Cardiac Tamponade

The Pericardium is made up of 2 layers; the visceral and parietal pericardium. These layers contain a small amount of fluid (< 50 mls) between them for lubrication. This lubrication allows the heart to beat w/o generating much friction. In a pericardial effusion, this potential space between the layers becomes more filled, therefore putting pressure on the heart and making it more difficult to expand during diastolic filling.

Pericardial effusion - Excess fluid collects in pericardial sac. This fluid can be:

• Transudative - low protein

• Exudative - high protein, and associated w/inflammation

• Blood

• Pus

• Gas - associated w/bacterial infections

Cardiac Tamponade - Effusion becomes large enough to increase the intra-pericardial pressure, therefore squeezing the heart and reducing it’s effectiveness during diastole AND systole → Reduced CO. This requires rapid drainage with Pericardiocentesis.

Causes

Transudative effusion - Due to an increased venous pressure, which reduces drainage from the pericardial cavity. This is typically caused by Congestive HF and Pulmonary HTN.

Exudative effusion - Due to inflammation of the pericardium (pericarditis). This can be caused by:

• Infection

• Autoimmune e.g. SLE, RA

• Injury to pericardium e.g. post-MI, surgery, trauma

• Uraemia secondary to renal impairment

• Cancer

• Medications e.g. methotrexate

Haemopericardium - Due to rupture of the heart/aortic root. This can be caused by Trauma, MI, Type A Aortic Dissection.

Presentation

A rapid collection of fluid can quickly cause haemodynamic instability and collapse (Cardiac tamponade), whereas a slower collection of fluid may initially be asymptomatic and, as pressure rises, the symptoms develop.

Pericardial effusion will present with:

• Chest pain

• SOB

• Orthopnoea

• Feeling of fullness in chest

• Compression of surrounding structures, leading to:

  • Phrenic nerve → Hiccups

  • Oesophagus → Dysphagia

  • Recurrent laryngeal nerve → Hoarse voice

Cardiac Tamponade presents with Beck’s Triad – Hypotension, Muffled heart sounds, Raised JVP.

Signs O/E include:

• Muffled heart sounds

• Pulsus Paradoxus (large fall in BP on inspiration)

• Hypotension

• Raised JVP

• Fever and pericardial rub with pericarditis

Investigations

• Echo

• Pericardiocentesis - Fluid analysis on the pericardial fluid to determine the underlying cause - Protein (distinguishes between transudative and exudative)

• ECG – Small QRS complexes

• CXR – Large globular heart

Management

If the patient is haemodynamically unstable, they need an urgent Pericardiocentesis. Complications that occur with this procedure are pneumothorax, myocardial damage etc. – CXR should be done post-procedure to exclude this.