An adaptor for delivering an aerosolized active agent to a patient with concomitant positive pressure ventilation includes an aerosol flow channel having an aerosol inlet port and a patient interface port, and defining an aerosol flow path from the aerosol inlet port to and through the patient interface port; and a ventilation gas flow channel in fluid communication with the aerosol flow channel and having a gas inlet port and a gas outlet port, and defining a ventilation gas flow path from the gas inlet port to and through the gas outlet port, wherein the ventilation gas flow path is at least partially offset from the aerosol flow path and at least partially encircles the aerosol flow path. Systems and methods for delivering an aerosolized active agent to a patient with concomitant positive pressure ventilation incorporate the adaptor.