Obstetrics

Front 1

Analgesia for Labour

Back 1

1. Epidural
2. CSE
3. PCA
a. Fentanyl
b. Remifentanil
4. Nitrous
5. Non-pharmacological techniques

Front 2

Contraindications to Epidural

Back 2

1. Patient refusal
2. Untrained staff
3. Local or general sepsis
4. Hypovolaemia
5. Coagulation disorder
6. Concurrent treatment with anticoagulant drugs

Front 3

Coagulopathy especially thrombocytopenia

Back 3

1. Few studies
2. Pre-eclampsia
a. Not just decreased number but function as well.
b. Rapid changing
c. < 50 definitely no
d. 50-100 grey zone
3. Grey zone: risk and benefit of procedure discuss with patient and consent.

Front 4

Anticoagulant & Epidural

Back 4

1. LMWH
a. Therapeutic 24 hours
b. Prophylaxis 12 hours
c. Consider factor Xa assay especially poor renal function wait till normal levels
2. Heparin (UFH)
a. Consider APTT
b. Usually 6 hours is fine
3. Warfarin
a. INR < 1.3
4. Low dose aspirin: ok
5. Supplements: clinical bleeding stop for > 1 day

Front 5

Spina bifida

Back 5

1. Group of disorders that are characterised by failure of development of vertebral arches and abnormal development of structures derived from the neural tube and the meninges.
2. Neural tube defect: congenital anomaly and abnormal closure of the neural tube
3. Abnormal innervation of the organs supplied by the affected part of the spinal cord
4. Multiple organ involvement: effects on the bladder and bowel and denervation of muscles and sensory organs.

Front 6

Neuraxial block and Spina bifida

Back 6

1. Epidural increase risk of dural puncture
2. Not to insert at the level of defect usually above the defect
3. Some may have obliterated epidural space: poor spread of epidural
4. Risk of excessive cranial spread
5. Spinal cord tethering: spinal cord may end lower than usual. MRI to confirm level and spinal not as safe.

Front 7

Epidural Back surgery

Back 7

1. Adhesion may hinder spread of epidural

Front 8

Epidural fetal death in utero

Back 8

1. DIC possible but very uncommon
2. FBE, PLT, fibrinogen

Front 9

Epidural and multiple sclerosis

Back 9

Multiple sclerosis is a demyelinating disease of the central nervous system. Exacerbations can be triggered by infection, emotional trauma, injury and pregnancy. Relapses associated with pregnancy > 50% occurs in postpartum period.
1. Local toxicity on demyelinated nerve: lower concentrations
2. Epidural less risk than spinal as the concentration in the white matter in spinal cord would be less.
3. Avoid adrenaline containing solutions

Front 10

Increased ICP neuraxial block

Back 10

1. Increased dural puncture
2. Increased leak
3. CSF flow → coning

Front 11

Hypovolaemia neuraxial block

Back 11

It is one of the contraindications

Front 12

Consent for Epidural during labour

Back 12

1. College guideline: clearly states not to perform procedure until consent is given.
2. Editorial by Dr M Paech AIC 2005 commented obligation to do good. Patient is in pain and a retrospective consent is adequate.

Front 13

First thing to say in performing an epidural (in exam)

Back 13

After first ensuring I have adequately trained assistant, emergency drugs and equipments are readily available and IV access has been secured, I would….

Front 14

PCEA vs Infusion

Back 14

Both works
PCEA uses less drugs and probably less motor block.
Require patient motivation

Front 15

COMET trial

Back 15

Epidural use
High concentration bupivacaine 0.25% has increased instrumentation assisted delivery
Low concentration bupivacaine 0.125% has no increased instrumentation rate.

Front 16

Blood in epidural catheter

Back 16

Withdrawal and repeat if < 3.5 cm left in space

Front 17

Dural puncture

Back 17

Consider leaving catheter intrathecal
1. ↓ PDPH only in one small study and no other study was able to reproduce it.

