28/08/2025
The cardiovascular system is responsible for delivering oxygen and nutrients to tissues while removing waste products.
It includes the heart, blood vessels, and blood, and works closely with the respiratory system to maintain homeostasis.
For respiratory therapists...
Understanding cardiovascular function is essential because heart and lung function are deeply interconnected.
Problems in one often affect the other!
Here are some important tips to remember:
Know the flow of blood: Understand the path of blood through the heartโfrom the vena cava to the right atrium, through the lungs, and out the left ventricle to the body. This helps interpret hemodynamic data and heart-lung interactions.
Understand cardiac output: It's calculated as stroke volume ร heart rate. A drop in either one can lead to inadequate tissue perfusion. Watch for changes in these values in critically ill patients.
Recognize signs of poor perfusion: Low blood pressure, cool extremities, cyanosis, decreased urine output, and altered mental status can indicate reduced cardiac output or shock.
Interpret key pressures: Central venous pressure (CVP) reflects right heart preload. Pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure (PCWP) reflect left heart function and can help diagnose conditions like CHF or pulmonary hypertension.
Oxygen delivery depends on both systems: Even if the lungs are working fine, poor cardiac output means tissues may still be hypoxic