Professional and Linguistic Assessments Board (PLAB) Practice Exam

What is the maintenance fluid requirement for children weighing 20 kg?

1. 1500 ml

2. 1000 ml

3. 2000 ml

4. 1200 ml

The correct answer is: 1500 ml

To determine the maintenance fluid requirement for a child weighing 20 kg, the standard formula used is based on the "4-2-1 rule." This rule states that for the first 10 kg of body weight, the child requires 4 ml/kg/hour, for the next 10 kg, 2 ml/kg/hour, and any additional weight beyond this is 1 ml/kg/hour. Applying the rule for a child weighing 20 kg: - The first 10 kg requires: 10 kg x 4 ml/kg/hour = 40 ml/hour - The next 10 kg requires: 10 kg x 2 ml/kg/hour = 20 ml/hour Adding these two amounts gives a total hourly requirement of 60 ml/hour. To find the total daily requirement, multiply this hourly rate by 24 hours: 60 ml/hour x 24 hours = 1440 ml/day. However, if rounding to the nearest convenient volume, it is acceptable to provide a rough estimate for daily maintenance that is in keeping with common practice, which often leads to a figure like 1500 ml being cited as a practical value in clinical settings for children in that weight range. This aligns with the need for proper hydration and nutrient delivery in