Obstetric Anaesthesia Flashcards
Immediately after giving a test dose for a labour epidural in a healthy multiparous parturient, you notice she has difficulty breathing and a reduced GCS. What is the most appropriate immediate management?
- Left lateral tilt and 6mg bolus of ephedrine
- Intralipid
- Removal of epidural catheter
- Immediate rapid sequence induction and caesarean section
- Immediate rapid sequence induction and monitor patient
- Immediate rapid sequence induction and monitor patient
This lady has signs of a total spinal and so needs ventilatory support.
While the CTG is normal, she can be monitored and caesarean section delayed, but this needs to be a senior clinician decision.
Intralipid is indicated only if displaying signs of toxicity.
What are your anaesthetic concerns regarding a patient with anterior placenta praevia undergoing caesarean section?
High risk of significant blood loss
- Arterial line for blood pressure monitoring
- Wide bore IV access
- Cross match blood and consent for transfusion
- Rapid infusor ready
- Regional anaesthesia associated with reduced blood loss
- Consent for rapid conversion to general anaesthesia in case of major haemorrhage
- Consider cell salvage
- Tranexamic acid
- Senior anaesthetic input required
What are the forms of abnormal placental adherence?
Most common: Placenta accreta
- Placenta is adherent to the uterine wall
Intermediate: Placenta Increta
- Placenta invading into but not through through uterine wall
Least common: Placent Percreta
- Placenta invading through the uterine wall
What are the types of placenta praevia?
- Grade 1 - No contact with internal cervical os
- 10% of patients with a low-lying placenta at 20 weeks will have placenta previa at term - Grade 2 - Contact with margin of internal cervical os
- Grade 3 - Partial coverage of internal os
- Grade 4 - Completely obstructs cervical os
What are the common risk factors for developing placenta praevia?
- Low lying placenta
- Multiparous
- Geriatric pregnancy (Age over 40 years)
- Smoking
- Previous placenta praevia
- Previous termination of pregnancy or caesarean section
- Endometrial pathology:
- Scarring
- Endometritis
- Previous manual removal of placenta
- Known fibroid
- Assisted conception
What normal cardiovascular changes are seen during pregnancy?
- Cardiac output increases by 30-50%
- Systemic vascular resistance falls by 30%
- Systolic blood pressure falls by 10mmHg
- CVP remains the same because venodilation is compensated for by increased blood volume
- Physiological multivalvular regurgitation due to chamber enlargement and physiological volume overload
What is the most common cause of maternal death during pregnancy?
The MBRRACE-UK: Saving lives, improving mothers’ care report in 2020 found that cardiac disease is the leading cause of maternal death during pregnancy and in the first six weeks after delivery
What is the incidence of venous air embolism during caesarean section?
25% (using doppler ultrasound and echocardiography)
What proportion of ASA1 women undergoing caesarean section demonstrate ischaemic ECG changes?
Approximately 35%
What criteria must be met for a diagnosis of post-partum cardiomyopathy?
New onset left ventricular failure between the last month of pregnancy and five months post partum
Absence of another identifiable cause of cardiomyopathy
Ejection fraction of less than 45%
Post partum cardiomyopathy is very similar to dilated cardiomyopathy
What ECG signs might you expect to see in a normal, uncomplicated pregnancy?
Left axis deviation
Sinus tachycardia
T wave inversion
Q waves
Atrial and ventricular ectopics
What are the risk factors for post-partum cardiomyopathy?
Pre-existing hypertension
Obesity
Multiple pregnancy
Multiparous
Maternal age over thirty years old
Afro-Carribean ethnicity
Cocaine abuse
What are the anaesthetic implications of combined-spinal-epidural anaesthesia in an obstetric patient with cardiomyopathy?
Avoid tachycardia
Avoid hypotension
Avoid fluid overload
Maintain preload
Avoid aortocaval compression with left lateral tilt
Invasive arterial monitoring
Maintain sinus rhythm
What are the complications of combined spinal-epidural anaesthesia?
Failure of spinal
Failure of epidural
Misplacement or migration of epidural catheter
Damage to spinal needle or catheter
Subarachnoid spread of drug
Neurological damage
- Paraesthesia
- Subdural haematoma
- Cauda equina syndrome
- Aseptic meningitis
Post-dural puncture headache
Infection
- Bacterial meningitis
- Abscess (epidural, subdural)
What are the disadvantages of uterotonic drugs for a patient with cardiomyopathy?
Oxytocin
- decreased SVR
- tachycardia
- coronary vasoconstriction
Ergometrine
- vasoconstriction, including coronary, pulmonary and systemic
Avoid ergometrine in patients with cardiomyopathy, and give oxytocin slowly
In which obstetric conditions is disseminated intravascular coagulation most commonly seen?
Placenta praevia
Placental abruption
Amniotic fluid embolism
Eclampsia
Can you give oxytocin to a woman with congenital heart disease?
It depends on the condition
Ideally not, but also yes, if you give a small amount slowly or omit the bolus dose altogether
You have to weight up the effects of oxytocin* against the alternative treatments for haemorrhage, which usually involve giving lots of fluid or blood, with wobbly blood pressure
*Oxytocin decreases systemic vascular resistance, resulting in a tachycardia, and also causes fluid retention, because it’s incredibly similar to ADH in its structure
Which drugs can safely be given to a pregnant woman with heart failure?
Diuretics
Digoxin
Hydralazine
Nitrates
How should anticoagulation in the peripartum period be managed for women with mechanical heart valves?
Unfractionated heparin should be stopped 4–6 hours before planned delivery
It should then be restarted 4–6 hours after delivery if there are no bleeding complications
There remains significant debate about how best to manage the bleeding vs thrombosis risk seen in pregnant women, but this is the current advice specific to delivery or caesarean section.
Which patients are at high risk of aortic aneurysm and dissection?
Marfan syndrome
Turner syndrome
Loeys–Dietz syndrome
Ehlers–Danlos type 4
Bicuspid aortic valve with aortic dilatation
Previous complex aortic surgery such as coarctation repair
When considering parturients with congenital heart defects, what is the definition of pulmonary artery hypertension?
Mean pulmonary artery pressure of more than 25mmHg
What are your main priorities in a parturient with congenital cardiac disease?
Early identification
Risk assessment
Optimisation
Regular monitoring for deterioration
MDT planning of delivery,
Close monitoring for deterioration in the post-partum period
How is severity of pulmonary stenosis classfied?
Peak velocity (m/s)
Mild = <3
Moderate = 3-4
Severe = >4
Pressure gradient (mmHg)
Mild = <36
Moderate = 36-64
Severe = >64
It’s a good idea to check there isn’t significant tricuspid regurgitation to ensure your pulmonary pressure values aren’t overestimated
What are the maternal complications of antepartum haemorrhage?
Coagulopathy
Infection
Anaemia
Shock
Renal tubular necrosis
Post partum haemorrhage
Prolonged hospital stay
Psychological sequelae
Sheehan’s syndrome
Complications of transfusion
Death
