Bed with Integrated Personalized Ventilation for Minimizing Cross Infection

Normally we protect ourselves from cross infection by supplying fresh air to a room by a diffuser. This air is then distributed in the room according to different principles as e.g. mixing ventilation, displacement ventilation, etc. That means that it is necessary to supply a very large amount of air to the whole room to ensure a dilution of airborne infection.

Personalized ventilation has proven to be a very efficient system to protect people from cross infection because clean air is supplied direct to the breathing zone. Most designs of personalized ventilation are based on a supply jet. The problem with those systems is the fact that the jet entrains air from the surroundings and, therefore, reduces the amount of fresh air which reaches the breathing zone. The entrainment is minimized in the system discussed here, especially when the source of clean air is located in the boundary layer close to the breathing zone (face). The present idea utilizes the fact that the head or the body is in natural contact with surfaces as mattresses, pillows, neck support pillows, clothing, blankets, etc., and those surfaces are designed also to be a supply opening of fresh air.

A pillow and a blanket (mattress) have been tested, and it is shown that the protection is influenced by the positions of the breathing zone relative to the textile surfaces. Very high protection can be obtained in positions where the patient is lying on the side on the supply textile surface. An effectiveness up to 95% is reached, and the system will in general have an effectiveness larger than 50% to 80%. The flow rate to the system should be at a level of 10 l/s in most cases.