Approach to dehydrated patient management

Definition

Dehydration is the loss of body water, with or without salt, at a rate greater than the body can replace it. It results from a combination of physiological and disease processes.

Individuals at greatest risk include those with:

• Diarrhoea

• Vomiting

• Fever

• Diabetes

• Infections

• Impaired level of consciousness

Classification of dehydration

Investigations

Recommended investigations include:

• Blood chemistry (especially sodium, potassium, and bicarbonate)

• Blood urea nitrogen (BUN) and serum creatinine

• Complete blood count

• Blood gas analysis

• Serum lactate

• Bedside ultrasound (assessment of the inferior vena cava)

• Urine specific gravity

Additional investigations may be performed to determine the underlying cause of dehydration, for example:

• Blood glucose to assess for diabetes mellitus

Non-pharmacological treatment

• Perform both primary and secondary assessment and provide appropriate interventions when indicated.

• Administer oxygen if the patient is hypoxic or has increased work of breathing.

• Insert two large-bore intravenous cannulas for fluid resuscitation.

For minor dehydration, oral fluid replacement and correction of ongoing fluid losses are usually the most effective treatment.

Pharmacological treatment

In moderate to severe dehydration, replace water and electrolyte losses using one of the following:

Oral rehydration

Oral rehydration salts (ORS)

Intravenous fluid therapy

0.9% Sodium chloride (IV)

• Adults: 1–2 litres.

• Children: 20 mL/kg.

OR

Compound sodium lactate (IV)

• Adults: 1–2 litres.

• Children: 20 mL/kg.

Patients without electrolyte loss

If there is no evidence of electrolyte loss, administer:

Dextrose 5% (IV)

Reassessment

• Reassess the patient after fluid resuscitation.

• Continue management according to the patient's clinical response.

If an underlying disease is identified, treat according to the relevant disease-specific guideline.

Referral

Refer the patient to a higher-level facility with appropriate expertise if there is no clinical improvement.