2. Obstetrics

Question 1

Q1 — Pre-eclampsia
A 25-year-old woman who is 37 weeks pregnant and known to have preeclampsia
is admitted to the labour ward with a blood pressure of
160/110mmHg on several readings.

a) What is the definition of pre-eclampsia?

Answer 1

Pre-eclampsia is a multisystem disorder with:

● Hypertension (BP >140/90mmHg) presenting after 20 weeks’
gestation.

● Significant proteinuria, i.e,
spot urinary protein: creatinine ratio
>30mg/mmol or a
24-hour urine collection with >300mg protein.

Question 2

b) Define gestational hypertension.

Answer 2

Hypertension presenting after 20 weeks’ gestation without significant
proteinuria.

Question 3

c) How can you define severe pre-eclampsia?

Answer 3

Proteinuria with severe hypertension (BP >160/110mmHg).

OR

Mild to moderate hypertension (140/90 to 159/109mmHg) with any of the
following features:

● Severe headache.
● Visual disturbance such as flashing lights or blurring.
● Vomiting.
● Subcostal pain.
● Papilloedema.
● Clonus (³3 beats).
● Liver tenderness.
● Thrombocytopenia (<100 × 109/L).
● Abnormal liver enzymes.
● HELLP syndrome

Question 4

d) Explain the pathogenesis of pre-eclampsia.
**

Answer 4

● Impaired trophoblastic cell invasion.

● Failure of spiral artery dilatation.

● Placental hypoperfusion and hypoxia.

● Releases cytokines and inflammatory factors into the maternal
circulation triggering endothelial dysfunction.

● Increase in vascular reactivity, permeability, and coagulation cascade
activation.

● Organ damage.

Question 5

e) Which related symptoms should pregnant women be told to
report immediately?

Answer 5

● Severe headache.
● Problems with vision, such as blurring or flashing before the eyes
● Severe pain just below the ribs or abdominal pain.
● Vomiting.
● Sudden swelling of the face, hands or feet.
● Reduced foetal movement.

Question 6

f) How should this patient be monitored following admission to
the labour ward?

Answer 6

● Obstetric consultant-led care with input from anaesthetic and
neonatology teams.

● Monitor for signs and symptoms of severe pre-eclampsia.

● Monitor with the following — ECG, NIBP/IABP, pulse oximetry, RR,
fluid input/output, hourly reflexes.

● Six-hourly blood tests to monitor the platelet count, renal function
and liver enzymes.

● Foetal monitoring — US scan and CTG.

Question 7

g) How would you control BP in this patient?

Answer 7

Maintain systolic pressure <150mmHg and diastolic pressure 80-
100mmHg.

● Reduce BP at the rate of 1-2mmHg per minute.

● First-line — oral labetalol.

● Oral methyldopa and nifedipine if labetalol is contraindicated
(bronchial asthma).

● Refractory hypertension — administer IV labetalol or IV hydralazine.

● Intra-arterial BP monitoring and HDU care may be considered.

Question 8

h) What changes would you make to your airway management for
a pregnant woman, if this woman needed a general anaesthetic
for a caesarean section?

Answer 8

Anticipate a difficult airway.
● Manage the hypertensive response to laryngoscopy with alfentanil,
remifentanil, esmolol, atenolol.
● Manage hypertension at emergence with the same drugs.
● Smaller size ETT due to upper airway oedema.
● Gentle airway instrumentation to avoid trauma

Question 9

i) What are the other considerations for GA?

Answer 9

● Non-depolarising muscle relaxants are potentiated by magnesium
sulphate; hence, smaller doses should be used with neuromuscular
monitoring.

● Appropriate neonatal resuscitation facilities.

● A higher risk of PPH but avoid ergometrine.

● Good postoperative analgesia/regional techniques like TAP blocks.
● Avoid NSAIDs.

● The likelihood of postoperative airway oedema
and pulmonary
oedema.

● Postoperative HDU/ITU care.

Question 10

j) What are the complications of pre-eclampsia?

Answer 10

Maternal complications:
● Eclampsia.
● Intracerebral haemorrhage.
● Pulmonary oedema.
● Acute renal failure.
● Liver dysfunction.
● Coagulation abnormalities

Foetal complications:
● Abruptio placentae.
● Intrauterine growth restriction.
● Premature delivery.
● Intrauterine foetal death.

Question 11

Q2 — Postdural puncture headache
The obstetric team tell you about a patient who is 2 days postpartum with
a suspicion of a postdural puncture headache (PDPH).
a) What is the differential diagnosis for this patient with a
suspected postpartum headache?

Answer 11

● Non-specific — dehydration, caffeine withdrawal, sleep deprivation.
● Tension headache.
● Lactation headache.
● Migraine.
● Sinusitis.
● Pre-eclampsia/eclampsia.
● Cortical vein thrombosis.
● Subarachnoid haemorrhage.
● Posterior reversible leukoencephalopathy syndrome.
● Space-occupying lesion — brain tumour, subdural haematoma.
● Cerebral infarction/ischaemia.
● Meningitis, encephalitis.

Question 12

b) What features, in this patient, would lead you to consider a
serious underlying cause?

Answer 12

● Focal neurological deficit.
● Seizures.
● Altered conscious level.
● Absence of postural component.
● Presence of infectious markers.
● Hypertension and proteinuria — pre-eclampsia/eclampsia.

Question 13

c) What is the mechanism/pathogenesis of headache in PDPH?

Answer 13

CSF leakage and a decrease in intracranial pressure causes:
● Traction on unsupported intracranial pain-sensitive structures such as
the tentorium and blood vessels.
● Compensatory vasodilatation of intracranial blood vessels.**

Question 14

d) List the clinical features of PDPH.

Answer 14

● 90% of headaches develop within 3 days of the procedure.

● Headache is often frontal-occipital.

● Aggravated in the upright position, and when coughing or straining.

● Relieved on lying down.

● Associated symptoms include neck stiffness, nausea and vomiting,
visual disturbance, photophobia, auditory symptoms, cranial nerve
palsies.

Question 15

e) List the management strategies for this patient who is suffering
with a PDPH.

Question 16

f) You diagnose a PDPH and arrange treatment by an epidural
blood patch (EBP). How is an epidural blood patch performed?

