Maternity Nursing: cram pack

Formula sheets, the key method steps for every topic and 6 practice problems, with full solutions at the back.

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1Formulas and methods

Maternity & obstetric nursing

Method

  1. Place the woman in time: weeks of pregnancy, stage of labour or day after birth, and decide what is normal at that point.
  2. Look for the patient in danger: the mother, the fetus or the newborn, or more than one of them.
  3. Link the finding to its cause: VEAL CHOP for decelerations, the four Ts for bleeding, BUBBLE-HE after birth.
  4. Choose the action that improves blood flow and oxygen first (side-lying, stopping oxytocin, fundal massage), then escalate.

Dosage calculations

Dose from strength
volume = dose / strength
Weight-based dose
dose = mg/kg × body weight
Tablets
number = dose / tablet strength
Units
1 g = 1000 mg, 1 mg = 1000 mcg

Method

  1. Convert the ordered dose and the stock strength to the same unit.
  2. Use desired over have times quantity: (D/H) × Q.
  3. For weight-based doses, multiply by the weight in kg first, then divide the daily dose by the number of doses.
  4. Estimate first and check that the answer is reasonable.

IV infusion rates

Pump rate
mL/h = volume (mL)/time (h)
Drip rate
drops/min = volume (mL) × drop factor / time (min)
Infusion time
time (h) = volume (mL)/rate (mL/h)

Method

  1. Pump rate in mL/h: volume divided by time in hours.
  2. Drip rate in drops/min: volume × drop factor divided by time in minutes.
  3. For time remaining: volume left divided by the rate.
  4. Round as the question or the equipment requires.

2Practice problems

1.Maternity & obstetric nursingMedium

Which baby is at greatest risk of early-onset group B streptococcal infection?

  1. AA baby whose mother was GBS-negative at 36 weeks
  2. BA baby born at 40 weeks to a mother with no risk factors
  3. CA baby of a GBS-positive mother with no antibiotics
  4. DA baby born by planned caesarean with intact membranes
2.Maternity & obstetric nursingHard

Which postpartum task can be delegated to an assistive staff member (healthcare assistant)?

  1. ATaking vital signs of a stable woman
  2. BAssessing the fundus of a woman with heavy bleeding
  3. CTeaching a first-time mother about breastfeeding
  4. DEvaluating a woman for signs of postpartum depression
3.Dosage calculationsMedium
80 kg5 mg/kgD = ? mg

A patient weighs 80 kg and is prescribed 5 mg/kg as a single dose. Find the dose D in mg.

80 kg5 mg/kg
D = mg
4.Dosage calculationsHard
00.10.20.30.40.50.60.70.80.911 mL

The prescription is 1180 micrograms. The ampoule contains 2 mg/mL. Draw up the dose in the 1 mL syringe: what volume V do you give?

1180 mcg2 mg/mL
V = mL
5.IV infusion ratesMedium
500 mL15 gtt/mL4 h? gtt/min

Infuse 500 mL over 4 hours with a giving set of 15 gtt/mL. Find the drip rate R in drops per minute. Round to the nearest whole number.

500 mL4 h15 gtt/mL
R = gtt/min
6.IV infusion ratesHard
910 mLleft? mL/h8 h left

1000 mL was ordered over 10 hours. After 2 hours you find that 910 mL is still in the bag, and the order must still finish on time. By what percentage Δ must the original pump rate be increased?

1000 mL / 10 hafter 2 h: 910 mL
Δ = %

3Solutions

1.Maternity & obstetric nursing

Answer: C · A baby of a GBS-positive mother with no antibiotics

Why this is the answer

GBS colonisation, no intrapartum antibiotics, prolonged rupture of membranes, maternal fever and prematurity increase the risk. Intrapartum IV antibiotics greatly lower early-onset GBS disease.

Answer

C · A baby of a GBS-positive mother with no antibiotics
2.Maternity & obstetric nursing

Answer: A · Taking vital signs of a stable woman

Why this is the answer

Routine vital signs for a stable patient can be delegated, with the nurse interpreting results. Assessment, teaching and evaluation of unstable patients are nursing responsibilities.

Answer

A · Taking vital signs of a stable woman
3.Dosage calculations

Answer: D = 400 mg

Dose calculation: the amount to give equals what is prescribed divided by what you have, times the quantity it comes in: amount = (desired dose/stock strength) × stock volume. Always keep the units the same (convert g to mg, mg to mcg first) and check that the answer is sensible.

Dose

5·80 = 400 mg

Answer

D = 400 mg
4.Dosage calculations

Answer: V = 0.59 mL

Drawing up a dose: volume = (prescribed dose/stock strength) × stock volume. Convert to the same units first, then check that the volume fits the syringe and lands on one of its graduations.

Same units

2 mg/mL = 2000 mcg/mL

Volume

V = 1180/2000 = 0.59 mL

Answer

V = 0.59 mL
5.IV infusion rates

Answer: R = 31 gtt/min

Infusion rates: a pump is set in mL/h = volume/time in hours. A gravity drip is counted in drops per minute: gtt/min = volume (mL) × drop factor (gtt/mL)/time (min). The drop factor is printed on the tubing package: macrodrip sets deliver 10, 15 or 20 gtt/mL (blood sets often 10 gtt/mL in the US, 15 in the UK) and microdrip sets 60 gtt/mL. Always use the drop factor the question or package gives.

Time in minutes

4·60 = 240 min

Drip rate

R = 500·15/240 = 31.25 ≈ 31 gtt/min

Answer

R = 31 gtt/min

At the bedside you round to the nearest whole drop: 31 gtt/min.

6.IV infusion rates

Answer: Δ = 13.75 %

Infusion rates: a pump is set in mL/h = volume/time in hours. A gravity drip is counted in drops per minute: gtt/min = volume (mL) × drop factor (gtt/mL)/time (min). The drop factor is printed on the tubing package: macrodrip sets deliver 10, 15 or 20 gtt/mL (blood sets often 10 gtt/mL in the US, 15 in the UK) and microdrip sets 60 gtt/mL. Always use the drop factor the question or package gives.

Original rate

1000/10 = 100 mL/h

New rate

R = 910/8 = 113.8 mL/h

Percentage change

Δ = (113.8 − 100)/100·100% = 13.75%

Answer

Δ = 13.75%

Many hospitals allow such an adjustment up to 25% without a new order; check local policy.

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