Aetiology and Management of Acute Cardiac

Tamponade
D. COLLINS
Department of Anaesthesia and Intensive Care, Mater Misericordiae Hospital, Dublin, IREIAND

Objective: To review current concepts in the aetiology and management of patients with cardiac
tamponade.
Data sources: A review of articles reported on acute cardiac tamponade.
Summary of review: Cardiac tamponade is defined as a haemodynamically significant cardiac
compression caused by pericardial fluid. The fluid may be blood, pus, effusion (transudate or exudate) or
air and treatment involves correction of the cardiac diastolic restriction by removing pericardial fluid
during either pericardiocentesis or thoracotomy.
Pericardiocentesis is usually performed for urgent management of an acute tamponade. A thoracotomy
is required when a tamponade exists following coronary artery bypass grafting, cardiac rupture,
penetrating or closed cardiac trauma and aortic dissection or where a pericardial clot is likely. Removal of
pericardial fluid by percutaneous catheterisation of the pericardial sac traditionally uses the subxiphoid
‘blind’ approach., However, pericardial aspiration is often currently performed under transthoracic
echocardiographic guidance with the commonest site of needle entry being on the chest wall at or near the
apex and the needle directed perpendicular to the skin. The pericardial fluid is drained using an indwelling
‘pigtail’ catheter, preferably with close monitoring of the pulmonary artery wedge pressure, as rapid
removal of large volumes of pericardial fluid (> 500 mL) may result in a ‘decompressive syndrome’
causing pulmonary oedema. The fluid is sent for culture and Gram-stain and analysed for glucose, protein,
lactate dehydrogenase, haemoglobin and white cell count. If appropriate the fluid is also analysed for
amylase, and cholesterol and sent for cytology, serology and parasitic studies and viral, mycobacterial and
fungal cultures.
Conclusions: Cardiac tamponade may present as an acute or subacute syndrome of elevated central
venous pressure and hypotension. Pericardiocentesis using echocardiographic guidance and right heart
catheter control is often the method of choice for acute removal of fluid. (Critical Care and Resuscitation
2004; 6: 54-58)

Key words: Cardiac tamponade, pericardiocentesis, pericardial infection

The pericardium consists of a thin serous membrane protective functions.1 For example, it prevents acute
covering the epicardial surface (visceral pericardium) atrial dilation of the heart during exercise and
and a serous membrane-lined fibrous sac (parietal hypervolaemia, prevents acute atrial-ventricular valve
pericardium). They are fibrous structures with limited regurgitation, lubricates the moving heart, and prevents
elastic properties. The pericardial space separates the spread of infection to the myocardium from surrounding
two layers and contains approximately 20 mL of fluid. structures.2 An acute accumulation of pericardial fluid
Congenital absence of the pericardium or peri- of greater than 100 mL will produce haemodynamic
cardiectomy are not associated with deleterious effects of tamponade whereas a chronic pericardial
cardiovascular effects, indicating that the pericardium is collection of fluid up to 2000 mL may occur without
not essential for life. Nevertheless, it does have several imposing any effect upon cardiac output.3

Correspondence to: Dr. D. Collins, Department of Anaesthesia and Intensive Care, The Mater Misericordiae Hospital, Eecles St,
Dublin 7, Ireland

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Critical Care and Resuscitation 2004; 6: 54-58 D. COLLINS

