Saunders Comprehensive Review for the NCLEX-PN®
Examination
9th Edition
• Author(s)Linda Anne Silvestri; Angela Silvestri
TEST BANK
Question 1 — mg/kg → mL
Order: Gentamicin 3 mg/kg IV single dose.
Patient: 55 kg.
Available: Gentamicin 40 mg/mL vial.
How many mL should the nurse prepare? (Round to nearest
tenth of a mL.)
A. 3.8 mL
B. 4.0 mL
C. 4.1 mL
D. 4.5 mL
E. 4.9 mL
Answer: C. 4.1 mL
Step-by-step calculation (dimensional analysis, digit-by-digit):
1. Calculate dose in mg: 3 mg/kg × 55 kg = 165 mg.
o 3 × 55 = 165 mg.
, 2. Concentration: 40 mg per 1 mL. Want mL for 165 mg.
o mL = (165 mg) × (1 mL / 40 mg) = 165/40 mL.
3. Division: 165 ÷ 40 = 4.125 mL.
4. Rounding: to nearest tenth = 4.1 mL.
Rationale (correct): Use mg/kg to get total mg, then convert mg
→ mL using vial concentration. Dimensional analysis ensures
units cancel (mg → mg). Rounding to tenths is safe for an
injection syringe.
Why distractors are wrong:
• A (3.8 mL): underestimates dose (would deliver 152 mg).
• B (4.0 mL): slight underdose (4.0 mL × 40 mg/mL = 160
mg).
• D & E: overestimates (4.5 mL = 180 mg; 4.9 mL = 196 mg).
Incorrect rounding or decimal placement errors are
common mistakes.
Safety checks: Verify weight calculation, allergy history, and
that calculated mL is within typical dose range for gentamicin;
use correct syringe.
Question 2 — IV flow (gtt/min)
Order: Infuse 1,000 mL D5W over 8 hours.
IV set: 15 gtt (drops)/mL.
,What is the drip rate in gtt/min? (Round to whole drops per
minute.)
A. 20 gtt/min
B. 25 gtt/min
C. 31 gtt/min
D. 36 gtt/min
E. 42 gtt/min
Answer: C. 31 gtt/min
Step-by-step calculation:
1. mL/hr = 1,000 mL ÷ 8 hr = 125.0 mL/hr.
2. gtt/min = (mL/hr × gtt/mL) ÷ 60 min/hr.
o = (125.0 × 15) ÷ 60.
3. Multiply: 125.0 × 15 = 1,875 drops/hr.
4. Divide: 1,875 ÷ 60 = 31.25 gtt/min.
5. Round to whole drop = 31 gtt/min.
Rationale (correct): Use mL/hr then convert to drops/minute
using drop factor and 60 min/hr. Round to whole drop because
you can’t deliver fractional drops.
Why distractors are wrong:
• A/B too low (calculation errors or wrong division by 60
before multiplying).
• D/E too high (likely result of rounding before final division
or using wrong drop factor).
, Safety checks: Recheck IV tubing drop factor and ensure rate
appropriate for patient condition.
Question 3 — mcg/kg/min (vasopressor) → mL/hr
Order: Dopamine 5 mcg/kg/min IV.
Patient: 70 kg.
Available: Dopamine prepared as 400 mg in 250 mL D5W.
(Note: 1 mg = 1,000 mcg.)
What pump rate in mL/hr (round to nearest tenth) will deliver
the ordered dose?
A. 9.6 mL/hr
B. 11.7 mL/hr
C. 13.1 mL/hr
D. 15.4 mL/hr
E. 21.0 mL/hr
Answer: C. 13.1 mL/hr
Step-by-step calculation:
1. Ordered dose: 5 mcg/kg/min × 70 kg = 350 mcg/min.
2. Convert to mcg/hr: 350 mcg/min × 60 min/hr = 21,000
mcg/hr.
3. Available concentration: 400 mg/250 mL → convert mg →
mcg: 400 mg × 1,000 mcg/mg = 400,000 mcg in 250 mL.
4. mcg/mL = 400,000 mcg ÷ 250 mL = 1,600 mcg/mL.
