Evaluation and Initial Stabilization of Undifferentiated Shock.

Vascular Interventional Radiologists (VIRs) are increasingly involved in consultation and management of patients with circulatory shock. The ability to recognize the underlying pathophysiology of a patient's shock and treat appropriately is therefore critical to VIR practice. Here, we discuss the initial evaluation and stabilization of undifferentiated shock. Shock is defined as tissue hypoperfusion from inadequate oxygen delivery and/or impaired tissue oxygen utilization. The etiologies of shock can be grouped into 3 main categories: distributive, hypovolemic, cardiogenic, and obstructive; each of which are associated with characteristic hemodynamic and metabolic derangements such as decreased preload or impaired cardiac contractility. Presentation typically involves 1) hypotension and tachycardia as indicators of impaired cardiac output, and 2) evidence of ongoing end-organ hypoperfusion such as oliguria, altered mental status, and lactic acidosis. Initial management includes control of airway and oxygenation/ventilation, identification of underlying hemodynamic and cardiovascular derangements, and support of cardiac output with intravenous fluid (IVF), blood products, diuresis, and/or vasopressors and inotropes. More detailed hemodynamic analysis can be performed with arterial catheters, blood gases, pulmonary artery catheters, and echocardiography to further tailor therapy. Finally, definitive evaluation for causative etiology should be initiated immediately with biochemical studies, cultures, imaging, and hemodynamic assessment so that etiology-specific treatment (e.g. antibiotics, blood products) can be initiated.