HYPOVOLAEMIC SHOCK

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