Cardiac tamponade is a relatively rare condition. If a
pericardial effusion compromises hemodynamics, pericardiocentesis
can be lifesaving. The cause of cardiac tamponade may be
determined by fluid analysis after pericardiocentesis (Table
37-1 Etiologies of Pericardial Effusions
| Save Table
37-1 Etiologies of Pericardial Effusions
|Sagrista-Sauleda* (n = 322) (%)||Corey GR† (n = 75)
(%)||Levy PY‡ (n = 204) (%)||Kil UH# (n = 116) (%)|
In a small study of medical cardiac tamponade, the mean volume drained
was 593 ± 313 mL. When the primary cause was malignancy, nearly
80% of the patients had a 1-year mortality.1
Maintain a high degree of suspicion of cardiac tamponade for
oncology patients who fit the clinical signs and symptoms of tamponade.
Blunt cardiac rupture is rare, occurring approximately once in
2400 blunt trauma patients. Of this subgroup, 89% arrive
alive to the ED.2 Those who arrive alive may benefit
from a bedside US examination to detect a traumatic effusion. Tamponade
may require a temporizing pericardiocentesis while the patient is
prepared for definitive surgical repair.
In a South African study, mortality from gunshot wounds compared
to stab wounds was 81% and 15.6%, respectively.3 This
comparison underlines the probability that patients with stab wounds
to the heart are more likely to survive to the ED and may benefit
The pericardium is a fibrocollagenous sac covering the heart
that contains a small amount of physiologic serous fluid. The fibrocollagenous
pericardium has elastic properties and will stretch in response
to increases in intrapericardial fluid. Accumulation of fluid that
exceeds the stretch capacity of the pericardium precipitates hemodynamic
compromise and results in pericardial tamponade.
The initial portion of the pericardial volume–pressure
curve is flat, so early on, relatively large increases in volume
result in comparatively small changes in intrapericardial pressure.
The pericardium becomes less elastic as the slope of the curve marches
upward. As fluid continues to accumulate, intrapericardial pressure
rises to a level greater than that of the filling pressures of the
right atrium and ventricle. When this occurs, ventricular filling
is restricted and results in cardiac tamponade.4
Pulsus paradoxus is commonly seen with cardiac tamponade. The pathophysiology
of this abnormal pulse is that, during an inspiratory cycle, intrathoracic
pressure is reduced, allowing more venous return to the heart and
increasing the volume of the right ventricle. On the next cardiac
cycle, the pulmonary vascular beds fill, thus exceeding the output of
the right ventricle. This causes a decrease in blood returned to
the left ventricle and a decrease in the atrial and ventricular
pressures during inspiration. Increases in intracardiac pressure,
as seen in tamponade, further decrease left ventricular filling,
leading to a larger drop in systolic blood pressure during inspiration,
which results in a paradoxical pulse.5
In blunt trauma, forces within the thorax can compress the right
atrium, resulting in rupture of the atrium or the right atrial appendage.
This occurs when blood continues to fill the relatively inelastic
pericardial sac. Deceleration injuries can lead to a cardiac or
pericardial rupture, herniation, or a myocardial contusion with
intrapericardial hemorrhage. During an acute rapidly expanding
pericardial effusion, stroke volume will increase with removal of
even a small amount of fluid (as little as 50 cc) from the pericardial
sac (Figure 37-1).
Acute versus chronic effusion. Pericardial volume–pressure
curve with acute (solid line) versus chronic effusion
(dotted line). [Reproduced with permission
from Reardon RF, Joing SA: Cardiac, in Ma OJ, Mateer J, Blavais
M (eds): Emergency Ultrasound, 2nd ed. New York,
Trauma as a cause of pericardial tamponade is generally evident
from history and clinical presentation. Oncology patients comprise
the largest group with pericardial effusions leading to hemodynamic
compromise. Other conditions that may predispose a patient to pericardial
effusion and tamponade include acute infection (viral, bacterial,
mycoplasma, fungal, parasitic, or endocarditis) or radiation exposure.
Other chronic conditions in which this diagnosis may be considered
include tuberculosis, renal failure, autoimmune diseases, drugs
that induce a lupuslike syndrome, hypothyroidism, or ovarian hyperstimulation
syndrome.6 Many cases are idiopathic.
The key symptoms of tamponade are dyspnea and chest pain. Trauma patients
may or may not exhibit pleuritic pain, tachypnea, and dyspnea before
becoming confused, losing consciousness, or developing shock.7 Other
symptoms include chest fullness, nausea, esophageal pain, or abdominal
pain from hepatic and visceral congestion. Other nonspecific symptoms
include lethargy, fever, weakness, fatigue, anorexia, palpitations,
and shock. Emergency physicians need to be aware of these symptoms
and accordingly focus the examination to exclude life-threatening conditions,
such as cardiac tamponade.
Common clinical signs of cardiac ...