Answer 16

● Obtain consent.
● IV access.
● Complete asepsis by both anaesthetists.
● Position the patient — usually laterally for patient comfort.
● Performed at or one space below the original site of dural puncture.
● The epidural space is identified.
● The assistant should aseptically withdraw 20ml of blood from a
peripheral vein.
● 10-20ml should be injected into the epidural space.
● Should radicular pain occur, slow or stop injecting.

Question 17

g) What advice would you give to the patient after an EBP?

Answer 17

● Post-procedure, the patient should lie flat for 1-2 hours.
● Refrain from vigorous activity or lifting for a few days.
● Consider prescribing stool softeners to avoid constipation.
● Before leaving hospital, patients should be counselled to report fever,
severe back pain, or radicular pain immediately

Question 18

h) Describe the mechanism of action of EBP.

Answer 18

● Tamponade effect of blood in the epidural space.
● Increased intracranial pressure and relief from headache.
● Formation of a clot seals the puncture site preventing further CSF
leak

Question 19

i) What are the described risks of an EBP?

Answer 19

Risk of an epidural:
● Dural puncture.
● Permanent and temporary nerve damage.
● Meningitis.
● Risk of haematoma.

Risk of an EBP:
● Early complications:
- backache during injection;
- fever;
- bradycardia;
- seizures.

● Late complications include:
- meningitis;
- subdural haematoma;
- arachnoiditis;
- radicular pain;
- recurrence of headache.

Question 20

a) Which methods of testing may be used to confirm the
adequacy of a spinal (intrathecal) block for an elective
caesarean section?

Answer 20

Sensory block:
● Temperature — ethyl chloride spray/cold sensation.
● Pin prick.
● Pressure.
● Touch.
● Proprioception, vibration.
A block to cold sensation at T2-4 and pin prick at T4-T5 confirms the
adequacy of the block for a caesarean section.
Motor block using the Bromage scale:
● 0 = no motor block.
● 1 = inability to straight leg raise but able to move knee and feet.
● 2 = inability to straight leg raise or move knee, able to move feet.
● 3 = complete motor block.
A score of 3 indicates a higher lumbar block.
Autonomic block:
● Hypotension.
● Bradycardia.
● Temperature changes

Question 21

b) Describe the actions you could take if your spinal block proves
inadequate on testing prior to starting surgery for an elective
(category 4) caesarean section.

Answer 21

● Tilting the patient head down.
● If there is no evidence of block after 20 minutes, repeat the same
dose of spinal or do a combined spinal epidural.
● If the block is inadequate, consider an epidural catheter and gradual
top-ups. Repeating the spinal in this case may lead to a high/total
spinal.
● Consider GA.
● Discussion with the mother, surgeon and senior colleague, and foetal
monitoring to influence decision-making.

Question 22

c) What are the early symptoms and signs of a spinal block that is
ascending too high?

Answer 22

T1-T4 block:
● Weak cough, shortness of breath (paralysis of intercoastal muscles).
● Hypotension and bradycardia (cardiac sympathetic block).
● Nausea and vomiting.
● Foetal compromise.

C6-C8 block:
● Paraesthesia of hands and arms.

C3-C5 block:
● Desaturation and respiratory arrest (diaphragmatic paralysis).
● Brainstem involvement and intracranial spread:
- a difficulty in phonation and swallowing;
- loss of consciousness.

Question 23

d) How should you manage a patient who complains of pain
during an elective caesarean section under spinal anaesthesia?

Answer 23

● Stop surgery if required.

● Reassure.

● Communication with the mother and surgeon.

● Offer analgesia.

● Entonox®.

● Intravenous opioid:
- 25-50mg fentanyl, repeat as necessary;
- inform the neonatologist if this is given before delivery of the baby.

● Surgical infiltration of local anaesthetic.

● Epidural opioid/LA.

● General anaesthesia.

Question 24

Categories of section

Answer 24

Category 1.
Immediate threat to the life of the woman or fetus
(for example, suspected uterine rupture,
major placental abruption,
cord prolapse, fetal hypoxia or
persistent fetal bradycardia).

Perform category 1 caesarean birth as soon as possible, and in most situations within 30 minutes of making the decision

Category 2. Maternal or fetal compromise which is not immediately life-threatening.

Perform category 2 caesarean birth as soon as possible, and in most situations within 75 minutes of making the decision.

Category 3. No maternal or fetal compromise but needs early birth.

Category 4. Birth timed to suit woman or healthcare provider.

Question 25

Q4 — Intrauterine foetal death
A woman, who has had an intrauterine foetal death (IUFD) at 36 weeks’
gestation in her first pregnancy, is admitted to the delivery suite for
induction of labour.
a) List the causes of IUFD.

Answer 25

Antepartum:
● Congenital malformation.
● APH.
● Pre-eclampsia/eclampsia.
● Maternal diabetes mellitus.

Intrapartum:
● Abruptio placentae.
● Severe maternal or foetal infection.
● Cord prolapse.
● Uterine rupture.

Question 26

b) Describe the important non-clinical aspects of her
management.

Answer 26

● Psychological distress needs to be addressed.

● One-to-one midwifery care.

● Care provided in a quiet room.

● Free access to family members if the mother wishes.

● Pain relief options to be discussed by an anaesthetist.

● May require HDU care.

Question 27

c) What are the considerations when providing pain relief for this
woman prior to delivery?

Answer 27

Patient factors:
● Address psychological distress.
● Consider pre-existing comorbidities.
● Sepsis.
● Coagulopathy.

Obstetric factors:
● Cause of IUFD.

● Mode of delivery:
- early induction of labour;
- may require a caesarean section.

Others:
● One-to-one midwifery care.
● MEOWS charting.
● May require HDU care.
● Consider sedation.

Question 28

d) What are the options for pain relief?

Answer 28

d) What are the options for pain relief?
● Entonox®.

● Parenteral opioids — diamorphine/pethidine IM, morphine/fentanyl/
remifentanil PCA.

● Supplementary regular IV/oral paracetamol.

● Regional anaesthesia with epidural PCEA — if not contraindicated

Question 29

e) If this patient requires a caesarean section what are the
advantages of using regional anaesthesia, other than the
avoidance of the effects of general anaesthesia?

