Saunders Comprehensive Review for the NCLEX-PN®
Examination
9th Edition
• Author(s)Linda Anne Silvestri; Angela Silvestri
TEST BANK
1 — Pediatric mg/kg, divided dosing
Order: Amoxicillin 40 mg/kg/day PO in 3 divided doses (q8h).
Patient: 15 kg child.
Question: How many mg per dose should be administered?
Answer: 200 mg per dose
Step-by-step (dimensional analysis):
1. Total daily dose = 40 mg/kg × 15 kg = 600 mg/day.
2. Number of doses per day = 24 hr ÷ 8 hr = 3 doses.
3. Dose per administration = 600 mg ÷ 3 = 200 mg.
Patient safety checks / rationale: Confirm weight (kg),
calculation uses mg/kg/day, and divide by frequency. Always
verify the concentration of available product and check
allergies.
,Common incorrect approaches:
• Forgetting to divide by the number of doses (→ gives 600
mg as mistaken single dose).
• Using lb instead of kg (weight must be in kg).
2 — Pediatric mg/kg → volume from concentration
Order: Phenobarbital loading 20 mg/kg IV once.
Patient: Infant 12 kg. Available: Phenobarbital 50 mg/mL.
Question: How many mg will you give? How many mL will you
draw up?
Answer: Dose = 240 mg; Volume = 4.8 mL
Calculation:
1. Dose (mg) = 20 mg/kg × 12 kg = 240 mg.
2. Volume (mL) = dose ÷ concentration = 240 mg ÷ (50
mg/mL) = 4.8 mL.
Safety checks / rationale: Confirm correct mg/kg dosing and
concentration; phenobarbital is typically given slowly IV —
check recommended max mL/min and monitor respirations.
Incorrect approaches:
• Rounding volume to 5 mL without checking accuracy for
infant dosing; document if rounding done and assess
safety.
, • Forgetting to convert units (none needed here), but always
confirm mg vs mg/mL.
3 — IV flow rate (mL/hr and gtt/min)
Order: D5W 1000 mL to infuse over 8 hours. Drop factor: 15
gtt/mL.
Question: What is the infusion rate in mL/hr and gtt/min?
Answer: 125 mL/hr; 31 gtt/min (rounded)
Calculation:
• mL/hr = 1000 mL ÷ 8 hr = 125 mL/hr.
• gtt/min = (1000 mL × 15 gtt/mL) ÷ (8 hr × 60 min/hr) =
(15,000) ÷ 480 = 31.25 gtt/min → 31 gtt/min (round to
whole drop).
Safety checks / rationale: Round gtt/min to whole drops only
when using a manual roller clamp; if exact flow needed, use an
infusion pump and program 125 mL/hr.
Incorrect approaches: Using 60 gtt/mL drop factor by mistake
(would double the gtt/min).
4 — Concentration & units/hr (IV infusion of a drug)
Order: Heparin 25,000 units in 500 mL D5W. Infuse at 18 mL/hr.
Question: What is the heparin delivered in units/hr and
units/min?
, Answer: 50 units/mL; 900 units/hr; 15 units/min
Calculation:
1. Units per mL = 25,000 units ÷ 500 mL = 50 units/mL.
2. Units per hr = 50 units/mL × 18 mL/hr = 900 units/hr.
3. Units per min = 900 ÷ 60 = 15 units/min.
Safety checks / rationale: Verify institutional heparin protocol
(bolus/maintenance), double-check concentration and infusion
pump settings, confirm indication and lab monitoring (aPTT).
Incorrect approaches: Multiplying 25,000 × 18 instead of using
units/mL first.
5 — Reconstitution concentration & volume for ordered dose
Order: Vial contains 500 mg powder. Reconstitute with 10 mL
sterile water. Order: 125 mg IV.
Question: After reconstitution, what concentration (mg/mL) is
produced and what volume will you draw for 125 mg?
Answer: 50 mg/mL; 2.5 mL
Calculation:
• Concentration = 500 mg ÷ 10 mL = 50 mg/mL.
• Volume needed = 125 mg ÷ 50 mg/mL = 2.5 mL.
