Maternity Nursing: cram pack

Formula sheets, the key method steps for every topic and 6 practice problems, with full solutions at the back.

New problemsBack to the course

In the print window, choose “Save as PDF” to keep a copy on your device.

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 set of findings is consistent with hypovolaemia after a postpartum haemorrhage?

  1. AIncreased urine output and flushed skin
  2. BSlow breathing and a rising blood pressure
  3. CRising pulse, falling blood pressure, low urine output
  4. DSlow heart rate, high blood pressure and warm, dry skin
2.Maternity & obstetric nursingHard

A woman needs an emergency caesarean under general anaesthesia. Why is she given an antacid such as sodium citrate before induction?

  1. ATo lower her blood pressure before surgery
  2. BTo speed up gastric emptying for surgery
  3. CTo prevent nausea after the operation
  4. DTo make aspirated stomach contents less acidic
3.Dosage calculationsMedium
26 kgBSA = 0.91 m²375 mg/m²D = ? mg

A patient weighing 26 kg has a body surface area of 0.91 m². The prescription is 375 mg/m². Find the dose D in mg.

26 kgBSA = 0.91 m²375 mg/m²
D = mg
4.Dosage calculationsHard
00.10.20.30.40.50.60.70.80.911 mL

The prescription is 3900 units of a drug that comes as 5000 units/mL. Draw up the dose in the 1 mL syringe: what volume V do you give?

3900 units5000 units/mL
V = mL
5.IV infusion ratesMedium
250 mL20 gtt/mL10 h? gtt/min

Infuse 250 mL over 10 hours with a giving set of 20 gtt/mL. Find the drip rate R in drops per minute. Round to the nearest whole number.

250 mL10 h20 gtt/mL
R = gtt/min
6.IV infusion ratesHard
600 mL15 gtt/mL42 gtt/mint = ? h

A drip runs at 42 gtt/min through a set of 15 gtt/mL. There are 600 mL left in the bag. How many hours t until it is empty? Round to one decimal place.

42 gtt/min15 gtt/mL600 mL
t = h

3Solutions

1.Maternity & obstetric nursing

Answer: C · Rising pulse, falling blood pressure, low urine output

Why this is the answer

Tachycardia is often the earliest sign, then narrowing pulse pressure, falling blood pressure, pale clammy skin, restlessness and oliguria. Blood pressure may stay normal until a large loss has occurred.

Answer

C · Rising pulse, falling blood pressure, low urine output
2.Maternity & obstetric nursing

Answer: D · To make aspirated stomach contents less acidic

Why this is the answer

Pregnant women are at high risk of aspirating stomach contents under general anaesthesia. Sodium citrate neutralises gastric acid, reducing the severity of lung injury if aspiration happens.

Answer

D · To make aspirated stomach contents less acidic
3.Dosage calculations

Answer: D = 341.3 mg

Body-surface-area dosing: many cytotoxic and some paediatric doses are prescribed per square metre of body surface area: dose (mg) = dose per m² × BSA (m²). The Mosteller formula estimates BSA = √(height (cm) × weight (kg)/3600).

Dose

D = 375·0.91 = 341.3 mg

Answer

D = 341.3 mg
4.Dosage calculations

Answer: V = 0.78 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 = 3900/5000 = 0.78 mL

On the syringe

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

Answer

V = 0.78 mL
5.IV infusion rates

Answer: R = 8 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 = 250·20/600 = 8.333 ≈ 8 gtt/min

Answer

R = 8 gtt/min

At the bedside you round to the nearest whole drop: 8 gtt/min.

6.IV infusion rates

Answer: t = 3.6 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

42·60/15 = 168 mL/h

Time left

t = 600/168 = 3.571 ≈ 3.6 h

Answer

t = 3.6 h

ExamProblems · examproblems.com/courses/maternity-nursing