Hypovolemic shock happens when the body loses so much blood or fluid that the heart cannot pump enough to feed the organs. Bleeding from trauma or the gut is the most common cause, followed by severe vomiting, diarrhea or burns.
Key symptoms
- Thirst, weakness and dizziness on standing
- Anxiety, then confusion or drowsiness
- Little or no urine
- Visible bleeding, black stool, vomiting blood or heavy diarrhea
What you find on exam
- Fast heart rate early; low blood pressure is a late sign
- Cool, pale, clammy skin and slow capillary refill
- Weak, thready pulses and flat neck veins
- Look for the source: wounds, abdomen, pelvis, long bones
Tests
- Lactate and blood gas for poor tissue perfusion
- Blood count, type and crossmatch, coagulation tests
- Electrolytes and creatinine; pregnancy test in women of childbearing age
- Bedside ultrasound (FAST) for internal bleeding
Treatment basics
- Stop the bleeding: direct pressure, tourniquet, surgery or endoscopy
- Two large-bore IVs or an intraosseous line
- Early blood products in hemorrhage, with plasma, platelets and red cells in a balanced ratio
- Balanced crystalloid such as lactated Ringer for fluid losses
- Tranexamic acid within 3 hours of major traumatic bleeding
Red flags
- Systolic pressure under 90 mmHg or a shock index above 1
- Altered mental status
- Ongoing bleeding despite pressure, or a rising lactate
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Sources: NASEMSO National Model EMS Clinical Guidelines; NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations. Written by Making Synapses. Making Synapses is not affiliated with these organizations.