Practice exercise (made-up values, not clinical guidance). A 78 kg adult (BMI below 30) needs 30 kcal/kg/day. The tube feed provides 1.5 kcal/mL and runs by pump for 24 hours a day. At what rate R do you set the pump, in mL/h? Round to the nearest whole number.
78 kg30 kcal/kg/day1.5 kcal/mL24 h
R = mL/h
2.Enteral & parenteral nutrition calculationsHard
Practice exercise (made-up values, not clinical guidance). A child who weighs 7 kg receives 5% dextrose at 33 mL/h. Find the glucose infusion rate GIR in mg/kg/min. Round to two decimal places.
7 kg5%33 mL/h
GIR = mg/kg/min
3.IV fluids & fluid balanceMedium
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 total intake I in mL. Count ice chips as half their volume.
milk: 100 mLtea: 240 mLice chips: 240 mLIV infusion: 80 mL/h × 12 hIV antibiotic: 2 × 100 mL
I = mL
4.IV fluids & fluid balanceHard
Practice exercise (made-up values, not clinical guidance). A 1000 mL bag was started at 08:15 and runs by pump at 125 mL/h. How many mL V are left in the bag at 09:15?
1000 mL125 mL/h08:15 → 09:15
V = mL
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: R = 65 mL/h
Needs and free water: energy needs are often estimated as kcal/kg/day × weight and protein needs as g/kg/day × weight. A formula is only partly water, so its free water = volume × water fraction; water flushes make up the rest of the daily fluid goal. Ideal body weight (Devine): IBW = 50 kg + 2.3 kg for every inch over 5 feet (60 in) for men, and 45.5 kg + 2.3 kg per inch over 60 in for women; 1 in = 2.54 cm. The formula is meant for adults at least 152.4 cm (5 ft) tall. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Energy needed
E = 30·78 = 2340 kcal/day
Daily volume
V = 2340/1.5 = 1560 mL/day
Pump rate
R = 1560/24 = 65 mL/h
Answer
R = 65 mL/h
2.Enteral & parenteral nutrition calculations
Answer: GIR = 3.93 mg/kg/min
Parenteral nutrition: dextrose provides 3.4 kcal/g, amino acids 4 kcal/g and lipid emulsion the kcal/mL stated (2 kcal/mL for 20%, 1.1 kcal/mL for 10%). Grams = % × mL/100. Non-protein kcal (NPC) = dextrose + lipid kcal; nitrogen = protein/6.25. The glucose infusion rate (GIR) in mg/kg/min = dextrose mg/(kg × minutes). The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Dextrose concentration
5% = 50 mg/mL
Dextrose per minute
50·33/60 = 27.5 mg/min
Per kilogram
GIR = 27.5/7 = 3.929 ≈ 3.93 mg/kg/min
Answer
GIR = 3.93 mg/kg/min
Shortcut: GIR = % dextrose × mL/h/(6 × kg).
3.IV fluids & fluid balance
Answer: I = 1620 mL
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.
Add the intake
oral: 100 + 240 = 340 mL
ice chips: 240/2 = 120 mL
IV infusion: 80·12 = 960 mL
IV antibiotic: 2·100 = 200 mL
I = 1620 mL
Answer
I = 1620 mL
4.IV fluids & fluid balance
Answer: V = 875 mL
Infusion time: time (h) = volume to infuse (mL)/rate (mL/h); use the volume still left in the bag, not the bag size. Volume infused = rate × time. Convert decimal hours to hours and minutes with the fraction × 60 (0.5 h = 30 min, not 50 min). The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.