4.2. Indoor environmental standardization
Operating room working areas require efficient ventilation systems. They provide adequate working conditions for patients and medical staff involved into surgical activities. An overview of the main European standards for the operation of the ventilation system for operating rooms allows identification of the most common problems at actual locations. The problems are, among others, insufficient air intake within the OR, poor control in closed thermal conditions, and inefficient functioning of ventilation systems. International standards ISO 14644-1 and ISO 14698-1 define requirements for clean rooms and controlled environments concerning biocontamination control.43,44 According to contamination level, risk zones are identified, as well as monitoring methods to avoid contamination in OR areas.
Clean air and ventilation systems are important to decrease the probability of contamination in OR areas. Healthcare buildings need adequate ventilation and air conditioning systems, where especially important is laminar airflow.45 Robert Koch Institute proposed hygiene guidelines for OR ventilation,46 while German Society for Hygiene of Hospitals sets out several recommendations supporting DIN 1946 standard concerning OR ventilation and use of laminar airflow even in small ORs emphasizing that this solution is superior to conventional turbulent ventilation.47
An important recommendation is to take care of the contamination in the air of the immediate surrounding area of the operating table and instrument table, which may result in direct or indirect contamination of the site.25 There is a difference in the context of ventilation systems for hospital purposes in different countries. Germany and Austria also introduced standards for ventilation systems in ORs enabling adequate air flow that is enough clean.48,49 French Standard NF S90-351 recommends the medical requirements for each area, where the ORs are classified as Level 4 risk areas. ASHRAE proposes ventilation of health care facilities requiring an outdoor air change rate, as well as how to consider contaminants affecting the delivery of medical care services to patients and the occupational safety and health of workers and visitors.50