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 newborn is at greatest risk of hypoglycaemia in the first hours after birth?

  1. AA baby born by planned caesarean to a healthy mother
  2. BA term baby of average weight who is breastfeeding well
  3. CA large baby of a mother with diabetes
  4. DA baby with an APGAR of 9 at 5 minutes
2.Maternity & obstetric nursingHard

A woman at 34 weeks with type 1 diabetes has a blood glucose of 2.8 mmol/L (50 mg/dL), is sweating and shaky but is alert. What should the nurse do first?

  1. AWait until her next meal
  2. BCheck the fetal heart rate before any treatment
  3. CGive fast-acting glucose by mouth and recheck
  4. DGive her usual insulin dose
3.Dosage calculationsMedium
30 kg2 mg/kg/day4× per dayD = ? mg

A patient weighs 30 kg. The prescribed dose is 2 mg/kg per day, given in 4 equal doses. How many milligrams D are given per dose?

30 kg2 mg/kg/day4× per day
D = mg
4.Dosage calculationsHard
40 mg/1 mLV = ? mL

A child weighing 24 kg is prescribed 5 mg/kg per dose of an oral suspension that contains 40 mg in 1 mL. What volume V do you give?

24 kg5 mg/kg40 mg/1 mL
V = mL
5.IV infusion ratesMedium
250 mL15 gtt/mL3 h? gtt/min

Infuse 250 mL over 3 hours with a giving set of 15 gtt/mL. Find the drip rate R in drops per minute. Round to the nearest whole number.

250 mL3 h15 gtt/mL
R = gtt/min
6.IV infusion ratesHard
4 g500 mL? mL/h1 mg/min

A bag contains 4 g of a drug in 500 mL. The order is 1 mg per minute. At what rate R do you set the pump, in mL/h?

4 g/500 mL1 mg/min
R = mL/h

3Solutions

1.Maternity & obstetric nursing

Answer: C · A large baby of a mother with diabetes

Why this is the answer

High maternal glucose crosses the placenta and the fetus makes extra insulin. After the cord is cut, the glucose supply stops but the insulin stays high. Preterm, small and cold babies are also at risk.

Answer

C · A large baby of a mother with diabetes
2.Maternity & obstetric nursing

Answer: C · Give fast-acting glucose by mouth and recheck

Why this is the answer

An alert patient with hypoglycaemia is given fast-acting oral carbohydrate, then glucose is rechecked after about 15 minutes and followed by a snack or meal. Treating the mother also protects the fetus.

Answer

C · Give fast-acting glucose by mouth and recheck
3.Dosage calculations

Answer: D = 15 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.

Total per day

2·30 = 60 mg

Per dose

D = 60/4 = 15 mg

Answer

D = 15 mg
4.Dosage calculations

Answer: V = 3 mL

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 from weight

5·24 = 120 mg

Volume

V = (120/40)·1 = 3 mL

Answer

V = 3 mL
5.IV infusion rates

Answer: R = 21 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

3·60 = 180 min

Drip rate

R = 250·15/180 = 20.83 ≈ 21 gtt/min

Answer

R = 21 gtt/min

At the bedside you round to the nearest whole drop: 21 gtt/min.

6.IV infusion rates

Answer: R = 7.5 mL/h

Dose-based infusions: concentration = amount of drug in the bag/bag volume. Pump rate (mL/h) = dose per hour/concentration, and dose per hour = mL/h × concentration. Convert per-minute doses to per-hour (× 60) and keep the mass units the same (1 g = 1000 mg, 1 mg = 1000 mcg).

Concentration

4000 mg/500 mL = 8 mg/mL

Dose per hour

1·60 = 60 mg/h

Pump rate

R = 60/8 = 7.5 mL/h

Answer

R = 7.5 mL/h

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