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

The fundus is boggy, above the umbilicus and displaced to the right. What is the most likely cause?

  1. AA tear in the perineum
  2. BA full bladder
  3. CRetained placental tissue on the left
  4. DA normal finding on day 1
2.Maternity & obstetric nursingHard

On abdominal palpation, the nurse feels a hard, round, movable mass in the fundus, and the fetal heart is heard above the umbilicus. What does this suggest?

  1. AA breech presentation
  2. BA transverse lie with the head in the pelvis
  3. CAn occiput posterior position
  4. DA cephalic presentation
3.Dosage calculationsMedium
1 g+ 4.2 mLV = ? mL

A vial contains 1 g of powder. The label says: add 4.2 mL of water for injection to give a total volume of 5 mL. The prescription is 200 mg. What volume V of the reconstituted solution do you give?

1 g+ 4.2 mL → 5 mL200 mg
V = mL
4.Dosage calculationsHard
250 mg/5 mLV = ? mL

A patient weighs 178.2 lb. The prescription is 10 mg/kg as a single dose, and the stock contains 250 mg in 5 mL. Using 1 kg = 2.2 lb, what volume V do you give?

178.2 lb10 mg/kg250 mg/5 mL1 kg = 2.2 lb
V = mL
5.IV infusion ratesMedium
540 mLleft? mL/h5 h left

1000 mL was ordered over 10 hours. After 5 hours you find that 540 mL is still in the bag, and the order must still finish on time. To what rate R in mL/h must the pump be reset?

1000 mL / 10 hafter 5 h: 540 mL
R = mL/h
6.IV infusion ratesHard
1000 mg250 mL60 gtt/mL300 mg/h? gtt/min

1000 mg of a drug is diluted in 250 mL and given by gravity through a set of 60 gtt/mL. The order is 300 mg per hour. Find the drip rate R in drops per minute.

1000 mg/250 mL300 mg/h60 gtt/mL
R = gtt/min

3Solutions

1.Maternity & obstetric nursing

Answer: B · A full bladder

Why this is the answer

A full bladder lifts and displaces the uterus, usually to the right, and stops it contracting well. Helping the woman to empty her bladder usually lets the fundus return to the midline and firm up.

Answer

B · A full bladder
2.Maternity & obstetric nursing

Answer: A · A breech presentation

Why this is the answer

A hard, round, ballotable head in the fundus means the buttocks are presenting. The fetal heart in breech presentations is usually heard above the umbilicus.

Answer

A · A breech presentation
3.Dosage calculations

Answer: V = 1 mL

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 after mixing

1000 mg/5 mL = 200 mg/mL

Volume

V = 200/200 = 1 mL

Answer

V = 1 mL
4.Dosage calculations

Answer: V = 16.2 mL

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.

Weight in kg

178.2/2.2 = 81 kg

Dose

10·81 = 810 mg

Volume

V = (810/250)·5 = 16.2 mL

Answer

V = 16.2 mL
5.IV infusion rates

Answer: R = 108 mL/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.

Original rate

1000/10 = 100 mL/h

New rate

R = 540/5 = 108 mL/h

Answer

R = 108 mL/h

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

6.IV infusion rates

Answer: R = 75 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

1000/250 = 4 mg/mL

Volume per hour

300/4 = 75 mL/h

Drip rate

R = 75·60/60 = 75 gtt/min

Answer

R = 75 gtt/min

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