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

In the leg check of BUBBLE-HE, how is a postpartum woman assessed for venous thromboembolism today?

  1. ACheck only the capillary refill of the toes
  2. BMassage the calf to feel for a clot
  3. CForcefully bend the foot upward and rely on calf pain (Homans' sign)
  4. DLook for one-sided swelling, warmth, redness and tenderness of the leg
2.Maternity & obstetric nursingHard

A woman at 16 weeks says she drinks four cups of strong coffee a day. Which response is most appropriate?

  1. ATell her to switch to strong tea, which has no caffeine
  2. BAdvise switching to energy drinks, which contain less caffeine
  3. CTell her coffee has no effect on pregnancy and she can continue
  4. DAdvise limiting caffeine to about 200 mg a day, roughly two cups of coffee
3.Dosage calculationsMedium
024681010 mL

A child weighing 32 kg is prescribed 2.5 mg/kg of a drug. The stock solution contains 40 mg/mL. Draw up the dose: what volume V do you give?

32 kg2.5 mg/kg40 mg/mL
V = mL
4.Dosage calculationsHard
20k units250 mL? mL/h1000 units/h

An infusion contains 20000 units of a drug in 250 mL. The prescription is 1000 units per hour. At what rate R do you set the pump, in mL/h?

20000 units/250 mL1000 units/h
R = mL/h
5.IV infusion ratesMedium
1500 mL15 gtt/mL12 h? gtt/min

Infuse 1500 mL over 12 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 mL12 h15 gtt/mL
R = gtt/min
6.IV infusion ratesHard
190 mLleft? mL/h2 h left

500 mL was ordered over 6 hours. After 4 hours you find that 190 mL is still in the bag, and the order must still finish on time. By what percentage Δ must the original pump rate be increased?

500 mL / 6 hafter 4 h: 190 mL
Δ = %

3Solutions

1.Maternity & obstetric nursing

Answer: D · Look for one-sided swelling, warmth, redness and tenderness of the leg

Why this is the answer

Homans' sign is unreliable and is no longer recommended. Assess for unilateral swelling, warmth, redness and pain, and report breathlessness or chest pain at once. Massaging the calf could dislodge a clot.

Answer

D · Look for one-sided swelling, warmth, redness and tenderness of the leg
2.Maternity & obstetric nursing

Answer: D · Advise limiting caffeine to about 200 mg a day, roughly two cups of coffee

Why this is the answer

Guidelines advise limiting caffeine to about 200 mg a day in pregnancy because higher intakes are linked to low birth weight and miscarriage. Energy drinks and some teas also contain caffeine.

Answer

D · Advise limiting caffeine to about 200 mg a day, roughly two cups of coffee
3.Dosage calculations

Answer: V = 2 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 = 2.5·32 = 80 mg

Volume

V = 80/40 = 2 mL

On the syringe

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

Answer

V = 2 mL
4.Dosage calculations

Answer: R = 12.5 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 = 1000/80 = 12.5 mL/h

Answer

R = 12.5 mL/h
5.IV infusion rates

Answer: R = 31 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

12·60 = 720 min

Drip rate

R = 1500·15/720 = 31.25 ≈ 31 gtt/min

Answer

R = 31 gtt/min

At the bedside you round to the nearest whole drop: 31 gtt/min.

6.IV infusion rates

Answer: Δ = 14 %

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.

Original rate

500/6 = 83.33 mL/h

New rate

R = 190/2 = 95 mL/h

Percentage change

Δ = (95 − 83.33)/83.33·100% = 14%

Answer

Δ = 14%

Many hospitals allow such an adjustment up to 25% without a new order; check local policy.

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