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 finding is expected in a healthy breastfed newborn on day 3?

  1. AA weight loss of about 6% of birth weight
  2. BA weight loss of about 15% of birth weight
  3. CNo wet nappies in the last 24 hours
  4. DA weight gain of 300 g since birth
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. AAn occiput posterior position
  2. BA transverse lie with the head in the pelvis
  3. CA breech presentation
  4. DA cephalic presentation
3.Dosage calculationsMedium
2%5 mLm = ? mg

How many milligrams of drug m are in 5 mL of a 2% (w/v) solution?

2% w/v5 mL
m = mg
4.Dosage calculationsHard
25%stockV₁ = ? mL

You must prepare 500 mL of a 2.5% (w/v) solution from a 25% (w/v) stock solution. What volume of stock V₁ do you need?

C₁ = 25%C₂ = 2.5%V₂ = 500 mL
V₁ = mL
5.IV infusion ratesMedium
V = ?60 gtt/mL30 gtt/min6 h

A drip runs at 30 gtt/min through a set of 60 gtt/mL. How many millilitres V does the patient receive in 6 hours?

30 gtt/min60 gtt/mL6 h
V = mL
6.IV infusion ratesHard
200 mg100 mL20 gtt/mL150 mg/h? gtt/min

200 mg of a drug is diluted in 100 mL and given by gravity through a set of 20 gtt/mL. The order is 150 mg per hour. Find the drip rate R in drops per minute.

200 mg/100 mL150 mg/h20 gtt/mL
R = gtt/min

3Solutions

1.Maternity & obstetric nursing

Answer: A · A weight loss of about 6% of birth weight

Why this is the answer

A loss of up to about 7–10% of birth weight is common in the first days, with birth weight usually regained by about 10–14 days. A larger loss or too few wet nappies needs a feeding assessment.

Answer

A · A weight loss of about 6% of birth weight
2.Maternity & obstetric nursing

Answer: C · 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

C · A breech presentation
3.Dosage calculations

Answer: m = 100 mg

Solution strengths: a percentage strength is grams per 100 mL, so 1% = 1 g/100 mL = 10 mg/mL. A ratio strength 1:1000 means 1 g in 1000 mL = 1 mg/mL; 1:10 000 is 0.1 mg/mL. For a dilution the amount of drug stays the same: C₁·V₁ = C₂·V₂.

Concentration

2% = 2 g/100 mL = 20 mg/mL

Mass of drug

m = 20·5 = 100 mg

Answer

m = 100 mg
4.Dosage calculations

Answer: V₁ = 50 mL

Solution strengths: a percentage strength is grams per 100 mL, so 1% = 1 g/100 mL = 10 mg/mL. A ratio strength 1:1000 means 1 g in 1000 mL = 1 mg/mL; 1:10 000 is 0.1 mg/mL. For a dilution the amount of drug stays the same: C₁·V₁ = C₂·V₂.

Volume of stock

V₁ = 2.5·500/25 = 50 mL

Answer

V₁ = 50 mL
5.IV infusion rates

Answer: V = 180 mL

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.

Rate in mL/h

30·60/60 = 30 mL/h

Volume

V = 30·6 = 180 mL

Answer

V = 180 mL
6.IV infusion rates

Answer: R = 25 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

200/100 = 2 mg/mL

Volume per hour

150/2 = 75 mL/h

Drip rate

R = 75·20/60 = 25 gtt/min

Answer

R = 25 gtt/min

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