Fluids: maintenance requirement: practice question

A General Surgery question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Surgery · Fluids: maintenance requirement

Sample item

Using the 4-2-1 rule, what is the hourly maintenance fluid requirement of a 70 kg adult?

A90 mL per hourB70 mL per hourC110 mL per hourD140 mL per hour

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. 110 mL per hour

The 4-2-1 rule gives 4 mL/kg/hour for the first 10 kg, 2 mL/kg/hour for the next 10 kg and 1 mL/kg/hour for each kg above 20. For 70 kg this is 40 plus 20 plus 50, which is 110 mL per hour. Replacement of deficits and ongoing losses is added to this.

Option by option

A. 90 mL per hour
90 mL per hour underestimates the weight above 20 kg.
B. 70 mL per hour
70 mL per hour is simply 1 mL/kg.
C. 110 mL per hour (correct)
Correct. 40 plus 20 plus 50 equals 110 mL per hour.
D. 140 mL per hour
140 mL per hour overestimates the requirement.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this General Surgery question

What is the answer to this General Surgery question?

The best answer is C, 110 mL per hour. The 4-2-1 rule gives 4 mL/kg/hour for the first 10 kg, 2 mL/kg/hour for the next 10 kg and 1 mL/kg/hour for each kg above 20.

Why is "90 mL per hour" not the answer?

90 mL per hour underestimates the weight above 20 kg.

Why is "70 mL per hour" not the answer?

70 mL per hour is simply 1 mL/kg.

Why is "140 mL per hour" not the answer?

140 mL per hour overestimates the requirement.

What concept does this question test?

It tests Fluids: maintenance requirement in General Surgery. For 70 kg this is 40 plus 20 plus 50, which is 110 mL per hour. Replacement of deficits and ongoing losses is added to this.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Fluids: maintenance requirement?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.