Anaesthetics and the Pregnant Woman

Question 1

How does the maternal CV system adapt to pregnancy?

Answer 1

CO increases 40%
HR increases 15%
SV increases 35%
Peripheral resistance decreased 35%

Question 2

What is the effect of aorto-caval compression?

Answer 2

Hypotension

Supine hypotension syndrome in 15% of women at term

Question 3

How much does the blood volume change?

Answer 3

TBW - increases 40%

Plasma volume by 50% and RBC by 30% therefore there is physiological dilution

Question 4

Why are women hypercoaguable?

Answer 4

Clotting factors increase by 800%

Question 5

Why are pregnant more prone to reflux?

Answer 5

Increase acid production

Lower LOS pressure - due to reduced diaphragmatic closure of LOS

Question 6

Why do women get oedematous?

Answer 6

Decrease in concentration of total protein, albumin, and globulin therefore decrease in oncotic pressure

Question 7

What happens to sensitivity to narcotics in pregnancy?

Answer 7

Increases

Question 8

Why does the afterload increase after delivery?

Answer 8

Loss of placenta - loss pressure shunt

Question 9

Why does preload increase after delivery?

Answer 9

Uterus contraction

Question 10

When is the high risk time for cardiac failure? and VTE?

Answer 10

Cardiac failure - immediately after delivery

VTE - 5 days after delivery

Question 11

Why might it be difficult to intubate?

Answer 11

Weight gain and fluid retention
Laryngeal oedema
Breast enlargement

Question 12

What are the risk with pregnant airways?

Answer 12

More difficult to intubate
Higher risk of aspiration
Low saturations

Question 13

What causes pain in labour?

Answer 13

First stage - visceral pain from dilatation of cervix

Second stage - somatic pain from distension of outlet, vagina, vulva, perineum

Question 14

How must you take NO?

Answer 14

Hyperventilate in the first 30s of a contraction

Immediately stop at end of contraction

Question 15

When is pethidine used?

Answer 15

No longer at all due to metabolic side effects in the fetu

Question 16

What is are opioids of choice? What is the dose?

Answer 16

Morphine, IM, 100mg 2-3 hourly
Fentanyl, IV 50-100ug, PCA, used in epidurals
Remifentanil, PCA

Question 17

What is remifentanil? What are the difficulties with it?

Answer 17

Ultra short acting synthetic opioid

Narrow therapeutic window

Question 18

What proportion of women get epidurals?

Answer 18

50% in first pregnancies

40% in multiparous

Question 19

Why do an epidural in someone with cardiac disease?

Answer 19

Because the pain itself causes increased cardiac stress

Question 20

What are the contraindications for epidural use?

Answer 20

Relative

• Hypovolaemia
• Coagulopathy
• Sepsis
• Active neurological
• Obstetrical

Question 21

What are the indications for epidurals?

Answer 21

Pain
Cardiac disease
Pre-eclampsia

Question 22

What are the advantages of epidural use?

Answer 22

Very effective pain relief
Allows instrumental delivery
More synchronised contractions

Question 23

What are some complications?

Answer 23

Immediate
- Hypotension, dural puncture, high block, total spinal, intravascular injection

Delayed

• PDPH
• Backache
• Neurological
• Infective complications
• Haematoma

Question 24

How do you treat post epidural headache?

Answer 24

Blood patch

Question 25

What agents are used in epidurals?

Answer 25

Ropivacaine + fentanyl

Bupivacaine

Question 26

What anaesthetics are used in caesareans?

Answer 26

Spinal - majority of electives
Epidural top up - if already in labour with one
GA - if emergency and no time for epidural placement

Question 27

What is used post delivery?

Answer 27

Multimodal