Front 18

Unilateral block, patchy block

Back 18

1. Pull catheter back to 4 cm
2. Proper bolus (5 + 5 mL of bupivacaine 0.25% bupivacaine)
3. Replace if ineffective

Front 19

CSE vs Epidural

Back 19

Cochrane review 2007
1. Little difference
2. Faster onset with CSE 5 vs 15 mins
3. More itch with CSE

Front 20

Fentanyl PCA

Back 20

Useful in setting of contraindications to neuraxial block
Titrate loading usually 50-200 mcg
Bolus of 20 mcg lockout 3-5 mins
Not as good as epidural better than nothing

Front 21

Remifetanil PCA

Back 21

Safe but
Many episode of apnoea
Optimal dose regime not clear
1. 40-50 mcg bolus 1-2 min lock out
2. May be better with background + PCA
Kinetic is still not fast enough
1. Average contraction 70 secs
2. Remi onset 1.2 mins

Front 22

Nitrous oxide

Back 22

Safe
Little effect on physiology of labour
Quickly reversed after cessation
Simple and inexpensive
Self administered
Often effective

Front 23

Non-Pharmacological

Back 23

Continuous one to one support decreases analgesic use, operative delivery rates and dissatisfaction
Acupuncture decrease need for pain relief
Women taught self hypnosis had decreased pharmacological requirements
The efficacy of acupressure, aromatherapy, audio-analgesia, relaxation or massage has not been established

Front 24

Why regional for C-sections

Back 24

1. Mother direct death due to anaesthesia lower with regional from UK data 2000-2002
2. Baby
a. Higher Apgar score at 1 and 5 mins
b. Less acidaemia from umbilical artery blood

Front 25

Which regional technique SSS vs CSE

Back 25

SSS
1. Overdose for almost 50%
a. Hypotension
b. Nausea
2. Failure
a. 2-3%
3. High block: 0.2%

CSE
1. More expensive more than $20 extra
2. Technically more difficult and slower
3. Can choose have less in the spinal
a. Avoid hypotension
b. Less nausea
c. Cardiac patients
4. Rescue available if spinal inadequate: untested catheter

Front 26

When to use CSE

Back 26

1. Difficult to predict dose
a. Extremes of height
b. Long surgery
2. Previous failed regional
a. Too much or too little
3. Haemodynamic stability important (GA preferred for AS and MS)

Front 27

Which vasopressor for C-section

Back 27

1. Sheep data 1974
a. Metaraminol increase bradycardia
b. No fetal acidosis
2. Human Can J Anaes 2003 A &A 2003 and Anaesthesiology 2001
a. Metaraminol consistently better than ephedrine at maintaining BP within normal limits.
b. Ephedrine associated with more fetal acidosis
c. Metaraminol effective as bolus and infusion
d. Less nausea and vomiting

Front 28

Issues with C-section

Back 28

1. Anaesthetics
a. Pain
i. Test block always
ii. Option of GA unless contraindicated
b. Hypotension
i. Fluid, metaraminol, ephedrine, glycopyrrolate
c. Nausea
i. Treat hypotension
ii. 5HT3 blockers effective even with ergometrine
d. High block
i. Reassurance
ii. Unable to lift arms: prepare to tube
2. Surgical
a. Haemorrhage
i. Observe packs, suction, field
b. Plan
i. Call for help early
ii. Begin transfusion early
iii. Suggest hysterectomy
iv. Recombinant factor VII

Front 29

Drugs for Uterine Atony

Back 29

1. Oxytocin
a. Watch for vasodilatation
b. > 40 units not efficacious
2. Misoprostil
a. PR/PV intrauterine 600-1200 mcg
b. For after c-section not acute bleeding
3. Ergometrine
a. Vasoconstriction, nausea give in increments
4. PGF2
a. Hypertension, bronchospasm, nausea
b. Dilute ampoule 5 mg to 10 mL 1 mLs at a time maximum of 3 mg (6 mL)

Front 30

Surgical treatment for urine Atony

Back 30

1. B-Lynch suture
2. Bakri balloon
3. Hysterectomy
4. Radiological embolisation
5. Uterine/Internal iliac artery ligation
6. Look for other source of bleeding

Front 31

Obstetric & Recombinant Factor VIIa

Back 31

Useful in medical bleeding DIC (not useful for surgical bleeding)
Bypasses much of clotting cascade
Still need platelets and fibrinogen: transfuse platelets and cryo prior
Dose 90 mg/kg ($5000)
Yet to have definitive indication and be aware of possible thrombotic complications

