Clinical Nutrition: practice problems and exam questions

Enteral and parenteral nutrition calculations: tube-feeding rates, energy and protein delivered, free-water flushes, ideal body weight, energy and protein needs, parenteral nutrition energy and the glucose infusion rate, together with maintenance fluids. All values are made up for practice and are not clinical guidance.

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Cram pack (PDF)Formula sheets, method steps and practice problems with full solutions, ready to print.

Topics in this course

  1. Enteral & parenteral nutrition calculationstube feeding: rates, energy and protein · needs, ideal body weight and free water · parenteral nutrition and obesity rulescalculations
  2. IV fluids & fluid balancemaintenance fluids (Holliday–Segar 4-2-1) · intake and output balance · infusion completion timecalculations

Exam tips for Clinical Nutrition

  • Convert energy to volume with kcal/(kcal/mL) before you divide by hours.
  • Only part of a formula is free water: use the water fraction on the label.
  • In parenteral nutrition, dextrose gives 3.4 kcal/g and amino acids 4 kcal/g.

Worked examples

Enteral & parenteral nutrition calculationsEasy
1.5 kcal/mL63 g protein/L50 mL/h24 h/dayE = ? kcal/day

Practice exercise (made-up values, not clinical guidance). A tube feed that provides 1.5 kcal/mL runs at 50 mL/h for 24 hours a day. How many kilocalories E does the patient receive per day?

50 mL/h24 h/day1.5 kcal/mL

Find E (kcal/day)

Show hints
  1. Daily volume = rate × hours of feeding.
  2. Energy (kcal) = volume in mL × kcal/mL.
  3. 50·24 = 1200 mL.
Show the answer and the step-by-step solution

Tube feeding: a continuous feed runs at rate (mL/h) = daily volume/hours of feeding, and each bolus is the daily volume/number of feeds. The daily volume for an energy goal is kcal/formula concentration (kcal/mL). Energy delivered = mL × kcal/mL, and protein = litres × g/L. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.

Daily volume

V = 50·24 = 1200 mL = 1.2 L

Energy

E = 1200·1.5 = 1800 kcal/day

Answer

E = 1800 kcal/day
IV fluids & fluid balanceMedium
IntakeOutput12-hour shiftsoup150 mLtea200 mLmilk200 mLIV infusion75 mL/h × 12 hIV antibiotic2 × 100 mLurine275 mLurine250 mLurine300 mLvomit100 mL

Practice exercise (made-up values, not clinical guidance). The record shows a patient's intake and output for one 12-hour shift. The IV infusion ran at the rate shown for the whole shift. Find the fluid balance B = intake − output in mL (a negative answer means a net loss).

soup: 150 mLtea: 200 mLmilk: 200 mLIV infusion: 75 mL/h × 12 hIV antibiotic: 2 × 100 mLurine: 275 mLurine: 250 mLurine: 300 mLvomit: 100 mL

Find B (mL)

Show hints
  1. Add up the intake and the output separately.
  2. The IV infusion volume is rate × number of hours.
  3. total intake = 1650 mL.
Show the answer and the step-by-step solution

Intake and output: intake counts everything that goes in (oral fluids, IV infusions, IV medications and flushes, tube feeds); ice chips count as half their volume. Output counts urine, drains, vomit and other losses. Balance = total intake − total output; a negative balance is a net loss. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.

Total intake

oral: 150 + 200 + 200 = 550 mL
IV infusion: 75·12 = 900 mL
IV antibiotic: 2·100 = 200 mL
total intake = 1650 mL

Total output

275 + 250 + 300 + 100 = 925 mL

Balance

B = 1650 − 925 = 725 mL

Answer

B = 725 mL

Positive: more fluid went in than came out.

How practising works

  • “Practise this course” mixes problems from all its topics, like a real exam.
  • Every problem has new values, so you learn the method instead of an answer.
  • Stuck? Open a small hint first, and the full explanation only when you need it.
  • Mock exams are timed and have no hints, and you get your score and a full review at the end.

Calculators for this course

BMI calculator (body mass index for adults)Ideal body weight calculator (Devine) and adjusted body weightTube feeding calculator (enteral rate, calories, protein, free water)Intake and output calculator (fluid balance)Parkland formula calculator (burn fluid resuscitation)Maintenance fluids calculator (Holliday–Segar)

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Nursing Fundamentals and Clinical PracticeNursing MathPediatric NursingIV Fluids and Fluid BalanceNCLEX-style dosage calculationsNCLEX-style practice questions (RN)NCLEX-PN-style practice questions (LPN/LVN)Lab Values for Nurses
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