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

Why is the hearing of newborns screened before discharge or soon after birth?

  1. AIt is required before vitamin K can be given
  2. BHearing loss can be cured with a single injection
  3. CEarly support improves language development
  4. DIt detects congenital heart disease
2.Maternity & obstetric nursingHard

A woman at 26 weeks receiving terbutaline for preterm contractions has a heart rate of 132/min and chest tightness. What should the nurse do?

  1. AGive the next dose early to stop contractions
  2. BReassure her that this is expected and continue
  3. CWithhold the next dose and report the findings
  4. DIncrease her IV fluids rapidly to lower her heart rate
3.Dosage calculationsMedium
024681010 mL

A child weighing 32 kg is prescribed 4 mg/kg of a drug. The stock solution contains 40 mg/mL. Draw up the dose: what volume V do you give?

32 kg4 mg/kg40 mg/mL
V = mL
4.Dosage calculationsHard
50k units1000 mL? mL/h1000 units/h

An infusion contains 50000 units of a drug in 1000 mL. The prescription is 1000 units per hour. At what rate R do you set the pump, in mL/h?

50000 units/1000 mL1000 units/h
R = mL/h
5.IV infusion ratesMedium
1000 mL15 gtt/mL5 h? gtt/min

Infuse 1000 mL over 5 hours with a giving set of 15 gtt/mL. Find the drip rate R in drops per minute.

1000 mL5 h15 gtt/mL
R = gtt/min
6.IV infusion ratesHard
250 mg500 mL30 mL/h? mg/h

A bag contains 250 mg of a drug in 500 mL and runs at 30 mL/h. How many milligrams per hour D does the patient receive?

250 mg/500 mL30 mL/h
D = mg/h

3Solutions

1.Maternity & obstetric nursing

Answer: C · Early support improves language development

Why this is the answer

Early detection of hearing loss allows hearing aids, cochlear implants or other support in the first months, which greatly improves language outcomes.

Answer

C · Early support improves language development
2.Maternity & obstetric nursing

Answer: C · Withhold the next dose and report the findings

Why this is the answer

Terbutaline can cause maternal tachycardia, palpitations, chest pain, pulmonary oedema and hyperglycaemia, so it is used only short term. A maternal heart rate above about 120/min or chest pain means the drug should be held and the provider informed.

Answer

C · Withhold the next dose and report the findings
3.Dosage calculations

Answer: V = 3.2 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 = 4·32 = 128 mg

Volume

V = 128/40 = 3.2 mL

On the syringe

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

Answer

V = 3.2 mL
4.Dosage calculations

Answer: R = 20 mL/h

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.

Concentration

50000/1000 = 50 units/mL

Pump rate

R = 1000/50 = 20 mL/h

Answer

R = 20 mL/h
5.IV infusion rates

Answer: R = 50 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

5·60 = 300 min

Drip rate

R = 1000·15/300 = 50 gtt/min

Answer

R = 50 gtt/min
6.IV infusion rates

Answer: D = 15 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

250/500 = 0.5 mg/mL

Dose rate

D = 0.5·30 = 15 mg/h

Answer

D = 15 mg/h

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