Answer 29

● Good postoperative analgesia.

● Early mobilisation.

● Decreased risk of PPH.

● Decreased risk of DVT.

● Fewer drugs — less chance of anaphylaxis and drowsiness.

Question 30

Q5 — Obesity and pregnancy
A primiparous patient with a BMI of 55kg/m2 presents in the high-risk
anaesthetic antenatal assessment clinic at 34 weeks’ gestation. She is
hoping to have a normal delivery.

a) What are the specific cardiorespiratory effects of obesity in the
pregnant patient?

Answer 30

Cardiovascular system:
● Increase in stroke volume, heart rate, and increased pulse pressure
associated with pregnancy may be poorly tolerated.

● Hypertension, ischaemic heart disease and congestive heart failure.

● Exaggerated response to aortocaval compression due to increased
intra-abdominal fat.

● Peripartum cardiomyopathy.

Respiratory system:
● Decrease in FRC associated with normal pregnancy is aggravated.
● Postoperative hypoxia and atelectasis.
● Obstructive sleep apnoea.
● Pulmonary hypertension and cor pulmonale.
● Restrictive respiratory pattern.

Question 31

b) What are the specific obstetric concerns associated with a
raised BMI in pregnancy?

Answer 31

Increased risks of:

● Gestational DM, PIH, pre-eclampsia.

● Thromboembolic disorders.

● Instrumental and caesarean delivery.

● Postpartum haemorrhage.*

● Postoperative infections (surgical wound and chest infections).**

● Peripartum cardiomyopathy.**

Question 32

c) What are the foetal risks associated with a high BMI?

Answer 32

Increased risks of:

● Miscarriage, preterm birth, still birth.**

● Meconium aspiration.

● Foetal distress.**

● Shoulder dystocia.**

● Neural tube defects, macrosomia.**

● Low Apgar score.**

● A higher incidence of neonatal intensive care admissions.

Question 33

d) What are your anaesthetic concerns in this obstetric patient
with a high BMI?

Answer 33

● Difficult intravenous access.

● Difficulty performing neuraxial techniques
and a high risk of dural puncture.

● A higher incidence of failed blocks due to altered spread of LA
secondary to fat deposition in the epidural space.

● Risks with GA:

• difficult airway;
• risk of aspiration;
• short apnoea time due to decreased FRC
  and increased oxygen consumption;
• increased oxygen requirements postoperatively.

● Equipment issues and staff:
- maximum weight supported by operating table;
- risk to staff involved in manual handling;
- longer spinal and epidural needles;
- larger BP cuffs, TEDs, Flowtron®;
- US for venous access, arterial and central venous cannulation.

Question 34

e) What are your considerations when you provide labour
analgesia?

Answer 34

● Review of antenatal consultation notes with obstetric anaesthetist.

● Difficult IV access.

● Early epidural to allow time for a difficult procedure.

● US scan of the back to facilitate epidural insertion.

● Supplemental analgesia with Entonox® and oral/IV paracetamol.

● Analgesic options in the case of a failed epidural —
remifentanil/fentanyl PCA.

● If opioids are used, supplemental oxygen, pulse oximetry and one-to one
midwifery care is needed.

Question 35

Q6 — Surgery in pregnancy
A 28-year-old woman presents for an acute appendicectomy under general
anaesthesia; she is 22 weeks pregnant.

a) List the risks to the foetus during anaesthesia in this situation

Answer 35

● Spontaneous abortion.

● Preterm labour.

● IUGR.

● Foetal death.

● Placental ischaemia and foetal hypoxia.

● Foetal acidosis/ion trapping and myocardial depression.

● Teratogenicity in the first trimester.

Question 36

b) How can the risks to the foetus be minimised?

Answer 36

● Timing of surgery.

● Avoid foetal hypoxia.

● Prevention of preterm labour.

● Consider the effects of anaesthetic drugs on the foetus.

Question 37

c) How does timing the surgery reduce the foetal risk?

Answer 37

● Elective surgeries to be postponed at least
6 weeks postpartum, if possible.

● Alternatively, delay surgeries into the
second trimester to avoid the
teratogenic effects of drugs.

Question 38

e) List any four drugs used in anaesthetic practice and their
adverse effects on the foetus.

Answer 38

● Ketamine increases uterine tone and vasoconstriction
in the first two trimesters.

● NSAIDs in the third trimester cause closure of the ductus arteriosus.

● Nitrous oxide interferes with DNA synthesis.

● Single-dose opioids and benzodiazepines are safe.
Long-term use causes withdrawal when the foetus is delivered.

Question 39

f) What additional preoperative and intraoperative steps would
you take to ensure foetal safety if she is 27 weeks pregnant
instead

Answer 39

The foetus is viable as it is at 27 weeks’ gestation.
Preoperatively:

● Discussion with the obstetric team to plan for preterm labour and
delivery.

● Discussion with paediatricians/PICU.

● Consider steroids for lung maturation.

● FHR and FHR variability monitoring. FHR variability is observed from
25 weeks onwards.

● CTG monitoring preoperatively and postoperatively.

Intraoperatively:
● The physiological effects of pregnancy may be more pronounced.

● The presence of obstetricians/midwife on site.

Question 40

d) What steps would you take to avoid foetal hypoxia?

Answer 40

● Avoid maternal hypoxia:
- adequate pre-oxygenation
- anti-aspiration prophylaxis;
- RSI.

● Maintain maternal haemodynamic stability.

● Avoid maternal hypocapnia and hypercapnia
(maintain PaCO2 around 4kPa):

• hypocapnia causes placental vasoconstriction;
• hypercapnia decreases the transfer of CO2 from the foetus to the
  mother across the placental barrier, causing foetal acidosis.

● Avoid hypovolaemia and anaemia.

● Light planes of anaesthesia increase catecholamine secretion —
placental vasoconstriction and hypoperfusion.

● Effective postoperative analgesia —
pain causes placental
vasoconstriction and foetal hypoxia.

● Detection and suppression of premature labour with tocolytics.

Question 41

a) What factors may contribute to difficulties encountered when
securing the airway under general anaesthesia in the pregnant
patient?

Answer 41

Obstetric factors:
● Decreased FRC and increased oxygen consumption —
decreases the safe apnoea time.

