antenatal and intrapartum analgesia

Question 1

outline the pain pathway in the 1st stage of labour

Answer 1

pain signals from uterine contractions and cervical dilation are carried via sensory nerves to T10- L1 spinal cord segment

Question 2

outline the pain pathway in the 2nd stage of labour

Answer 2

pain from the distension of the perineum and the stretching of the pelvic ligaments is carried via the pudendal nerve to S2/S4

Question 3

outline the pain pathway in the 2nd stage of labour

Answer 3

pain from the distension of the perineum and the stretching of the pelvic ligaments is carried via the pudendal nerve to S2/S4

Question 4

List the dermatomes that need to be anaesthetised for the different procedures that may need to be performed during labour

Answer 4

Epidural for labour - T10-S4
trial of forceps - T5-S4
C/S - T5- S4
MROP - T6-S4
Cervical/vaginal repair.- S2-S4
perineal repair - S2-S4

Question 5

what are 3 common misconceptions regarding the risk of epidural in labour?

Answer 5

No association with a prolonged first stage
No increased rates fo C/S
No long term back problems

Question 6

List some common side effects of an epidural

Answer 6

opiate itch, shivering

Question 7

what are 2 unfavourable obstetric outcomes associated with an epidural?

Answer 7

prolonged 2nd stage

increased instrumental delivery rates

Question 8

List 2 Relative contraindications to regional anaesthesia

Answer 8

• Risk of significant haemorrhage

- h/o spinal surgery with spinal anatomical abnormalities

Question 9

List 3 contraindications for regional anaesthesia:

Answer 9

• Coagulopathy (platelets <80, INR >1.4)
  
  • Systemic infection due to risk of seeding infection
  • Lack of trained staff to provide adequate care
    Maternal refusal

Question 10

Describe the cause of a post epidural headache

Answer 10

• Puncture of the dura mater allowing CSF to leak out of the vertebral canal
  If the rate of leakage is greater than the rate of CSF production then the CSF volume will actually falling causing the headache

Question 11

List 3 groups of women who are particularly at risk from a GA and explain why

Answer 11

• Women with PET - surge in BP from tracheal intubation can lead to intracranial haemorrhage
  
  • Women with high BMI - higher risk of failed intubation and aspiration
    Women with known airway difficulty - higher risk of failed intubation

Question 12

List 3 reasons why an anaesthetist might use general rather than regional anaesthetic?

Answer 12

• Multiple failed attempts at a regional block
  
  • Contraindications to regional anaesthetics e.g. coagulopathy
    Maternal refusal for regional analgesia

Question 13

Describe the treatment options and evidence for post epidural headache

Answer 13

• Conservative - mild PDPH can be managed using bed rest and simple analgesia. Caffeine has been used classically however no high quality evidence for its use - patients who normally drink caffeine should be encouraged to do so as they otherwise may develop a caffeine withdrawal headache
  Surgical - epidural blood patch - injection of a patients own blood through a needle into the epidural space - to create a clot that patches up the dural puncture.

Question 14

List 3 complications of labour analgesia associated with obesity

Answer 14

• Multiple attempts at regional anaesthesia
  
  • Higher rates of dural puncture
    Epidural migration into fatty subcutaneous tissue

Question 15

What is the time frame required before regional anaesthesia is safe following:
Prophylactic dose clexane

Answer 15

12 hours

Question 16

What is the time frame required before regional anaesthesia is safe following:

Answer 16

Therapeutic dose clexane - 24 hours

Question 17

In a patient with PET what measures should be taken prior to regional anaesthetic placement?

Answer 17

• Platelet count in the last 6 hours in mild/moderate PET
• In severe PET - platelet count immediately prior to insertion
• If platelet count < 100 then coags should also be done

Question 18

List 2 evidence based (Cochrane evidence) forms of analgesia in labour

Answer 18

• Epidural
• CSE
• Entonox

Question 19

List 2 methods of analgesia that MAY work in labour (Cochrane evidence)

Answer 19

• water

- massage

Question 20

List 2 methods of analgesia with inadequate evidence to make a judgment (according to Cochrane review) as to their efficacy in labour

Answer 20

• TENS

- Hypnosis

Question 21

List 3 obstetric interventions that may reduce the risk of instrumental delivery during labour with an epidural?

Answer 21

• 1:1 midwifery support in labour
• oxytocinon augmentation
• passive decent for up to 2 hours in nulliparous - leads to fewer rotational and mid cavity instrumentals
• manual rotation

Question 22

What is the evidence regarding maternal satisfaction associated with epidural pain relief in labour?

Answer 22

there is level 1 evidence that epidural and CSE are preferable to women when cf any other form of pain relief in labour

Question 23

List one adverse outcome associated with epidural analgesia when cf systemic opiate use in labour?

Answer 23

• increases the 2nd stage slightly

Question 24

List 5 benefits using epidural analgesia when cf opiate analgesia in labour?

Answer 24

• less nausea and vomiting
• more effective pain relief
• reduced risk of fetal acidosis
• reduced risk of neonatal naloxone

Question 25

List an anaesthetic intervention that has been shown to reduce rate of instrumental delivery?

Answer 25

lower concentration of local anaesthetic in epidural

Question 26

what is the risk with NSAID use in pregnancy?

Answer 26

• even short term use in the third trimester is associated with premature closure of the ductus arteriosus

Question 27

a woman presents concerned that she has heard that Panadol use in pregnancy leads to childhood asthma, what would you tell her?

Answer 27

Retrospective epidemiological studies linking paracetamol use in pregnancy to later development of childhood asthma are inherently confounded (U); when adjusted for respiratory tract infections in the child the association is lost (Q) (Level III-2 SR)

Question 28

List 3 interventions for low back and pelvic pain and indicate the evidence for these interventions

Answer 28

exercise - reduces low back and pelvic pain level 1 evidence
manual therapy - reduce intensity of pain when cf relaxation but not when cf sham intervention level 1 evidence
the use of pelvic support belt may reduce pelvic girdle pain (clinical expertise and expert opinion)