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

How can a cephalhaematoma be told apart from caput succedaneum?

  1. AA cephalhaematoma is present at birth and disappears within a few days
  2. BA cephalhaematoma crosses the midline of the skull
  3. CA cephalhaematoma does not cross the suture lines
  4. DA cephalhaematoma is a soft swelling of the scalp skin only
2.Maternity & obstetric nursingHard

A woman has a postpartum haemorrhage. Which nursing action should be done first while help is coming?

  1. AWeigh the used pads and record the total
  2. BMassage the fundus and look for the source
  3. CGive the baby a bath to free the mother's time
  4. DDocument the estimated blood loss in the notes
3.Dosage calculationsMedium
024681010 mL

A child weighing 16 kg is prescribed 2.5 mg/kg of a drug. The stock solution contains 40 mg/mL. Draw up the dose: what volume V do you give?

16 kg2.5 mg/kg40 mg/mL
V = mL
4.Dosage calculationsHard
29 kg128 cmBSA = √(h·w/3600)135 mg/m²D = ? mg

A patient is 128 cm tall and weighs 29 kg. The prescription is 135 mg/m². Using the Mosteller formula BSA = √(height (cm) × weight (kg)/3600), find the dose D in mg.

128 cm29 kg135 mg/m²
D = mg
5.IV infusion ratesMedium
V = ?20 gtt/mL50 gtt/min6 h

A drip runs at 50 gtt/min through a set of 20 gtt/mL. How many millilitres V does the patient receive in 6 hours?

50 gtt/min20 gtt/mL6 h
V = mL
6.IV infusion ratesHard
1000 mg500 mL15 mL/h? mg/h

A bag contains 1000 mg of a drug in 500 mL and runs at 15 mL/h. How many milligrams per hour D does the patient receive?

1000 mg/500 mL15 mL/h
D = mg/h

3Solutions

1.Maternity & obstetric nursing

Answer: C · A cephalhaematoma does not cross the suture lines

Why this is the answer

Caput is oedema of the scalp, present at birth, crossing sutures and resolving within days. A cephalhaematoma is a subperiosteal bleed limited by the sutures; it appears after birth, lasts weeks and can increase jaundice.

Answer

C · A cephalhaematoma does not cross the suture lines
2.Maternity & obstetric nursing

Answer: B · Massage the fundus and look for the source

Why this is the answer

The first priority is to stop the bleeding: massage a boggy fundus, check for tears, empty the bladder and give uterotonics per protocol. Weighing pads gives a more accurate blood loss but comes after life-saving actions.

Answer

B · Massage the fundus and look for the source
3.Dosage calculations

Answer: V = 1 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 = 2.5·16 = 40 mg

Volume

V = 40/40 = 1 mL

On the syringe

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

Answer

V = 1 mL
4.Dosage calculations

Answer: D = 137.1 mg

Body-surface-area dosing: many cytotoxic and some paediatric doses are prescribed per square metre of body surface area: dose (mg) = dose per m² × BSA (m²). The Mosteller formula estimates BSA = √(height (cm) × weight (kg)/3600).

Body surface area

BSA = √(128·29/3600) = √1.031 = 1.015 m²

Dose

D = 135·1.015 = 137.1 mg

Answer

D = 137.1 mg
5.IV infusion rates

Answer: V = 900 mL

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.

Rate in mL/h

50·60/20 = 150 mL/h

Volume

V = 150·6 = 900 mL

Answer

V = 900 mL
6.IV infusion rates

Answer: D = 30 mg/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.

Concentration

1000/500 = 2 mg/mL

Dose rate

D = 2·15 = 30 mg/h

Answer

D = 30 mg/h

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