O&G · Intrapartum care — analgesia and anaesthesia
Obstetric analgesia and anaesthesia
Also known as Labour epidural · Spinal anaesthesia · Combined spinal-epidural · Remifentanil PCA · Obstetric general anaesthesia · Neuraxial analgesia
Exam-exhaustive FRANZCOG fellowship reference on obstetric analgesia and anaesthesia — the labour analgesia efficacy ladder with real numbers, epidural technique and the Cochrane evidence, the COMET and RESPITE trials, spinal for caesarean with hyperbaric bupivacaine, hypotension prevention with phenylephrine (international consensus), accidental dural puncture and post-dural puncture headache with the epidural blood patch, the OAA-DAS failed-intubation drill, NAP5 awareness, and remifentanil PCA monitoring. RANZCOG/ANZCA-primary, globally tagged to MRCOG and ABOG.
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Red flags
- A headache that is not postural is not a post-dural puncture headache until proven otherwise — fever, focal neurology or seizure changes everything
- A block that should be wearing off and is not is a vertebral canal haematoma until MRI says otherwise
- Remifentanil PCA without one-to-one midwifery care and continuous oximetry kills — the analgesia is not the hard part, the monitoring is
- Paralysing a woman for a category 1 caesarean and under-dosing the hypnotic is the NAP5 awareness scenario
- Siting or removing an epidural catheter inside the low-molecular-weight heparin exclusion window causes a vertebral canal haematoma
- Phenylephrine in a fixed cardiac output lesion; neuraxial block in uncorrected hypovolaemia — the two haemodynamic killers
She is 4 cm dilated, in agony, and asking for "the needle in my back". The decision you make in the next two minutes — and the way you explain it — is half the station. Obstetric analgesia is examined relentlessly because it sits where physiology, pharmacology, communication and risk collide, and because the obstetric airway is still the place young women die under anaesthesia. Know the ladder, know the doses, and know the drills.[1][5]
Overview — the analgesia ladder
Labour analgesia is a ladder, and the rungs matter because each trades pain relief against intervention and monitoring. [1][4]
- Non-pharmacological — hydrotherapy, massage, hypnobirthing, positional change, continuous support. Real but modest; never denigrate a woman's choice, but do not pretend it replaces effective analgesia for established labour pain.[1]
- Inhalational — nitrous oxide (Entonox), a 50:50 mix with oxygen. Self-administered via a demand valve. The systematic review position: less effective than epidural, but safe, with few maternal or neonatal side effects, and valued by women who want something that does not tether them to a monitor or a needle.[4]
- Systemic opioid — intramuscular pethidine is the ANZ default. Limited efficacy, maternal sedation and nausea, and neonatal respiratory depression if given close to delivery. Falling out of favour for good reason.[8]
- Remifentanil PCA — intravenous, patient-controlled, short half-life. Halves the rate of epidural conversion compared with pethidine, but demands one-to-one monitoring because it depresses respiration.[3][9]
- Neuraxial — epidural, spinal, combined spinal-epidural. The most effective analgesia available, and the only method that can be extended to surgical anaesthesia for caesarean without a separate procedure.[1]
The three numbers that frame the ladder
References13ShowHide
- [1]Anim-Somuah M, Smyth RM, Cyna AM, et al. Epidural versus non-epidural or no analgesia for pain management in labour Cochrane Database Syst Rev, 2018.PMID 29781504
- [2]Comparative Obstetric Mobile Epidural Trial (COMET) Study Group UK Effect of low-dose mobile versus traditional epidural techniques on mode of delivery: a randomised controlled trial Lancet, 2001.PMID 11454372
- [3]Wilson MJA, MacArthur C, Hewitt CA, et al. Intravenous remifentanil patient-controlled analgesia versus intramuscular pethidine for pain relief in labour (RESPITE): an open-label, multicentre, randomised controlled trial Lancet, 2018.PMID 30115484
- [4]Likis FE, Andrews JC, Collins MR, et al. Nitrous oxide for the management of labor pain: a systematic review Anesth Analg, 2014.PMID 24356165
- [5]Mushambi MC, Kinsella SM, Popat M, et al. Obstetric Anaesthetists' Association and Difficult Airway Society guidelines for the management of failed tracheal intubation in obstetrics Anaesthesia, 2015.PMID 26449292
- [6]Kinsella SM, Carvalho B, Dyer RA, et al. International consensus statement on the management of hypotension with vasopressors during caesarean section under spinal anaesthesia Anaesthesia, 2018.PMID 29090733
- [7]Pandit JJ, Andrade J, Bogod DG, et al. 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors Br J Anaesth, 2014.PMID 25204697
- [8]Leong WL, Sng BL, Sia AT A comparison between remifentanil and meperidine for labor analgesia: a systematic review Anesth Analg, 2011.PMID 21890889
- [9]Van de Velde M, Carvalho B Remifentanil for labor analgesia: an evidence-based narrative review Int J Obstet Anesth, 2016.PMID 26777438
- [10]Heesen M, Klöhr S, Rossaint R, et al. Insertion of an intrathecal catheter following accidental dural puncture: a meta-analysis Int J Obstet Anesth, 2013.PMID 23219220
- [11]Sng BL, Han NLR, Leong WL, et al. Hyperbaric vs. isobaric bupivacaine for spinal anaesthesia for elective caesarean section: a Cochrane systematic review Anaesthesia, 2018.PMID 29044483
- [12]Heesen M, Hilber N, Rijs K, et al. Intrathecal catheterisation after observed accidental dural puncture in labouring women: a meta-analysis and systematic review Int J Obstet Anesth, 2020.PMID 31522933
- [13]Tubog TD, Ramsey VL, Filler L Minimum Effective Dose (ED50 and ED95) of Intrathecal Hyperbaric Bupivacaine for Cesarean Delivery: A Systematic Review AANA J, 2018.PMID 31584404