Shock and Resuscitation
Core concepts
Shock is inadequate tissue perfusion. Classify it as hypovolemic, distributive, cardiogenic, obstructive, or neurogenic, and recognize compensated versus decompensated states. Resuscitation includes airway and breathing support, vascular access, fluids or blood products when indicated, vasopressors, and correction of reversible causes. In cardiac arrest, follow current ACLS principles: high-quality CPR, early defibrillation for shockable rhythms, epinephrine, antiarrhythmics per protocol, and post-arrest care. Capnography, lactate, mentation, urine output, and skin perfusion help guide response.
Traps
A normal blood pressure does not exclude shock. Giving large crystalloid boluses in cardiogenic or obstructive shock can worsen the patient. Epinephrine is not a substitute for hemorrhage control. Post-arrest hypothermia and hypotension worsen outcomes. Do not forget reversible causes such as hypoxia, hypovolemia, tension pneumothorax, tamponade, toxins, and thrombosis.
Rule of thumb
Use the shock index: heart rate divided by systolic blood pressure. An elevated shock index suggests occult shock even when blood pressure appears acceptable. Trend it with perfusion and mentation.
Worked example
A trauma patient has a heart rate of 120 and systolic pressure of 100 mm Hg. The shock index is 1.2, suggesting significant hypoperfusion. Prioritize hemorrhage control, blood products if available, and rapid transport rather than relying on the “normal” systolic pressure.