● Increased weight gain, large breasts —
difficult laryngoscopy.

● Airway oedema —
a smaller-sized ETT may be required.

● Increased vascularity of the mucosa —
bleeding on airway instrumentation.

● High risk of aspiration.

Human factors:
● Cognitive load — concerns for mother and baby.

● Time restrictions — often an emergency situation.

● Declining frequency of obstetric GA.

Technical factors:
● Remote location of obstetric units.

● Poor access to the airway under the drapes.

● Misplaced cricoid pressure.

Question 42

b) What measures can be taken to reduce airway-related
morbidity and mortality associated with general anaesthesia in
a pregnant woman?

Answer 42

● Assessment of the airway.

● Identify senior help and call for help early.

● Mark the cricothyroid membrane and
call for surgical help if a difficulty is anticipated.

● Adequate pre-oxygenation —
3-4 minutes of tidal breathing or 4-5
vital capacity breaths.

● Ramped up position —
tragus in line with or above the sternal notch.

● Apnoeic oxygenation.

● Anti-aspiration prophylaxis.

● Training staff to be familiar with the
Difficult Airway Society (DAS) guidelines.

● Multidisciplinary team briefing with regard to
waking up the patient
or not after a failed intubation is declared.

Question 43

c) What are the recommendations in the 4th National Audit
Project (Major Complications of Airway Management in the UK,
NAP4) regarding airway management in the pregnant woman?

Answer 43

Obstetric anaesthetists to maintain airway skills including a
difficult/failed intubation and CICV.

● Anaesthetists to be familiar and skilled with rescue secondgeneration
supraglottic airway devices (SADs).

● Department to provide skills and equipment to deliver AFOI
whenever it is needed.

● All staff in the recovery area of a delivery suite must be competency
trained; skills to be regularly updated.

Question 44

Q8 — Mitral stenosis in pregnancy

A 27-year-old woman is 13 weeks pregnant. In the antenatal clinic she is
found to have an asymptomatic heart murmur. A subsequent
echocardiogram shows moderate to severe mitral stenosis.

Question 45

a) List the causes of mitral stenosis (MS).

Answer 45

● Rheumatic heart disease.
● Congenital.
● Diseases affecting multiple systems, e.g. sarcoidosis.
● Infiltrating diseases

Question 46

b) What are the echocardiographic criteria for the diagnosis of
severity of MS?

Answer 46

Mitral stenosis is classified as per:
● Valve area:
- mild MS — 1.6-2cm2;
- moderate MS — 1.5-1cm2;
- severe MS — <1cm2.

● Pressure gradients across the valve:
- mild MS — <5mmHg;
- moderate MS — 6-10mmHg;
- severe MS — >10mmHg.

Question 47

c) What is the normal mitral valve area and at what point does the
patient become symptomatic with MS?

Answer 47

● Normal area = 4-6 cm2.

● The patient becomes symptomatic at a valve area <2cm2.

Question 48

d) What are the cardiovascular changes in pregnancy that could
exacerbate the pathophysiology of MS?

Answer 48

● Increase in heart rate.

● Increased cardiac output.

● Blood volume increases.

● Decreased systemic vascular resistance.

● Pain and anxiety in labour further increase cardiac output.

● Autotransfusion during the second stage.

Question 49

e) How do the cardiovascular changes in pregnancy exacerbate
the pathophysiology of MS?

Answer 49

● Mitral stenosis underfills the left ventricle causing pressure and
volume overload in the pulmonary circulation.

Tachycardia of pregnancy decreases diastolic filling time,
further decreasing left ventricular filling,
increases pulmonary pressures causing pulmonary
congestion.
Pulmonary oedema can develop with AF.

● The fixed cardiac output state of MS results in a worsening of pressure
through the pulmonary circulation and into the right heart.

● Increased blood volume of pregnancy increases preload and
exacerbates pulmonary oedema.

● Because the cardiac output is fixed,
any decrease in systemic vascular
resistance decreases the coronary perfusion pressures.

● The risk of decompensation depends on severity.
Anything worse than moderate disease (valve area <1.5cm2)
frequently results in heart failure,
which usually develops in the second or third trimester
and is progressive.

Question 50

f) What are your cardiovascular goals when she presents in
labour?

Answer 50

● Control of rate and rhythm:
- avoid tachycardia;
- avoid a rapid ventricular response in AF.
● Maintain afterload.
● Avoid an increase in preload.
● Avoid hypoxia, hypercarbia and acidosis as they exacerbate
pulmonary hypertension.

Question 51

g) Outline your management of this patient in labour.

Answer 51

● Early epidural to avoid sympathetic stimulation.

● Establishment of a block gradually to avoid precipitous hypotension.

● Use of alpha-agonists to treat hypotension.

● Nitrous oxide increases pulmonary vascular resistance.

● Assist second stage to cut short labour and limit Valsalva manoeuvre.

● Caution with oxytocin as it decreases SVR and increases PVR.

● Ergometrine is contraindicated as it is a pulmonary vasoconstrictor.

Question 52

h) Explain the mechanism of pulmonary oedema post-delivery.

Answer 52

A sudden increase in preload due to:
● Autotransfusion due to uterine contraction.

● Decompression of the IVC.

Question 53

A 39-year-old multiparous woman is admitted post-term with spontaneous
rupture of membranes and meconium-stained liquor. After an epidural
catheter is inserted, a syntocinon infusion is started as she is in early labour.
She started contracting shortly and the foetal heart rate drops. She
becomes breathless and cyanosed; her blood pressure has dropped.

a) What are the differential diagnoses for this presentation?

Answer 53

Obstetric causes:
● Amniotic fluid embolism.
● Uterine rupture.
● Eclampsia.
● Placental abruption.
● Acute haemorrhage.
● Cardiomyopathy.
● Uterine inversion.

Non-obstetric causes:
● Pulmonary embolism.
● Air or fat embolism.
● Tension pneumothorax.
● Anaphylaxis.
● High spinal/epidural, local anaesthetic toxicity.
● Pulmonary oedema, heart failure, myocardial infarction.
● Sepsis.
● Transfusion reaction.
● Aspiration.
● Respiratory condition exacerbation.
● Intracranial bleed.

Question 54

b) What are the risk factors for an amniotic fluid embolism (AFE)?

