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 4 hours after birth has severe perineal pain and pressure. Her fundus is firm, lochia is normal, and her heart rate is rising. What should the nurse suspect?

  1. AA vulvar or vaginal haematoma
  2. BUterine atony
  3. CA urinary tract infection
  4. DNormal afterpains
2.Maternity & obstetric nursingHard

A woman at 34 weeks with type 1 diabetes has a blood glucose of 2.8 mmol/L (50 mg/dL), is sweating and shaky but is alert. What should the nurse do first?

  1. AGive fast-acting glucose by mouth and recheck
  2. BGive her usual insulin dose
  3. CCheck the fetal heart rate before any treatment
  4. DWait until her next meal
3.Dosage calculationsMedium
18 kg25 mg/kg/day3× per dayD = ? mg

A patient weighs 18 kg. The prescribed dose is 25 mg/kg per day, given in 3 equal doses. How many milligrams D are given per dose?

18 kg25 mg/kg/day3× per day
D = mg
4.Dosage calculationsHard
10%stockV₁ = ? mL

You must prepare 200 mL of a 2.5% (w/v) solution from a 10% (w/v) stock solution. What volume of stock V₁ do you need?

C₁ = 10%C₂ = 2.5%V₂ = 200 mL
V₁ = mL
5.IV infusion ratesMedium
500 mL10 gtt/mL8 h? gtt/min

Infuse 500 mL over 8 hours with a giving set of 10 gtt/mL. Find the drip rate R in drops per minute. Round to the nearest whole number.

500 mL8 h10 gtt/mL
R = gtt/min
6.IV infusion ratesHard
1 g500 mL? mL/h4 mg/min

A bag contains 1 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?

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

3Solutions

1.Maternity & obstetric nursing

Answer: A · A vulvar or vaginal haematoma

Why this is the answer

A haematoma causes severe pain and pressure out of proportion to the birth, often with a firm uterus and normal lochia. Signs of hidden blood loss such as tachycardia must be reported.

Answer

A · A vulvar or vaginal haematoma
2.Maternity & obstetric nursing

Answer: A · Give fast-acting glucose by mouth and recheck

Why this is the answer

An alert patient with hypoglycaemia is given fast-acting oral carbohydrate, then glucose is rechecked after about 15 minutes and followed by a snack or meal. Treating the mother also protects the fetus.

Answer

A · Give fast-acting glucose by mouth and recheck
3.Dosage calculations

Answer: D = 150 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

25·18 = 450 mg

Per dose

D = 450/3 = 150 mg

Answer

D = 150 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 = 2.5·200/10 = 50 mL

Answer

V₁ = 50 mL
5.IV infusion rates

Answer: R = 10 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

8·60 = 480 min

Drip rate

R = 500·10/480 = 10.42 ≈ 10 gtt/min

Answer

R = 10 gtt/min

At the bedside you round to the nearest whole drop: 10 gtt/min.

6.IV infusion rates

Answer: R = 120 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

4·60 = 240 mg/h

Pump rate

R = 240/2 = 120 mL/h

Answer

R = 120 mL/h

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