Practice exercise (made-up values, not clinical guidance). A 75 kg adult (BMI below 30) needs 30 kcal/kg/day. The tube feed provides 1.5 kcal/mL and runs by pump for 24 hours a day. At what rate R do you set the pump, in mL/h? Round to the nearest whole number.
75 kg30 kcal/kg/day1.5 kcal/mL24 h
R = mL/h
2.Enteral & parenteral nutrition calculationsHard
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 1200 mL of parenteral nutrition with final concentrations of 15% dextrose and 5% amino acids, plus 100 mL of 20% lipid emulsion (2 kcal/mL). Find the non-protein energy NPC in kcal per day. Round to the nearest whole number.
1200 mLdextrose 15%amino acids 5%lipid 100 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 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.
juice: 200 mLtea: 200 mLice chips: 100 mLIV infusion: 125 mL/h × 8 hIV antibiotic: 1 × 100 mL
I = mL
4.IV fluids & fluid balanceHard
Practice exercise (made-up values, not clinical guidance). A 500 mL infusion starts at 14:00 at 75 mL/h. After 3 hours the rate is changed to 100 mL/h and is not changed again. How many hours t after the start will the bag be empty? Round to one decimal place.
500 mL75 mL/h · 3 h100 mL/h
t = h
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: R = 63 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 = 30·75 = 2250 kcal/day
Daily volume
V = 2250/1.5 = 1500 mL/day
Pump rate
R = 1500/24 = 62.5 ≈ 63 mL/h
Answer
R = 63 mL/h
2.Enteral & parenteral nutrition calculations
Answer: NPC = 812 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: 15·1200/100 = 180 g
amino acids: 5·1200/100 = 60 g
Kilocalories per component
dextrose: 180·3.4 = 612 kcal
amino acids: 60·4 = 240 kcal
lipid: 100·2 = 200 kcal
Non-protein energy
NPC = 612 + 200 = 812 kcal/day
Answer
NPC = 812 kcal/day
3.IV fluids & fluid balance
Answer: I = 1550 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: 200 + 200 = 400 mL
ice chips: 100/2 = 50 mL
IV infusion: 125·8 = 1000 mL
IV antibiotic: 1·100 = 100 mL
I = 1550 mL
Answer
I = 1550 mL
4.IV fluids & fluid balance
Answer: t = 5.8 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
500 − 225 = 275 mL left
Second part
275/100 = 2.75 h
Total time
t = 3 + 2.75 = 5.75 ≈ 5.8 h
Answer
t = 5.8 h
That is about 5 h 45 min, so the bag runs out at about 19:45.