Answer 54

● Induction of labour by any method.
● Use of oxytocin.
● Assisted delivery (forceps/ventouse) or caesarean section.
● Maternal age >35 years.
● Multiple pregnancy.
● Polyhydramnios.
● Eclampsia.
● Uterine rupture.
● Cervical trauma.
● Placenta praevia.
● Placental abruption.
● Ethnic minority.

Question 55

c) Describe the pathogenesis of AFE

Answer 55

Exposure of maternal circulation to amniotic fluid
or foetal antigens is a prerequisite.

● There are two main theories —
mechanical and immune-mediated.

● Anaphylactoid syndrome.

● Phase 1 — lasts 30 minutes, entry of amniotic fluid into the
circulation, the pulmonary artery pressure rises, right ventricular
failure, microvascular damage, hypotension. Microthrombi are
formed once DIC develops.

● Phase 2 — left ventricular failure, endothelial activation and leakage,
leading to DIC

Question 56

d) What are the clinical features of AFE?

Answer 56

● Hypotension and foetal distress are identified in all cases of AFE.

● Sudden cardiovascular collapse or cardiac arrest.

●Cyanosis, dyspnoea, seizures, coagulopathy,
pulmonary oedema, ARDS.

● Uterine atony, bronchospasm, cough, headache, chest pain.

Question 57

e) How would you diagnose AFE?

Answer 57

● Clinical symptoms once other causes are ruled out.

● Postmortem — foetal squames or hair in lungs.

Question 58

f) What is the incidence of AFE?

Answer 58

● 1.7 per 100,000 pregnancies.

● The case fatality is 19%.

● 120 cases between 2005 and 2014; UKOSS register.

● Fifth direct cause of maternal mortality (MBRRACE-UK report).

Question 59

g) List the management strategies for AFE.

Answer 59

Supportive management depending on the clinical presentation:

● Senior clinicians should be involved, teamwork,
urgent decision to deliver,
need for critical care support.

● Advanced Life Support® guidelines — ABC.

● Haemorrhage control.

● Coagulation abnormalities to be corrected; involve the senior
haematology consultant

Question 60

a) Describe the pain pathways associated with the first and
second stages of labour.
**

Answer 60

● The first stage of labour:
pain from the uterus,
lower uterine segment
and vagina is transmitted via sensory fibres which accompany
sympathetic nerves and ends in the dorsal horns of T10-L1.

● The second stage of labour:
afferent nerves innervating the vagina
and perineum travel via the pudendal nerve
to dorsal root ganglia of S2-S4.

Question 61

b) Explain how and why the nature of the pain experienced
changes as labour progresses.

Answer 61

● The first stage of labour: visceral pain,
which is poorly localised and
diffuse in nature.

● Pain is felt in the lower abdomen and lumbosacral area.

● The second stage of labour:
somatic pain, which is better localised.

Question 62

c) What dermatomes should be blocked for labour analgesia and
a lower segment caesarean section (LSCS)?

Answer 62

● Labour analgesia — T10-S5.

● LSCS — T4-S5.

Question 63

d) Why is it essential to achieve a higher dermatomal level of
regional block for a caesarean section than for analgesia in
labour?

Answer 63

A higher level of block is required for LSCSs — due to peritoneal traction

Question 64

e) Why do you sometimes observe bradycardia during regional
anaesthesia for a caesarean section?

Answer 64

● Parasympathetic over-activity due to spinal sympathetic block.

● Decreased venous return triggers the
Bainbridge reflex and Bezold-
Jarisch reflex.

● Blockade of cardio-accelerator fibres from T1-T4.

● Surgical manoeuvres, e.g. exteriorising the uterus.

Question 65

f) List any five specific situations in which labour epidurals may be
beneficial.
**

Answer 65

● Pre-eclampsia (without severe thrombocytopenia or coagulopathy).

● High Body Mass Index (BMI).

● Anticipated difficult airway or other risk factors for a general
anaesthetic.

● High risk for assisted vaginal delivery,
e.g. breech or multiple gestation.

● Trial of labour after a previous caesarean section.

● Maternal cardiovascular, cerebrovascular or respiratory disease

Question 66

g) What is puerperal sepsis?
**

Answer 66

Puerperal sepsis is infection of the genital tract occurring at any time
between rupture of membranes or labour and the 42nd day postpartum
associated with two or more of the following:
● Pelvic pain.

● Fever, abnormal vaginal discharge.

● Abnormal smell of discharge.

● Delay in reduction in the size of the uterus.

Question 67

h) Name the organisms implicated in sepsis in the UK.

Answer 67

● Group A Streptococcus.

● Streptococcus pneumoniae.

● Escherichia coli.

● H1N1 influenza virus.

Question 68

i) List the risk factors for sepsis

Answer 68

Obstetric factors:

● During pregnancy:
- amniocentesis;
- cervical suture.

● During vaginal delivery:
- prolonged rupture of membranes;
- prolonged labour;
- vaginal trauma;
- surgical procedures — episiotomy, caesarean section;
- retained products.

Non-obstetric factors:
● Obesity.
● Diabetes.
● Immunosuppression.
● Anaemia.
● Socioeconomic deprivation.
● History of pelvic inflammatory disease.

Question 69

BJA Obesity article

Key Points

Answer 69

• Maternal obesity is increasing worldwide and is associated with adverse outcomes for both mother and baby.
• Multidisciplinary team involvement is vital for managing the parturient with obesity.
• Neuraxial analgesia should be offered early in labour.

*Continuous neuraxial techniques are optimal for Caesarean delivery.

