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

Which baseline variability is considered moderate (normal)?

  1. AAn amplitude of more than 25 bpm
  2. BAn amplitude of 0 to 2 bpm
  3. CAn amplitude of 3 to 5 bpm
  4. DAn amplitude of 6 to 25 bpm
2.Maternity & obstetric nursingHard

A newborn boy's scrotum is empty on one side and the testis cannot be felt in the groin. What is appropriate?

  1. AMassage the groin daily to push it down
  2. BTell the parents it will never descend
  3. CArrange emergency surgery on the testis today
  4. DRecord it and arrange follow-up; many descend later
3.Dosage calculationsMedium
024681010 mL

A child weighing 33 kg is prescribed 2 mg/kg of a drug. The stock solution contains 10 mg/mL. Draw up the dose: what volume V do you give?

33 kg2 mg/kg10 mg/mL
V = mL
4.Dosage calculationsHard
25k units500 mL? mL/h500 units/h

An infusion contains 25000 units of a drug in 500 mL. The prescription is 500 units per hour. At what rate R do you set the pump, in mL/h?

25000 units/500 mL500 units/h
R = mL/h
5.IV infusion ratesMedium
1000 mL15 gtt/mL5 h? gtt/min

Infuse 1000 mL over 5 hours with a giving set of 15 gtt/mL. Find the drip rate R in drops per minute.

1000 mL5 h15 gtt/mL
R = gtt/min
6.IV infusion ratesHard
1 g500 mL? mL/h2 mg/min

A bag contains 1 g of a drug in 500 mL. The order is 2 mg per minute. At what rate R do you set the pump, in mL/h?

1 g/500 mL2 mg/min
R = mL/h

3Solutions

1.Maternity & obstetric nursing

Answer: D · An amplitude of 6 to 25 bpm

Why this is the answer

Moderate variability (6–25 bpm) shows an oxygenated fetus with a functioning autonomic nervous system. Minimal (5 bpm or less) or absent variability can mean hypoxia, sleep or medication effects; more than 25 bpm is marked variability.

Answer

D · An amplitude of 6 to 25 bpm
2.Maternity & obstetric nursing

Answer: D · Record it and arrange follow-up; many descend later

Why this is the answer

An undescended testis is common, especially in preterm boys, and often descends in the first months. If it has not descended by about 6 months, referral for surgery (orchidopexy) is recommended.

Answer

D · Record it and arrange follow-up; many descend later
3.Dosage calculations

Answer: V = 6.6 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 = 2·33 = 66 mg

Volume

V = 66/10 = 6.6 mL

On the syringe

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

Answer

V = 6.6 mL
4.Dosage calculations

Answer: R = 10 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

25000/500 = 50 units/mL

Pump rate

R = 500/50 = 10 mL/h

Answer

R = 10 mL/h
5.IV infusion rates

Answer: R = 50 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 = 1000·15/300 = 50 gtt/min

Answer

R = 50 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

1000 mg/500 mL = 2 mg/mL

Dose per hour

2·60 = 120 mg/h

Pump rate

R = 120/2 = 60 mL/h

Answer

R = 60 mL/h

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