Practice exercise (made-up values, not clinical guidance). A 67 kg adult (BMI below 30) needs 30 kcal/kg/day. The tube feed provides 1.2 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.
67 kg30 kcal/kg/day1.2 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 1500 mL of parenteral nutrition with final concentrations of 20% dextrose and 6% amino acids, plus 250 mL of 10% lipid emulsion (1.1 kcal/mL). Find the total energy E the patient receives in kcal per day. Round to the nearest whole number.
1500 mLdextrose 20%amino acids 6%lipid 250 mL · 1.1 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 12-hour shift. The patient weighs 77 kg. Find the average urine output U in mL/kg/h. Round to two decimal places.
Practice exercise (made-up values, not clinical guidance). A 1000 mL infusion starts at 17:00 at 150 mL/h. After 4 hours the rate is changed to 50 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 mL150 mL/h · 4 h50 mL/h
t = h
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: R = 70 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 = 30·67 = 2010 kcal/day
Daily volume
V = 2010/1.2 = 1675 mL/day
Pump rate
R = 1675/24 = 69.79 ≈ 70 mL/h
Answer
R = 70 mL/h
2.Enteral & parenteral nutrition calculations
Answer: E = 1655 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: 20·1500/100 = 300 g
amino acids: 6·1500/100 = 90 g
Kilocalories per component
dextrose: 300·3.4 = 1020 kcal
amino acids: 90·4 = 360 kcal
lipid: 250·1.1 = 275 kcal
Total energy
E = 1020 + 360 + 275 = 1655 kcal/day
Answer
E = 1655 kcal/day
3.IV fluids & fluid balance
Answer: U = 1.43 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
175 + 400 + 275 + 475 = 1325 mL
Per kilogram per hour
U = 1325/(77·12) = 1.434 ≈ 1.43 mL/kg/h
Answer
U = 1.43 mL/kg/h
4.IV fluids & fluid balance
Answer: t = 12 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
150·4 = 600 mL
1000 − 600 = 400 mL left
Second part
400/50 = 8 h
Total time
t = 4 + 8 = 12 h
Answer
t = 12 h
That is about 12 h 00 min, so the bag runs out at about 05:00.