Hypovolemic Shock

Cardiology (12%) Core Clinical Conditions

1A: Able to diagnose and manage

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Definition Aetiology Pathophysiology Risk factor Sign and Symptoms Investigations Diagnosis Management

Hypovolemic shock occurs when the heart is unable to pump enough blood to the body due to significant blood or other fluid loss. Numerous organs may stop functioning as a result of this kind of shock.

Common causes are:

• Myocardial infarction (MI)

• Tension pneumothorax,

• Cardiac tamponade

• Pulmonary embolism (PE)

• Septic shock

• Anaphylactic shock

• Hypotension

Hypovolemic shock results from a blood loss of at least one fifth of your normal blood volume. This is generally caused by perfused bleeding from wounds or internal bleeding. 

However, it can also be caused by the following reasons: 

• Diarrhoea and vomiting (excessively)

• Severe dehydration 

• Severe burns

Pre-shock state: increased heart rate, increased cardiac contraction, and vasoconstriction during the compensatory stage. As a result, the diastolic blood pressure rises, mildly raising blood pressure.

Shock state: when the volume keeps dropping, the patient enters a state of shock. Systolic blood pressure decreases as a result, along with tachycardia and oliguria. It ultimately results in decreased oxygen supply to the body's important organs and an inability to meet the demand for oxygen. The blood flow to the heart and brain is conserved by being redirected from other organs. Blood flow is diverted, which results in lactic acid accumulation and tissue ischemia. If left untreated, this causes several organs to fail and ultimately results in death.

• Recent illness, injury causing blood loss

• Chronic medical conditions 

• Dehydration, vomiting and diarrhoea

• Increased thirst

• Abdominal pain

• Chest pain

• Sweaty / increased perfusion 

• Confusion

• Generalised weakness

• Change in skin colour (pallor)

• Reduced or absent urine production (oliguria) 

• Tachypnoea (rapid breathing)

• Unconsciousness (lack of responsiveness) 

• Blood in stool

• FBC, U&E, LFT.

• Coagulation screen

• Blood gases (arterial or venous) may show a metabolic acidosis 

• Urine output, which may require a catheter.

• CT scan, x-ray or ultrasound as appropriate

• Echocardiogram 

• ECG

Physical examination:

• Hypotension 

• Hypothermia 

• Tachycardia

• Keep patient warm to avoid hypothermia 

• Keep patient laying down flat

• Avoid oral fluid 

• Perform Cardiopulmonary resuscitation (CPR) if patient is unconscious

• Need urgent hospital admission and treatment will mainly involve intravenous treatment, oxygen and other treatments as appropriate.

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