Obstetric anaesthesia Flashcards
What is the mortality of an amniotic fluid embolism?
20%
What is the incidence of AFE?
1/8,000 to 1/80,000
When does a presentation of AFE typically occur?
During labour or within 30 minutes of delivery
What are the core features of AFE?
- Bronchospasm
- Pulmonary hypertension
- Left ventricular failure
- Coagulopathy
What are the most common presenting features of AFE?
- Aura (restlessness, agitation, numbness) - 30%
- Dyspnoea - 20%
- Acute foetal compromise - 20%
What are the most common features of AFE?
- Maternal haemorrhage - 65%
- Hypotension - 63%
- Shortness of breath - 62%
- Coagulopathy - 62%
- Aura - 47%
- Foetal compromise - 43%
- Cardiac arrest - 40%
- Cardiac dysrhythmias - 27%
- Seizures - 20%
How is a diagnosis of AFE confirmed?
It is a clinical diagnosis, however it can only be confirmed on post mortem examination of the pulmonary vessels containing foetal squames and hair.
What are the likely biochemical results of AFE?
- ↓ fibrinogen
- ↓ Platelets
- ↑ fibrin degradation products
- ↑ APTT
- ↑ PT
Why is cryoprecipitate of particular use in AFE?
Cryoprecipitate contains fibronectin which activates the reticuloendothelial system and helps to filter antigenic material
Which sensory nerve roots are responsible for transmitting the pain of the 1st stage of labour?
T10-L1
Which sensory nerve roots are responsible for transmitting the pain of the 2st stage of labour?
S2-S4
What are the advantages of a PCEA bolus regimen
- Potentially lower motor block
- Improved satisfaction
- Reduced staff resources
What is a standard regimen for a remifentanyl PCA for labour analgesia?
0.3-0.5 mcg/kg 2-3 min lockout. i.e. for 60 kg patient 30 mcg bolus.
Define pre-eclampsia
- New hypertension
- Presenting after 20 weeks
- Significant proteinuria.
Define severe pre-eclampsia
pre-eclampsia with severe hypertension and/or with symptoms, and/ or biochemical and/or haematological impairment.
Mild Hypertension
- SBP 140-149mmHg
- DBP 90-99mmHg
Moderate Hypertension
- SBP 150-159mmHg
- DBP 100–109mmHg
Severe Hypertension
- SBP > 160mmHg
- DBP > 110mmHg
Symptoms of Pre-eclampsia?
- severe headache
- problems with vision, such as blurring/ashing
- severe pain just below the ribs
- vomiting
- sudden swelling of the face, hands or feet.
Which patients are at increased risk of pre-eclampsia?
- 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.
What is the proposed therapy for those at increased risk of pre-eclampsia?
Aspirin daily 75 mg
What is the success rate of epidural blood patch?
60-90%
Differential diagnosis for PDPH
- Simple tension headache
- Migraine
- Venous sinus thrombosis
- Intracranial haemorrhage
- Intracranial mass
- Pre-eclampsia
- Meningitis
What is the proceedure for epidural blood patch?
- 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
