To save money, Respiratory Therapy stopped using the recommended D/X800 expiratory filter when ventilating adult or pediatric patients. Instead a Neo mode adapter is used along with a HEPA filter "Teed" to a water trap. The vent passes the SST with this modified setup but fails the EST. The therapists do not do an EST, only an SST, between patients. Puritan Bennett says the modified setup has not been "validated" and recommends that the D/X800 filter be used. Is the modified setup described OK to use? What if any consequences are there?