Classification of Hypovolaemia

The table (Table 1) shows the various changes seen with progressively worsening hypovolaemic shock.

In addition, an increase in respiratory rate is a sensitive but non-specific early sign of blood loss.

In Class 3 hypovolaemia how might the clinical signs differ between an 18 year old and an 80 year old?

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Class of Hypovolaemia	1 Minimal	2 Mild	3 Moderate	4 Severe
Percentage blood volume lost / depleted	10	20	30	Over 40
Volume lost (ml)	500	1000	1500	Over 2000
Heart rate (beats/min)	Normal	100-120	120-140	Over 140
Arterial pressure (mmHg)	Normal	Orthostatic hypotension	Systolic below 100	Systolic below 80
Urinary output (ml/h)	Normal (60-70)	20-30	10-20	Nil
Conscious level	Normal	Normal	Restless	Impaired consciousness
State of peripheral circulation	Normal	Cool and pale	Cold pale, slow capillary refill	Peripheral cyanosis

Table 1 Classification of hypovolaemia

The table (Table 1) shows the various changes seen with progressively worsening hypovolaemic shock.

In addition, an increase in respiratory rate is a sensitive but non-specific early sign of blood loss.

In Class 3 hypovolaemia how might the clinical signs differ between an 18 year old and an 80 year old?

Answer:

Compensation is less effective in the elderly because:

Fluid compartment volumes reduce with increasing age; blood volume is reduced by 20 % by the age of 75
Autonomic nervous system function declines with age

Class of Hypovolaemia	1 Minimal	2 Mild	3 Moderate	4 Severe
Percentage blood volume lost / depleted	10	20	30	Over 40
Volume lost (ml)	500	1000	1500	Over 2000
Heart rate (beats/min)	Normal	100-120	120-140	Over 140
Arterial pressure (mmHg)	Normal	Orthostatic hypotension	Systolic below 100	Systolic below 80
Urinary output (ml/h)	Normal (60-70)	20-30	10-20	Nil
Conscious level	Normal	Normal	Restless	Impaired consciousness
State of peripheral circulation	Normal	Cool and pale	Cold pale, slow capillary refill	Peripheral cyanosis

Table 1 Classification of hypovolaemia