Clinical Manifestations and Types of Shock

Introduction to Shock

Shock is characterized by decreased perfusion manifested by altered mental status, capillary refill >2 seconds or flash capillary refill, diminished or bounding peripheral pulses, mottled cool extremities, and decreased urine output <1 mL/kg/h, according to the American College of Critical Care Medicine 1, 2

Altered or decreased mental status, ranging from irritability and confusion to lethargy and becoming unarousable, is a neurological sign of shock, as stated by the American College of Critical Care Medicine 3
Tachycardia is an early compensatory mechanism to maintain cardiac output in shock, as noted by the American Heart Association 4
Abnormal pulse quality, including weak pulses in hypovolemic and cardiogenic shock, and bounding peripheral pulses in warm/distributive shock, is a cardiovascular sign of shock, according to the American College of Critical Care Medicine 1, 4
Prolonged capillary refill time >2 seconds in cold shock and flash capillary refill in warm shock are skin findings in shock, as stated by the American College of Critical Care Medicine 1
Decreased urine output (<1 mL/kg/h) is a sensitive indicator of inadequate perfusion in shock, according to the American College of Critical Care Medicine 1, 2

Hypovolemic shock is characterized by venoconstriction, low jugular venous pressure, poor tissue perfusion, tachycardia, and cold extremities, as noted by the European Society of Cardiology 5
Cardiogenic shock is characterized by signs of heart failure, elevated jugular venous pressure, weak peripheral pulses, cool extremities, systolic pressure <90 mmHg, and central filling pressure >20 mmHg, according to the European Society of Cardiology 5
Distributive shock is characterized by warm extremities, bounding peripheral pulses, wide pulse pressure, and flash capillary refill, as stated by the American College of Critical Care Medicine 1, 3

Decreased mixed venous oxygen saturation (ScvO2 <70%) and decreased superior vena cava flow (<40 mL/kg/min in neonates) are laboratory findings in shock, according to the American College of Critical Care Medicine 6
Abnormal arterial blood gases are a laboratory finding in shock, as noted by the European Society of Cardiology 5

Compensated shock is characterized by tachycardia, increased systemic vascular resistance, and normal blood pressure, as stated by the American Heart Association 4
Decompensated shock is characterized by failure of compensatory mechanisms resulting in hypotension, according to the American Heart Association 4
Refractory shock is characterized by persistent shock despite goal-directed use of inotropic agents, vasopressors, vasodilators, and maintenance of metabolic and hormonal homeostasis, as noted by the American College of Critical Care Medicine 1