Labour anaesthesia

• Analgesia


  The loss or modulation of pain perception. (local, systemic)
• Anaesthesia


  The total loss of sensory perception (light touch, pain, temperature, and her capacity for vasomotor control), and may include loss of consciousness
• The first to use Ether and Chloroform for pain relief in labour in the UK was the eminent Scottish Obstetrician, Sir James Young Simpson, Professor of Midwifery at the university of Edinburg. On January 19, 1847 he administered ether to an obstetric patient and thus began a new era in the effective management of pain in childbirth.
• The first woman anaesthetized for childbirth in the US was Fanny Longfellow in 1847 for her third child. She was the wife of the American poet Henry Wadsworth Longfellow who actually administered the ether.
• The second woman who was to become famous was Emma Darwin, the wife of Charles Darwin, the eminent 19th century Naturalist.Emma had chloroform given to her by her husband for the last 2 of her 8 births. The first time she used chloroform was in 1847 which was before Queen Victoria (1853) and no doubt it left an indelible impression upon her so much so that for her last birth she was screaming " get me chloroform".
• The third and most famous and most influential of them was Queen Victoria who was in 1853, undaunted by the clergy and with strong encouragement of her husband prince Albert, convinced her reluctant physicians to have chloroform administered to her by Dr John Snow for her 8th confinement of Prince Leopold.
• Regional anaesthetic techniques were introduced to obstetrics in 1900, when Oskar kreis described the use of spinal anaesthesia.
• Pathways of labour pain: Basis for labour analgesia


  1. First stage of labour: Pain is caused by stretching of the lower uterine segment (LUS) and cervix, which stimulates the mechanoreceptors. Noxious impulses are carried by sensory nerve fibres (A-d(delta) and C), which accompany sympathetic nerve endings, travel through paracervical ganglion and hypogastric plexus to the lumbar sympathetic chain which enter the spinal cord at T10, T11, T12 and L1 spinal segments.

  2. Second stage of labour: Pain is caused by distension of pelvic structures and the perineum due to the descent of the presenting part, ischaemia and frank injury and is carried by somatic affarent nerve fibres that transmit impulses through the pudendal nerve to the spinal cord at S1,S2, S3 and S4 levels.
• Pain of the 1st stage does not end with the beginning of 2nd stage but is superseded by pain of 2nd stage.
• Characteristics of the ideal labour-analgesic drugs


  • Safe for both mother and fetus
  • Ease of administration
  • Consistent and predictable with rapid onset of action
  • Maintains maternal composure and co-operation during both the 1st and 2nd stages of labour
  • High technical success rates
  • Analgesia through all stages of labour
  • Devoid of motor blockade
  • Retains maternal expulsive efforts
  • Facilitates the delivery of anaesthesia for cesarean section
• Why do we need obstetric Analgesia?


  • Humanitarian reasons
  • Medical reasons
• Effects of labour pain on mother and foetus


  • Marked stimulation of respiration and circulation in mother
  • Activation of sympathetic nervous system
  • Mental disturbance- postpartum depression and post traumatic stress disorder
• Techniques of Labour Analgesia


  • Complementary or Alternative treatment
  • Conventional Treatments
• Mind-body interventions


  • Psychoprophylactic methods: Breathing exercises, Deep abdominal breathing, Prepared childbirth method, Hypnosis, Biofeedback
  • Energy yoga: relaxation, concentration, meditation
  • Haptonomy: science of affectivity
  • Music Therapy
• Acupuncture


  Techniques have been used in China both for surgery as well as for pain
• Transcutaneous electrical nerve stimulation


  Electrical impulses are applied to skin via electrodes
• Intradermal saline injection


  25G needle, 0.1-0.15 ml intracutaneous injections of sterile water
• Inhalational Agents


  • Entonox (N2O: O2 in 50:50)
  • Isoflurane (0.2-0.25%)
  • Desflurane (1-4.5% in O2 or Entonox)
  • Sevoflurane (0.5-3%)
• Entonox


  50% nitrous oxide in oxygen, provides analgesia within 20-30 seconds of inhalation with a max effect after about 45 seconds
• Sevoflurane


  Used as 0.8% with O2, recent studies suggest sevoflurane as an effective labour analgesic, when compared with entonox, provided superior pain relief
• Systemic Analgesia: IV Opioids


  • Pethidine
  • Fentanyl
  • Remifentanyl
  • Tramadol
  • Diamorphine
  • Nalbuphine
  • Butorphanol
• Pethidine


  Most commonly used opioid, cheap, IM: 50-100 mg, IV: 25-50 mg, Analgesic effect: 3-4 h, Fetal exposure: maximum 2-3 h
• Fentanyl


  Short half life & no active metabolites, can be used as IV bolus or as PCA, usual dose 25-50 ug IV; peak effect in 3-5 min, Analgesic effect: 30-60 min, Suitable for prolonged use in labour, Minimal neonatal respiratory depression
• Remifentanyl


