An ambulatory respiratory assist device utilizes a cuirass worn on the chest and/or abdomen and supported by a hip belt so that it does not place a load on the patient's shoulders. The belt also supports a ventilator that includes a pump and its power supply, valving, controls and auxiliary equipment. The device is optionally integrated with auxiliary features such as chest wall vibration, which can be achieved by utilizing cuirass pressure modulation, with shoulder or upper arm supports for simulating the “tripod position”, with positive pressure ventilation apparatus, or with patient monitoring. Shoulder or upper arm supports can extend directly from the belt to the shoulders or upper arms, utilized independently of the cuirass, and optionally integrated with one or more of the above-mentioned auxiliary features.