The two most prominent mechanical mediators of heart-lung interaction are changes in thoracic volume and intra-thoracic pressure. These are depicted on the Campbell Diagram laying into the page [on the x,z axes]. The Guyton Diagram remains on the x, y axes. Because the x-intercept of the cardiac function curve assumes intra-thoracic pressure, changes in intra-thoracic pressure are represented by parallel shifts in the cardiac function curve. The distending pressure or 'trans-mural' pressure of the right atrium is defined by the central venous pressure minus the intra-thoracic pressure.
A novel, graphical means of relating changes of thoracic volume and intra-thoracic pressure [as a function of pulmonary, chest wall and airway mechanics] to alterations in cardiac function and venous return.
Heart-lung.org will provide a comprehensive, on-line tutorial in cardiovascular and respiratory physiology for the interested medical student, resident and fellow.
The first 4 chapters will cover basic physiology and pathophysiology with an emphasis on the Campbell and Guyton Diagrams.
The remaining 4 chapters will focus on clinically-relevant topics in the intensive care unit; the discussions will be largely drawn from the physiology covered in the first half of the textbook.