There is no specific therapy for myocardial contusion, other than treatment of any resultant arrhythmia and circulatory support as necessary More significant blunt cardiac injuries, such as disruption of the atria, ventricle, or valves require emergent surgical repair In the unstable patient in whom pericardial tamponade is suspected, treatment includes control of the airway, intravascular volume resuscitation, and immediate pericardiocentesis ( Fig 115.6 ) Bedside US may assist in both diagnosis and management and can often be performed concurrently with the physical examination A US showing a large pericardial effusion in the clinical context of tamponade physiology should be sufficient to proceed with pericardiocentesis; additional findings, including diminished or paradoxical septal wall motion and poor cardiac output, may be evident to the more experienced sonographer Pericardiocentesis is performed by inserting a 20-gauge spinal needle below the xiphoid process at a 45-degree angle toward the left shoulder ( Fig 115.7 ) Dynamic US guidance can help assure proper placement of the needle Continuous EKG monitoring can be used as well, as a current should be noted on the EKG monitor if the needle touches the heart Blood aspirated from the pericardial sac can be differentiated from intracardiac blood because pericardial blood is defibrinated and does not clot Alternatively, pigtail catheters can be placed into the pericardial sac over a guidewire for continual drainage of blood using commercially available equipment kits designed for this purpose Even though patients may show transient improvement after removal of blood from the pericardial sac, the patient should be taken to the operating room immediately for a pericardial window or other surgical intervention (see Chapters 130 Procedures, section on Pericardiocentesis , and 131 Ultrasound ) For the stable patient with suspected pericardial tamponade, echocardiogram is the study of choice CXR may show an enlarged heart and an EKG may show low-voltage QRS waves While these patients will also require pericardiocentesis, consultation with the pediatric trauma surgery team, cardiac surgeon, and/or interventional cardiologist to perform this in the operating room or cardiac catheterization laboratory is recommended provided the patient’s clinical condition allows time for these resources to be mobilized