Cardiac tamponade is defined as a haemo- and pregnancy. Pulsus paradoxus may also be prevented
dynamically significant cardiac compression caused by from occurring in patients with cardiac tamponade if the
pericardial fluid.4 The fluid may be blood, pus, effusion patient’s tidal volume is reduced (e.g. the patient
(transudate or exudate) or air.5 The principal haemo- becomes obtunded) or is mechanically ventilated or if
dynamic effect is a constraint on atrial filling with a severe left ventricular dysfunction, or a regional
reduction in atrial diastolic volume,6 which causes an tamponade, atrial septal defect or aortic regurgitation
increase in atrial diastolic pressure.7 During the early coexist.10-13
stages of cardiac tamponade, cardiac output and organ
perfusion are maintained by an increase in the ejection Table 1 Causes of cardiac tamponade
fraction to 70% - 80% (the normal ejection fraction
ranges from 50% - 70%), tachycardia and peripheral Haemorrhagic
vasoconstriction.3 Trauma
Penetrating and blunt chest trauma
Causes Cardiac catheterisation, pacemaker insertion,
The causes of a cardiac tamponade include an acute central venous cannulation,
accumulation of pericardial fluid from a ruptured percutaneous coronary artery angioplasty
myocardium (following myocardial infarction, blunt or Post operative thoracotomy
penetrating cardiac trauma or cardiac perforation Pericardiocentesis
following cardiac catheterisation), proximal dissecting External cardiac compression
aortic aneurysm, carcinomatous infiltrate of the Myocardial infarction
pericardium and acute pericarditis. As the fluid may be Rupture
blood, blood stained (sero-sanguinous), pus, transudate Anticoagulation, thrombolytic therapy,
or exudates, the aetiology of the tamponade may be antiplatelet agents
classified as haemorrhagic, sero-sanguinous, serous or Dissecting aortic aneurysm
purulent (Table 1). Anticoagulant therapy
Serous or sero-sanguinous
Clinical features Neoplastic
The classical presentation of a cardiac tamponade is Lung or breast cancer, lymphoma
an elevated venous pressure, decreased systemic arterial Connective tissue diseases
pressure and a quiet heart (i.e. Beck’s triad).8 However, Systemic lupus erythematosus,
in one study of 56 patients with cardiac tamponade the rheumatoid arthritis
triad was often absent (most did not have a quiet heart Rheumatic fever, polyarteritis
and the blood pressure was often well maintained).9 Idiopathic thrombocytopenic purpura
The major symptoms are often dyspnoea (the patient Uraemia
often is found leaning forward or sitting in the knee- Radiation therapy
chest position to relieve the breathlessness), fatigue and Idiopathic
light-headedness. Purulent
The signs include tachypnoea, tachycardia, hypo- Infectious
tension (although hypertension may occur, particularly Bacterial
in patients with pre-existing hypertension),10 shock (i.e. Viral (coxsackie B, influenza,
pale, cool clammy extremities and poor peripheral infectious mononucleosis)
perfusion), faint heart sounds, pericardial rub and Mycobacterial, yeast
pulsus paradoxus. Pulsus paradoxus describes a pulse
that demonstrates a systolic blood pressure reduction
greater than 10 mmHg during quiet inspiration. It The central venous pressure is characteristically
represents an exaggeration of the normal decline in elevated (although it may not be elevated if the
pulse pressure on inspiration, which occurs due to a tamponade is localised to the left atrium or ventricle)13
reduction in left ventricular stroke volume caused by a and does not increase on inspiration (i.e. Kussmaul’s
decrease in preload and increase in afterload. It is sign is negative).14 The lungs are usually clear, although
characteristically found in acute cardiac tamponade9 a large pericardial effusion may produce Ewart’s sign
although, it can also be found in right ventricular (i.e. dullness to percussion and bronchial breathing at
infarction, severe congestive cardiac failure, the left lung base due to compression of the left lung
myocarditis, emphysema, acute asthma, hypovolaemic base). However, this is a non-specific finding and may
shock, pulmonary embolism, extreme obesity, ascites occur in any patient with cardiomegaly.15

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D. COLLINS Critical Care and Resuscitation 2004; 6: 54-58

