A breathing assistance device may include a turbine for generating flow of pressurized respiratory gas, a duct for carrying pressurized gas to a patient, and a mechanism to control gas pressure capable of elaborating a pressure setting for the turbine. The turbine is connected to a speed sensor for acquiring the rotation speed of a rotating element of the turbine. A mechanism controls a calculation in order to elaborate a pressure setting and to send the pressure setting to the turbine. A method regulates the pressure of a respiratory gas delivered by a turbine to a patient. The method involves elaborating a pressure setting for the turbine. The pressure setting is elaborated using a signal representative of the rotation speed of a rotating element of the turbine.