A ventilator adaptor for switching between ventilator devices while maintaining respiratory support to a patient is described. The ventilator adaptor has a first movable element with a first inlet and a second inlet, and a second movable element movably attached to the first movable element and with an outlet. The outlet has an inner diameter of 14.5-15.5 mm, preferably 15 mm, and the first inlet and the second inlet have an outer diameter of 14.5-15.5 mm, preferably 15 mm. The outlet is in fluid communication with the first inlet in a first position or with the second inlet in a second position by moving the second movable element relative to the first movable element thereby aligning the outlet with the first inlet or the second inlet. The outlet may be attached to an endotracheal tube in order to form a ventilation assembly.