Front 32

Propofol and Obstetrics

Back 32

1. Worse neurobehavioural scores
2. Lower APGAR score than thiopentone
3. Safe for breast feeding 0.027% enters breast milk.
4. Insufficient evidence for increased awareness
5. Faster wakening than thiopentone
6. Less PONV: no studies in caesarean section

Front 33

Narcotics

Back 33

1. Parental opioid in mother is associated with lower APGAR score and neonatal respiratory depression
2. Alfentanil more rapidly crosses to the neonate
a. Unknown clinical relevance

Front 34

Failure to intubate in Obstetrics

Back 34

1 in 239 to 1 in 750
8-10 times more likely than in the non-obstetric patient
Often only 10 GA CS/year → 1 in 10 years
1. False sense of security
2. Corner cutting in preparation for GA
3. Inadequate preparation for emergency response

Front 35

Non Obstetric Surgery in Pregnant Patient Issues

Back 35

Teratogenesis
Drugs effect on foetus
CTG monitoring
Laparoscopy
Pre-term labour

Front 36

Teratogenesis

Back 36

Occurs mostly during organogenesis 15-56 days
Majority of anaesthetic drugs are safe: nitrous may not be safe

Front 37

Other Drug Effects

Back 37

NSAIDs:
1. > 32 weeks can cause premature closure of ductus arteriosus closure especially > 48 hours use
2. Useful as tocolytics agents
Beta-blockers
1. Well slow fetal heart rate as well
Ketamine
1. May cause uterine contraction
2. 2 mg/kg increase uterine pressure as much as ergot

Front 38

CTG monitoring

Back 38

1. Can start from 18 weeks
2. Variability start at 25 weeks
a. Reduced variability with GA
3. Allow monitoring for bradycardia
a. No evidence to improve outcome

Front 39

Laparoscopy

Back 39

1. CO2 and fetal acidosis only animal studies
2. No difference to fetal outcome
3. Usually easier to manage mother after laparoscopy compared to laparotomy

Front 40

Preterm Labour

Back 40

1. More common after intra-abdominal surgery ~ 5%
2. Increase with uterus manipulation or infection
3. Efficacy of tocolytics agents not proven: not recommended for routine prophylaxis
4. Monitor for pre-term labour post op: consider tocolytics if labour begins

Front 41

Pre-Eclampsia

Back 41

1. This is a medical condition of pregnancy causing multiorgan dysfunction with a triad of hypertension, proteinuria and non-dependent oedema
2. Aim to identify those with low platelets and risk of seizures
3. Difficult to identify clinically
a. Many are investigated and treated will not have progression of disease

Front 42

Low platelet in PIH

Back 42

1. No real safe level
2. Condition can be progressive
3. May need to proceed to GA LSCS if time critical

Front 43

Magnesium for Pre-eclampsia

Back 43

1. 58% reduction in seizures in treatment group vs placebo (Magpie)
a. NNT 91 for all pre-eclampsia
b. NNT 61 for severe
c. NNT 105 for mild
2. Better than Phenytoin and diazepam at preventing 2nd seizure in eclampsia
a. 52% less than diazepam
b. 67% less than Phenytoin

Front 44

HELLP Syndrome

Back 44

1. Haemolysis, elevated liver enzymes, low platelets
2. Often don’t have other signs of pre-eclampsia: first sign seizure
3. RUQ: think subcapsular hematoma
4. Clotting defect can be profound

Front 45

Preeclampsia and Eclampsia Specific Recommendation

Back 45

1. Treat BP > 160 mmHg systolic
2. Induction anticipate increase BP: i.e. give opioid
3. Avoid ergometrine

Front 46

Gestational Diabetes Issues

Back 46

1. Large baby
a. Likely CS
b. Likely PPH
2. Post-operative insulin rarely required
3. Ideally early on the list
4. 5% develop NIDDM

Front 47

Placenta praevia

Back 47

1. 15-20% of APH
2. Location: anterior or posterior
3. Negotiate with patient and surgeon
a. GA if anterior
b. Regional possible if posterior

