Wed3November0832PM 8

A 7-year-old child has undergone appropriate fluid resuscitation and electrolyte replacement following an admission to hospital for bouts of vomiting secondary to acute appendicitis.

The patient weighs 25 kg and is apyrexial. The plasma sodium is 138 mmol/l and blood glucose 6.4 mmol/l.

Which one of the following fluid maintenance regimens is the most appropriate in this patient?

(Please select 1 option)

40 ml/hr 0.9% NaCl with 0% glucose

40 ml/hr 0.45% NaCl with 5% glucose Incorrect answer selected

65 ml/hr 0.18% NaCl with 4% glucose

65 ml/hr hartmann's solution with 0% glucose This is the correct answer

65 ml/hr 0.9% NaCl with 0% glucose

Explanation

The child has already been adequately resuscitated and deficits replaced.

The child is "nil by mouth" and will need a maintenance fluid regimen prescribed. The volume given per hour can be calculated using the Holliday-Segar formula (4-2-1 rule).

Body weight:

1-10 kg 4 ml/kg/hour

10-20 kg 40 ml + 2 ml/kg/hour above 10 kg

20 kg 60 ml + 1 ml/kg/hour above 20 kg.

Baseline estimates are affected by fever (increasing by 12% for each degree > 37.8°C)

In this example the infusion rate should commence at 65 ml/hour and be reviewed.

The fluid given should be isotonic with plasma.

A recent European consensus statement (2011) recommended that an intraoperative fluid should have an osmolarity close to the physiological range in children in order to avoid hyponatraemia - an addition of 1-2.5% instead of 5% glucose in order to avoid hypoglycaemia, lipolysis or hyperglycaemia and should also include metabolic anions (that is, acetate, lactate or malate) as bicarbonate precursors to prevent hyperchloraemic acidosis.

Dextrose may be required to prevent hypoglycaemia while the child is fasted for theatre. However the stress response to starvation and surgery causes a rise in blood sugar, and per-operative hypoglycaemia is actually rare in most children.

Of the incorrect answer options:

40 ml/hr 0.9% NaCl with 0% glucose - this is a suboptimal infusion rate

40 ml/hr 0.45% NaCl with 5% glucose - this is a suboptimal infusion rate

65 ml/hr 0.9% NaCl with 0% glucose - this is administered at an appropriate rate and is isotonic, but large volumes can lead to a hyperchloraemic acidosis

65 ml/hr 0.18% NaCl with 4% glucose - this is a hypotonic solution and can potentially lead to hypontraemia (particularly 0.18% NaCl with 4% glucose)

Reference:

https://www.ncbi.nlm.nih.gov/pubmed/21654319

Answer Statistics

1

4%

2

22%

3

34%

4

36%

5

6%

Times answered: 265