Practice exercise (made-up values, not clinical guidance). Use the Devine formula to find the ideal body weight IBW of a man who is 192 cm tall (1 in = 2.54 cm). Round to one decimal place.
192 cmman1 in = 2.54 cm
IBW = kg
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 10% dextrose and 5% amino acids, plus 250 mL of 20% lipid emulsion (2 kcal/mL). Find the non-protein energy NPC in kcal per day. Round to the nearest whole number.
2000 mLdextrose 10%amino acids 5%lipid 250 mL · 2 kcal/mL
NPC = 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 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.
tea: 150 mLsoup: 180 mLice chips: 200 mLIV infusion: 50 mL/h × 12 hIV antibiotic: 2 × 100 mL
I = mL
4.IV fluids & fluid balanceHard
Practice exercise (made-up values, not clinical guidance). A 500 mL bag was started at 09:45 and runs by pump at 120 mL/h. How many mL V are left in the bag at 12:15?
500 mL120 mL/h09:45 → 12:15
V = mL
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: IBW = 85.9 kg
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.
Height in inches
192 cm/2.54 = 75.59 in
Ideal body weight (Devine)
IBW = 50 + 2.3·(75.59 − 60) = 85.86 ≈ 85.9 kg
Answer
IBW = 85.9 kg
2.Enteral & parenteral nutrition calculations
Answer: NPC = 1180 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: 10·2000/100 = 200 g
amino acids: 5·2000/100 = 100 g
Kilocalories per component
dextrose: 200·3.4 = 680 kcal
amino acids: 100·4 = 400 kcal
lipid: 250·2 = 500 kcal
Non-protein energy
NPC = 680 + 500 = 1180 kcal/day
Answer
NPC = 1180 kcal/day
3.IV fluids & fluid balance
Answer: I = 1230 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 + 180 = 330 mL
ice chips: 200/2 = 100 mL
IV infusion: 50·12 = 600 mL
IV antibiotic: 2·100 = 200 mL
I = 1230 mL
Answer
I = 1230 mL
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.