Causes of Haemorrhagic Shock

When major blood loss occurs, whether from an accident, injury, or internal bleeding. Our body can quickly go into haemorrhagic shock. This guide explains the common causes, warning signs, and essential first-aid steps to manage this emergency.

What Is Haemorrhagic (Hypovolemic) Shock?

Haemorrhagic shock, also known as hypovolemic shock, is caused by blood loss. It occurs when the body loses a significant amount of blood, reducing its ability to circulate oxygen to vital organs. Without immediate treatment, this can be life-threatening.

In first aid terms, haemorrhagic shock is a medical emergency often seen after accidents, trauma, or internal bleeding. In Australia, first aid responders are trained to follow certain guidelines before controlling the bleeding and calling Triple Zero (000) for emergency services.

Common Causes of Haemorrhagic Shock

Haemorrhagic shock can be triggered by external injuries or internal bleeding. Recognising these types of bleeding is essential for lifesaving intervention.

Trauma & External Injuries

External causes usually involve visible blood loss. These include:

• Severe cuts and lacerations (e.g., workplace accidents, machinery injuries)
  
• Gunshot or stab wounds
  
• Major burns (which damage blood vessels and tissue)
  
• Road traffic accidents cause blunt force trauma and bleeding
  
• Sporting injuries such as compound fractures with vessel rupture
  

Internal Bleeding Sources

Internal haemorrhage may be harder to detect but is just as dangerous. Examples include:

• Gastrointestinal bleeding (e.g., ulcers, ruptured liver or spleen)
  
• Ectopic pregnancy rupture
  
• Aneurysm rupture
  
• Internal trauma after falls or car accidents
  
• Organ injury (pancreas, kidney, etc.)
  

Signs and Stages of Blood Loss Shock

Medical professionals classify haemorrhagic shock into four stages based on blood loss percentage and symptoms:

• Class I (up to 15% blood loss)
  
  • Mild or no symptoms
    
  • Slight increase in heart rate
    
• Class II (15–30% blood loss)
  
  • Fast heartbeat (tachycardia)
    
  • Breathing rate increases
    
  • Anxiety, pale skin
    
• Class III (30–40% blood loss)
  
  • Rapid, weak pulse
    
  • Low blood pressure
    
  • Confusion, sweating, restlessness
    
• Class IV (over 40% blood loss)
  
  • Critical drop in blood pressure
    
  • Very weak or absent pulse
    
  • Loss of consciousness
    
  • Life-threatening without immediate intervention
    

These stages help first aiders identify when the casualty is progressing into severe or life-threatening haemorrhagic shock.

First-Aid Response for Haemorrhagic Shock

In Australia, recommended first aid tips for haemorrhagic shock include:

• Follow DRSABCD
  
  • Ensure the area is safe.
    
  • Check responsiveness.
    
  • Call 000 for an ambulance.
    
• Control bleeding immediately
  
  • Apply direct pressure on the wound using a sterile pad or clean cloth.
    
  • Use elevation if possible (unless fractures are suspected).
    
• Apply a tourniquet if required
  
  • Only if bleeding is uncontrollable by pressure.
    
  • Place above the wound, tighten until bleeding stops.
    
  • Note the time applied and inform expert.
    
• Prevent shock worsening
  
  • Lay the person flat.
    
  • Cover with a blanket to maintain warmth.
    
  • Reassure and monitor breathing/pulse until help arrives.
    

How to Prevent and Minimise Risk

While accidents can’t always be avoided, some preventive measures can lower the risk of severe blood loss emergencies:

• Workplace safety
  
  • Use protective equipment (helmets, gloves, shields).
    
  • Follow occupational health and safety rules.
    
• Road and home safety
  
  • Wear seatbelts.
    
  • Use child safety seats correctly.
    
  • Secure sharp tools and kitchen knives.
    
• Health monitoring
  
  • Get medical checks for conditions like ulcers or aneurysms.
    
  • Pregnant women should seek immediate care for abdominal pain or heavy bleeding.
    
• First aid training
  
  • Learn bleeding control techniques, including proper tourniquet use.
    
  • Courses improve confidence and response time during emergencies.
    

Explore our  CPR First Aid Courses to prepare for trauma and bleeding emergencies.

When to Call Emergency Services in Australia

In Australia, call Triple Zero (000) if:

• Bleeding is severe or uncontrolled
  
• The casualty shows signs of shock (pale, weak pulse, rapid breathing, confusion)
  
• You suspect internal bleeding (rigid abdomen, vomiting blood, fainting)
  
• The injured person becomes unconscious
  

Ambulance services in Australia are trained to provide rapid fluid resuscitation, oxygen, and surgical support. Always err on the side of caution if in doubt, call 000.

Frequently Asked Questions

Can you stop haemorrhagic shock at home?

No. While first aid can slow blood loss (e.g., pressure or tourniquet use), definitive treatment requires hospital intervention, including blood transfusions and surgery.

When should I use a tourniquet?

Use a tourniquet only when direct pressure fails to control life-threatening bleeding from a limb. Ensure proper training before applying one.

Do burns cause haemorrhagic shock?

Yes. Severe burns can damage blood vessels and tissues, leading to fluid loss and haemorrhage, which may progress to shock if untreated.