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1Formulas and methods
Pediatric nursing
Method
Note the child’s age first: it sets the normal vital signs, the milestones and the right pain scale.
Assess airway, breathing and circulation, remembering that children compensate and then deteriorate fast.
Match the action to the development stage and involve the family.
Check that the answer is safe for a child: weight-based, no aspirin in viral illness, no codeine under 12.
Pediatric & critical-care dosing
Daily dose
mg/day = mg/kg/day × weight (kg)
Doses per day
number = 24 h / dosing interval (h)
Pounds to kilograms
kg = lb / 2.2
Infusion concentration
units/mL = units in bag / bag volume
Pump rate
mL/h = dose per hour / concentration
Titrated drip
mL/h = mcg/kg/min × kg × 60 / (mcg/mL)
Dose from pump rate
mcg/kg/min = mL/h × (mcg/mL) / (60 × kg)
Units
1 mg = 1000 mcg
IV fluids & fluid balance
Holliday–Segar per hour
4 mL/kg (first 10 kg) + 2 mL/kg (next 10 kg) + 1 mL/kg (each kg above 20)
Holliday–Segar per day
100 / 50 / 20 mL/kg for the same bands
Fluid balance
intake − output
Ice chips
count as half their volume
Urine output
mL/kg/h = mL / (kg × h)
Infusion time
time (h) = volume left (mL) / rate (mL/h)
Volume infused
mL = rate × time
2Practice problems
1.Pediatric nursingMedium
In a child with hypovolaemic shock, which finding is usually a late sign?
AProlonged capillary refill
BCool extremities
CTachycardia
DLow blood pressure
2.Pediatric nursingHard
Which finding in a teenager with anorexia nervosa most clearly suggests the need for hospital admission?
AFainting episodes with a very slow heart rate and low potassium
BWeighing 2 kg less than at last month's clinic visit
CMissing one menstrual period after starting a new diet
DWanting to exercise every day
3.Pediatric & critical-care dosingMedium
Practice exercise (made-up values, not clinical guidance). A bag contains 25 000 units of heparin in 250 mL. The order is 18 units/kg/h for a patient who weighs 100 kg. At what rate R do you set the pump, in mL/h? Round to one decimal place.
25 000 units/250 mL18 units/kg/h100 kg
R = mL/h
4.Pediatric & critical-care dosingHard
Practice exercise (made-up values, not clinical guidance). A bag contains dobutamine 500 mg in 250 mL. The order is 12.5 mcg/kg/min for a patient who weighs 58 kg. At what rate R do you set the pump, in mL/h? Round to one decimal place.
500 mg/250 mL12.5 mcg/kg/min58 kg
R = mL/h
5.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).
Practice exercise (made-up values, not clinical guidance). A 1000 mL bag runs by pump at 120 mL/h. At 07:30, 750 mL have already been infused. How many hours t until the bag is empty? Round to one decimal place.
1000 mL750 mL infused120 mL/h
t = h
3Solutions
1.Pediatric nursing
Answer: D · Low blood pressure
Why this is the answer
Children maintain blood pressure through vasoconstriction and tachycardia until a large volume is lost. Hypotension means decompensated shock and impending collapse.
Answer
D · Low blood pressure
2.Pediatric nursing
Answer: A · Fainting episodes with a very slow heart rate and low potassium
Why this is the answer
Admission is considered for medical instability, such as marked bradycardia, low or postural blood pressure, fainting, hypothermia, electrolyte problems or refusal to eat. Medical risk is judged on the whole picture, not on weight alone.
Answer
A · Fainting episodes with a very slow heart rate and low potassium
3.Pediatric & critical-care dosing
Answer: R = 18 mL/h
Heparin and insulin infusions: concentration = units in the bag/bag volume (units/mL). Pump rate (mL/h) = units per hour/concentration, and units per hour = mL/h × concentration. For a weight-based order, units/h = units/kg/h × weight first. A bolus volume = units needed/vial strength. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Units per hour
18·100 = 1 800 units/h
Concentration
25 000/250 = 100 units/mL
Pump rate
R = 1800/100 = 18 mL/h
Answer
R = 18 mL/h
4.Pediatric & critical-care dosing
Answer: R = 21.8 mL/h
Titrated drips: first find the concentration in mcg/mL (mg × 1000/mL). For a weight-based order, mcg/min = mcg/kg/min × weight. Then mL/h = mcg/min × 60/concentration. Working backwards, mcg/kg/min = mL/h × concentration/(60 × weight). The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Concentration
500 mg = 500 000 mcg
500 000/250 = 2000 mcg/mL
Dose per minute and per hour
12.5·58 = 725 mcg/min
725·60 = 43500 mcg/h
Pump rate
R = 43500/2000 = 21.75 ≈ 21.8 mL/h
Answer
R = 21.8 mL/h
5.IV fluids & fluid balance
Answer: B = 410 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: 100 + 120 + 150 = 370 mL
IV infusion: 50·12 = 600 mL
IV antibiotic: 2·50 = 100 mL
total intake = 1070 mL
Total output
175 + 425 + 60 = 660 mL
Balance
B = 1070 − 660 = 410 mL
Answer
B = 410 mL
Positive: more fluid went in than came out.
6.IV fluids & fluid balance
Answer: t = 2.1 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.
Volume left
1000 − 750 = 250 mL
Time
t = 250/120 = 2.083 ≈ 2.1 h
Answer
t = 2.1 h
That is about 2 h 05 min, so the bag runs out at about 09:35.