• General anaesthesia poses significant risk in these high-risk patients

Question 70

Maternal complications

Answer 70

Gestational diabetes

Gestational HTN PET

OSA

CVS

VTWE

Infection + Sepsis

Instrumental Delivery
+ Failed

Section

PPH

LOS

Question 71

BJA Extra points

Logistics

Analgesia

Answer 71

1. Logistical planning
   Women with obesity should only have their baby delivered in obstetric units that have services adequate to meet their

including staffing, equipment and accessibility

consultant-led unit with appropriate anaesthesia and neonatal services

Specialised anaesthetic equipment should be readily available, such as difficult airway equipment, US machines, long spinal and epidural needles,

t. An NIBP cuff on the forearm may be used if it is not possible to use an appropriately sized blood pressure cuff on the upper arm.7

Even with appropriate equipment, transporting women with BMI >50 kg m−2 to the operating theatre in the event of an emergency can be challenging

2. Neuraxial

They provide the most effective analgesia with the fewest adverse effects for both mother and baby. Furthermore, with neuraxial techniques, labour analgesia can be readily converted to surgical anaesthesia should the need for CD arise,

accidental dural puncture (ADP) compared with patients of normal BMI (4% vs 1%

An ITC can also be placed to provide continuous labour analgesia. Whilst placement of an ITC is usually only considered after inadvertent ADP, elective placement in women with BMI >50 kg m−2 may be an option for neuraxial analgesia,

3. Other analgesia

Inhaled nitrous oxide and oxygen

Opioids should be judiciously used in parturients with obesity because the incidence of OSA and the risk of respiratory depression are both increased.

Accupuncture and transcutaneous electrical nerve stimulation, could also be considered

Question 72

BJA Extra points

Logistics

Analgesia

Answer 72

1. Logistical planning
   Women with obesity should only have their baby delivered in obstetric units that have services adequate to meet their

including staffing, equipment and accessibility

consultant-led unit with appropriate anaesthesia and neonatal services

Specialised anaesthetic equipment should be readily available, such as difficult airway equipment, US machines, long spinal and epidural needles,

t. An NIBP cuff on the forearm may be used if it is not possible to use an appropriately sized blood pressure cuff on the upper arm.7

Even with appropriate equipment, transporting women with BMI >50 kg m−2 to the operating theatre in the event of an emergency can be challenging

2. Neuraxial

They provide the most effective analgesia with the fewest adverse effects for both mother and baby. Furthermore, with neuraxial techniques, labour analgesia can be readily converted to surgical anaesthesia should the need for CD arise,

accidental dural puncture (ADP) compared with patients of normal BMI (4% vs 1%

An ITC can also be placed to provide continuous labour analgesia. Whilst placement of an ITC is usually only considered after inadvertent ADP, elective placement in women with BMI >50 kg m−2 may be an option for neuraxial analgesia,

3. Other analgesia

Inhaled nitrous oxide and oxygen

Opioids should be judiciously used in parturients with obesity because the incidence of OSA and the risk of respiratory depression are both increased.

Acupuncture and transcutaneous electrical nerve stimulation, could also be considered

Question 73

Peripartum anaesthetic management: CD

Answer 73

neuraxial anaesthesia or GA has been chosen as the primary anaesthetic, all patients with obesity should be placed in the ‘ramped position’ with left uterine displacement

Retraction of the panniculus may be needed for adequate exposure for surgery especially when Pfannenstiel incision is used. Many obstetricians choose to tape the panniculus in the cephalad direction.

Cephalad retraction is associated with aortocaval compression that can lead to maternal hypotension and non-reassuring fetal heart tones

Obesity is a risk factor for surgical site infection after CD.

Advancing a Tuohy needle may be technically easier, and once the epidural space has been located, it can be used as an introducer for the long spinal needle as part of a needle-through-needle CSE technique

More commonly, catheter-based techniques are chosen to deliver extended neuraxial anaesthesia for CD. If a patient has a labour epidural catheter in situ,

General anaesthesia
There are significant risks associated with GA for parturients who are obese. The importance of patient positioning, preoxygenation, presence of adequate personnel and difficult airway equipment cannot be emphasised enough

However, it is advised that lean body weight should be used to calculate initial doses of i.v. induction agents rather than total body weight

By contrast, suxamethonium should be dosed to total body weight because of increased circulating plasma cholinesterase. If non-depolarising neuromuscular blocking drugs are being used on induction of anaesthesia, these should be given based on ideal body weight

as the risk of aspiration exists during this time as well. To minimise risk, the stomach should be decompressed with an orogastric tube and the patient should be awake, obeying commands and able to protect her airway before tracheal extubation. .

ried out with the patient in the head-up position to allow control of the airway and improve respiratory mechanics. If the parturient has OSA, it is advised to commence CPAP immediately to avoid airway obstruction and hypoxia

Question 74

Maternal Critical Care

Answer 74

Peripartum women should receive high-quality critical care provision irrespective of their location.

Close working between the critical care and maternity teams is essential.

Checklists and local standard operating procedures can be helpful when a maternity patient is admitted to critical care.

Every effort should be made to keep mother and baby together.

Women can sustain psychological injury through birth trauma and critical illness.

Question 75

Maternal Critical care checklists

Within 1 h

Answer 75

Alert poster

Airway alert poster

Obs consultant

CMM

Neonatal resuscitaire in unit

Delvery pack and crash section trolley

Question 76

Maternal Critical care checklists

Within 12h

Answer 76

Consultant bedside review
fetal compromise
?need for fetal monitroing

involve link midwife

Medical speciality referall?

Surgical review

Crit care pharmacy
CC dietician

NOK

Proteinuria?

Breastfeeding review

Question 77

During crit care

Answer 77

Senior clinician review

Psychology referall?

Midwifery input

Contact mother baby

breast milk expression as desired

Question 78

Equipment

Answer 78

Intubation
Short handled laryngoscope
Sodium citrate
Ramp (e.g. Oxford pillow)

Birth/review
Neonatal resuscitation equipment
Caesarean section equipment tray
Speculum
Uterotonic drugs
(oxytocin, ergometrine, carboprost, misoprostol)

Fetal assessment Fetal Doppler
Breastfeeding & psychological care Breast pump
iPad (FaceTime)
Patient/baby diaries
Digital or instant camera/memory card

Question 79

Challenges airway breathing

Answer 79

Aspiration –
assume a full stomach even if starved H2RA or PPI i.v. in anticipation
Aspirate nasogastric tube (if in situ)
Sodium citrate 0.3 M solution –
give 30 mmol immediately before induction
Head-up tilt
Cricoid pressure
Limit any facemask ventilation to non-excessive pressures using airway adjuncts as required

Desaturation – decreased FRC, increased oxygen consumption
Consider high flow humidified nasal oxygen for preoxygenation (CAUTION – worsens aerosol generation if concerns of infection)
Modify RSI to include manual ventilation with cricoid pressure in respiratory failure

