Wed3November0840PM 2

A 4-year-old girl is injured in a road traffic accident. She is unconscious (GCS 8), hypotensive and has a scalp laceration. She has no chest or abdominal bruising or visible injury.

Are each of the following true or false in these circumstances?

True / False

An urgent CT scan of the head and neck is warranted Correct

An uncuffed 4.5 mm endotracheal tube will protect the lungs against aspiration Correct

Her blood volume is approximately 1200 ml Correct

The blood may have been lost from the scalp wound Correct

More than 300 ml of blood has been lost Incorrect answer selected

Explanation

A formula to calculate body weight for children over the age of one year is:

weight in kg = (age in years + 4) × 2.

Therefore, our 4-year-old girl has an estimated weight of 16 kg. The blood volume calculation is based on 80 ml/kg up to 2 years of age and 70 ml/kg thereafter. The injured girl therefore has an estimated blood volume of 1120 ml or approximately 1200 ml.

In children older than one year the following formula is used to calculate the internal diameter of an appropriate endotracheal tube:

internal diameter = (age/4) + 4

A size 5.0 tube would be appropriate in this child. It is clear that a size 4.5 tube may be too small for the girl, but in practical terms a tracheal tube 0.5 mm above and below the calculated tube size should be available. A size 4.5 tube will secure the upper airway, and is unlikely to expose the child to the risk of post-extubation mucosal oedema, but it is uncuffed and so will not protect the lungs against aspiration.

Traumatic brain injury is responsible for >85% of deaths in paediatric trauma victims and the patient's neurological status warrants further investigation.

The systolic blood pressure in a child can be calculated using:

systolic blood pressure = (age in years × 2) + 80.

Hypotension is often a late sign in hypovolaemic children, as the blood pressure is well maintained and only falls when the heart rate reaches the maximum. More than 25% of the blood volume may be lost before hypotension occurs, which is >300 ml for our injured girl. Large volumes of blood can be lost from paediatric scalp wounds and may represent a significant proportion of the child's blood volume. Nevertheless, the child should be examined to exclude occult injuries in the head, chest or abdomen.

Answer Statistics

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Average score: 83.11%

Times answered: 264