TY - CHAP M1 - Book, Section TI - Chapter 93. Tamponade A1 - Tsai, Tony P. A2 - Atchabahian, Arthur A2 - Gupta, Ruchir PY - 2013 T2 - The Anesthesia Guide AB - Occurs when fluid or clots accumulate rapidly in the pericardial space, decreasing pericardial compliance; a large amount of pericardial fluid can accumulate over an extended period of time without causing tamponadeVentricular compliance is decreased, leading to decreased diastolic filling and decreased stroke volumeSystemic venous return is impaired and as RA and RV collapse occurs, blood accumulates in the venous circulation, which further decreases cardiac output and venous returnIn the extreme, pressures equalize in all heart cavities, with no blood flowCompensatory mechanisms:Tachycardia to maintain cardiac outputIncreased vascular resistance to maintain BPSpontaneous ventilation, by decreasing intrathoracic pressure on inspiration, facilitates RV filling and ejectionThree phases of hemodynamic changesPhase I: Increased stiffness of ventricle due to pericardial fluid accumulation, requiring a higher filling pressure (LV and RV filling pressures >intrapericardial pressure)Phase II: Pericardial pressure increases above ventricular filling pressure, resulting in decreased cardiac outputPhase III: Cardiac output decreases even more because of equilibration of pericardial and LV filling pressuresMedical emergency, needs to be treated immediately to avoid deathAny acute hemodynamic deterioration in a patient post cardiac surgery should lead to an emergent re-exploration, unless another obvious cause is present SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/04/19 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=57261795 ER -