BNF for Children (BNFC) 2018-2019

deficit should be corrected slowly to avoid the risk of osmotic
demyelination syndrome; the rise in plasma sodium
concentration should be no more than 10 mmol/litre in
24 hours.
Sodium chloride with glucose solutions are indicated when
there is combinedwater and sodium depletion.A 1 : 1 mixture
of isotonic sodium chloride and 5 % glucose allows some of
the water (free of sodium) to enter body cells which suffer
most from dehydration while the sodium salt with a volume
of water determined by the normal plasma Na+remains
extracellular.
Combined sodium, potassium, chloride, and water
depletion may occur, for example, with severe diarrhoea or
persistent vomiting; replacement is carried out with sodium
chloride intravenous infusion 0. 9 % and glucose intravenous
infusion 5 % with potassium as appropriate
Compound sodium lactate(Hartmann’s solution) can be
used instead of isotonic sodium chloride solution during or
after surgery, or in the initial management of the injured or
wounded.

Intravenous glucose
Glucose solutions are used mainly to replace water deficit.
Water depletion (dehydration) tends to occur when losses
are not matched by a comparable intake, as may occur in
coma or dysphagia.
Water loss rarely exceeds electrolyte losses but this can
occur in fevers, hyperthyroidism, and in uncommon water-
losing renal states such as diabetes insipidus or
hypercalcaemia. The volume of glucose solution needed to
replace deficits varies with the severity of the disorder; the
rate of infusion should be adjusted to return the plasma-
sodium concentration to normal over 48 hours.

Glucose solutions are also used to correct and prevent

hypoglycaemia and to provide a source of energy in those

too ill to be fed adequately by mouth; glucose solutions are a

key component of parenteral nutrition.

Glucose solutions are given with insulin for the emergency

management ofhyperkalaemia. They are also given, after

correction of hyperglycaemia, during treatment of diabetic

ketoacidosis, when they must be accompanied by continuous

insulin infusion.

Intravenous potassium

Potassium chloride with sodium chloride intravenous

infusion p. 588 is the initial treatment for the correction of

severe hypokalaemiaand when sufficient potassium cannot

be taken by mouth.

Repeated measurements of plasma-potassium

concentration are necessary to determine whether further

infusions are required and to avoid the development of

hyperkalaemia, which is especially likely in renal

impairment.

Initial potassium replacement therapy shouldnotinvolve

glucose infusions, because glucose may cause a further

decrease in the plasma-potassium concentration.

Bicarbonate and trometamol

Sodium bicarbonate is used to control severemetabolic

acidosis(pH< 7. 1 ) particularly that caused by loss of

bicarbonate (as in renal tubular acidosis or from excessive

gastro-intestinal losses). Mild metabolic acidosis associated

with volume depletion shouldfirst be managed by

appropriatefluid replacement because acidosis usually

resolves as tissue and renal perfusion are restored. In more

severe metabolic acidosis or when the acidosis remains

unresponsive to correction of anoxia or hypovolaemia,

Electrolyte concentrations—intravenousfluids

Millimoles per litre

Intravenous infusion Na+ K+ HCO 3 – Cl– Ca^2 +

Normal plasma values 142 4. 5 26 103 2. 5

Sodium Chloride 0. 9 % 150 –– 150 –

Compound Sodium Lactate (Hartmann’s) 131 5 29 111 2

Sodium Chloride 0. 18 % and Glucose 4 %

(Adults only)

30 –– 30 –

Sodium Chloride 0. 45 % and Glucose 5 %

(Children only)

75 –– 75 –

Potassium Chloride 0. 15 % and Glucose 5 %

(Children only)

• 20 – 20 –

Potassium Chloride 0. 15 % and Sodium

Chloride 0. 9 % (Children only)

150 20 – 170 –

Potassium Chloride 0. 3 % and Glucose 5 % – 40 – 40 –

Potassium Chloride 0. 3 % and Sodium Chloride

0. 9 %

150 40 – 190 –

To correct metabolic acidosis

Sodium Bicarbonate 1. 26 % 150 – 150 ––

Sodium Bicarbonate 8. 4 % for cardiac arrest 1000 – 1000 ––

Sodium Lactate (m/ 6 ) 167 – 167 ––

Electrolyte content—gastro-intestinal secretions

Millimoles per litre

Type of fluid H+ Na+ K+ HCO 3 – Cl–

Gastric 40 – 60 20 – 80 5 – 20 – 100 – 150

Biliary – 120 – 140 5– 15 30 – 50 80 – 120

Pancreatic – 120 – 140 5– 15 70 – 110 40 – 80

Small bowel – 120 – 140 5– 15 20 – 40 90 – 130

BNFC 2018 – 2019 Fluid and electrolyte imbalances 585

Blood and nutrition

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