Which of the following statement(s) is/are true concerning traumatic pericardial tamponade?

c. Two-dimensional echocardiography has replaced diagnostic pericardiocentesis in most hemodynamically stable patients

Injuries to the heart resulting in cardiac tamponade can occur from either blunt or penetrating trauma, though penetrating injuries are much more common. Pericardial tamponade occurring after blunt trauma usually results from rupture of a chamber of the heart, with many associated with death at the scene. Penetrating trauma is the usual cause of pericardial tamponade and the outcome is directly related to the character of the weapon. Reported survival rates for small injuries to a single chamber are between 60 and 87%, although patients who arrive moribund do poorly regardless of care. The diagnosis of pericardial tamponade should be considered in any patient with penetrating chest trauma, particularly to the central portion of the chest. The classic Beck’s triad, consisting of muffled heart sounds, decreased pulse pressure, and jugular venous distention, occurs in only the minority of patients. The diagnosis of pericardial tamponade can be somewhat difficult but should be suspected in patients with trauma who remain hypotensive and have no evidence of external blood loss or hemorrhage into the thorax, abdomen, or pelvis. Unfortunately, CVP measurements are neither sensitive or specific for the diagnosis of pericardial tamponade, and are dependent upon the patient’s volume status and the level of agitation. Two-dimensional echocardiography is very sensitive to the presence of pericardial fluid and wall motion abnormalities. If available in a timely fashion, cardiac echo is a very good diagnostic test to rule out cardiac tamponade in a stable patient. Under most circumstances, there is no role for diagnostic pericardiocentesis.