Ventilation masks are described herein. A ventilation mask includes a mask body and a gas manifold. The mask body defines a patient cavity and further includes a patient opening in fluid communication with the patient cavity; and at least one vent opening formed through the mask body, the at least one vent opening in fluid communication with the patient cavity, wherein the at least one vent opening is disposed generally opposite to the patient opening. The gas manifold is coupled to the mask body. The gas manifold can define a gas channel. The gas manifold can include a plurality of vectored gas ports in fluid communication with the gas channel, wherein the plurality of vectored gas ports are configured to create a curtain effect gas flow within the patient cavity to form a gas curtain within the patient cavity and adjacent to the at least one vent opening.