Front 48

Placenta Accreta

Back 48

1. Generally require hysterectomy
2. 10% of praevia
3. Increase with repeated CS
4. GA only

Front 49

Placenta abrupion

Back 49

1. Early separation of placenta
2. 20-25% of APH
3. Bleeding can be concealed
4. Fetal distress if > 30%
5. Coagulopathy chance is high

Front 50

Cardiac disease in pregnancy

Back 50

1. Multidisciplinary approach: O&G, ICU, Anaesthetic, cardiology
2. Tertiary centre with ICU available
3. Invasive monitoring: labour in ICU or CCU
4. Vaginal delivery generally preferred
a. Less blood loss
b. Except aortic dissection and Marfans with dilated aortic root
5. Avoid sudden changes in pre and afterload
a. Gentle regional
b. Autotransfusion
c. Oxytocin

Front 51

Mitral Valve Disease

Back 51

1. Mitral Stenosis most common rheumatic valve lesion
2. Hypervolaemia
a. ↑ CO
b. Tachycardia
c. Worsen LA dilatation
3. Precipitate Atrial fibrillation → cardiac failure
4. Mitral valve area best prognostic factor for pulmonary oedema
a. 1:4 mild > 1.5 cm
b. 1:3 moderate 1~1.5 cm
c. 1:2 severe < 1 cm
5. Functional status have been associated with mortality
a. Stress ECHO
b. Pregnant woman: SOB often
6. Mitral valvuloplasty can be performed in the pregnant patient

Front 52

Marfan’s Syndrome

Back 52

1. Hyperdynamic circulation causing aortic root distension and dissection
2. Most patient beta blocked
3. Serial ECHO: aortic root > 5 cm consider delivery
4. Avoid straining
a. Vaginal birth possible if aortic root < 4 cm
5. Maternal mortality decreased from 30% to 1% over the last 30 years

Front 53

Pulmonary Hypertension

Back 53

1. Maternal mortality 30-50%
2. Don’t get pregnant
3. Greatest risk is week post delivery
a. Increase pulmonary emboli risk
b. Exaggerated pulmonary vascular reactivity
c. Decline myocardial contractility in presence of decreased filling state
4. Management
a. Pulmonary vasodilatation

Front 54

Multiple Sclerosis

Back 54

1. Relapse after delivery not uncommon: 50% increase in relapse rate compare with unpregnant state.
2. Not increased by epidural
3. High concentration of local may be associated with increased relapse.

Front 55

Von Willebrands disease

Back 55

Incidence 1:1000
Usually improve with pregnancy
Discuss with haematologist
DDAVP only beneficial in type I (0.3 mcg/kg)
1. Use to perform epidural?
2. Reserve for bleeding because of tachyphylaxis?

Front 56

HIV in pregnancy

Back 56

1. Prelabour caesarean section dramatically reduces vertical transmission in many groups.
2. Both GA and regional are relatively safe
3. Unknown whether blood patch is safe
4. Surveillance for other organ involvement
a. Respiratory infection
b. Cardiomyopathy
c. Neurological disease

Front 57

Resuscitation of Pregnant Woman Differences

Back 57

BLS
1. Left lateral tilt
2. CPR performed higher on the chest
3. Add cricoid pressure
ALS
1. Intubate early
2. Avoid the use of femoral and lower limb veins
3. Consider specific disease of pregnancy
4. Drug and defibrillation dose are the same
5. If doing CPR find scalpel! Perimortem CS within 5 mins of maternal arrest
a. 2/3 improves

Front 58

Magnesium toxicity

Back 58

Normal 0.7 -1.0
< 0.5 tetany seizure, arrhythmia
0.5-0.7 neuromuscular irritability
1.0-2.1 normal range
2.1-2.9 Lethargy, drowsiness, N/V, reduced deep tendon reflexes
2.9-5.0 somnolence, loss of deep tendon reflexes, hypotension and ECG changes
> 5.0 complete heart block, arrest, apnoea, paralysis

Front 59

Magnesium toxicity ECG changes

Back 59

1. Increased PR and QT intervals
2. Increased QRS
3. Variable decrease in P-wave voltage
4. Variable degree of T-wave peaking
5. Complete AV block, asystole

Front 60

Treatment for Magnesium toxicity

Back 60

1. Calcium
a. 5-10 mEq IV and repeated doses may be required
2. Remove ongoing source and increase elimination (dialysis, frusemide).