Difficult intubation Follow OAA-DAS guideline and make a plan for failed intubation and failed oxygenation
Ensure appropriate equipment including short handled laryngoscope
Ensure optimal positioning including ‘ramp’ for patients with high BMI
Ensure appropriate help and difficult airway equipment available

Intracerebral haemorrhage – stimulatory effects of direct laryngoscopy (pre-eclampsia)

Ensure BP well controlled before induction and modify RSI to use fast onset opioid (e.g. alfentanil) as a coinduction agent

yngeal oedema If laryngeal oedema is present then a smaller endotracheal tube may be required.∗

Aortocaval compression (pregnant) Ensure manual displacement or left lateral tilt in place when patient is supine
Vasopressor/vagolytic drugs immediately available

Question 80

Circulatory support

Answer 80

he first intervention for any new episode of maternal hypotension should be to exclude aortocaval compression by using the full left lateral decubitus position

. The onset of supine hypotension may be delayed and nausea is a common warning sign.

Vasopressor drugs alter uterine blood flow but this risk is outweighed by the requirement to resuscitate the mother. Invasive monitoring is essential as severe sudden increases in blood pressure can increase the risk of placental abruption.

Noradrenaline (norepinephrine) is recommended as the first-line agent.15 Arginine vasopressin is uterotonic and is consequently not used first line in pregnancy.

Adrenaline (epinephrine) is tocolytic and can cause fetal dysrhythmias, but its use in pregnancy is well established for resuscitation.

Question 81

Drugs

Answer 81

Both propofol and midazolam infusions are used, though midazolam can cause neonatal withdrawal if used for extended periods of time. Dexmedetomidine has also been used successfully but toxicity has been reported in animal studies: it can be used after a risk-benefit assessment

Neuromuscular blocking agents do not cross the placenta in significant amounts.

Paracetamol is safe to use. Non-steroidal anti-inflammatory drugs should be avoided after 30 weeks of gestation (they cause closure of the ductus arteriosus). Codeine phosphate should be avoided in breastfeeding because of unpredictable maternal metabolism and overdose risk in the infant; dihydrocodeine can be used with caution.

t are associated with respiratory depression in the neonate and as with midazolam there is a risk of neonatal withdrawal after prolonged usage

Question 82

Imaging

Care bundles

Answer 82

t. A CT scan of the pelvis typically results in a fetal dose of 10–50 mGy, which is not associated with miscarriage or teratogenesis, but there may be a small increased risk of malignancy.

Care bundles and nutrition
Pregnancy confers an additional risk of thromboembolic disease (over and above critical illness) extending for 6 weeks after

Conventional care bundles for stress ulcer prophylaxis and prevention of ventilator-associated pneumonia should be used. Both proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2RAs)

The relative energy, protein and micronutrient requirements are altered, and depend on gestation and underlying illness. The readily available ‘complete’ enteric feeds are not tailored to pregnant women. Expert advice from a dietician is recommended.

Question 83

The fetus

Answer 83

absence of a specific obstetric indication, continuous cardiotocography (CTG) monitoring is not used outside of labour, but it is common for obstetricians to operate a twice-daily routine CTG assessment when women have been admitted to critical care

CTG trace may also be indicative of compromised maternal physiology and optimisation of the mother can improve fetal physiology

Where fetal distress does not resolve, delivery needs to be arranged as an emergency, but should not endanger the life of the mother. In the meantime, fetal resuscitation should be undertaken:

1.
Stop oxytocin infusion (if in progress)
2.
Full left lateral decubitus position
3.
Tocolysis (terbutaline or glyceryl trinitrate spray)
4.
Improve cardiac output, correct hypotension – fluid bolus ± vasoactive agent
5.
Increase oxygen tension at placenta – give oxygen

ICU Delivery

1.
Environment: large side room
2.
Personnel: neonatal, obstetric and midwifery team aware of the patient’s location
3.
Equipment: specified by the neonatal and obstetric teams and may include: CTG monitor, Caesarean tray, neonatal resuscitation kit ± Resuscitaire
4.
Drugs: uterotonic drugs must be available

Question 84

Maternal Critical Care
Specific conditions

Answer 84

Multiple comorbidities in pregnant women can be more challenging to manage in critical illness.

Close working between the critical care, other specialist, and maternity teams is essential.

Maternal admissions to critical care result most frequently from major obstetric haemorrhage, sepsis, and pre-eclampsia.

Non-obstetric causes of deterioration should always be considered.

Question 85

Causes for obstetric haemorrhage—‘the 4 Ts’

Answer 85

Tone
Uterine atony
Haematoma

Trauma
Laceration
Inversion, uterine rupture, or both

Tissue
Retained tissue
Invasive placenta

Thrombin
Coagulopathy

Question 86

Uterotonic drugs used in PPH.

Answer 86

1. Oxytocin
   Syntocinon

2.Ergot alkaloids

3. Prostaglandin analogues

Question 87

1. Oxytocin

Answer 87

5 U i.v. or i.m.
Myometrial contraction

Onset within 1 min i.v. (4 min i.m.). May be repeated to total 10 U followed by infusion (e.g. 40 U over 4 h)

Causes transient hypotension, arrhythmias, and nausea. Structurally similar to antidiuretic hormone: causes water retention and hyponatraemia

Question 88

2.Ergot alkaloids

Answer 88

Ergometrine

250–500 μg i.m.

I.V. injection slowly with caution
Vasoconstriction and myometrial contraction

Highly emetogenic—give antiemetic.

Causes hypertension (can be severe),
coronary vasospasm, and pulmonary hypertension.

Avoid in PET, hypertension, coronary disease, aortopathies, aneurysms

Question 89

3. Prostaglandin analogues

Answer 89

1. Carboprost (e.g. Hemabate) 250 μg i.m.
   Prostaglandin F2α agonist:
   myometrial contraction

May only be given i.m. Dose of 250 μg may be repeated eight times at 15 min intervals.

Prostaglandin analogues can cause bronchospasm but may be given in asthma with atonic bleeding because of threat to life. Cause severe diarrhoea, hyperthermia, rash, dizziness
___________________________________

2. Misoprostol

600 μg per rectum
Prostaglandin E1 agonist: myometrial contraction and cervical relaxation See note above regarding unwanted effects in prostaglandin analogues

Question 90

MOH

Risk increased

Normal losss

MOH?

