Practice exercise (made-up values, not clinical guidance). A 64 kg adult (BMI below 30) needs 35 kcal/kg/day. The tube feed provides 1.5 kcal/mL and runs by pump for 16 hours a day. At what rate R do you set the pump, in mL/h? Round to the nearest whole number.
64 kg35 kcal/kg/day1.5 kcal/mL16 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 25% dextrose and 5% amino acids, plus 500 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 25%amino acids 5%lipid 500 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 patient weighs 67 kg. Find the average urine output U in mL/kg/h. Round to two decimal places.
67 kg8 hurine: 150 mLurine: 300 mL
U = mL/kg/h
4.IV fluids & fluid balanceHard
Practice exercise (made-up values, not clinical guidance). A 1000 mL infusion starts at 06:00 at 120 mL/h. After 2 hours the rate is changed to 75 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 mL120 mL/h · 2 h75 mL/h
t = h
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: R = 93 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 = 35·64 = 2240 kcal/day
Daily volume
V = 2240/1.5 = 1493 mL/day
Pump rate
R = 1493/16 = 93.33 ≈ 93 mL/h
Answer
R = 93 mL/h
2.Enteral & parenteral nutrition calculations
Answer: NPC = 2020 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: 25·1200/100 = 300 g
amino acids: 5·1200/100 = 60 g
Kilocalories per component
dextrose: 300·3.4 = 1020 kcal
amino acids: 60·4 = 240 kcal
lipid: 500·2 = 1000 kcal
Non-protein energy
NPC = 1020 + 1000 = 2020 kcal/day
Answer
NPC = 2020 kcal/day
3.IV fluids & fluid balance
Answer: U = 0.84 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
150 + 300 = 450 mL
Per kilogram per hour
U = 450/(67·8) = 0.8396 ≈ 0.84 mL/kg/h
Answer
U = 0.84 mL/kg/h
4.IV fluids & fluid balance
Answer: t = 12.1 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
120·2 = 240 mL
1000 − 240 = 760 mL left
Second part
760/75 = 10.13 h
Total time
t = 2 + 10.13 = 12.13 ≈ 12.1 h
Answer
t = 12.1 h
That is about 12 h 08 min, so the bag runs out at about 18:08.