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

A labouring woman's tracing shows variable decelerations. Which action should the nurse take first?

  1. AIncrease the oxytocin infusion
  2. BPlace her flat on her back
  3. CStart pushing efforts straight away
  4. DChange the woman's position
2.Maternity & obstetric nursingHard

A woman at 32 weeks with type 1 diabetes has nausea, vomiting, abdominal pain, rapid breathing and a glucose of 16 mmol/L (about 290 mg/dL). Which complication should be suspected?

  1. AHyperemesis gravidarum
  2. BNormal pregnancy nausea
  3. CHypoglycaemia
  4. DDiabetic ketoacidosis
3.Dosage calculationsMedium
024681010 mL

A child weighing 6 kg is prescribed 10 mg/kg of a drug. The stock solution contains 20 mg/mL. Draw up the dose: what volume V do you give?

6 kg10 mg/kg20 mg/mL
V = mL
4.Dosage calculationsHard
20k units250 mL? mL/h2000 units/h

An infusion contains 20000 units of a drug in 250 mL. The prescription is 2000 units per hour. At what rate R do you set the pump, in mL/h?

20000 units/250 mL2000 units/h
R = mL/h
5.IV infusion ratesMedium
60 gtt/mL200 mL/h? gtt/min

An infusion is ordered at 200 mL/h, but no pump is available. It runs by gravity through a giving set of 60 gtt/mL. Find the drip rate R in drops per minute.

200 mL/h60 gtt/mL
R = gtt/min
6.IV infusion ratesHard
300 mL20 gtt/mL30 gtt/mint = ? h

A drip runs at 30 gtt/min through a set of 20 gtt/mL. There are 300 mL left in the bag. How many hours t until it is empty? Round to one decimal place.

30 gtt/min20 gtt/mL300 mL
t = h

3Solutions

1.Maternity & obstetric nursing

Answer: D · Change the woman's position

Why this is the answer

Repositioning (side to side, or hands and knees) often relieves cord compression. If the decelerations persist, the provider is notified. Lying flat adds caval compression.

Answer

D · Change the woman's position
2.Maternity & obstetric nursing

Answer: D · Diabetic ketoacidosis

Why this is the answer

Diabetic ketoacidosis can develop quickly in pregnancy, even at moderately raised glucose, and carries a high risk of fetal death. Ketones and blood gases are checked urgently, and fluids and insulin are started.

Answer

D · Diabetic ketoacidosis
3.Dosage calculations

Answer: V = 3 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 = 10·6 = 60 mg

Volume

V = 60/20 = 3 mL

On the syringe

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

Answer

V = 3 mL
4.Dosage calculations

Answer: R = 25 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

20000/250 = 80 units/mL

Pump rate

R = 2000/80 = 25 mL/h

Answer

R = 25 mL/h
5.IV infusion rates

Answer: R = 200 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.

Millilitres per minute

200/60 = 3.333 mL/min

Drip rate

R = 3.333·60 = 200 gtt/min

Answer

R = 200 gtt/min

With a microdrip set (60 gtt/mL), gtt/min equals mL/h.

6.IV infusion rates

Answer: t = 3.3 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.

Rate in mL/h

30·60/20 = 90 mL/h

Time left

t = 300/90 = 3.333 ≈ 3.3 h

Answer

t = 3.3 h

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