Practice exercise (made-up values, not clinical guidance). Use the Devine formula to find the ideal body weight IBW of a woman who is 177 cm tall (1 in = 2.54 cm). Round to one decimal place.
177 cmwoman1 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 1000 mL of parenteral nutrition with final concentrations of 12.5% dextrose and 5% amino acids, plus 100 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.
1000 mLdextrose 12.5%amino acids 5%lipid 100 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 8-hour shift. The patient weighs 98 kg. Find the average urine output U in mL/kg/h. Round to two decimal places.
98 kg8 hurine: 225 mLurine: 250 mLvomit: 100 mL
U = mL/kg/h
4.IV fluids & fluid balanceHard
Practice exercise (made-up values, not clinical guidance). A 1000 mL bag runs by pump at 125 mL/h. At 12:00, 250 mL have already been infused. How many hours t until the bag is empty? Round to one decimal place.
1000 mL250 mL infused125 mL/h
t = h
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: IBW = 67.8 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
177 cm/2.54 = 69.69 in
Ideal body weight (Devine)
IBW = 45.5 + 2.3·(69.69 − 60) = 67.78 ≈ 67.8 kg
Answer
IBW = 67.8 kg
2.Enteral & parenteral nutrition calculations
Answer: E = 825 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: 12.5·1000/100 = 125 g
amino acids: 5·1000/100 = 50 g
Kilocalories per component
dextrose: 125·3.4 = 425 kcal
amino acids: 50·4 = 200 kcal
lipid: 100·2 = 200 kcal
Total energy
E = 425 + 200 + 200 = 825 kcal/day
Answer
E = 825 kcal/day
3.IV fluids & fluid balance
Answer: U = 0.61 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
225 + 250 = 475 mL
Per kilogram per hour
U = 475/(98·8) = 0.6059 ≈ 0.61 mL/kg/h
Answer
U = 0.61 mL/kg/h
4.IV fluids & fluid balance
Answer: t = 6 h
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.
Volume left
1000 − 250 = 750 mL
Time
t = 750/125 = 6 h
Answer
t = 6 h
That is about 6 h 00 min, so the bag runs out at about 18:00.