For better or worse?

The incidence of nosocomial infections in the hospital environment ranges from 5% to 8%. It is estimated that almost 20% of these infections are contracted in an operating theatre suite, with possible irreversible consequences for patients. According to the etymological meaning of the word (nosos – illness and komein - treat), the term nosocomial is used to describe infections contracted following treatment. When this type of infection is diagnosed, therefore, cause and responsibility rest with the healthcare facility. Regular media attention has led to increased involvement of members of the public, who not only demand more transparency, but also wish to understand how the health system works. At the same time, they are less willing to accept risk that they cannot control, or have not chosen. Each year in France, 60,000 to 100,000 patients admitted to hospital contract nosocomial infections, which corresponds to a prevalence in the range of 6-10%. Between 5,000 and 10,000 people die of these infections. In terms of public health, these figures are as alarming as the statistics for road-traffic accidents (7,800 deaths in 2002). To this picture must also be added the aspect of cost for the healthcare structures and, therefore, for the local authorities – nosocomial infections extend not only the list of treatments to be provided but also the length of stay in hospital. Faced with this issue, many European countries are currently drawing up documents intended to standardise the most reliable solutions.

New standards The recent French standard, NF S90-351:2003, relating to 'Cleanrooms and similar controlled environments in healthcare facilities', provides recommendations for the development of the project, as well as the construction and maintenance of air-treatment facilities. Spain has also adopted a new standard – UNE 100713:2003: 'air conditioning in hospitals' – with the same objectives. In the UK, hospital air conditioning is now under scrutiny from the Association of Local Authority Risk Managers (ALARM) – the UK national forum for risk management in the public sector. This body has stated that failing to manage the risks associated with heating and ventilation systems in premises, particularly hospitals, could have catastrophic results. Their view is that failure to control or minimise exposure to dust fumes, airborne contaminants and bacteria could leave anyone in the building at risk of developing a range of illnesses. The containment of the risk of Legionella has now been coupled with increased emphasis on the containment of methicillin resistant staphylococcus aureus (MRSA) and all hospital-acquired infections. Although cleanliness programmes are often aimed at 'contact spread', 'airborne spread' is now being treated increasingly seriously, and appropriate filter systems, particularly for recirculated air flows, are fundamental to the hospital's infection control team. Camfil offers consultative advice to prioritise the fitting of correct filter systems and on-going advice on hygienically focused preventative maintenance.

Risk assessment The emphasis is placed on the air handling unit (AHU) section and the operating theatre suite. Table 1 shows the standards for filters. The contamination control requirements vary in healthcare facilities according to the medical procedures carried out and the areas allocated to these activities. In response to these requirements, the NF S90-351 standard points out the need to initially conduct a risk assessment to define the particulate cleanliness classification appropriate to the specific needs of each area. Two factors determine the infection risk in an operating site. The first concerns the surgical procedure itself, the other the patient's state of health. The combination of these two factors determines the biocontamination risk specific to the procedure (see table 2). Having completed this procedure, the required performance efficiency for the facility can then be analysed and the most appropriate equipment selected in line with the surgical procedures carried out. With regards to the methods of use, the standard focuses on the air flow systems for the area to be protected (unidirectional or non-unidirectional flow), the air exchange rate in the room and the decontaminable aspects of the exposed materials. The following types of operating theatre suites are normally classified as level 4 risk areas: traumatology, ophthalmology (OPH), major burns, cardiovascular surgery and neurosurgery, etc. The procedures carried out in these operating theatre suites combine the risk factors associated with the procedure (duration and complexity of the procedures, etc.) and the risk factors associated with the state of the patient's health (for example, age, effectiveness of the antibiotic therapy and immune-deficient condition). According to NFS90-351, level 4 risk areas must fulfil the following criteria: •minimum filtration chain – F6 (AHU input), F7 (AHU outlet) and H13 (ceiling diffusion); •ISO 5 particulate classification (ISO 14644-1); •CP10 particulate decontamination kinetic classification; •target bacteriological classification - B10; •use of easily decontaminable materials; •unidirectional flow; •air exchange rate of the room > 50vol/h. Rooms for operating theatre suites (according to UNE100713:2003) must meet the following criteria: •three stages of filtration, (F6 and F9) in AHU and H13/H14 (ceiling diffusion); •filters F6 and F9, according to En 779; •filters H13 according EN 1822; •two types of air flow for classes 1, A or B •type 1A – unidirectional flow; •type 1B – unidirectional flow or non-unidirectional flow; •air exchange rate of the room > 30vol/h; •100% fresh air; •roomside access for filters controls.

With a view to providing a point-by-point response to this new standard as regards to level 4 risk areas (and/or 3), Camfil has developed a unidirectional flow filtration ceiling, the CamHOSP Screentek finish, see figure 1. The company's engineering department has concentrated on: •swift implementation with guaranteed results (class B seal, according to EN 1886, EN-1822- and En779:2002-certified filters); •reduced maintenance costs through the use of universal mechanical seal filters, ensuring that filters can be replaced easily and independently. This system is particularly suitable for hospitals as it allows frequent and efficient cleaning and disinfection. The CamHOSP complies with Appendix D paragraph 1.2 of standard NF S90-35, as it is free of surface unevenness and porosity that could retain particulate and chemical contamination or the development of microbiological contamination.