Practice exercise (made-up values, not clinical guidance). A 54 kg patient has a fluid goal of 30 mL/kg/day and receives all fluid through a feeding tube. The formula is 84% free water and runs at 60 mL/h for 24 hours a day. The rest of the fluid is given as water flushes every 8 hours. What volume V is each flush? Round to the nearest whole number.
54 kg30 mL/kg/day84%60 mL/h · 24 hevery 8 h
V = mL
2.Enteral & parenteral nutrition calculationsHard
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 2000 mL of parenteral nutrition with final concentrations of 25% dextrose and 3.5% amino acids, plus 250 mL of 20% lipid emulsion (2 kcal/mL). Find the total energy E the patient receives in kcal per day. Round to the nearest whole number.
2000 mLdextrose 25%amino acids 3.5%lipid 250 mL · 2 kcal/mL
E = kcal/day
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 patient weighs 58 kg. Find the average urine output U in mL/kg/h. Round to two decimal places.
58 kg12 hurine: 275 mLurine: 475 mLwound drain: 120 mL
U = mL/kg/h
4.IV fluids & fluid balanceHard
Practice exercise (made-up values, not clinical guidance). A 500 mL bag was started at 14:00 and runs by pump at 75 mL/h. How many mL V are left in the bag at 18:00?
500 mL75 mL/h14:00 → 18:00
V = mL
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: V = 137 mL
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.
Fluid goal
30·54 = 1620 mL/day
Free water from the formula
60·24 = 1440 mL
1440·0.84 = 1210 mL
Water still needed
1620 − 1210 = 410.4 mL/day
Volume per flush
24/8 = 3 flushes
V = 410.4/3 = 136.8 ≈ 137 mL
Answer
V = 137 mL
2.Enteral & parenteral nutrition calculations
Answer: E = 2480 kcal/day
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.
Grams of dextrose and amino acids
dextrose: 25·2000/100 = 500 g
amino acids: 3.5·2000/100 = 70 g
Kilocalories per component
dextrose: 500·3.4 = 1700 kcal
amino acids: 70·4 = 280 kcal
lipid: 250·2 = 500 kcal
Total energy
E = 1700 + 280 + 500 = 2480 kcal/day
Answer
E = 2480 kcal/day
3.IV fluids & fluid balance
Answer: U = 1.08 mL/kg/h
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 urine
275 + 475 = 750 mL
Per kilogram per hour
U = 750/(58·12) = 1.078 ≈ 1.08 mL/kg/h
Answer
U = 1.08 mL/kg/h
4.IV fluids & fluid balance
Answer: V = 200 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.