Protection Against Cross Infection in Hospital Beds with Integrated Personalized Ventilation

Normally we protect ourselves from cross infection by supplying fresh air to a room by a diffuser, and the air is then distributed in the room according to different principles such as: mixing ventilation, displacement ventilation, vertical ventilation, etc.

However, there is a possibility to supply air directly to the breathing zone when people are lying in beds, e.g. in a hospital ward. This principle, called "Personalized Ventilation" has shown to be very efficient in the protection of people from cross infection.

The system supplies fresh air into the breathing zone through a pillow or a blanket. The system can also be used to reduce the emission of viruses or bacteria from the exhalation of a source patient. The air supplied from the personalized ventilation (PV) diffuser rises to the ceiling and with the right air distribution system it can be removed from the room.

The experiments in this paper are carried out with tracer gas and two thermal manikins in the experimental SARS ward at Hong Kong University. One of the manikins is the source manikin, and the other one the target. The measurements show that a very high degree of protection can be obtained with this system. Optimum flow rate and temperature of the supply air are addressed in the research work.