Does it matter whether the breathing circuit filter is placed between the patient and the QED-100, or the QED-100 and the breathing circuit “Y” connector?
Location of a filter has a minimal effect on the performance of the QED-100. If the filter includes a heat/moisture exchanger (HME), then performance of the HME is improved if it is closer to the patient. The QED-100 most likely would perform better if the HME is placed between it and the patient. The reason for this is that the water vapor associated with each breath the patient exhales could potentially occupy surface area on the charcoal that could otherwise be occupied by molecules of anesthetic.