While cardiac tamponade may be suspected hypotension rather than confirm the diagnosis of cardiac
clinically in a patient with dyspnoea, a clear chest, tamponade.
elevated systemic venous pressure, tachycardia and
paradoxical arterial pulse,13 the patient may present with Chest X-ray. The chest X-ray may be within normal
hypotension or shock without any of the characteristic limits although features suggestive of pericardial fluid
clinical features. include an enlarged globular cardiac shadow with loss
of the hilar waist (if the pericardial effusion is greater
Investigations than 250 mL) with a normal pulmonary vascular
Echocardiography. This is the most reliable and pattern. Other signs include prominence of the superior
convenient way of diagnosing pericardial fluid, clot and vena cava (reflecting an elevation in the central venous
the haemodynamic effects of the effusion. It can detect pressure), pleural effusions (transudates which may be
signs of tamponade before clinical signs occur or an caused by a raised central venous pressure) and the
effect on cardiac output is found.16 For example epicardial fat pad sign (which is best seen on the lateral
tamponade will be detected by an abnormal septal chest radiograph as a radiolucent line between the
motion (both ventricular and atrial septa move sharply epicardial fat and the mediastinal fat and represents the
leftward on inspiration and reverse with inspiration), pericardium. It should be 2 mm or less, so any increase
right atrial and right ventricular diastolic collapse suggests fluid or thickening in the pericardium).
(indicative of an elevated intrapericardial pressure that
transiently exceeds the intra-cavity pressure with the Haemodynamic monitoring
collapse of the atrial and ventricular walls), and reduced a) Arterial catheter. Direct assessment of the
respiratory variation of the diameter of the inferior vena arterial pressure is useful as it allows
cava (Doppler assessment of intracardiac flows and identification of an abnormal pulsus paradoxus.
their relationship to respiration may also play a useful b) Right heart catheterisation. The characteristic
role in the diagnosis).17 In patients without heart disease haemodynamic changes associated with cardiac
the ejection fraction is normal or increased. tamponade include:19
In addition to detecting an effusion, it can assess the - a right atrial pressure wave with a prominent
distribution of the effusion (e.g. loculated or ‘x’ descent (i.e. forward venous flow occurs
concentric). Trans-oesophageal echocardiography will only during systole) but not a prominent ‘y’
facilitate detection of a tamponade if a mitral valve or descent
aortic valve prosthesis is present or a localised posterior - equalisation of diastolic pressures (to within
clot exists in the post cardiac surgery patient. 3 - 4 mmHg) in the right atrium, right
Other investigations include ventricle, pulmonary artery and left atrium
(i.e. all average diastolic pressures at 12 - 25
ECG. This may reveal sinus tachycardia, low- mm/Hg in the absence of pulmonary
voltage complexes and non-specific ST segment and T oedema).18
wave changes or ST segment elevation due to - pulsus paradoxus in the pulmonary artery
pericarditis. Electrical alternans (due to a pendular pressure that is out of phase with the
swinging motion of the heart within a pericardial systemic pulsus paradoxus.
effusion) is characteristically seen only with a large
effusion.3 Combined P and QRS alternation is said to The differences between the two cardiac restrictive
be pathognomonic for tamponade.18 Nonetheless, an disorders of cardiac tamponade and constrictive
ECG is largely used to rule out other causes of pericarditis are listed in table 2.

Table 2. A comparison of the features of cardiac tamponade and constrictive pericarditis

Tamponade Constrictive pericarditis

Pericardial effusion Present Absent

Pericardial calcification Absent Often present
Dip and plateau pattern Inconspicuous Prominent
RAP waveform Prominent ‘x’ descent Prominent ‘x’ and ‘y’ descent
Pulsus paradoxus Prominent Inconspicuous
Kussmaul’s sign Absent Often present
Diastolic ‘knock’ Absent Often present

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Critical Care and Resuscitation 2004; 6: 54-58 D. COLLINS

