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 at 37 weeks had a placental abruption. Which laboratory finding suggests she is developing disseminated intravascular coagulation (DIC)?

  1. AA raised haemoglobin level
  2. BA low fibrinogen level and low platelets
  3. CA low white cell count only
  4. DA high fibrinogen level and high platelets
2.Maternity & obstetric nursingHard

Six hours after birth, a woman has not passed urine. The fundus is boggy and displaced to the right, and bleeding has increased. Why is this a priority?

  1. AIt shows that the epidural is still working well
  2. BA full bladder prevents the uterus from contracting and increases bleeding
  3. CA full bladder is a sign of normal recovery
  4. DUrine retention only matters after a caesarean birth, not after a vaginal one
3.Dosage calculationsMedium
18 kg5 mg/kg/day2× per dayD = ? mg

A patient weighs 18 kg. The prescribed dose is 5 mg/kg per day, given in 2 equal doses. How many milligrams D are given per dose?

18 kg5 mg/kg/day2× per day
D = mg
4.Dosage calculationsHard
00.10.20.30.40.50.60.70.80.911 mL

The prescription is 610 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?

610 units1000 units/mL
V = mL
5.IV infusion ratesMedium
1500 mL15 gtt/mL4 h? gtt/min

Infuse 1500 mL over 4 hours with a giving set of 15 gtt/mL. Find the drip rate R in drops per minute. Round to the nearest whole number.

1500 mL4 h15 gtt/mL
R = gtt/min
6.IV infusion ratesHard
200 mg250 mL12 mL/h? mcg/min

An infusion of 200 mg in 250 mL runs at 12 mL/h. How many micrograms per minute D does the patient receive?

200 mg/250 mL12 mL/h
D = mcg/min

3Solutions

1.Maternity & obstetric nursing

Answer: B · A low fibrinogen level and low platelets

Why this is the answer

In DIC, widespread clotting consumes fibrinogen and platelets, leading to bleeding. Fibrinogen is normally raised in pregnancy, so a low level is especially concerning.

Answer

B · A low fibrinogen level and low platelets
2.Maternity & obstetric nursing

Answer: B · A full bladder prevents the uterus from contracting and increases bleeding

Why this is the answer

A distended bladder pushes the uterus up and aside, causing atony and more bleeding. Help her to void, or catheterise per order, then reassess the fundus and the bleeding.

Answer

B · A full bladder prevents the uterus from contracting and increases bleeding
3.Dosage calculations

Answer: D = 45 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.

Total per day

5·18 = 90 mg

Per dose

D = 90/2 = 45 mg

Answer

D = 45 mg
4.Dosage calculations

Answer: V = 0.61 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 = 610/1000 = 0.61 mL

On the syringe

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

Answer

V = 0.61 mL
5.IV infusion rates

Answer: R = 94 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

4·60 = 240 min

Drip rate

R = 1500·15/240 = 93.75 ≈ 94 gtt/min

Answer

R = 94 gtt/min

At the bedside you round to the nearest whole drop: 94 gtt/min.

6.IV infusion rates

Answer: D = 160 mcg/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

200000 mcg/250 mL = 800 mcg/mL

Dose per hour

12·800 = 9600 mcg/h

Dose per minute

D = 9600/60 = 160 mcg/min

Answer

D = 160 mcg/min

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