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

On day 2, a newborn has red blotches with small yellow-white centres on the trunk. The baby is well. What is most likely?

  1. AHerpes simplex infection
  2. BNeonatal sepsis
  3. CErythema toxicum
  4. DPort-wine stain
2.Maternity & obstetric nursingHard

A woman 2 hours after birth asks for help to the bathroom. She had an epidural that is now off. What is the main safety concern?

  1. ALeg weakness or numbness causing a fall
  2. BFainting from low blood glucose only
  3. CIncreased lochia from walking
  4. DReopening of the epidural site
3.Dosage calculationsMedium
500 mg+ 4.6 mLV = ? mL

A vial contains 500 mg of powder. The label says: add 4.6 mL of water for injection to give a total volume of 5 mL. The prescription is 240 mg. What volume V of the reconstituted solution do you give?

500 mg+ 4.6 mL → 5 mL240 mg
V = mL
4.Dosage calculationsHard
250 mg/5 mLV = ? mL

A child weighing 8 kg is prescribed 12.5 mg/kg per dose of an oral suspension that contains 250 mg in 5 mL. What volume V do you give?

8 kg12.5 mg/kg250 mg/5 mL
V = mL
5.IV infusion ratesMedium
1500 mL15 gtt/mL8 h? gtt/min

Infuse 1500 mL over 8 hours with a giving set of 15 gtt/mL. Find the drip rate R in drops per minute. Round to the nearest whole number.

1500 mL8 h15 gtt/mL
R = gtt/min
6.IV infusion ratesHard
500 mg250 mL60 gtt/mL60 mg/h? gtt/min

500 mg of a drug is diluted in 250 mL and given by gravity through a set of 60 gtt/mL. The order is 60 mg per hour. Find the drip rate R in drops per minute.

500 mg/250 mL60 mg/h60 gtt/mL
R = gtt/min

3Solutions

1.Maternity & obstetric nursing

Answer: C · Erythema toxicum

Why this is the answer

Erythema toxicum is a common, benign rash that appears in the first days and resolves without treatment. A well baby with a typical rash needs only reassurance, but blistering or an unwell baby needs review.

Answer

C · Erythema toxicum
2.Maternity & obstetric nursing

Answer: A · Leg weakness or numbness causing a fall

Why this is the answer

After an epidural, the nurse checks that leg sensation and strength have returned before she stands. Combined with orthostatic hypotension and blood loss, this makes the first walk a high fall risk.

Answer

A · Leg weakness or numbness causing a fall
3.Dosage calculations

Answer: V = 2.4 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.

Concentration after mixing

500 mg/5 mL = 100 mg/mL

Volume

V = 240/100 = 2.4 mL

Answer

V = 2.4 mL
4.Dosage calculations

Answer: V = 2 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

12.5·8 = 100 mg

Volume

V = (100/250)·5 = 2 mL

Answer

V = 2 mL
5.IV infusion rates

Answer: R = 47 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

8·60 = 480 min

Drip rate

R = 1500·15/480 = 46.88 ≈ 47 gtt/min

Answer

R = 47 gtt/min

At the bedside you round to the nearest whole drop: 47 gtt/min.

6.IV infusion rates

Answer: R = 30 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

60/2 = 30 mL/h

Drip rate

R = 30·60/60 = 30 gtt/min

Answer

R = 30 gtt/min

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