Hemodynamics
Hemodynamics is defined as the forces affecting the flow of blood throughout the body. Human beings cannot survive without adequate oxygenation, and the primary function of the cardiopulmonary system is to deliver an appropriate amount of oxygen and nutrients to meet the metabolic demands of the body and then to remove metabolic waste products.
A healthy body constantly regulates the amount of blood ejected by the heart, cardiac output, to maintain adequate tissue perfusion. In disease states, however, hemodynamic imbalances occur and the body is forced to compensate, often severely, for cardiovascular and systemic vascular dysfunction. Most (if not all) cardiac drugs administered for both acute and chronic conditions, affect either directly and indirectly one of the four factors that comprise cardiac output:
| Component | Meaning |
|---|---|
| Preload | Volume of blood in the ventricle at the end of diastole |
| Contractility | Rate of shortening of myocardial muscle fibers |
| Afterload | Force heart must overcome to expel blood into the vasculature |
| Heart Rate | Number heart beats per minute |
The measurement of cardiac output and its derivatives allow clinicians to make timely patient assessment, diagnosis, prognosis, and treatment decisions. It has been well established that both trained and untrained physicians alike are unable to estimate cardiac output through physical assessment alone.
Read more about this topic: Impedance Cardiography