An anesthesia delivery device can be coupled to a ventilation system. The device includes an inspiratory gas line having a machine end and a patient end. The machine end can be fluidly coupled to the ventilation system, and the patient end can be received within the naris of the patient. A face mask having a dome portion can cover the patient's nose without covering the patient's mouth and defines an inside air space between the patient's nose and the dome portion, and an outside air space exterior of the dome portion. A vent allows gas to pass between the inside and outside air spaces. An exhaust port can be fluidly coupled to the exhaust gas output. The exhaust port and vent can cooperatively exert a negative pressure on the outside air space for preventing inspiratory gas from entering the outside air space.