5. Why is it important to use a breathing filter also in anesthesia? Contrary to some old myths, Sodalime does not kill all bacteria and viruses. Many studies show the actual transmission of pathogens even when exposed to Sodalime for a considerable time. (Please contact us for a copy of these magazine articles.) The American Society of Anesthesiology has published guidelines for the transmission of tuberculosis, which is one of the more important bacteria. The ASA recommends the use of a filter with 99.97% efficiency at 0.3 microns particle size to protect patients and caregivers. . Unfortunately, in anesthesia it is not always possible to know the complete track record of a patient. Emergency procedures may be scheduled and patients could be infected without their own knowledge. Therefore it is always adviseable to use a filter with the highest possible filtration efficiency to protect patients and staff from possible infections.