The classical clinical scenario of Beck’s triad (increased jugular venous pressure, hypotension and muffled heart sounds) is frequently difficult to diagnose in a postoperative sedated and ventilated patient. A decrease in the hourly urine output is often an early indicator that cardiac output is compromised. Chest drains might have precipitously stopped draining if a clot has formed. Hypotension, tachycardia and a worsening metabolic acidosis can be the next signs.