Practice exercise (made-up values, not clinical guidance). A 65 kg adult (BMI below 30) needs 25 kcal/kg/day. The tube feed provides 1.5 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 kg25 kcal/kg/day1.5 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 1200 mL of parenteral nutrition with final concentrations of 10% dextrose and 3.5% amino acids, plus 500 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.
1200 mLdextrose 10%amino acids 3.5%lipid 500 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 IV infusion ran at the rate shown for the whole shift. Find the fluid balance B = intake − output in mL (a negative answer means a net loss). Count ice chips as half their volume.
Practice exercise (made-up values, not clinical guidance). A 1000 mL bag was started at 10:15 and runs by pump at 100 mL/h. How many mL V are left in the bag at 13:45?
1000 mL100 mL/h10:15 → 13:45
V = mL
3Solutions
1.Enteral & parenteral nutrition calculations
Answer: R = 54 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 = 25·65 = 1625 kcal/day
Daily volume
V = 1625/1.5 = 1083 mL/day
Pump rate
R = 1083/20 = 54.17 ≈ 54 mL/h
Answer
R = 54 mL/h
2.Enteral & parenteral nutrition calculations
Answer: E = 1126 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: 10·1200/100 = 120 g
amino acids: 3.5·1200/100 = 42 g
Kilocalories per component
dextrose: 120·3.4 = 408 kcal
amino acids: 42·4 = 168 kcal
lipid: 500·1.1 = 550 kcal
Total energy
E = 408 + 168 + 550 = 1126 kcal/day
Answer
E = 1126 kcal/day
3.IV fluids & fluid balance
Answer: B = 975 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.
Total intake
oral: 200 + 150 + 200 = 550 mL
ice chips: 100/2 = 50 mL
IV infusion: 100·12 = 1200 mL
IV antibiotic: 1·50 = 50 mL
total intake = 1850 mL
Total output
325 + 325 + 225 = 875 mL
Balance
B = 1850 − 875 = 975 mL
Answer
B = 975 mL
Positive: more fluid went in than came out.
4.IV fluids & fluid balance
Answer: V = 650 mL
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.