Final Answer:
Systemic Vascular Resistance (SVR) and Pulmonary Vascular Resistance (PVR) are measures of the resistance faced by blood flow in the systemic and pulmonary circulations, respectively. SVR relates to the resistance in the systemic arteries, while PVR pertains to the resistance in the pulmonary arteries.
Step-by-step explanation:
Systemic Vascular Resistance (SVR) is a measure of the resistance that the systemic circulation presents to blood flow. It is crucial in assessing the workload on the heart and the efficiency of peripheral blood perfusion.
The calculation for SVR involves dividing the mean arterial pressure (MAP) by cardiac output (CO) and multiplying the result by 80, as SVR is usually expressed in dynes·s/cm^5. The formula is represented as SVR = (MAP / CO) × 80. Clinically, SVR is significant in conditions such as hypertension, sepsis, and heart failure, where alterations in vascular resistance impact cardiac function and overall hemodynamics.
On the other hand, Pulmonary Vascular Resistance (PVR) assesses the resistance within the pulmonary circulation. It is calculated by dividing the difference between the mean pulmonary artery pressure (MPAP) and left atrial pressure (LAP) by cardiac output. The formula is PVR = (MPAP - LAP) / CO. PVR is crucial in evaluating pulmonary hypertension and conditions affecting the pulmonary vasculature.
Understanding both SVR and PVR is essential in managing cardiovascular diseases, as they provide insights into the balance between the heart's pumping ability and the resistance encountered by blood in both systemic and pulmonary circulations.