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 statement describes the "4 Ts" causes of postpartum haemorrhage?

  1. ATemperature, tachycardia, tears and time
  2. BTone, trauma, tissue and thrombin
  3. CTone, tachycardia, transfusion and tissue
  4. DTrauma, tension, temperature and thrombosis
2.Maternity & obstetric nursingHard

Which newborn finding requires immediate follow-up?

  1. AAcrocyanosis at 2 hours
  2. BGrunting, nasal flaring and chest retractions at 1 hour
  3. CMoulding of the head shape after a vaginal birth at term
  4. DSmall white spots (milia) on the nose
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 100 mg. What volume V of the reconstituted solution do you give?

500 mg+ 4.6 mL → 5 mL100 mg
V = mL
4.Dosage calculationsHard
200 mg/5 mLV = ? mL

A child weighing 10 kg is prescribed 15 mg/kg per dose of an oral suspension that contains 200 mg in 5 mL. What volume V do you give? Round to one decimal place.

10 kg15 mg/kg200 mg/5 mL
V = mL
5.IV infusion ratesMedium
1500 mL10 gtt/mL10 h? gtt/min

Infuse 1500 mL over 10 hours with a giving set of 10 gtt/mL. Find the drip rate R in drops per minute.

1500 mL10 h10 gtt/mL
R = gtt/min
6.IV infusion ratesHard
1 g250 mL? mL/h2 mg/min

A bag contains 1 g of a drug in 250 mL. The order is 2 mg per minute. At what rate R do you set the pump, in mL/h?

1 g/250 mL2 mg/min
R = mL/h

3Solutions

1.Maternity & obstetric nursing

Answer: B · Tone, trauma, tissue and thrombin

Why this is the answer

The 4 Ts are tone (atony), trauma (tears, haematomas, rupture), tissue (retained placenta or clots) and thrombin (clotting disorders). Tone is the most common cause.

Answer

B · Tone, trauma, tissue and thrombin
2.Maternity & obstetric nursing

Answer: B · Grunting, nasal flaring and chest retractions at 1 hour

Why this is the answer

Grunting, flaring and retractions are signs of respiratory distress and need urgent assessment. Acrocyanosis, milia and moulding are common normal findings.

Answer

B · Grunting, nasal flaring and chest retractions at 1 hour
3.Dosage calculations

Answer: V = 1 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 = 100/100 = 1 mL

Answer

V = 1 mL
4.Dosage calculations

Answer: V = 3.8 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

15·10 = 150 mg

Volume

V = (150/200)·5 = 3.75 ≈ 3.8 mL

Answer

V = 3.8 mL
5.IV infusion rates

Answer: R = 25 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

10·60 = 600 min

Drip rate

R = 1500·10/600 = 25 gtt/min

Answer

R = 25 gtt/min
6.IV infusion rates

Answer: R = 30 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

1000 mg/250 mL = 4 mg/mL

Dose per hour

2·60 = 120 mg/h

Pump rate

R = 120/4 = 30 mL/h

Answer

R = 30 mL/h

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