Cardiac tamponade

Cardiac tamponade is a condition of reduced cardiac output due to mechanical compression of the heart.

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What causes cardiac tamponade?

• Recent heart surgery, especially if:
  • After the operation, bleeding from the drains was massive;
  • the pleura was not opened during the operation;
  • The operation was repeated.
• Chest trauma (blunt or penetrating).
• Coagulopathy (both hyper- and hypocoagulation).
• Hypothermia.

How does cardiac tamponade manifest itself?

• Systemic hypotension with an increase and equalization of ventricular filling pressures (RA (CVP) and LA (PCWP)); decreased pulse pressure, increased pressure in the external jugular vein; pulsus paradoxus; absence of "y" - decrease in the pulse wave of the central vein.
• Oliguria. Decreased peripheral perfusion, cyanosis, metabolic acidosis, hypoxemia.
• Dyspnea/respirator "resistance".
• A sudden decrease or disappearance of blood actively flowing through a pleural drainage system in a patient after cardiac surgery.
• Heart failure.

How is cardiac tamponade recognized?

• Chest X-ray (widened mediastinum).
• ECG (low voltage, electrical alternans, T wave changes).
• Echocardiogram/TEE Doppler (pericardial fluid collection; small, non-filling ventricles).
• Floating pulmonary artery catheter (low cardiac output, systemic vasoconstriction, high PCWP).

Differential diagnosis

• Tension pneumothorax.
• Cardiogenic shock / myocardial failure / myocardial infarction.
• Pulmonary embolism.
• Excessive transfusion, fluid overload.
• Anaphylaxis.

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What to do if there is cardiac tamponade?

• Respiratory tract - breathing - circulation... 100% 02.
• Assess the state of vital functions.
• Establish adequate venous access if not already done, begin intravenous fluids, inotropic support.
• After heart surgery - release/"milk" the drainage tubes, try to remove clots from their lumens by suction with a soft catheter. Call the surgeons; notify the operating room; prepare to open the chest (if necessary - in the cardiology recovery room).
• If a penetrating foreign body is present, DO NOT remove it.
• Initiate anaesthesia before opening the chest: technique should maintain sympathetic tone (eg, etomidate/ketamine; suxamethonium/pancuronium; fentanyl); once the chest is opened, intubation and ventilation will be required; be prepared to open the chest (wire cutters) immediately after induction.
• If hemodynamics cannot be controlled, open the chest immediately.
• Pericardiocentesis will help to gain time and mitigate the hemodynamic catastrophe.
• Order blood and clotting factors if needed.

Further management

• Maintain filling pressure and sympathetic tone; avoid bradycardia.
• The use of vasodilators is controversial.
• Expect a sharp jump in blood pressure immediately after opening the chest and removing the tamponade; usually, evacuation of the mediastinal contents is quickly followed by stabilization of hemodynamics.
• Make sure the surgeon has found the source of the bleeding and cleared the drains of clots.
• Correct metabolic acidosis.
• Mechanical ventilation may worsen tamponade and aggravate hypotension.
• If the chest was opened, repeat the antibiotics.

Pediatric Features

• Cardiac tamponade can occur when a very small amount of blood enters the mediastinum.
• Cardiac tamponade can be completely sudden and immediately manifest as cardiac arrest.
• The risk is increased in cyanotic states, complex reoperations, and coagulation disorders in combination with liver congestion.

Special considerations

Electrical alternants - the shift of the QRS axis from contraction to contraction is accompanied by mechanical rocking of the heart in a large volume of accumulating fluid. Pathognomonic for a condition such as cardiac tamponade, although not always observed.

After cardiac surgery, there should be high alertness for such a pathological condition as cardiac tamponade.

A definitive diagnosis is only possible after opening the chest - even a small accumulation of fluid in the pericardium, detected by echocardiography, can have a significant hemodynamic impact if it compresses the right atrium.

The diagnosis of cardiac tamponade can be quite difficult, especially if there is a possibility of failure or overload.

Severe coronary blood flow impairment may cause myocardial ischemia, further complicating the diagnosis. The clinical picture may develop slowly or very rapidly. Patients with hypocoagulability are more likely to have pericardial hemorrhage. Patients with hypercoagulability are more likely to have pleural drainage thrombosis (NB: use of aprotinin in severe postoperative bleeding may cause drainage thrombosis).

In cases of penetrating wounds to the heart, including stab wounds and gunshot wounds, the patient must be immediately transferred to the operating room and the pericardium opened. Percutaneous drainage of the pericardium is usually ineffective - it should be reserved for situations where surgery is not possible.