Practice exercise (made-up values, not clinical guidance). A 60 kg adult (BMI below 30) needs 30 kcal/kg/day. The tube feed provides 2 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.
60 kg30 kcal/kg/day2 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 1800 mL of parenteral nutrition with final concentrations of 20% dextrose and 6% 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.
1800 mLdextrose 20%amino acids 6%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 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.
Practice exercise (made-up values, not clinical guidance). A 1000 mL bag runs by pump at 50 mL/h. At 20:30, 200 mL have already been infused. How many hours t until the bag is empty? Round to one decimal place.
1000 mL200 mL infused50 mL/h
t = h
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: R = 45 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 = 30·60 = 1800 kcal/day
Daily volume
V = 1800/2 = 900 mL/day
Pump rate
R = 900/20 = 45 mL/h
Answer
R = 45 mL/h
2.Enteral & parenteral nutrition calculations
Answer: NPC = 2224 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: 20·1800/100 = 360 g
amino acids: 6·1800/100 = 108 g
Kilocalories per component
dextrose: 360·3.4 = 1224 kcal
amino acids: 108·4 = 432 kcal
lipid: 500·2 = 1000 kcal
Non-protein energy
NPC = 1224 + 1000 = 2224 kcal/day
Answer
NPC = 2224 kcal/day
3.IV fluids & fluid balance
Answer: I = 1540 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 + 240 + 240 = 680 mL
ice chips: 240/2 = 120 mL
IV infusion: 80·8 = 640 mL
IV antibiotic: 1·100 = 100 mL
I = 1540 mL
Answer
I = 1540 mL
4.IV fluids & fluid balance
Answer: t = 16 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 − 200 = 800 mL
Time
t = 800/50 = 16 h
Answer
t = 16 h
That is about 16 h 00 min, so the bag runs out at about 12:30.