Examination
9th Edition
• Author(s)Linda Anne Silvestri; Angela Silvestri
TEST BANK
1 — Pediatric mg/kg, divided dosing
Order: Amoxicillin 40 mg/kg/day PO in 3 divided doses (q8h).
Patient: 15 kg child.
Question: How many mg per dose should be administered?
Answer: 200 mg per dose
Step-by-step (dimensional analysis):
1. Total daily dose = 40 mg/kg × 15 kg = 600 mg/day.
2. Number of doses per day = 24 hr ÷ 8 hr = 3 doses.
3. Dose per administration = 600 mg ÷ 3 = 200 mg.
Patient safety checks / rationale: Confirm weight (kg),
calculation uses mg/kg/day, and divide by frequency. Always
verify the concentration of available product and check
allergies.
,Common incorrect approaches:
• Forgetting to divide by the number of doses (→ gives 600
mg as mistaken single dose).
• Using lb instead of kg (weight must be in kg).
2 — Pediatric mg/kg → volume from concentration
Order: Phenobarbital loading 20 mg/kg IV once.
Patient: Infant 12 kg. Available: Phenobarbital 50 mg/mL.
Question: How many mg will you give? How many mL will you
draw up?
Answer: Dose = 240 mg; Volume = 4.8 mL
Calculation:
1. Dose (mg) = 20 mg/kg × 12 kg = 240 mg.
2. Volume (mL) = dose ÷ concentration = 240 mg ÷ (50
mg/mL) = 4.8 mL.
Safety checks / rationale: Confirm correct mg/kg dosing and
concentration; phenobarbital is typically given slowly IV —
check recommended max mL/min and monitor respirations.
Incorrect approaches:
• Rounding volume to 5 mL without checking accuracy for
infant dosing; document if rounding done and assess
safety.
, • Forgetting to convert units (none needed here), but always
confirm mg vs mg/mL.
3 — IV flow rate (mL/hr and gtt/min)
Order: D5W 1000 mL to infuse over 8 hours. Drop factor: 15
gtt/mL.
Question: What is the infusion rate in mL/hr and gtt/min?
Answer: 125 mL/hr; 31 gtt/min (rounded)
Calculation:
• mL/hr = 1000 mL ÷ 8 hr = 125 mL/hr.
• gtt/min = (1000 mL × 15 gtt/mL) ÷ (8 hr × 60 min/hr) =
(15,000) ÷ 480 = 31.25 gtt/min → 31 gtt/min (round to
whole drop).
Safety checks / rationale: Round gtt/min to whole drops only
when using a manual roller clamp; if exact flow needed, use an
infusion pump and program 125 mL/hr.
Incorrect approaches: Using 60 gtt/mL drop factor by mistake
(would double the gtt/min).
4 — Concentration & units/hr (IV infusion of a drug)
Order: Heparin 25,000 units in 500 mL D5W. Infuse at 18 mL/hr.
Question: What is the heparin delivered in units/hr and
units/min?
, Answer: 50 units/mL; 900 units/hr; 15 units/min
Calculation:
1. Units per mL = 25,000 units ÷ 500 mL = 50 units/mL.
2. Units per hr = 50 units/mL × 18 mL/hr = 900 units/hr.
3. Units per min = 900 ÷ 60 = 15 units/min.
Safety checks / rationale: Verify institutional heparin protocol
(bolus/maintenance), double-check concentration and infusion
pump settings, confirm indication and lab monitoring (aPTT).
Incorrect approaches: Multiplying 25,000 × 18 instead of using
units/mL first.
5 — Reconstitution concentration & volume for ordered dose
Order: Vial contains 500 mg powder. Reconstitute with 10 mL
sterile water. Order: 125 mg IV.
Question: After reconstitution, what concentration (mg/mL) is
produced and what volume will you draw for 125 mg?
Answer: 50 mg/mL; 2.5 mL
Calculation:
• Concentration = 500 mg ÷ 10 mL = 50 mg/mL.
• Volume needed = 125 mg ÷ 50 mg/mL = 2.5 mL.
