Apparatus and methods are disclosed by which a closed ventilating system accommodates multiple access to the respiratory system of an intubated medical patient without compromising the closed character of the system. Access to the respiratory system through one or more access sites of the closed system apparatus is provided at proximal adapter ports to ventilate the lungs of the patient with gas or gases, to aspirate secretions from the lungs, to oxygenate the lungs to eliminate or reduce residual co2 therefrom, to visually inspect selected parts of the respiratory system, to sample sputum and gases, to sense parameters such as flow rates, pressure, and temperature, to flush with washing solution, and/or to administer medication, gases, and/or lavage. A distal swivel fitting provides multiple sealing sites by which entry of atmosphere is prevented.