Obstetrics

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? (4)

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%
Hypoxaemia
Hypotension

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 containsfibronectinwhich activates thereticuloendothelialsystem and helps to filter antigenic material, and contains fibrinogen which is low in AFE

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 2nd stage of labour?

Answer 11

S2-S4

Question 12

What are the advantages of a PCEA bolus regimen

Answer 12

Improved satisfaction
Reduced staff resources
Potentially lower motor block

Question 13

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

Answer 13

0.3-0.5 mcg/kg 2-3 min lockout
Usually 40 mcg bolus

Question 14

Define pre-eclampsia

Answer 14

Disorder of pregnancy:
- New-onset hypertension (systolic blood pressure ≥140 mmHg and/or a diastolic blood pressure ≥90 mmHg)
- After 20 weeks’ gestation

Although often accompanied by new-onset proteinuria, it may present in the absence of proteinuria in some women

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
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 hypertension
Type 1 or 2 diabetes
Chronic kidney disease
Autoimmune disease such as SLE or antiphospholipid syndrome

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

50-80%

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 procedure 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 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 teratogenicity of anaesthetic agents?

Answer 28

Week 3-8 gestation 21-56 days

Question 29

What are the treatment options for severe PET?

Answer 29

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

Question 30

What are the features of an epidural haematoma?

Answer 30

Back pain: often severe and local, and can radiate to the arms or legs Weakness: progressive weakness in the lower extremities, often bilateral Paraesthesias: numbness or other sensory deficits in the lower extremities Bowel and bladder dysfunction Pain when pressure is applied: can be aggravated by direct pressure on the spine, coughing, sneezing, or straining

Question 31

Phase 1 of AFE

Answer 31

Phase 1 (~30 mins) Amniotic fluid + foetal cells enter maternal circulation Release of biochemical mediators Pulmonary artery vasospasm → pulmonary hypertension Elevated right ventricular pressures + right ventricular dysfunction Hypoxaemia + hypotension Myocardial and capillary damage

Question 32

Phase 2 of AFE

Answer 32

Phase 2 (if phase 1 survived) Left ventricular failure Pulmonary oedema Biochemical mediators trigger DIC → massive haemorrhage + atony