  Ultrashort acting opioid derivative of fentanyl, Metabolism is independent of hepatic or renal function, Half-life: 1.3 min, Prolonged administration doesn't cause any accumulation, Foetal exposure minimal
• Regional Analgesia Techniques


  • Epidural
  • Subarachnoid
  • Combined spinal-epidural blocks
  • Lumbar sympathetic
  • Paracervical block
  • Pudendal block
• Indications for neuraxial labour analgesia


  • Maternal request
  • Hypertensive disorders of pregnancy
  • Pre-existing medical disease
  • Multiple pregnancies
  • Previous cesarean section
  • Prolonged labour
  • Deterioration in fetal well-being
• Contraindications for neuraxial labour analgesia


  • Maternal refusal
  • Coagulopathy and thrombocytopenia
  • Local or systemic infection
  • Inadequate staffing or facilities
  • Increased intracranial pressure
  • Uncorrected maternal hypovolemia
• Continuous caudal analgesia


  Caudal analgesia was the first form of regional analgesia used during labour. However, it is not the technique of choice for labour analgesia due to the following disadvantages: Require larger amounts of local anaesthetics in the first stage, Difficult to perform as more anatomical anomalies are seen in the sacrum than in the lumbar vertebrae, thereby increasing failure rates, Risk of puncturing the rectum and fetal head, if the procedure is carried out during the later part of 2nd stage of labour.
• Lumbar Epidural Analgesia


  Neuraxial techniques are accepted as the gold standard for intrapartum labour analgesia. Studies have demonstrated lower maternal pain scores and higher maternal satisfaction with epidural analgesia compared with other techniques.
• Contraindications for neuraxial labour analgesia


  • Maternal refusal
  • Coagulopathy and thrombocytopenia
  • Local or systemic infection
  • Inadequate staffing or facilities
  • Increased intracranial pressure
  • Uncorrected maternal hypovolemia
• Techniques of neuraxial analgesia

  1. Continuous caudal analgesia

  2. Lumbar Epidural Analgesia
• Continuous caudal analgesia


  • Requires larger amounts of local anaesthetics in the first stage
  • Difficult to perform as more anatomical anomalies are seen in the sacrum than in the lumbar vertebrae, thereby increasing failure rates
  • Risk of puncturing the rectum and fetal head, if the procedure is carried out during the later part of 2nd stage of labour
• Lumbar Epidural Analgesia


  • Neuraxial techniques are accepted as the gold standard for intrapartum labour analgesia
  • Studies have demonstrated lower maternal pain scores and higher maternal satisfaction with neuraxial analgesia
  • Low doses of local anaesthetic or opioid combinations are administered to provide a continous T10-L1 sensory block during the first stage of labour
  • Safe and effective
  • Without appreciable motor blockade
  • Extended to provide surgical anaesthesia
• Fluid preloading


  • May be beneficial prior to labour epidurals in situations where fetus is at increased risk
  • Routine use of preload in current epidural practice is questionable and may lead to prolonged labour due to decreased uterine activity
• Test dose


  • Classic test dose (1.5% lodocaine with epinephrine 1: 200,000) can increase the motor block of the subsequent epidural and therefore reduce the possibility of walking
  • Ultra-dilute solution of LA such as less than 0.1% bupivacaine with fentanyl, could not possibly harm a patient
  • Test dose should be considered for operative delivery (LSCS)
• Patient Positioning


  • Sitting or lateral
  • There is little evidence that patient position influences the extent of neuroblockade during initiation of epidural analgesia/anaesthesia
• Lumbar epidural analgesia


  1. Epidural catheter positioned and placement verified

  2. Initial block- Bupivacaine 0.125% to 0.2% (10-15 ml) with fentanyl 2 ug/ml

  3. Maintenance of epidural analgesia
• Maintenance of epidural analgesia


  • Intermittent bolus injections: Breakthrough pain is the greatest disadvantage
  • Continuous infusion of the analgesic: Continuous epidural infusion (CEI) of a dilute solution of LA is a popular technique
  • Benefits of CEI: Maintenance of stable level of analgesia, Diminished risk of maternal hypotension, Chances of systemic LA toxicity reduces, Satisfactory perineal analgesia, Decreased workload for anesthesiologist
• Patient Controlled Epidural Analgesia (PCEA)


  • New continuous infusion pumps have been developed with capability to receive patient input and deliver medication on demand
  • Advantages: Excellent patient satisfaction, Less maternal hypotension and motor block, Total amount of LA used is reduced, Gives many parturient a feeling of empowerment, Reduces the demands on staff on the labour floor
• Complications of neuraxial analgesia


  • Dislodgement of catheters
  • Haemodynamic instability
  • Hypotension & bradycardia
  • Respitatory consequences
  • Total spinal anaesthesia
  • Transient paraesthesia
  • Intravascular injection of the local anaesthetic drug
  • Foetal bradycardia