Practice exercise (made-up values, not clinical guidance). A 65 kg adult (BMI below 30) needs 30 kcal/kg/day. The tube feed provides 1 kcal/mL and runs by pump for 20 hours a day. At what rate R do you set the pump, in mL/h? Round to the nearest whole number.
65 kg30 kcal/kg/day1 kcal/mL20 h
R = mL/h
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 20% dextrose and 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 20%amino acids 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 8-hour shift. The IV infusion ran at the rate shown for the whole shift. Find the total intake I in mL.
juice: 120 mLsoup: 150 mLIV infusion: 80 mL/h × 8 hIV antibiotic: 2 × 50 mL
I = mL
4.IV fluids & fluid balanceHard
Practice exercise (made-up values, not clinical guidance). A 1000 mL infusion starts at 19:30 at 75 mL/h. After 3 hours the rate is changed to 60 mL/h and is not changed again. How many hours t after the start will the bag be empty? Round to one decimal place.
1000 mL75 mL/h · 3 h60 mL/h
t = h
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: R = 98 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 = 30·65 = 1950 kcal/day
Daily volume
V = 1950/1 = 1950 mL/day
Pump rate
R = 1950/20 = 97.5 ≈ 98 mL/h
Answer
R = 98 mL/h
2.Enteral & parenteral nutrition calculations
Answer: E = 2260 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: 20·2000/100 = 400 g
amino acids: 5·2000/100 = 100 g
Kilocalories per component
dextrose: 400·3.4 = 1360 kcal
amino acids: 100·4 = 400 kcal
lipid: 250·2 = 500 kcal
Total energy
E = 1360 + 400 + 500 = 2260 kcal/day
Answer
E = 2260 kcal/day
3.IV fluids & fluid balance
Answer: I = 1010 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: 120 + 150 = 270 mL
IV infusion: 80·8 = 640 mL
IV antibiotic: 2·50 = 100 mL
I = 1010 mL
Answer
I = 1010 mL
4.IV fluids & fluid balance
Answer: t = 15.9 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.
First part
75·3 = 225 mL
1000 − 225 = 775 mL left
Second part
775/60 = 12.92 h
Total time
t = 3 + 12.92 = 15.92 ≈ 15.9 h
Answer
t = 15.9 h
That is about 15 h 55 min, so the bag runs out at about 11:25.