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

A woman at 20 weeks says her gums bleed when she brushes her teeth. What is the best advice?

  1. AAvoid all dental visits until after the baby is born
  2. BStop brushing until the bleeding has settled after birth
  3. CReport it at once because it is a sign of a clotting disorder
  4. DUse a soft brush and keep up routine dental care
2.Maternity & obstetric nursingHard

A newborn passed no meconium by 48 hours and has a swollen abdomen and green vomiting. Which condition should be suspected?

  1. AHirschsprung disease
  2. BErythema toxicum
  3. CDevelopmental hip dysplasia
  4. DPhysiological jaundice
3.Dosage calculationsMedium
024681010 mL

A child weighing 6 kg is prescribed 15 mg/kg of a drug. The stock solution contains 25 mg/mL. Draw up the dose: what volume V do you give?

6 kg15 mg/kg25 mg/mL
V = mL
4.Dosage calculationsHard
47 kg136 cmBSA = √(h·w/3600)135 mg/m²D = ? mg

A patient is 136 cm tall and weighs 47 kg. The prescription is 135 mg/m². Using the Mosteller formula BSA = √(height (cm) × weight (kg)/3600), find the dose D in mg.

136 cm47 kg135 mg/m²
D = mg
5.IV infusion ratesMedium
320 mLleft? mL/h6 h left

500 mL was ordered over 12 hours. After 6 hours you find that 320 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 / 12 hafter 6 h: 320 mL
R = mL/h
6.IV infusion ratesHard
200 mL60 gtt/mL50 gtt/mint = ? h

A drip runs at 50 gtt/min through a set of 60 gtt/mL. There are 200 mL left in the bag. How many hours t until it is empty?

50 gtt/min60 gtt/mL200 mL
t = h

3Solutions

1.Maternity & obstetric nursing

Answer: D · Use a soft brush and keep up routine dental care

Why this is the answer

Gum swelling and bleeding are common because of oestrogen-related vascular changes. Good oral hygiene and routine dental care are safe and recommended in pregnancy.

Answer

D · Use a soft brush and keep up routine dental care
2.Maternity & obstetric nursing

Answer: A · Hirschsprung disease

Why this is the answer

Delayed meconium, abdominal distension and bilious vomiting suggest bowel obstruction, such as Hirschsprung disease. Bilious vomiting in a newborn is always an emergency.

Answer

A · Hirschsprung disease
3.Dosage calculations

Answer: V = 3.6 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 = 15·6 = 90 mg

Volume

V = 90/25 = 3.6 mL

On the syringe

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

Answer

V = 3.6 mL
4.Dosage calculations

Answer: D = 179.9 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 = √(136·47/3600) = √1.776 = 1.332 m²

Dose

D = 135·1.332 = 179.9 mg

Answer

D = 179.9 mg
5.IV infusion rates

Answer: R = 53.33 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

500/12 = 41.67 mL/h

New rate

R = 320/6 = 53.33 mL/h

Answer

R = 53.33 mL/h

This is more than a 25% increase: most hospitals require you to contact the prescriber instead of catching up, and to assess the patient for fluid overload.

6.IV infusion rates

Answer: t = 4 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.

Rate in mL/h

50·60/60 = 50 mL/h

Time left

t = 200/50 = 4 h

Answer

t = 4 h

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