Building layouts ===
- existing buildings with measured footprint and scaled spatial layout on site plan;
- current functional allocation (use) of existing buildings;
- level of utilisation of buildings;
- national monument status;
- building condition assessment (high level and quick professional estimate on scale one condemn to five as new);
- evaluate of the level of accessibility of proposed new structures and linkages to existing buildings; and
- evaluation of existing pedestrian and vehicular routes (i.e. staff, visitors, and service vehicular and pedestrian routes) to determine optimum layout of proposed new buildings.
[[Image:|top]]
Figure 7: Recommended suitability coding for site appraisal
[[Image:|top]]
Figure 8: Recommended condition assessment coding for site appraisal=== Site Information ===
- Major landscaping, trees and features;
- Site access points for staff, patients and service personnel and access constraints;
- Existing fencing and level of security provided;
- Service connection points, main service runs, water tanks (as they are currently being constructed), transformers, substations, generators, etc.; and
- Flood lines, water table levels, site storm water drainage and general potential for flooding.
Engineering and bulk services
* Power: Analysis of existing power supply – types, current load, reliability, capacity, potential for expansion,
- Water supply: Analysis of existing water supply – source/s, storage, condition, current and projected demand,
- Sewage: Analysis of existing sewage reticulation and disposal system, connections, capacity, condition, current and projected load,
- ICT services: Telephones, internet connectivity, intranet connectivity. Analysis of existing supply – types, load, reliability, capacity, potential for expansion,
- Other services as identified by consultant team (gas, steam etc.)
=== Climatic and sustainability considerations ===
=== Future development ===
== Additional Project Studies, Approvals and Requirements ==
Environmental Impact Assessment (EIA)
=== Local authority submissions ===
* A site development plan (SDP);
- A copy of a set of working drawings;
- A traffic engineer’s report; and
- A fire department.
Phasing and decanting
=== Commissioning and validation ===
=== Post-occupancy evaluation ===
=== Operation and maintenance manual (O&M) ===
* Description, make, model number of all equipment installed; and
- Contact details of suppliers and /or manufacturers etc.
* Design data sheets, containing all design and selection parameters, calculations, selection curves, etc.;
- Settings and values recorded during commissioning;
- Manufacturer's brochures and pamphlets;
- Maintenance data and schedules;
- The lapse of time between services and the description of the service required of each part, lubrication requirements, etc.;
- Schedule of spares; and
- A complete electrical equipment schedule.
* "as built drawings";
- architectural work drawing;
- structural drawings;
- site works drawings;
- electrical reticulation drawings;
- mechanical installation drawings (i.e. all workshop and equipment layout drawings required for the manufacture and erection of the installations); and
- instrumentation/control drawings, such as schematic control diagrams and electronic/ electrical layout drawings.
Operational narrative and user room requirements
Daily Schedule
Table 5: Sample: Current daily activities at long-term care facility
TIME | ACTIVITY | VENUE | DESIGN IMPLICATION |
---|---|---|---|
5:00 | Patients are woken up, urged to complete ablutions, and dress. | Wards | Each patient will have his own bedroom and adjoining bathroom.
Each bed will have an adjacent cupboard for clothes and possessions, and space for a bedside table. |
Patients to produce sputum | Sputum booth | 1.Monthly sputum samples taken from relevant patients | |
07:00 | Nursing on day shift attend a handover meeting with night staff. This includes discussing problems, and planning activities for the day. | Nursing station | The nursing station is a general area where much clinical information is shared between staff and between disciplines and is a separate area in the ward. Secure cupboards (and a safe), under desk shelving and notice board space are required.
|
Matron’s office | While office should be separate from nursing station due to space requirements, easy communication and visible access should be available. Built-in office furniture with network points, plugs, telephone, filing space, lockable cupboards, enough space for at least three filing cabinets, appropriate storage and availability for ward stationery (some open and others locked), additional filing workspace, provision of pigeon holes for each for each patient file board, key cupboard. | ||
7:30 | Daily injection given to patients | Procedure room | Nurses prepare injections according to medicine chart per individual patient.
The room requires a clinical hand-wash basin with clinical taps, lock-up cupboards, worktops, a patient couch, good lighting |
08:30 | Breakfast and issuing of medication | Dining hall | This adjoins the kitchen and food delivery area. The nursing station should be nearby so that medication and general nursing tasks can be co-ordinated efficiently.
