Pathophysiology and clinical assessment of the cardiovascular system (including pulmonary artery catheterization)

The underlying pathophysiological derangements of the cardiovascular system in many medical conditions are often complex. Acute circulatory dysfunction can be related broadly to a cardiogenic cause leading to acute heart failure or be secondary to hypovolaemia or vascular dysfunction (e.g. sepsis). Different mechanisms may be involved, including left ventricular diastolic and/or systolic dysfunction and/or right ventricular dysfunction. Many aspects of left ventricular function are explained by considering ventricular pressure–volume characteristics. Epidemiological studies show that clinical signs at admission, morbidity, and mortality differ between the main scenarios of acute heart failure: left ventricular diastolic dysfunction, left ventricular systolic dysfunction, right ventricular dysfunction, and cardiogenic shock. Although echocardiography is usually the first investigation used to assess the mechanism of cardiac dysfunction, in selected cases (in particular, in cases of refractory shock secondary to both vascular and heart dysfunction or in cases of refractory haemodynamic instability associated with severe hypoxaemia), the pulmonary artery catheter can help to assess and monitor the cardiovascular status and evaluate response to treatments.