"By measuring the concentration of the gas over time, we were able to quantify the exposure at each bed and therefore the potential risk to a patient in that bed," said Laura Pickin, one of the members of the research team. "We were also able to use the same data to measure the overall ventilation rate in the ward."
The UK Department of Health recommends that a ward should be ventilated at six air changes per hour, which means replacing the equivalent volume of air in the room six times every hour.
"When the windows were left open in the ward, we recorded ventilation rates that were either satisfactory or better than the UK standard" said Dr Carl Gilkeson, a Research Fellow who worked on the project. "When the windows were closed, the measured exposure to infection was typically four times higher, equivalent to a ventilation rate of only 1.5 air changes an hour".
The researchers found mechanical ventilation systems to be an effective alternative to natural ventilation. The installation of small extractor fans, similar to a domestic bathroom ventilator, beside each bed had a marked positive effect on ventilation, reducing risks to a comparable level to opening the windows.
The study also looked at the effect of partitioning an old "Nightingale" ward to create single bays, a common solution to the problems of privacy posed by traditional designs. Although partitioning slightly increased risks to people in the immediate vicinity of an infected patient, it reduced risks elsewhere in the ward. The findings indicate that it is feasible to partition wards to create a better patient environment without significantly increasing the overall risk of infection.
"These wards still exist and in the current economic environment they are likely to remain for some time. However, we have shown that they can
|Contact: Chris Bunting|
University of Leeds