As patients mostly will proceed to the dining area from various other activity areas (sleeping, clinic, recreational, OT etc.) it will have to be in a central location, easily accessible from other patient areas. Food must be delivered through a dedicated staff access point that allows for minimal patient contact. |
09:30 – 12:30 | Therapeutic activities | ||
Medical officer
The ward will have at least one medical officer. |
Consulting room | These should have enough space for interviewing at least 3 people, as well as a desk, examining coach and x-ray box. | |
Occupational Therapy (OT) | Games room and lounge | During the day most patients will be allowed to attend the OT programme. | |
Psychologists & Social Workers
Interviews, psychotherapy and counselling with patients or their families (often together) occur daily, usually by appointment. |
Counselling rooms | Each office will need built-in desks, computer and telephone points, and secure storage space. | |
12:30 – 13:30 | Lunch and using of medication | Dining hall | |
13:30 – 14:00 | Rest period | General rest areas | Some patients may retire to their rooms for a brief period, but most will be in general areas (lounge, restricted outdoor areas). |
14:00 – 16:30 | Continuation of many morning activities | ||
Sport and Recreation | Outdoor field | These patients will have easier access to outdoor areas. | |
Indoor group area | For use for group leisure. | ||
Lounge | A comfortable furnished area containing a TV, board games (such as Kerem). This area has to be fully visible from the nursing station. Public telephones should be situated nearby. It may be helpful if this was close to the dining area. | ||
Visiting
Families, friends (and occasionally others) are allowed to visit during two afternoons per week and each evening between 19:00 to 20:00 |
Visitors area | Although visiting times are regulated, families here have easier access to the patients, and there does not have to be a strict separation between patients and visitors. | |
16:30 – 17:30 | Supper | Dining area | Activities as for other mealtimes. |
17:30 – 19:00 | Leisure time | Lounge | Access to enclosed courtyards allows patients to smoke and relax in the restricted outdoors before retiring to sleep. |
18:00 | Nursing handover to night staff | Nursing station | The same as in the morning |
19:00 – 21:30 | Preparation for sleep
Dispensing of night medication |
Lounge and sleeping areas | Usually a snack and hot drink is given to patients. Many watch TV, others socialise or smoke (the latter activity will take place in designated courtyard areas that adjoin onto the ward, but without direct access to the general campus area). |
22:00 – 07:00 | Night activities | Sleeping areas,
Nursing station |
User room requirements
=== TB outpatient services ===
Consulting room
Counselling room
Diagnostic radiology services
Sputum collection and induction
Figure 9: An illustration of local exhaust ventilation device (sputum booth) (source; CSIR 2014)
# Instructions inside the sputum collection booth about the sputum collection procedure.
- Time-lags between patients producing a sputum specimen in the same booth.
- Reminders to healthcare workers to wear respirators in the sputum collection area.
Pharmacy
Laboratory services
=== Patient accommodation ===
Table 6: Patient accommodation cohorts for short-term accommodation
Service type | Accommodation | Occupancy | Notes |
---|---|---|---|
Paediatric
(unisex) |
|||
TB and MDR TB (female) | |||
TB and MDR TB (male) | |||
XDR (male/unisex) | |||
XDR (female/unisex) | |||
XDR paediatrics (unisex) | |||
Former correctional services/(unisex isolation) | |||
Psychiatric TB patients/ (unisex isolation) |
Clinical support services for inpatient care
Duty station/ nurse’s station
Clean linen area
Dirty utility room
Sluice room
Surgery services (operating theatre)
Staff facilities
* airborne infection control
- a “break-away” venue to rest following patient contact periods away from the demands of the work environment
Procedure room
Store rooms
Medical store
Matron’s office
Mortuary
=== Patient Support ===
Visitor’s area
Visitor’s ablution
Dining facilities
Business centre
Resource centre/ media room/ library
Games room
TV room
Kitchenette
Patient laundry
Other recreation
=== Allied healthcare services ===
Occupational therapy
Audiology
Physiotherapy
Clinical psychology
Social services
=== Support services ===
School
Kitchen
Laundry
=== Facilities management ===
Waste management
Maintenance services - building
Clinical engineering
Gardening services
Cleaning services
=== Administration ===
Office accommodation is to be provided in accordance with the following reference: Department of Public Works, 2005. Space planning norms and standards for office accommodation used by organs of state. (Government notice 1665). Cape Town South Africa: Government Gazette.=== Other ===
Co-located institutions/ activities
Overnight stay
Commercial support (tuck shop, ATM)
Staff accommodation
= Case studies =
List of case studies
- Areas comparison of long-term XDR TB care facilities at:
- Bongani Hospital, Mpumalanga
- Tshepong Hospital, North West
- Modimolle Hospital, Limpopo
- Modimolle TB Hospital
- site layout
- patient rooms
- natural ventilation design
- Catherine Booth TB Hospital, KwaZulu-Natal
- Roof ventilation and windows concept drawings
- Two-bed patient rooms plan
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BIBLIOGRAPHY
Carroll, K.B., Secombe, C.J. and Pepys, J., 1976. Asthma due to non-occupational exposure to toluene (tolylene) di-isocyanate. Clinical Allergy, 6(2), pp.99–104.
