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 woman on day 3 after a caesarean has calf pain, swelling and warmth in one leg. What should the nurse do?

  1. AApply a heating pad and reassess tomorrow
  2. BReport it promptly and avoid massaging the leg
  3. CEncourage her to do vigorous leg exercises
  4. DMassage the calf to relieve the cramp
2.Maternity & obstetric nursingHard

A woman at 37 weeks has severe itching of the palms and soles, worse at night, without a rash. Which condition should be considered?

  1. AAn allergy to washing detergents
  2. BNormal stretching of the abdominal skin
  3. CPre-eclampsia only
  4. DIntrahepatic cholestasis of pregnancy
3.Dosage calculationsMedium
024681010 mL

A child weighing 40 kg is prescribed 5 mg/kg of a drug. The stock solution contains 50 mg/mL. Draw up the dose: what volume V do you give?

40 kg5 mg/kg50 mg/mL
V = mL
4.Dosage calculationsHard
63 kg156 cmBSA = √(h·w/3600)25 mg/m²D = ? mg

A patient is 156 cm tall and weighs 63 kg. The prescription is 25 mg/m². Using the Mosteller formula BSA = √(height (cm) × weight (kg)/3600), find the dose D in mg.

156 cm63 kg25 mg/m²
D = mg
5.IV infusion ratesMedium
V = ?15 gtt/mL20 gtt/min4 h

A drip runs at 20 gtt/min through a set of 15 gtt/mL. How many millilitres V does the patient receive in 4 hours?

20 gtt/min15 gtt/mL4 h
V = mL
6.IV infusion ratesHard
500 mg500 mL60 gtt/mL100 mg/h? gtt/min

500 mg of a drug is diluted in 500 mL and given by gravity through a set of 60 gtt/mL. The order is 100 mg per hour. Find the drip rate R in drops per minute.

500 mg/500 mL100 mg/h60 gtt/mL
R = gtt/min

3Solutions

1.Maternity & obstetric nursing

Answer: B · Report it promptly and avoid massaging the leg

Why this is the answer

One-sided calf pain, swelling and warmth suggest deep vein thrombosis, and the postnatal period is a high-risk time. The leg should not be massaged, and the provider should be informed for urgent assessment.

Answer

B · Report it promptly and avoid massaging the leg
2.Maternity & obstetric nursing

Answer: D · Intrahepatic cholestasis of pregnancy

Why this is the answer

Itching of the hands and feet without a rash suggests intrahepatic cholestasis of pregnancy. Raised bile acids are linked with stillbirth, so liver function and bile acids are checked and timing of birth may be planned.

Answer

D · Intrahepatic cholestasis of pregnancy
3.Dosage calculations

Answer: V = 4 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 = 5·40 = 200 mg

Volume

V = 200/50 = 4 mL

On the syringe

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

Answer

V = 4 mL
4.Dosage calculations

Answer: D = 41.31 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).

Body surface area

BSA = √(156·63/3600) = √2.73 = 1.652 m²

Dose

D = 25·1.652 = 41.31 mg

Answer

D = 41.31 mg
5.IV infusion rates

Answer: V = 320 mL

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

20·60/15 = 80 mL/h

Volume

V = 80·4 = 320 mL

Answer

V = 320 mL
6.IV infusion rates

Answer: R = 100 gtt/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

500/500 = 1 mg/mL

Volume per hour

100/1 = 100 mL/h

Drip rate

R = 100·60/60 = 100 gtt/min

Answer

R = 100 gtt/min

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