Answer 90

Uterine blood flow at term is 600–900 ml min−1. Uncontrolled bleeding from the uteroplacental bed is the commonest cause of maternal death worldwide and it is the most frequent obstetric reason for admission to critical care

Emergency Caesarean section,
prolonged labour,
multiple pregnancy,
polyhydramnios, macrosomia, obesity, intrapartum sepsis, and uterine inversion are all associated with an increased risk

Blood loss of ≤500 ml after a vaginal delivery or ≤1000 ml after Caesarean section is considered normal.

f MOH and while a loss of ≥1500 ml is commonly suggested for convenience

Question 91

If drugs fail

Answer 91

Uterine-preserving interventions include

arterial ligation,

B-Lynch compression sutures,

uterine packing and

uterine balloon tamponade.

Timely hysterectomy should be performed if necessary to save life

MOH is anticipated (morbidly adherent placenta) prophylactic bilateral placement of arterial balloon catheters before Caesarean section may be uterus-preserving

Resuscitative endovascular balloon occlusion of the aorta (REBOA) does not require radiological expertise

Question 92

Sepsis

Answer 92

The physiology of normal pregnancy and response to labour may mask the presence of sepsis. Intrapartum, women may be tachypnoeic with increases in temperature, white cell count, and lactate even in the absence of infection. Assessment by the multidisciplinary team (MDT) with close attention to physiological trends and a high index of suspicion. Delirium is an ominous sign in maternal sepsis; it is seen infrequently in the labour suite and may be misdiagnosed as puerperal psychosis.

‘Maternal sepsis is a life-threatening condition defined as organ dysfunction resulting from infection during pregnancy, childbirth, post-abortion, or postpartum period.

The maternal sepsis bundle should be initiated without delay

Fluid resuscitation of 30 ml kg−1 may be deemed excessive, especially peripartum, as the maternal circulation is vulnerable to fluid overload. Reassessment after each 500 ml is prudent

t. Special care should be applied in the context of comorbid PET. Vasopressor therapy may be needed concurrently with resuscitation with i.v. fluids. Noradrenaline (norepinephrine) is the first-line agent. A target MAP of ≥65 mmHg applies to non-pregnant patients, but is nevertheless a reasonable starting point

Obstetric infections are usually polymicrobial and initial antimicrobial therapy must cover both Group A Streptococcus and E. coli

bstetric sites of infection include retained products of conception, chorioamnionitis, endometritis, pelvic abscess, and wound infection

Question 93

PET

Answer 93

new-onset hypertension after 20 weeks’ gestation associated with proteinuria, evidence of end-organ involvement, or utero-placental dysfunction

. A protein-creatinine ratio of ≥30 mg mmol

PET can rapidly progress from a ‘mild’ condition to one with severe end-organ

A diagnosis of ‘PET with severe features’ is made if the patient has a systolic BP (SBP) ≥160 mmHg or any of the following features: cerebral involvement (e.g. headache, visual disturbance, or altered mental state), an otherwise unexplained severe right upper quadrant pain, serum transaminases more than twice the normal limit, platelets less than 100×109 L−1, progressive renal insufficiency, or pulmonary oedema.

Question 94

PET RX

Answer 94

The treatment of PET is delivery of the placenta. It should be noted that PET is frequently diagnosed after birth and can persist and worsen initially before resolvin

Supportive measures
In the context of PET, a BP of 160/110 mmHg is an obstetric emergency. The goal of treatment is to aim for a SBP of <140 mmHg: it is systolic pressure that is associated with adverse endpoints such as intracerebral haemorrhage. SBP≥180

symptoms such as headache may be seen as BP improves. Infusion of an antihypertensive agent is usually considered an indication for invasive monitoring of arterial BP

Question 94

PET RX

Answer 94

The treatment of PET is delivery of the placenta. It should be noted that PET is frequently diagnosed after birth and can persist and worsen initially before resolvin

Supportive measures
In the context of PET, a BP of 160/110 mmHg is an obstetric emergency. The goal of treatment is to aim for a SBP of <140 mmHg: it is systolic pressure that is associated with adverse endpoints such as intracerebral haemorrhage. SBP≥180

symptoms such as headache may be seen as BP improves. Infusion of an antihypertensive agent is usually considered an indication for invasive monitoring of arterial BP

Question 95

Antihtn in PET

Answer 95

Hydralazine
Y Y
Maternal hypotension and tachycardia.

Adequate hydration before administration is important

Labetalol Y Y Y Nausea (4.1%)

Dizziness (4.1%)

Nifedipine MR Y

Headache (5.4%), maternal tachycardia (4.1%), dizziness (2.7%)

Question 96

PET emergencies—therapeutic options and considerations

Answer 96

Pulmonary oedema

Conventional supportive management including oxygen, diuretics and where necessary CPAP

Once stabilised expedite delivery

Neuraxial anaesthesia preferable where possible Most cases of PET pulmonary oedema are postpartum

Differential diagnoses:

1. Acute coronary syndrome (e.g. related to spontaneous coronary artery dissection)
2. Peripartum cardiomyopathy
3. Overzealous fluid administration (common)
4. Tocolytic use
5. Lung injury (e.g. transfusion/infection/ARDS)

Hypertensive encephalopathy:
*
Cerebral oedema
*
Intracranial haemorrhage

Supportive management and urgent optimisation of BP control

Magnesium infusion as eclampsia prophylaxis in all symptomatic PET

Cortical blindness is managed by controlling and optimising the BP

Differential diagnoses: metabolic abnormalities, drugs, infection, and cerebral venous sinus thrombosis

Eclampsia A 4 g loading dose of magnesium sulphate (MgSO4) followed by an infusion 1–2 g i.v.a

aAKI: halve the infusion dose.

Give additional bolus of MgSO4 should the woman have a fit while on MgSO4.

If refractory to MgS04 give antiepileptic drugs (e.g. benzodiazepines, levetiracetam) 1% Risk of recurrence of eclampsia in a future pregnancy

Subcapsular liver rupture Stabilise and contact nearest liver unit Subsequent pregnancies are infrequently complicated by HELLP (2–19%)