Clinical implications of heart-lung interactions.

As opposed to spontaneous respiration wherein small cyclic changes in transpulmonary, negative pressure coincide with lung volume changes, positive pressure (mechanical) ventilation results in a simultaneous rise in transpulmonary pressure and lung volumes. The changes may affect biventricular cardiac loading and function in dissimilar ways, depending on baseline cardiopulmonary function. This review is intended to update current knowledge on the pathophysiology of these heart-lung interactions in helping to explain the common circulatory alterations occurring during airway pressure changes and to better understand mechanisms of disease and modes of action of treatments, during spontaneous and mechanical ventilation.