Hypovolemic Shock: Causes, Recognition & Emergency Management

Hypovolemic shock is a life-threatening state where intravascular volume loss → inadequate tissue perfusion → cellular hypoxia → organ failure → death if untreated.

Causes

• Hemorrhagic: Trauma (internal/external), GI bleed, ruptured aneurysm, ectopic pregnancy, postpartum hemorrhage, surgical bleeding.
• Non-hemorrhagic: Severe dehydration (vomiting, diarrhea, burns, diuretics, DKA, heat stroke), third-spacing (pancreatitis, sepsis, bowel obstruction).

Clinical Stages (ATLS Classification)

Class	Volume Loss	HR	BP	Pulse Pressure	RR	Urine Output	Mental Status
I	≤15% (≤750 mL)	<100	Normal	Normal	14–20	>30 mL/h	Normal
II	15–30% (750–1500 mL)	>100	Normal	↓	20–30	20–30 mL/h	Anxious
III	30–40% (1500–2000 mL)	>120	↓	↓↓	30–40	5–15 mL/h	Confused
IV	>40% (>2000 mL)	>140	↓↓	↓↓↓	>40	Negligible	Lethargic/comatose

Emergency Treatment

1. ABCs: Airway, Breathing, Circulation (2 large-bore IVs/IO).
2. Fluid resuscitation: Crystalloid (NS/RL) 1–2 L bolus; reassess. Blood products if hemorrhagic (1:1:1 PRBC:FFP:platelets per massive transfusion protocol).
3. Source control: Surgery, endoscopy, interventional radiology, uterine compression.
4. Vasopressors: Only as bridge—volume first. Norepinephrine preferred.
5. Monitor: Lactate, base deficit, ScvO₂, urine output, serial exams.

Early recognition and aggressive volume replacement save lives. "Time is tissue."