Infection Control Training

 
Bug expert Dr Andrew Sleigh said: "Although diseases such as tuberculosis are widely accepted as being airborne others may also be spread this way. "Numerous bacteria-carrying particles - such as tiny flakes of human skin - can be widely dispersed into the air within hospital wards through routine activities and potentially contribute to the risk of infection for patients."

His team at Leeds University 's Pathogen Control Engineering research group say inexpensive modifications to air flowpaths and bed lay-outs could be a critical factor in controlling SARS, influenza, tuberculosis and MRSA . Principal investigator Dr Sleigh said: "There is evidence that 10 to 20% of infections are spread through the air but until now their role in the infection chain has been largely overlooked as doctors tend to emphasise the importance of washing hands and avoiding physical contact."

His researchers whose findings will inform new guidelines for the ventilation of healthcare facilities used a laser counter to measure the number and size of particles present in the air of a respiratory ward at St James' University Hospital , Leeds , taking air samples every 30 minutes over a working day. They also sampled for micro-organisms in the air and kept a log of activities within the ward. They were able to show human activities such as ward rounds, changing the beds, drawing the curtains and patients using breathing machines callled nebulisers were linked to peaks in the number of airborne particles in the ward.

In a second phase of the Government-funded study civil engineering lecturer Dr Catherine Noakes modelled a tuberculosis ward in Peru to predict how airborne particles would travel from one patient's bed to another - spreading bugs across the room. The computer model showed moving the ventilation inlets and outlets to different positions could reduce the risk of airborne transmission by more than 75% - without having to increase the air supply into the ward, which would consume more electricity.

Dr Noakes also calculated the risks of an airborne disease outbreak in a hospital environment accounting for factors such as temperature and humidity.

This showed in some cases less than a 10% increase in the ventilation rate may be sufficient to prevent a major outbreak