Obstetrics

Question 1

What are the non-medical pain relief options avaliable in labour?

Answer 1

• Antenatal class preperation - relaxationand breathing
• Immersion in water (body temp)
• Mobilisation
• TENs
• Hypnotherapy
• Acupuncture
• Localised pressure on back
• Superficial heat or cold application
• Massage/aromatherapy

Question 2

What are the inhalational agents avaliable for labour? What are the pros and cons/SEs?

Answer 2

• Entonox - nitrous oxide and oxygen (50:50)
  
  • PROS: rapid onset and mild analgesic
  • CONS: insufficient pain relief for most
  • SEs: light headedness, nausea, hypervent

Question 3

What systemic opiates can you offer in labour? What are the pros and cons/SEs?

Answer 3

• IM Pethidine/meperidine or diamorhine
  
  • CONS: small analgesic effect
  • SEs: Nausea and vomiting (anti-emetics usually needed), sedation, confusion, respiratory depression in newborn - requires reversal with naloxone, reduced breastf feeding rates

Question 4

What other medical treatments are avaliable for pain relief in pregnancy and labour? What analgesics should be avoided?

Answer 4

• Paracetamol - throguhout preg. Little use in established labour
• Codeine (if more severe)
• Aspirin - ONLY if high risk of pre-eclampsia

AVOID NSAIDs

• Pot miscarriage and malformation in 1st T
• Closure of fetal ductus arteriousus (3rd T)
• Fetal oliguria
• Possible cerebral haem

Question 5

What are the gold standard pain relief for labour?

Answer 5

Regional techniques

Question 6

What spinal level are epidurals delivered?

Answer 6

• L3 - L4 or L4 - L5

Question 7

What three ligaments must you pass through to deliver an epidural? Where is the local anaesthetic delivered to?

Answer 7

• Supraspinous ligament
• Infraspinous ligament
• Ligamentum flavum

Local anaesthetic delivered into the epidural space (ie the space outside the dura mater)

Question 8

What is the effect of epidural analgesia?

Answer 8

• Variable effect. IDEALLY:
  
  • Complete sensory blockade (except pressure)
  • Partial motor blockade from upper abdomen to lower abdomen

Question 9

What local anaesthetics are used for epidurals? How do they work?

Answer 9

• Ropivacaine/bupivacaine in combo with an opioid (fentanyl) via indwelling catheter
  
  • Combo associated with sig reduction in postop pain vs alone
• Inhibition of conduction at the intradural nerve roots arising from the spine

Question 10

What are the general indications for epidural infusion?

Answer 10

Thoracic, abdominal and lower-limb surgical procedures:

Intraoperative analgesia

Postoperative analgesia

Analgesia for chest, abdomen, pelvis or lower-limb trauma.

Question 11

What are the indications for epidural anaesthesia in context of obstetrics?

Answer 11

• Suitable for ENTIRE labour - patient controlled doses are also available.
• Higher dosages if further obstetric interventions required (C-section or instrumental delivery).
  
  • For C section, combo of spinal and epidural = best! (rapid onset - spinal - and longer lasting anaesthesia - epidural)

Question 12

What are the cons of epidural anaesthesia?

Answer 12

CONS:

• Occassionally ineffective/incomplete (1 in 8)
• IV access required and epidural site = tender
• Transient hypotension, maternal fever and itching = common
• Reduced mobility
• Reduced bladder sensation (urinary retenion)
• ↑ risk of instrumental delivery (but NOT C-section)
• Pushing = directed as sensation ↓
• Prolonged labour (2nd stage delayed by 1 hr)
• Fetal ↓HR
  *

Question 13

What are the pros of epidural anaesthesia?

Answer 13

PROS:

• Only method which renders mum pain free
• ↓ BP in HTN
• Abolishes premature urge to push

Question 14

What are the major complications of epidural anaesthesia?

Answer 14

• Sig hypotension (1 in 50)
• Spinal Tap (0.5%) - puncture of dura mater, causing leakage of CSF and often severe headache (↑ sitting up, ↓ lying)
  
  • Tx - analgesia. If >48hrs: ‘Blood patch’ to seal leak
• LA toxicity - Intravenous injection - tingling around mouth, numb tongue, tinnitus, confusion, convulsions, coma, cardiac arrest)
• Total spinal analgesia (v rare) - injection of LA into CSF. Travel upwards, causing total spinal analgesia + respiratory paralysis
• Severe injury - nerve damage/paralysis (v v rare)

Question 15

What are the CIs for epidural analgesia?

Answer 15

Absolute CIs

• Severe sepsis
• LA allergy
• Coagulopathy or anticoagulation (unless low dose heparin)
• Local infection at the site of insertion.

Relative contraindications

• ↑ ICP
• Hypovolaemia
• Some skeletal anomalies
• Following some types of back surgery.

Question 16

What are the differences between spinal and epidural anaesthesia?

Answer 16

Question 17

When are spinal anesthesias used in context of pregnancy?

Answer 17

• For C-section or mid cavity instrumental vaginal delivery

Question 18

What are the major complications of spinal anesthesia?

Answer 18

• ↓ BP and RARELY total spinal analgesia (respiratory paralysis)