Ko, G., First, M.W. and Burge, H.A., 2002. The characterization of upper-room ultraviolet germicidal irradiation in inactivating airborne microorganisms. Environmental Health Perspectives, 110(1), pp.95- 101.
Singh, J.A., Upshur, R., and Padayatchi, N., 2007. XDR-TB in South Africa: No time for denial or complacency. PLoS Medicine, 4(1). January 2007; 4(1), 19-25.
The Occupational Health and Safety Act 1993. s.8(1). Cape Town South Africa: Government Gazette.
Abbreviations
ACGIH | American Conference of Governmental Hygienists |
ACH | Air changes per hour |
AIA | American Institute of Architects |
AIIR | Airborne infection isolation room |
ASHRAE | American Society of Heating, Refrigerating and Air-Conditioning Engineers |
CDC | Centers for Disease Control and Prevention (US agency) |
CSIR | Council for Scientific and Industrial Research |
CSSD | central sterile supply department |
DR | drug-resistant |
DR TB | drug-resistant TB |
EIA | environmental impact assessment |
IAQ | indoor air quality |
ICT | information communications technology |
IPC | infection prevention and control |
IRPA | International Radiation Protection Agency |
LEV | local exhaust ventilation |
MDR TB | multi-drug-resistant TB |
NDoH | National Department of Health |
NGO | non-governmental organisation |
NHLS | National Health Laboratory Service (SA agency) |
NHI | National Health Insurance |
NIOSH | National Institute of Occupational Safety and Health (US agency) |
OHS | occupational health and safety |
OPD | outpatient department |
OT | occupational therapy / occupational therapist |
PAC | Portable air cleaner |
PHC | primary healthcare |
PMV | predicted mean vote |
PPE | personal protective equipment |
QASA | Quadra-para Association of South Africa |
REL | recommended exposure limit |
RH | relative humidity |
RSE | relative spectral effectiveness |
SAHNORMS | South African hospital norms |
SDP | site development plan |
TB | tuberculosis |
TLV | threshold limit values |
UVA | ultraviolet “A” (wavelength 400 nm–315 nm) |
UVB | ultraviolet “B” (wavelength 315 nm–280 nm) |
UVC | ultraviolet “C” (wavelength 280 nm–100 nm) |
UVGI | ultraviolet germicidal irradiation |
WHO | World Health Organisation |
XDR TB | extreme (or extensively) drug-resistant TB |
- Indoor Sputum booth
Application
Background
[[Image:|none]]
Figure 10 Sputum booth, Rear View
Suggestions improvements on concept booth
- The mass of the unit is still too high for safe and resiliant transport. Solutions for weight reduction should be soughtExternal fold away handels could be included in the design for easier handling of the unit.
- The overall length of the booth could be reduced by about 150 mm. This would still provide enough space to accommodate a person in a wheelchair.
- The costs and mass of future units could be reduced by replacing the aluminium sandwich panelling with polymer sheeting
- The fan-filter unit could be constructed such that is an integral structural component of the booth, reducing size and weight of the overall unit.
- incorporating an additional flexible one-way membrane behind the screen of the pre filter would limit the reversed airflow back into the booth when the booth is non-operational or during transportation.
ARDUINO WIRING CODE FOR DOOR INTERLOCK TIMER
/*Begin*/
/*
Sputum booth door lock control Sample code 08/11/2013
Written by: Tobias van Reenen (CSIR)
This Arduino Uno sketch controls a 12V magnetic door lock for a mechanically ventilated sputum booth
The door in this sketch remains normally locked and is released on the press of the external and internal door release buttons
The internal door release button will always unlock the door while the external button will only release the door after it has remained locked
for the predetermined length of time. This is in order to allow the booth ventilation system to adequately flush the booth between occupants.
