Operating Room Ventilation: A View From Different Perspectives

This thesis explores different ventilation systems used for operating rooms (OR). Entrainment test methods are used in most European standards to determine the protected zone whereas the air quality in the periphery is often excluded. Furthermore, these measurements are mostly carried out in an at-rest situation where intermittent sampling during operation should be required. Most ORs in the Netherlands have an air handling system with an ultra-clean ventilation system (UCV). ORs are energy-intensive departments, where air handling systems consume the most. Relatively simple adjustments can be made to the air handling system to reduce energy, such as expanding relative humidity limits and introducing operational clock times. Lowering outside air quantity has the biggest impact on energy reduction, lowering the OR classification the least. Reducing the air change rate in the OR from an ultra-clean to a generic OR will reduce the recovery degree and the local air change rate. Lowering the air change rate in operating rooms could harm comfort conditions and (ultra-clean) air quality. The capital and operational expenditures of air handling installations with an UCV-system are higher than those with a conventional system. The investment pays for itself when 2 to 4 surgical wound infections are prevented over the lifetime of the OR. The type of surgery should be a leading consideration in determining the typology of the air handling system and the type of air supply system. Absence of evidence that surgical site infections are prevented in ORs equipped with UCV-systems is not evidence that these are not prevented.