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 congenital hypothyroidism included in newborn screening?

  1. AIt causes hip dysplasia
  2. BIt causes jaundice that cannot be treated
  3. CEarly treatment prevents brain damage
  4. DIt can only be treated before birth
2.Maternity & obstetric nursingHard

A newborn in the first hours sneezes, has a high-pitched cry, tremors and loose stools. The mother took opioids throughout pregnancy. Which intervention is most appropriate first?

  1. AA quiet, dim room, swaddling and small, frequent feeds
  2. BWithholding feeds until the symptoms settle
  3. CBright lights and frequent handling to keep the baby awake
  4. DGiving naloxone to reverse the opioids
3.Dosage calculationsMedium
10%2 mLm = ? mg

How many milligrams of drug m are in 2 mL of a 10% (w/v) solution?

10% w/v2 mL
m = mg
4.Dosage calculationsHard
00.10.20.30.40.50.60.70.80.911 mL

The prescription is 1200 units of a drug that comes as 10000 units/mL. Draw up the dose in the 1 mL syringe: what volume V do you give?

1200 units10000 units/mL
V = mL
5.IV infusion ratesMedium
250 mL10 gtt/mL4 h? gtt/min

Infuse 250 mL over 4 hours with a giving set of 10 gtt/mL. Find the drip rate R in drops per minute. Round to the nearest whole number.

250 mL4 h10 gtt/mL
R = gtt/min
6.IV infusion ratesHard
200 mg250 mL9 mL/h? mcg/min

An infusion of 200 mg in 250 mL runs at 9 mL/h. How many micrograms per minute D does the patient receive?

200 mg/250 mL9 mL/h
D = mcg/min

3Solutions

1.Maternity & obstetric nursing

Answer: C · Early treatment prevents brain damage

Why this is the answer

Untreated congenital hypothyroidism causes poor growth and intellectual disability. Daily levothyroxine started in the first weeks allows normal development.

Answer

C · Early treatment prevents brain damage
2.Maternity & obstetric nursing

Answer: A · A quiet, dim room, swaddling and small, frequent feeds

Why this is the answer

Neonatal abstinence (withdrawal) is managed first with non-drug care: low stimulation, swaddling, skin-to-skin, responsive feeding and rooming-in. Medication is added if scores stay high. Naloxone can precipitate seizures.

Answer

A · A quiet, dim room, swaddling and small, frequent feeds
3.Dosage calculations

Answer: m = 200 mg

Solution strengths: a percentage strength is grams per 100 mL, so 1% = 1 g/100 mL = 10 mg/mL. A ratio strength 1:1000 means 1 g in 1000 mL = 1 mg/mL; 1:10 000 is 0.1 mg/mL. For a dilution the amount of drug stays the same: C₁·V₁ = C₂·V₂.

Concentration

10% = 10 g/100 mL = 100 mg/mL

Mass of drug

m = 100·2 = 200 mg

Answer

m = 200 mg
4.Dosage calculations

Answer: V = 0.12 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.

Volume

V = 1200/10000 = 0.12 mL

On the syringe

On this 1 mL syringe every small line is 0.01 mL.

Answer

V = 0.12 mL
5.IV infusion rates

Answer: R = 10 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

4·60 = 240 min

Drip rate

R = 250·10/240 = 10.42 ≈ 10 gtt/min

Answer

R = 10 gtt/min

At the bedside you round to the nearest whole drop: 10 gtt/min.

6.IV infusion rates

Answer: D = 120 mcg/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

200000 mcg/250 mL = 800 mcg/mL

Dose per hour

9·800 = 7200 mcg/h

Dose per minute

D = 7200/60 = 120 mcg/min

Answer

D = 120 mcg/min

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