Figure 3.

The concept of organ perfusion pressure and its relationship to the balance of the mean arterial pressure (MAP), the central venous pressure, and the efficient output of the cardiac pump. Imbalances between the arterial inflow and central venous pressures affect the end organ flow efficiency (curved red and blue arrows) and contribute to venous congestion and organ dysfunction. Eventually, the state of iatrogenic edema leads to inefficient end organ functioning. Note that, in addition to inotrope regulation of cardiac pump, both the arterial and central venous sides of the equation can be modified using a combination of vasopressor, volume removal or resuscitation, or continuous renal replacement therapy (in cases of renal failure). This diagram demonstrates the potential roles of central venous pressure as the “accelerator” and the pulmonary artery catheter as the “brake pedal”. Also note that central venous pressure in combination with transthoracic or (preferably) transesophageal echocardiography is capable of providing clinical information similar to that provided by the pulmonary artery catheter. Other less invasive methods of hemodynamic monitoring await full clinical validation