Obstetric Analgesia and Anaesthesia

Nitrous Oxide

  • Self-administered oxygen and nitrous oxide (50%) (Entonox).
  • Should be inhaled just as the woman feels contractions coming on- takes seconds to work

Paracetamol and Codeine

  • Useful in early labour

Diamorphine Injection (5-10mg IM; max 15mg; if >1 dose is needed, it must be 2 hours apart, and maternal sedation is not excessive)

  • Contra-indicated if there are any signs of foetal compromise and, ideally, not within 2 hours of delivery (although this can be difficult to estimate)
  • Side effects include
    • Sedation
    • Itch
    • Nausea/vomiting
      • May require anti-emetic cover e.g. cyclizine or ondansetron
    • Can cause respiratory depression of the foetus if given within 2 hours of delivery

Epidural and Patient Controlled Analgesia (T11-S4; injected in L4/5 or L5/S1 space)

  • Often provides very effective pain relief (can either be continuous infusion or a PCA)
  • Absolute* and relative contraindications
    • Local infection*
    • Bleeding disorder or low platelet count
    • Anticoagulant therapy (if well controlled then this may not be a contraindication)
    • Some neurological disorders, spinal deformities/operations
    • Pre-eclampsia (if clotting status unknown)
    • Rapid progression of labour (i.e. no point in inserting an epidural if the patient is about to give birth)
      • The exceptions to this are cases where (near-) full dilation may not indicate immediate delivery e.g. a high head in OP position of a primigravida woman; twins; breech presentation etc
  • Monitoring
    • Ideally, the woman should have fluids/IV access (and should have had a group/save)
    • Record BP at 5, 10, 15 and 30 minutes after initial dose and then hourly with PCEA infusion running
    • Mother’s observations e.g. resp rate, should also be monitored as per local guidance
    • Foetal heart rate should be monitored whilst the epidural is in progress
    • Epidural should be STOPPED either at the second stage (delivery) or 15 mins prior to delivery
  • Drugs
    • Bupivicaine + (Remi)fentanyl
  • Side effects
    • Dizziness/shivering; transient hypotension can occur; headaches
    • Can also increase the duration of the second stage and increase the likelihood of assisted/operative delivery
      • Patients may need help identifying contractions

Other pharmacological anaethesia

  • Pudendal block and field block (often used for tears/episiotomies)
  • Spinal block (often used for c-sections)

Other analgesia

  • Transcutaneous nerve stimulation (TENS) machine
    • Pad on the back which delivers electrical impulses to the nerves
    • No evidence but it may prolong the need for pharmacological pain relief
  • Immersion in water
  • Acupuncture

Anaesthesia (General)

  • Avoid where possible
  • Useful for emergency C-sections

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