Phillips, A.

Abstract Obstructive shock is rare, occurring in 2% of patients admitted to the intensive care unit (ICU) with shock. Understanding the unique pathophysiology of obstructive shock can aid in resuscitation efforts and significantly impact patient outcomes. Our goal is to expand the current understanding of possible shock etiologies and the treatment of obstructive shock. We present a case of an 88-year-old woman presenting to the ICU following an out-of-hospital cardiac arrest. Family found her unresponsive, called EMS, and started CPR. Upon EMS arrival, she had a pulse; the rhythm was identified as atrial fibrillation. She was cardioverted and transferred to the emergency room. Upon admission, she was intubated and sedated but hemodynamically stable. Shortly after arrival, she developed refractory shock requiring volume resuscitation and rapid titration of three vasoactive medications. She intermittently responded to volume but quickly developed recurrent shock following infusion completion. Bedside ultrasound showed collapse of the right atrium with a pericardial effusion and hyperechoic mobile mass within the pericardial space. Cardiology was called to the bedside for further evaluation of possible cardiac tamponade. There was lack of consensus regarding need for pericardiocentesis. Therefore, further chest imaging was ordered. CTA chest was negative for pulmonary emboli but showed a large hematoma in the anterior mediastinum with active bleeding. Formal echocardiogram confirmed a large extracardiac mass with extrinsic compression of the right atrium as well as a small-moderate circumferential pericardial effusion without obvious features of tamponade. She underwent an urgent IR angiogram with embolization of the internal mammary artery and placement of a 14F locking loop pigtail catheter into the anterior mediastinal hematoma felt to be contained within a known 3.5 cm benign cystic lesion. She experienced significant hemodynamic improvement following embolization and drain placement. The etiology of her presumed PEA arrest remained unclear, though it was concluded that the obstructive shock was due to the anterior mediastinal hematoma, a consequence of CPR. In this case we highlight the risk of arterial hemorrhage following resuscitation for cardiac arrest and the role it can play in the development of obstructive shock. There have been some documented cases of pericardial bleeding and the development of cardiac tamponade but limited case reports regarding arterial hemorrhage following CPR. Quickly identifying extracardiac compression allowed for appropriate and rapid IR embolization which led to clinical improvement in our patient.