Treatment However, blind pericardial aspiration is not

The patient is initially resuscitated with intravenous recommended as a routine procedure as it has an
fluids to promote maximum filling of the heart. unacceptably high complication rate with a recorded
However, increasing the intravascular volume is usually mortality and technical complication rate as high as 6
only helpful in hypovolaemic patients as intravenous and 50%, respectively.21,22 Currently, pericardial
fluids in normovolaemic or hypervolaemic patients may aspiration performed under transthoracic echocardio-
only increase right-ventricular filling at the expense of graphic guidance is the treatment of choice for
the left ventricle and has had disappointing results in percutaneous aspiration of the pericardial effusion.21,23
clinical trials.20 In general, inotropic agents that increase The echocardiogram will not only detect the pericardial
the stroke volume and support systemic resistance are fluid, but will determine whether there is any haemo-
also used, although one reviewer recommended dynamic effect (i.e. tamponade) whether it is largely
isoprenaline, as it reduces the cardiac size and clot (where a thoracotomy and surgical evacuation
diminishes the effective degree of tamponade while rather than pericardiocentesis may be required), whether
increasing cardiac output.3 it is loculated, where the fluid is predominantly found,
The definitive treatment of cardiac tamponade is the the chest surface location closest to the effusion and the
removal of the cardiac diastolic restriction by either angle and distance the needle has to travel (without
pericardiocentesis or thoracotomy. Pericardiocentesis is piercing intervening vital structures e.g. lung) before it
usually performed for urgent management of an acute enters the effusion. Using this approach the commonest
tamponade (the acute removal of as little as 50 mL of entry of the needle is on the chest wall at or near the
fluid is often sufficient to correct the acute apex and directed perpendicular to the skin.24 Any
hypotension). A thoracotomy is often required when a percutaneous site that is selected should avoid the
tamponade exists following coronary artery bypass internal mammary artery (3 - 5 cm from the parasternal
grafting, cardiac rupture, penetrating or closed cardiac border) and the vascular bundle at the inferior margin of
trauma and aortic dissection, where continuous blood each rib.21
loss occurs and the source of the bleeding often requires Continuous intra-arterial blood pressure and
surgical correction or where a pericardial clot is likely, pulmonary artery pressure measurements should be
which cannot be easily aspirated. It is also indicated performed during pericardial aspiration. When
when pericardiocentesis has failed to relieve the pericardial entry occurs, the first 100 - 200 mL of fluid
tamponade. should be drained rapidly. Thereafter the remainder is
Pericardiocentesis involves removal of pericardial drained slowly using an indwelling ‘pigtail’ catheter
fluid by percutaneous catheterisation of the pericardial (inserted over a guidewire), preferably with close
sac. The subxiphoid ‘blind’ approach to pericardio- monitoring of the pulmonary artery wedge pressure, as
centesis has been the traditional approach which rapid removal of large volumes of pericardial fluid (>
involves placing the patient in a supine 30º - 45º head- 500 mL) may result in a ‘decompressive syndrome’
up position to facilitate the movement of the effusion causing pulmonary oedema.25 The fluid is sent for
towards the anterior chest wall. A large-bore needle is glucose, protein, lactate dehydrogenase, haemoglobin,
inserted at the right side of the xiphisternum and white cell count, culture and Gram-stain. If appropriate
advanced subcostally, aiming towards the tip of the left the fluid is also sent for amylase, cholesterol, cytology,
shoulder, with continuous suction applied to a syringe serology (rheumatoid factor, antinuclear factor,
which is attached to the hub of the needle. The needle complement levels), viral, mycobacterial and fungal
can be used as a chest ECG lead to detect myocardial cultures and parasitic studies.
contact indicated by ST segment elevation (although If there is no drainage after 24 - 72 hr and a repeat
ECG monitoring may provide misleading results and is echocardiogram demonstrates no reaccumulation of
not uniformly recommended).18 If blood is aspirated fluid, the pigtail catheter is removed from the
from a cardiac chamber, it clots, unlike blood pericardial cavity.
withdrawn from the pericardial cavity; also, bloody
pericardial fluid on a gauze swab separates, with a
central deep red spot and a peripheral halo which is less Received 5 February 04
Accepted 20 February 04
red, whereas blood from a cardiac cavity spreads
uniformly throughout the gauze swab. A haemoglobin
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D. COLLINS Critical Care and Resuscitation 2004; 6: 54-58

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