A respiratory treatment device includes a housing enclosing a chamber, a chamber inlet configured to receive a flow of air into the chamber, a first chamber outlet configured to permit the flow of air to exit the chamber, and a second chamber outlet configured to permit the flow of air to exit the chamber. A vane mounted within the chamber is configured to rotate between a first position where the flow of air is directed to exit the chamber through the first chamber outlet, and a second position where the flow of air is directed to exit the chamber through the second chamber outlet. A blocking member disposed on the vane is moveable relative to the chamber inlet between a closed position where the flow of air through the chamber inlet is restricted, and an open position where the flow of air through the chamber inlet is less restricted.