Examination
9th Edition
• Author(s)Linda Anne Silvestri; Angela Silvestri
TEST BANK
Question 1 — mg/kg → mL
Order: Gentamicin 3 mg/kg IV single dose.
Patient: 55 kg.
Available: Gentamicin 40 mg/mL vial.
How many mL should the nurse prepare? (Round to nearest
tenth of a mL.)
A. 3.8 mL
B. 4.0 mL
C. 4.1 mL
D. 4.5 mL
E. 4.9 mL
Answer: C. 4.1 mL
Step-by-step calculation (dimensional analysis, digit-by-digit):
1. Calculate dose in mg: 3 mg/kg × 55 kg = 165 mg.
o 3 × 55 = 165 mg.
, 2. Concentration: 40 mg per 1 mL. Want mL for 165 mg.
o mL = (165 mg) × (1 mL / 40 mg) = 165/40 mL.
3. Division: 165 ÷ 40 = 4.125 mL.
4. Rounding: to nearest tenth = 4.1 mL.
Rationale (correct): Use mg/kg to get total mg, then convert mg
→ mL using vial concentration. Dimensional analysis ensures
units cancel (mg → mg). Rounding to tenths is safe for an
injection syringe.
Why distractors are wrong:
• A (3.8 mL): underestimates dose (would deliver 152 mg).
• B (4.0 mL): slight underdose (4.0 mL × 40 mg/mL = 160
mg).
• D & E: overestimates (4.5 mL = 180 mg; 4.9 mL = 196 mg).
Incorrect rounding or decimal placement errors are
common mistakes.
Safety checks: Verify weight calculation, allergy history, and
that calculated mL is within typical dose range for gentamicin;
use correct syringe.
Question 2 — IV flow (gtt/min)
Order: Infuse 1,000 mL D5W over 8 hours.
IV set: 15 gtt (drops)/mL.
,What is the drip rate in gtt/min? (Round to whole drops per
minute.)
A. 20 gtt/min
B. 25 gtt/min
C. 31 gtt/min
D. 36 gtt/min
E. 42 gtt/min
Answer: C. 31 gtt/min
Step-by-step calculation:
1. mL/hr = 1,000 mL ÷ 8 hr = 125.0 mL/hr.
2. gtt/min = (mL/hr × gtt/mL) ÷ 60 min/hr.
o = (125.0 × 15) ÷ 60.
3. Multiply: 125.0 × 15 = 1,875 drops/hr.
4. Divide: 1,875 ÷ 60 = 31.25 gtt/min.
5. Round to whole drop = 31 gtt/min.
Rationale (correct): Use mL/hr then convert to drops/minute
using drop factor and 60 min/hr. Round to whole drop because
you can’t deliver fractional drops.
Why distractors are wrong:
• A/B too low (calculation errors or wrong division by 60
before multiplying).
• D/E too high (likely result of rounding before final division
or using wrong drop factor).
, Safety checks: Recheck IV tubing drop factor and ensure rate
appropriate for patient condition.
Question 3 — mcg/kg/min (vasopressor) → mL/hr
Order: Dopamine 5 mcg/kg/min IV.
Patient: 70 kg.
Available: Dopamine prepared as 400 mg in 250 mL D5W.
(Note: 1 mg = 1,000 mcg.)
What pump rate in mL/hr (round to nearest tenth) will deliver
the ordered dose?
A. 9.6 mL/hr
B. 11.7 mL/hr
C. 13.1 mL/hr
D. 15.4 mL/hr
E. 21.0 mL/hr
Answer: C. 13.1 mL/hr
Step-by-step calculation:
1. Ordered dose: 5 mcg/kg/min × 70 kg = 350 mcg/min.
2. Convert to mcg/hr: 350 mcg/min × 60 min/hr = 21,000
mcg/hr.
3. Available concentration: 400 mg/250 mL → convert mg →
mcg: 400 mg × 1,000 mcg/mg = 400,000 mcg in 250 mL.
4. mcg/mL = 400,000 mcg ÷ 250 mL = 1,600 mcg/mL.
