Obstetric anaesthesia

Question 1

What is the mortality of an amniotic fluid embolism?

Answer 1

20%

Question 2

What is the incidence of AFE?

Answer 2

1/8,000 to 1/80,000

Question 3

When does a presentation of AFE typically occur?

Answer 3

During labour or within 30 minutes of delivery

Question 4

What are the core features of AFE?

Answer 4

• Bronchospasm
• Pulmonary hypertension
• Left ventricular failure
• Coagulopathy

Question 5

What are the most common presenting features of AFE?

Answer 5

• Aura (restlessness, agitation, numbness) - 30%
• Dyspnoea - 20%
• Acute foetal compromise - 20%

Question 6

What are the most common features of AFE?

Answer 6

• Maternal haemorrhage - 65%
• Hypotension - 63%
• Shortness of breath - 62%
• Coagulopathy - 62%
• Aura - 47%
• Foetal compromise - 43%
• Cardiac arrest - 40%
• Cardiac dysrhythmias - 27%
• Seizures - 20%

Question 7

How is a diagnosis of AFE confirmed?

Answer 7

It is a clinical diagnosis, however it can only be confirmed on post mortem examination of the pulmonary vessels containing foetal squames and hair.

Question 8

What are the likely biochemical results of AFE?

Answer 8

• ↓ fibrinogen
• ↓ Platelets
• ↑ fibrin degradation products
• ↑ APTT
• ↑ PT

Question 9

Why is cryoprecipitate of particular use in AFE?

Answer 9

Cryoprecipitate contains fibronectin which activates the reticuloendothelial system and helps to filter antigenic material

Question 10

Which sensory nerve roots are responsible for transmitting the pain of the 1st stage of labour?

Answer 10

T10-L1

Question 11

Which sensory nerve roots are responsible for transmitting the pain of the 2st stage of labour?

Answer 11

S2-S4

Question 12

What are the advantages of a PCEA bolus regimen

Answer 12

• Potentially lower motor block
• Improved satisfaction
• Reduced staff resources

Question 13

What is a standard regimen for a remifentanyl PCA for labour analgesia?

Answer 13

0.3-0.5 mcg/kg 2-3 min lockout. i.e. for 60 kg patient 30 mcg bolus.

Question 14

Define pre-eclampsia

Answer 14

• New hypertension
• Presenting after 20 weeks
• Significant proteinuria.

Question 15

Define severe pre-eclampsia

Answer 15

pre-eclampsia with severe hypertension and/or with symptoms, and/ or biochemical and/or haematological impairment.

Question 16

Mild Hypertension

Answer 16

• SBP 140-149mmHg
• DBP 90-99mmHg

Question 17

Moderate Hypertension

Answer 17

• SBP 150-159mmHg
• DBP 100–109mmHg

Question 18

Severe Hypertension

Answer 18

• SBP > 160mmHg
• DBP > 110mmHg

Question 19

Symptoms of Pre-eclampsia?

Answer 19

• severe headache
• problems with vision, such as blurring/ashing
• severe pain just below the ribs
• vomiting
• sudden swelling of the face, hands or feet.

Question 20

Which patients are at increased risk of pre-eclampsia?

Answer 20

• hypertensive disease during a previous pregnancy
• chronic kidney disease
• autoimmune disease such as systemic lupus erythematosis or antiphospholipid syndrome
• type 1 or type 2 diabetes
• chronic hypertension.

Question 21

What is the proposed therapy for those at increased risk of pre-eclampsia?

Answer 21

Aspirin daily 75 mg

Question 22

What is the success rate of epidural blood patch?

Answer 22

60-90%

Question 23

Differential diagnosis for PDPH

Answer 23

• Simple tension headache
• Migraine
• Venous sinus thrombosis
• Intracranial haemorrhage
• Intracranial mass
• Pre-eclampsia
• Meningitis

Question 24

What is the proceedure for epidural blood patch?

Answer 24

• Most senior anaesthetist
• Strict asepsis
• 20 mL blood - stop if pressure/pain
• Lie supine for 2 hours
• Gradually mobilise
• Follow up 2 hour, 24 hours, 1 week, 1 month

Question 25

Management of seizures in LA toxicity

Answer 25

benzodiazepine, thiopental or propofol in small incremental doses

Question 26

What should you do to follow up LA toxicity

Answer 26

• transfer to appropriate clinical area (ITU)
• Exclude pancreatitis by clinical review, daily amylase/lipase for 2 days
• Report cases to the NPSA
• Document lipid use at www.lipidregistry.org

Question 27

What are the doses of intralipid during LA toxicity

Answer 27

• 1.5 ml/kg over 1 min of 20% lipid emulsion
• Start infusion of 15 ml/kg/hr
• Give up to 2 rpt boluses
• Double infusion to 30 ml/kg/hr
• Maximum cumulative dose of 12 mL/kg

Question 28

When is the peak time for teratagenicity of anaesthetic agents

Answer 28

15-56 days

Question 29

What are the treatment options for severe PET?

Answer 29

• Labetolol (Oral/Infusion)
• Hydralazine IV
• Oral Nifedipine
• Magnesium
• Fluid Restrict
• Expedite Delivery

Question 30

What are the features of an epidural haematoma

Answer 30

• Backpain (75% of cases)
• +/- fever (66% of infected cases)
• Lower limb weakness which fails to resolve within four hours of cessation of infusion
• Delayed presentation after weeks or months following discharge from hospital
• Meningism