Hypotension

Exam Cram

• Hypotension defined as BP < 90/60 or MAP < 65

• Assessment of end organ perfusion:

  • • 1. Kidneys: urine output

      2. Cerebral: confusion

      3. Muscular: lactate

• Causes: hypovolaemia, cardiogenic, neurogenic, immune (sepsis, anaphylaxis)

• Management: usually IVF bolus but can be furosemide, vasopressors and adrenaline

Hypotension is commonly referred to as shock. 

Definitions

Hypotension definition: low blood pressure

Blood pressure

• Hypertension: > 140/90

• Normotensive: 120/80

• Hypotensive: < 90/60

Commonly the mean arterial blood pressure is used (MAP) or the systolic. Common BP aims are: 

• MAP > 65

• Systolic BP > 90

Assessment

Key question: are we achieving end organ perfusion?

This is assessed by:

• Brain: Is the patient confused, suggesting hypoxic delirium?

• Kidneys: Urine output sufficient

• Muscles: Receiving oxygenated blood for aerobic respiration, lactate can be a useful marker 

Assessment

If asked to see a patient with a blood pressure below 90/60, this is a medical emergency and requires an A-E response. 

1. Check true value- correct cuff, patient in a reasonable posture

2. GCS ?confusion/ delirium

3. Urine output- hourly via catheter can be helpful, aim > 0.5ml/kg/hr

4. Lactate

5. HR- if raised, can be a sign body isn't happy with the BP & vice versa

Causes

Acronym 'AH CIN', in order of most common

• Asymptomatic- vagal, common overnight for BP to naturally drop

• Hypovolaemia

  • Bleeding

  • Dehydration- sepsis, vomiting, diarrhoea

• Cardiogenic

• Immune related

  • Sepsis

  • Anaphylaxis

• Neurogenic

Management

Management of hypotension is dictated by underlying cause. 

1. Ward Management

Asymptomatic: nil intervention required, can encourage positional changes/ PO fluids

Hypovolemia:

• Dehydration- IVF 250mls to 500mls bolus

• Bleeding- replace blood with blood +- IVF

Cardiogenic: 

• Furosemide 40mg IV if overloaded +- another 40mg 

• Fast AF: betablockers, digoxin or amidoarone

Immune

• Sepsis- IVF, requires total of 2L 

• Anaphylaxis- adrenaline

2. HDU/ ICU

Vasopressors

• Hypotension not responding to IVF for IV furosemide, requires vasopressors 

• Vasopressors require HDU/ ICU level care. 

Resources and References

Written in 2025