ObsGyn

Question 1

what hapepns to sensitivity to IV anaesthetics in pregnancy

Answer 1

• Increased sensitivity to IV anaesthetics

-2020 first sitting question 9

Question 2

what happens to LA sensitivity in prengancy

Answer 2

• Increased LA sensitivity due to decreased α1-glycoprotein

-2020 first sitting question 9

Question 3

what happens to MAC in pregnancy

Answer 3

• Decreased MAC – Increased sensitivity to volatile anaesthetics

-2020 first sitting question 9

Question 4

what happens to MV/FRC in pregnancy

Answer 4

• ↑ MV/↓FRC
• ↑ washout of volatile agents

-2020 first sitting question 9

Question 5

what happens to RBF/GFR in pregnancy

Answer 5

• ↑ RBF/GFR (50%)
• ↑ clearance/↓ elimination t1⁄2 of water-soluble drugs

-2020 first sitting question 9

Question 6

does the Foetal liver have a functioning CYP450?

Answer 6

• Foetal liver has functioning CYP450
• Can metabolise drugs
• But requires transfer back to maternal circ for conjugation
-2020 first sitting question 9

Question 7

can the Placenta metabolise drugs?

Answer 7

• Placenta metabolises some drugs
-2020 first sitting question 9

Question 8

what happens to plasma cholinesterase in preganancy

Answer 8

• ↓ plasma cholinesterase (30%)
-2020 first sitting question 9

Question 9

Effect of Progesterone and Oestrogen on hepatic hepatic enzymes

Answer 9

• Progesterone → induces hepatic enzymes
• Oestrogen → inhibits hepatic enzymes
-2020 first sitting question 9

Question 10

in pregnancy do you get a
metabolic vs respiratory
acidosis vs alkalosis

Answer 10

• Ionisation (mild ↑pH alters ionisation based on pKa)
• ↑ MV = mild respiratory alkalosis
↑ transplacental transfer of basic drugs as they will have ↑ % in
unionized form
• (Base in base is less ionised)
• ↑ ion trapping in more acidotic foetal circulation
-2020 first sitting question 9

Question 11

what happens to A1AGP in pregnancy

Answer 11

• ↓ A1AGP (by 30%) →
• ↑ free % of basic drugs (Eg. LA, β blockers)
• ↓ dose required
• ↑ transplacental transfer of drug
-2020 first sitting question 9

Question 12

what happens to albumin in prengnacy

Answer 12

• ↓ albumin →
• ↑ free % of acidic drugs (Eg. STP, propofol)
• ↓ dose required
• ↑ transplacental transfer of drug.
-2020 first sitting question 9

Question 13

what happens to plasma protein in pregnancy

Answer 13

• ↓ plasma protein 2° to dilutional effect
-2020 first sitting question 9

Question 14

what happens to body fat in pregnancy

Answer 14

• ↑ body fat % (important for lipid soluble drugs)
-2020 first sitting question 9

Question 15

what happens to VD in pregnancy

Answer 15

• ↑ VD
• ↑ TBW/ECF (by 50%) (important for polar/ionized drugs)
-2020 first sitting question 9

Question 16

What happens in pregnancy to minute ventilation

Answer 16

increases
• Progesterone-mediated ↑ MV (by 50-70%)
-2020 first sitting question 9

Question 17

What happens in pregnancy to Inhalational absorption?

Answer 17

increases
• Progesterone-mediated ↑ MV (by 50-70%)
-2020 first sitting question 9

Question 18

in pregnancy what happens to cardiac otuput

Answer 18

increases 30-40%
-2020 first sitting question 9

Question 19

in pregnancy what happens to
Oral absorption
gastric absorption
intestinal absorption

Answer 19

↓ Oral absorption
↑ gastric absorption
↓intestinal absorption
-2020 first sitting question 9

Question 20

In pregnancy what causes a change to minute ventilation?

Answer 20

• Progesterone-mediated ↑ MV (by 50-70%)
-2020 first sitting question 9