Cardiac Tamponade

Quick Answer

Cardiac tamponade is life-threatening compression of the heart by fluid (blood, effusion) in the pericardial space impairing diastolic filling and reducing cardiac output. Pathophysiology: Pericardial pressure increases with fluid accumulation (pericardium stiff, limited compliance); when pressure exceeds ventricular diastolic pressure, chamber collapse occurs (initially RA, then RV, then LV); equalization of diastolic pressures (RA = RV = PAOP = pericardial pressure). Clinical features: Beck triad (hypotension, elevated JVP, muffled heart sounds—most specific but only 10-30% have all three), dyspnoea, orthopnoea, chest discomfort, tachycardia, pulsus paradoxus (systolic BP drop >10 mmHg with inspiration, due to ventricular interdependence and limited total cardiac volume), electrical alternans on ECG (alternating QRS amplitude due to heart swinging in fluid). Echocardiography: Diagnostic test showing pericardial effusion, RA collapse in diastole, RV collapse in early diastole, dilated IVC without inspiratory collapse, exaggerated respiratory variation in mitral/tricuspid inflow. Aetiology: Malignancy (lung, breast, lymphoma), viral pericarditis, post-cardiac surgery (5-10% incidence), trauma, aortic dissection, anticoagulation, uraemia, TB. Haemodynamic stages: Stage 1 (compensated, pericardial pressure <10 mmHg, normal BP), Stage 2 (rising pericardial pressure 10-15 mmHg, narrow pulse pressure), Stage 3 (severe, pericardial pressure >15 mmHg, severe hypotension, imminent cardiac arrest). Anaesthetic management (for pericardial drainage): Avoid induction until surgeon ready with scalpel (cardiac arrest possible); keep patient spontaneously breathing if possible (negative intrathoracic pressure maintains venous return); avoid vasodilators (worsen hypotension); consider local anaesthesia + sedation for drainage if patient stable; GA only if necessary (ketamine maintains SVR, avoid propofol/thiopental which vasodilate); invasive monitoring (arterial line); vasopressors (phenylephrine, norepinephrine) to maintain coronary perfusion. Drainage: Pericardiocentesis (subxiphoid approach, echo-guided) for effusions; surgical pericardial window (subxiphoid or thoracoscopic) for recurrent or loculated effusions, post-surgical tamponade, or when pericardiocentesis fails. Post-drainage: "Pericardial decompression syndrome"—acute RV failure, pulmonary oedema due to sudden afterload reduction; careful fluid management, inotropic support may be needed. Indigenous patients: Higher rates of TB (pericardial involvement), rheumatic heart disease; delayed presentation common due to geographic isolation—higher likelihood of advanced tamponade at diagnosis. [1-10]