Abstract: A T-shaped valve for use in supporting a nebulizer cup in a ventilation circuit. The valve comprises an inner sheath and an outer sheath for supporting the inner sheath. Both the inner and outer sheaths have apertures which selectively align and misalign with one another. The inner sheath further includes an integral control knob which passes through an opening in the outer sheath. A displacement of the control knob shifts the inner sheath circumferentially relative to the outer sheath which, in turn, displaces the aperture in the inner sheath relative to the aperture in the outer sheath. When the aperture in the inner sheath is in communication with the aperture in the outer sheath, the circuit is open to permit fluid flow through the nebulizer cup and when the aperture in the inner sheath is not in communication with the aperture in the outer sheath, the circuit is closed to restrict fluid flow through the nebulizer cup and thus enable the removal of the nebulizer cup from the ventilation circuit.