lung contusion is an entity involving injury to the alveolar capillaries, without any tear or cut in the lung tissue. this results in accumulation of blood and other fluids within the lung tissue. the excess fluid interferes with gas exchange leading to hypoxia. the pathophysiology of lung contusion includes ventilation/perfusion mismatching, increased intrapulmonary shunting, increased lung wa...

variability of tidal volume and respiratory rate in normally breathing man has long been demonstrated [1]. however because of lack of knowledge and technology primary ventilators could only deliver a fixed tidal volume in a fixed rate the so called volume controlled ventilation (vcv). vcv was volume preset time triggered and cycled and there was no synchronization with patient’s breaths. at tha...