Final answer:
Cardiac tamponade causes hypotension because the accumulation of excess fluid in the pericardial space prevents the heart from properly filling with blood, thus reducing stroke volume and blood pressure.
Step-by-step explanation:
Why Cardiac Tamponade Causes Hypotension
Cardiac tamponade occurs when excess fluid accumulates within the pericardial space, placing pressure on the heart, impairing its ability to properly relax and fill with blood during its relaxation phase. This condition leads to a reduction in the volume of blood that the heart can eject with each beat, known as stroke volume. As the heart pumps less blood, the blood pressure drops, resulting in hypotension. The pericardial cavity may accommodate excess fluid gradually in conditions such as hypothyroidism, but rapid fluid accumulation, which can happen with trauma, myocardial rupture, pericarditis, cancer, or post-cardiac surgery, can cause acute cardiac tamponade. Moreover, the premature removal of drainage tubes following cardiac surgery or clot formation within these tubes can also lead to tamponade. When untreated, cardiac tamponade can be fatal as it dramatically affects the blood circulation throughout the body.