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

Carboprost, a prostaglandin used for postpartum haemorrhage, should be avoided in women with:

  1. AHypertension
  2. BEpilepsy
  3. CAsthma
  4. DA previous caesarean birth
2.Maternity & obstetric nursingHard

Shortly after an epidural is started, a labouring woman's blood pressure falls to 86/50 mmHg and the fetal heart rate drops. What should the nurse do first?

  1. AIncrease the epidural infusion rate
  2. BAsk her to walk around the room
  3. CTurn her onto her side to move the uterus off the large vessels
  4. DRaise the head of the bed to a high sitting position to improve her breathing
3.Dosage calculationsMedium
024681010 mL

A child weighing 22 kg is prescribed 2 mg/kg of a drug. The stock solution contains 10 mg/mL. Draw up the dose: what volume V do you give?

22 kg2 mg/kg10 mg/mL
V = mL
4.Dosage calculationsHard
00.10.20.30.40.50.60.70.80.911 mL

The prescription is 650 units of a drug that comes as 1000 units/mL. Draw up the dose in the 1 mL syringe: what volume V do you give?

650 units1000 units/mL
V = mL
5.IV infusion ratesMedium
240 mLleft? mL/h4 h left

500 mL was ordered over 10 hours. After 6 hours you find that 240 mL is still in the bag, and the order must still finish on time. To what rate R in mL/h must the pump be reset?

500 mL / 10 hafter 6 h: 240 mL
R = mL/h
6.IV infusion ratesHard
380 mLleft? mL/h5 h left

500 mL was ordered over 8 hours. After 3 hours you find that 380 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?

500 mL / 8 hafter 3 h: 380 mL
Δ = %

3Solutions

1.Maternity & obstetric nursing

Answer: C · Asthma

Why this is the answer

Carboprost can cause bronchospasm, so it is avoided in asthma. Methylergonovine is the uterotonic to avoid in hypertension.

Answer

C · Asthma
2.Maternity & obstetric nursing

Answer: C · Turn her onto her side to move the uterus off the large vessels

Why this is the answer

A lateral position relieves aortocaval compression and improves venous return and placental flow. Then increase IV fluids as ordered, notify the anaesthetist or provider and give a vasopressor if prescribed.

Answer

C · Turn her onto her side to move the uterus off the large vessels
3.Dosage calculations

Answer: V = 4.4 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.

Dose from body weight

D = 2·22 = 44 mg

Volume

V = 44/10 = 4.4 mL

On the syringe

On this 10 mL syringe every small line is 0.2 mL.

Answer

V = 4.4 mL
4.Dosage calculations

Answer: V = 0.65 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.

Volume

V = 650/1000 = 0.65 mL

On the syringe

On this 1 mL syringe every small line is 0.01 mL.

Answer

V = 0.65 mL
5.IV infusion rates

Answer: R = 60 mL/h

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

500/10 = 50 mL/h

New rate

R = 240/4 = 60 mL/h

Answer

R = 60 mL/h

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

6.IV infusion rates

Answer: Δ = 21.6 %

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

500/8 = 62.5 mL/h

New rate

R = 380/5 = 76 mL/h

Percentage change

Δ = (76 − 62.5)/62.5·100% = 21.6%

Answer

Δ = 21.6%

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

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