Condition caused by severe acute loss of intravascular fluids leading to inadequate circulating volume and inadequate perfusion.
Causes
- Loss of blood due to internal or external haemorrhage (e.g. post partum haemorrhage, splenic rupture etc.)
- Acute loss of fluids, e.g. in gastroenteritis, or extensive burns
Clinical features
- High heart rate, fast breathing rate
- Thin or absent pulse, cold extremities, slow capillary refill
- Low blood pressure
- Mental agitation, confusion
Classification of hypovolaemia in adults
INDICATOR | CLASS 1 MILD |
CLASS 2 PROGRESSING |
CLASS 3 SEVERE |
CLASS 4 END STAGE |
---|---|---|---|---|
Blood loss (Litres) |
<0.75 | 0.75 – 1.5 |
1.5 –2 | >2 |
% of total blood volume loss |
<15 | 15- 30 | 30 – 40 | >40 |
Pulse rate | Normal | >100 | >120 | >140 |
Pulse pressure |
Normal | low | very low | very low or absent |
Systolic BP | Normal | N | low | very low |
Capillary refill |
Normal | high | very high | Absent |
Respiratory rate |
Normal | 20 – 30 | 30 – 40 | >45 or gasping |
Mental state | Alert | Anxious | Confused | Confused/ unconscious |
Urine output (ml/h) |
>30 | 20 – 30 | 5 – 20 | <5 |
Differential diagnosis
- Other types of shock
Management in adults
- Control obvious bleeding with pressure
- Keep patient laying down with raised legs
If established hypovolaemia class 2 and above
- Set 2 large bore IV lines
- IV fluids Normal Saline 0.9% (or Ringer’s lactate) 20-30 ml/kg over 60 minutes according to response
- If possible, warm the fluid
- Start rapidly, monitor BP
- Assess response to fluid resuscitation: BP, HR,
RR, capillary refill, consciousness and urinary output
- If internal or external haemorrhage, consider blood transfusion
If rapid improvement and stable (blood loss <20% and not progressing)
- Slow IV fluids to maintenance levels
- No immediate transfusion but do cross-matching
- Regular reassessment
- Detailed examination and definitive treatment according to the cause
If transient improvement (blood loss 20-40% or ongoing bleeding)
- Rapid administration of fluids
- Initiate blood transfusion (see section 11. 2)
- Regular reassessment
- Detailed examination and early surgery
If no improvement
- Vigorous fluid administration
- Urgent blood transfusion
- Immediate surgery
Caution
- Do not use glucose solutions or plain water as replacement fluids