A respiratory augmentation device to assist or augment a user's respiration may include a pressure generator configured to generate a supply of air at positive pressure, a transducer configured to output at least one signal indicative of at least one respiratory characteristic of the user, and a controller coupled with the pressure generator and transducer. The controller may determine a cyclic pressure profile for the pressurised air and control the pressure generator to achieve the pressure profile. The controller may further determine, using the output of the at least one transducer, whether adjustment of the cyclic pressure profile is required.