Practice exercise (made-up values, not clinical guidance). A 72 kg patient has a fluid goal of 35 mL/kg/day and receives all fluid through a feeding tube. The formula is 84% free water and runs at 90 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.
72 kg35 mL/kg/day84%90 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 1800 mL of parenteral nutrition with final concentrations of 17.5% dextrose and 6% amino acids, plus 250 mL of 10% lipid emulsion (1.1 kcal/mL). Find the total energy E the patient receives in kcal per day. Round to the nearest whole number.
1800 mLdextrose 17.5%amino acids 6%lipid 250 mL · 1.1 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 8-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.
Practice exercise (made-up values, not clinical guidance). A 1000 mL bag was started at 07:45 and runs by pump at 75 mL/h. How many mL V are left in the bag at 08:45?
1000 mL75 mL/h07:45 → 08:45
V = mL
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: V = 235 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
35·72 = 2520 mL/day
Free water from the formula
90·24 = 2160 mL
2160·0.84 = 1814 mL
Water still needed
2520 − 1814 = 705.6 mL/day
Volume per flush
24/8 = 3 flushes
V = 705.6/3 = 235.2 ≈ 235 mL
Answer
V = 235 mL
2.Enteral & parenteral nutrition calculations
Answer: E = 1778 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: 17.5·1800/100 = 315 g
amino acids: 6·1800/100 = 108 g
Kilocalories per component
dextrose: 315·3.4 = 1071 kcal
amino acids: 108·4 = 432 kcal
lipid: 250·1.1 = 275 kcal
Total energy
E = 1071 + 432 + 275 = 1778 kcal/day
Answer
E = 1778 kcal/day
3.IV fluids & fluid balance
Answer: I = 1430 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: 150 + 250 + 240 = 640 mL
ice chips: 100/2 = 50 mL
IV infusion: 80·8 = 640 mL
IV antibiotic: 1·100 = 100 mL
I = 1430 mL
Answer
I = 1430 mL
4.IV fluids & fluid balance
Answer: V = 925 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.