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 pregnant woman taking iron says her stools have turned black. What is the best response?

  1. AExplain that this is an expected effect of iron
  2. BTell her to double the dose of the tablets
  3. CTell her to stop the iron immediately
  4. DAdvise her to go to the emergency department now
2.Maternity & obstetric nursingHard

A woman at 34 weeks was in a car crash. She has abdominal pain, a rigid tender uterus and only slight vaginal bleeding. Late decelerations appear. Which statement is most accurate?

  1. AThe findings are typical of normal labour
  2. BLittle visible bleeding means blood loss is minor
  3. CShe may have a concealed abruption with major blood loss despite little visible bleeding
  4. DA rigid uterus after abdominal trauma is an expected finding and needs no further action
3.Dosage calculationsMedium
024681010 mL

A child weighing 19 kg is prescribed 10 mg/kg of a drug. The stock solution contains 25 mg/mL. Draw up the dose: what volume V do you give?

19 kg10 mg/kg25 mg/mL
V = mL
4.Dosage calculationsHard
00.10.20.30.40.50.60.70.80.911 mL

The prescription is 510 units of a drug that comes as 1000 units/mL. Draw up the dose in the 1 mL syringe: what volume V do you give?

510 units1000 units/mL
V = mL
5.IV infusion ratesMedium
500 mL15 gtt/mL5 h? gtt/min

Infuse 500 mL over 5 hours with a giving set of 15 gtt/mL. Find the drip rate R in drops per minute.

500 mL5 h15 gtt/mL
R = gtt/min
6.IV infusion ratesHard
2 g500 mL? mL/h4 mg/min

A bag contains 2 g of a drug in 500 mL. The order is 4 mg per minute. At what rate R do you set the pump, in mL/h?

2 g/500 mL4 mg/min
R = mL/h

3Solutions

1.Maternity & obstetric nursing

Answer: A · Explain that this is an expected effect of iron

Why this is the answer

Iron supplements commonly make stools dark green or black. This is harmless, unlike tarry stools with signs of bleeding such as dizziness.

Answer

A · Explain that this is an expected effect of iron
2.Maternity & obstetric nursing

Answer: C · She may have a concealed abruption with major blood loss despite little visible bleeding

Why this is the answer

Placental abruption can bleed into the space behind the placenta. Pain, rigidity and fetal compromise with little visible blood suggest a concealed abruption, which is an emergency for mother and fetus.

Answer

C · She may have a concealed abruption with major blood loss despite little visible bleeding
3.Dosage calculations

Answer: V = 7.6 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 = 10·19 = 190 mg

Volume

V = 190/25 = 7.6 mL

On the syringe

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

Answer

V = 7.6 mL
4.Dosage calculations

Answer: V = 0.51 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 = 510/1000 = 0.51 mL

On the syringe

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

Answer

V = 0.51 mL
5.IV infusion rates

Answer: R = 25 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

5·60 = 300 min

Drip rate

R = 500·15/300 = 25 gtt/min

Answer

R = 25 gtt/min
6.IV infusion rates

Answer: R = 60 mL/h

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

2000 mg/500 mL = 4 mg/mL

Dose per hour

4·60 = 240 mg/h

Pump rate

R = 240/4 = 60 mL/h

Answer

R = 60 mL/h

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