الاندحاس القلبي

Definition

Cardiac tamponade is compression of the heart by fluid or blood in the pericardial sac, so the ventricles cannot fill and cardiac output collapses.

Causes

• Penetrating chest trauma, or after cardiac surgery or catheterisation
• Pericarditis, cancer, kidney failure
• Ventricular free-wall rupture after MI, or aortic dissection

Signs

• Beck’s triad: hypotension, distended neck veins, muffled heart sounds
• Tachycardia and breathlessness
• Pulsus paradoxus: systolic pressure falling more than 10 mmHg on inspiration
• After heart surgery: chest-tube drainage that stops suddenly as BP falls

Diagnosis

Bedside echocardiography is fastest.

Treatment

• Pericardiocentesis or surgical drainage
• IV fluids to support filling until drainage

Nursing care

• Report immediately and prepare the drainage equipment
• Continuous BP, pulse and drain monitoring after heart surgery
• Avoid diuretics and nitrates, which reduce filling

Exam point

Tamponade and tension pneumothorax both cause hypotension and raised JVP, but breath sounds are normal in tamponade and absent on one side in pneumothorax.