Understanding Hypovolemic Shock CEN Review 2018

Hypovolemic Shock is defined as an emergency condition in which severe blood or fluid loss makes the heart unable to pump enough blood to the body. This is the MOST COMMON FORM OF SHOCK.

What causes Hypovolemic Shock?

  • Hemorrhage, whether traumatic or not, can lead to hypovolemic shock. Hemorrhage can be internal (ruptured aortic aneurysm, posterior epistaxis, GI bleed) or external (open wounds)
  • Fluid Shifts from burns and peritonitis
  • Fluid Losses from severe vomiting, diarrhea, diaphoresis, diabetic ketoacidosis, and diabetes insipidus

Hypovolemic Shock Assessment

  • Start by assessing Airway, Breathing, and Circulation (ABC)
  • Trend Vital Signs is the single most important assessment for shock
  • Laboratory analysis
    • CBC – red blood cell count (hemorrhagic)
  • Mean Arterial Pressure (MAP) must remain at 60 mmHg and above
    • Normal MAP is 70 to 110 mmHg
  • Urine Output
    • Adults should be urinating 30 mL/hr at a minimum
  • Level of Consciousness
    • Altered mental status can be another sign of fluid loss


Hypovolemic Shock Intervention

  • Determine the cause of hypovolemia and fix the problem
    • Control the Bleeding and/or Reduce the Fluid Loss
  • Replace circulating volume
    • Blood replacement is the definitive treatment for hemorrhagic shock
      • PRBCs (Packed Red Blood Cells) is the best for elevating oxygen carrying capacity
        • Best practice (if time allows) cross-match patient’s blood with blood time and antibody match or use O-negative blood is no time allowed
  • Massive transfusions happen in the Emergency Department or Trauma Centers
    • Defined as replacement of 10 units of red blood cells in 24 hours or 3 units over one hour
      • Packed Red Blood Cell’s lack clotting factors
      • Replace 1 unit of plasma and 1 unit is platelets for every 1 to 2 units of Packed Red
      • Blood Cells
      • Pro Tip: Each unit of blood contains 3 grams of citrate which binds to ionized calcium. Excessive citrate can lead to metabolic alkalosis and hypocalcaemia. Monitor pH and ionized calcium, replace calcium as necessary.
  • Circulating Volume Replacement
    • Isotonic Crystalloids is the Gold Standard of Fluid Replacement
      • 9% sodium chloride (Normal Saline)
        • Adults: 1 to 2 liters bolus
        • Pediatrics: 20 mL/kg/hr
      • Ringer’s Lactate
        • Use with caution as Ringer’s Lactate can elevate lactate levels
          • Especially in septic patients
        • Quickly metabolizes causing plasma to turn hypotonic