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 breastfeeding mother asks how she will know her baby is getting enough milk. Which sign is reassuring by day 5 or 6?

  1. AThe baby feeds for exactly 5 minutes each side
  2. BHer breasts never feel full
  3. CThe baby sleeps for 8 hours without feeding
  4. DAt least 6 wet nappies a day and yellow stools
2.Maternity & obstetric nursingHard

Which finding in a newborn at 6 hours requires the most urgent action?

  1. AAcrocyanosis of the hands and feet
  2. BMild moulding of the head
  3. CSmall white milia on the nose and chin
  4. DCentral cyanosis, fast breathing and grunting
3.Dosage calculationsMedium
30 kg10 mg/kgD = ? mg

A patient weighs 30 kg and is prescribed 10 mg/kg as a single dose. Find the dose D in mg.

30 kg10 mg/kg
D = mg
4.Dosage calculationsHard
25 kg105 cmBSA = √(h·w/3600)135 mg/m²D = ? mg

A patient is 105 cm tall and weighs 25 kg. The prescription is 135 mg/m². Using the Mosteller formula BSA = √(height (cm) × weight (kg)/3600), find the dose D in mg.

105 cm25 kg135 mg/m²
D = mg
5.IV infusion ratesMedium
250 mL60 gtt/mL6 h? gtt/min

Infuse 250 mL over 6 hours with a giving set of 60 gtt/mL. Find the drip rate R in drops per minute. Round to the nearest whole number.

250 mL6 h60 gtt/mL
R = gtt/min
6.IV infusion ratesHard
400 mg100 mL20 mL/h? mg/h

A bag contains 400 mg of a drug in 100 mL and runs at 20 mL/h. How many milligrams per hour D does the patient receive?

400 mg/100 mL20 mL/h
D = mg/h

3Solutions

1.Maternity & obstetric nursing

Answer: D · At least 6 wet nappies a day and yellow stools

Why this is the answer

Signs of adequate intake include 6 or more wet nappies and several yellow stools a day by day 5 or 6, steady weight gain and a content baby after feeds. Most babies regain birth weight by about 2 weeks.

Answer

D · At least 6 wet nappies a day and yellow stools
2.Maternity & obstetric nursing

Answer: D · Central cyanosis, fast breathing and grunting

Why this is the answer

Central cyanosis, tachypnoea and grunting indicate respiratory distress and need immediate assessment, oxygen and evaluation for causes such as infection, heart disease or lung problems.

Answer

D · Central cyanosis, fast breathing and grunting
3.Dosage calculations

Answer: D = 300 mg

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.

Dose

10·30 = 300 mg

Answer

D = 300 mg
4.Dosage calculations

Answer: D = 115.3 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).

Body surface area

BSA = √(105·25/3600) = √0.7292 = 0.8539 m²

Dose

D = 135·0.8539 = 115.3 mg

Answer

D = 115.3 mg
5.IV infusion rates

Answer: R = 42 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

6·60 = 360 min

Drip rate

R = 250·60/360 = 41.67 ≈ 42 gtt/min

Answer

R = 42 gtt/min

At the bedside you round to the nearest whole drop: 42 gtt/min.

6.IV infusion rates

Answer: D = 80 mg/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.

Concentration

400/100 = 4 mg/mL

Dose rate

D = 4·20 = 80 mg/h

Answer

D = 80 mg/h

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