| Etiology | ||||||
|---|---|---|---|---|---|---|
| Hemorrhage or Extensive Tissue Injury | Cardiac Tamponade | Myocardial Contusion | Pneumothorax or Hemothorax | Spinal Cord Injury | Sepsis | |
| Primary mechanisms | Hypovolemia | Ventricular inflow restriction | Diminished ventricular performance and elevated pulmonary vascular resistance | Lung collapse Mediastinal shift, causing inflow and outflow obstruction of the heart | Vasodilation and relative hypovolemia caused by loss of sympathetic tone | Intestinal perforation causing peritoneal contamination |
| Typical signs and symptoms | Tachycardia Narrow pulse pressure Cold, clammy skin from vasoconstriction | Tachycardia Hypotension Dilated and engorged neck veins Muffled heart sounds Diminished BP response to fluid challenge | Dysrhythmia Tachycardia Hypotension | Tachycardia Hypotension Dilated and engorged neck veins Absent breath sounds Hyperresonance to percussion Tracheal shift Dyspnea Subcutaneous emphysema | Hypotension without tachycardia, cutaneous vasoconstriction, or narrow pulse pressure | Develops mainly a few hours after colon injury In hypovolemic patients, signs and symptoms indistinguishable from hypovolemic shock In normovolemic patients, fever, modest tachycardia; warm, pink skin; near normal BP; wide pulse pressure Hypotension may develop |
| Treatment continuum, from least to most intense | Crystalloids initially Transfusion if 2,000 mL of crystalloid in 15 min does not restore BP | Pericardiocentesis Pericardial window ED thoracotomy | Fluids Fluids and vasodilators Fluids and inotropes | Release of air with 14-gauge catheter Chest tube | Fluids Fluids and vasopressors Fluids, vasopressors, and inotropes, if myocardial damage is present | Fluids and antibiotics Fluids, antibiotics, and inotropes for hypotension |
BP = blood pressure; ED = emergency department.
Reproduced with permission from American College of Surgeons, Committee on Trauma. Shock, Advanced Trauma Life Support Student Course Manual. Edited by the American College of Surgeons, 8th ed.Chicago: American College of Surgeons; 2008:55–71.