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 antihypertensive is commonly used in pregnancy but should be avoided in a woman with asthma?

  1. ALabetalol
  2. BHydralazine
  3. CMethyldopa
  4. DNifedipine
2.Maternity & obstetric nursingHard

A mother on day 1 is quiet, lets the nurse change the baby and talks repeatedly about the birth. How should the nurse interpret this?

  1. ARejection of the baby
  2. BSigns of postpartum psychosis
  3. CNormal taking-in behaviour
  4. DNormal letting-go behaviour
3.Dosage calculationsMedium
024681010 mL

A child weighing 11 kg is prescribed 10 mg/kg of a drug. The stock solution contains 50 mg/mL. Draw up the dose: what volume V do you give?

11 kg10 mg/kg50 mg/mL
V = mL
4.Dosage calculationsHard
100 mg/5 mLV = ? mL

A child weighing 20 kg is prescribed 12.5 mg/kg per dose of an oral suspension that contains 100 mg in 5 mL. What volume V do you give?

20 kg12.5 mg/kg100 mg/5 mL
V = mL
5.IV infusion ratesMedium
500 mL60 gtt/mL5 h? gtt/min

Infuse 500 mL over 5 hours with a giving set of 60 gtt/mL. Find the drip rate R in drops per minute.

500 mL5 h60 gtt/mL
R = gtt/min
6.IV infusion ratesHard
500 mg250 mL15 gtt/mL120 mg/h? gtt/min

500 mg of a drug is diluted in 250 mL and given by gravity through a set of 15 gtt/mL. The order is 120 mg per hour. Find the drip rate R in drops per minute.

500 mg/250 mL120 mg/h15 gtt/mL
R = gtt/min

3Solutions

1.Maternity & obstetric nursing

Answer: A · Labetalol

Why this is the answer

Labetalol is a beta and alpha blocker and can cause bronchospasm, so it is avoided in asthma. Nifedipine, a calcium channel blocker, is often used instead.

Answer

A · Labetalol
2.Maternity & obstetric nursing

Answer: C · Normal taking-in behaviour

Why this is the answer

In the first day or two, dependence, passivity and retelling the birth story are typical of the taking-in phase. The nurse supports rest and comfort and reassesses bonding later.

Answer

C · Normal taking-in behaviour
3.Dosage calculations

Answer: V = 2.2 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 = 10·11 = 110 mg

Volume

V = 110/50 = 2.2 mL

On the syringe

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

Answer

V = 2.2 mL
4.Dosage calculations

Answer: V = 12.5 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

12.5·20 = 250 mg

Volume

V = (250/100)·5 = 12.5 mL

Answer

V = 12.5 mL
5.IV infusion rates

Answer: R = 100 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 = 500·60/300 = 100 gtt/min

Answer

R = 100 gtt/min
6.IV infusion rates

Answer: R = 15 gtt/min

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

500/250 = 2 mg/mL

Volume per hour

120/2 = 60 mL/h

Drip rate

R = 60·15/60 = 15 gtt/min

Answer

R = 15 gtt/min

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