Which parameter is expected to increase in the presence of cardiac tamponade?

In cardiac tamponade, pericardial fluid accumulation restricts cardiac filling leading to decreased stroke volume and cardiac output. As a compensatory mechanism, the heart rate increases (tachycardia) to maintain cardiac output.

Oxygen saturation typically does not increase; it may be normal or decreased if tamponade leads to hypoperfusion. Systolic and diastolic blood pressures often decrease due to reduced cardiac output.

This physiological response is well described in clinical cardiology texts and ASE pericardial disease guidelines【12:ASE Pericardial Disease Guidelines†p.300-305】【16:Textbook of Clinical Echocardiography, 6e†p.280-285】