The following wiring connections are made:
Arduino________Interface
GND ------------------ gnd
5.0v------------------ Vcc
Magnet power---------- +12V & -12V
8 -------------------- Release Button (Internal)
9 -------------------- Unlock Button (External)
10 ------------------- Unlock LED (Green)
11 ------------------- Locked LED (Red)
12 ------------------- Door Magnet Relay
*/
//Initiate variables
int doorLOCK = 12;//5v relay pin, switching 12V Magnet
int lockedLED = 11;//redLED
int unlockLED = 10;//greenLED
int unlockButton = 9;//External Button requesting an door unlock. Cannot override timer --requires 10k pull-up resistor & 5V Vcc
int releaseButton = 8;//Internal button requesting a door release. Overrides timer --requires 10k pull-up resistor & 5V Vcc
float unlockDELAY = 3000;//3 seconds
float lockDELAY = 30000;//30 seconds
float unlockTimeStamp;
float lockTimeStamp;
int pressed = 0;
int unpressed = 1;
int UNLOCK = 1;
int LOCK = 0;//using normally closed relay config
int ON = 1;
int OFF = 0;
void setup() {
pinMode(doorLOCK,OUTPUT);
pinMode(lockedLED,OUTPUT);
pinMode(unlockLED,OUTPUT);
pinMode(unlockButton,INPUT);
pinMode(releaseButton,INPUT);
Serial.begin(9600);
Serial.println("restart");
digitalWrite(unlockLED,OFF);
digitalWrite(lockedLED,ON);
}
void loop() {
Serial.print("unlock: ");
Serial.print(digitalRead(unlockButton));
Serial.print(" release: ");
Serial.print(digitalRead(releaseButton));
Serial.print(" unlockLED: ");
Serial.println(digitalRead(unlockLED));
if (digitalRead(releaseButton) == pressed){//check for release button press
while (digitalRead(releaseButton) == pressed){//holds code until button released
unlockDOOR();// unlock door function
}
}
if (digitalRead(unlockButton) == pressed){//check for unlock button press
if (digitalRead(unlockLED) == ON){//only unlocks door if unlock LED is lit
while (digitalRead(unlockButton) == pressed){//holds code until button released
unlockDOOR();
}
}//unlock door function
}
if (millis()> (unlockTimeStamp+unlockDELAY)){//counts down unlock delay and then locks door again
Serial.print("CountDown: "); Serial.println((lockDELAY+unlockTimeStamp+unlockDELAY-millis())/1000);
if ((digitalRead(unlockButton) == unpressed)&&(digitalRead(releaseButton) == unpressed)){
if (digitalRead(doorLOCK)!=LOCK){//checks for unlock button hold before locking door
lockDOOR();//lock door function
}
}
}
if (millis()> (lockTimeStamp+lockDELAY)){
digitalWrite(unlockLED, ON);
}
}
void unlockDOOR(){
Serial.println("unlocking...");
unlockTimeStamp = millis();// initiate unlock counter
digitalWrite(lockedLED,OFF);
digitalWrite(unlockLED,OFF);
digitalWrite(doorLOCK,UNLOCK);
}
void lockDOOR(){
Serial.print("locking... ");
lockTimeStamp = millis();
digitalWrite(doorLOCK,LOCK);
digitalWrite(lockedLED,ON);
digitalWrite(unlockLED,OFF);
Serial.print("unlockLED: ");
Serial.println(digitalRead(unlockLED));
}
/*end*/
[[Image:]]
Figure 11 Sputum booth, Left View
[[Image:|top]]
Figure 12 Sputum booth, Front View
[[Image:]]
Figure 13 Sputum booth, ISOMETRIC View
[[Image:|top]]
Figure 14 Sputum booth, DOOR CONTROL LOGIC
Figure 15 Sputum booth, Door controller wiring
[[Image:|center]]
Figure 16 Sputum booth, DOOR CONTROLLER PCB (NTS)
- PRE-Fabricated Outdoor Sputum booth
[[Image:|center]]
[[Image:|middle]]
[[Image:]]#
- ↑ 74% compared with 88% for all high burden countries.
- ↑ 2 Prior to 2010, the National policy was for centralised management of drug-resistant TB. All confirmed DR patients were to be referred to a DR TB facility for a period of about six months being subject to two consecutive negative TB cultures taken 30 days apart as identified by the supporting diagnostic laboratory service (NDoH, 2010a, p.8). But whilst this minimum period of six months was sometimes met in practice, and despite high demand for beds, national average length of stay is reportedly closer to 183 days for MDR TB and in excess of 199 days (occasionally over two years) for XDR TB. Following the two consecutive negative TB cultures, the policy stipulated that the patient was to be discharged for ambulatory care at the nearest health facility with ongoing treatment and psychosocial support. Given the total stock of 1 854 for dedicated specialised TB beds (NDoH, 2010a, p.8); the national DR TB bed capacity is ill-matched to fulfil a hospitalisation policy. As only under one third of patients could be accommodated, either other patients are displaced, are treated in their communities, or alternatively remain untreated. The available DR TB dedicated beds have in most instances been established either within existing hospital wards or from reinstated old TB-sanatoria
- ↑ The National Department of Health National Health Council declared a moratorium on procurement of UVGI for use in public health establishments in SA in June 2011
- ↑ CDC, 2010. CDC self-study modules on tuberculosis, 1-5. (Module 1- Transmission and pathogenesis of tuberculosis). Atlanta, GA:CDC. Available at: http://www.cdc.gov/tb/publications/slidesets/selfstudymodules/pdf/ParticipantGuide1.pdf [Accessed 27 March 2014)
- ↑ greater than 5 μm
- ↑ Although emerging research indicates that this may soon be possible.
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