The document discusses various methods of labour analgesia including non-pharmacological techniques, systemic drugs, inhalational agents, epidural analgesia and spinal analgesia. It describes the stages of labour and mechanisms of labour pain. For epidural analgesia, it recommends bupivacaine with lipid-soluble opioids like fentanyl or sufentanil. It outlines administration techniques and discusses complications and fetal effects for different analgesic methods.

1. LABOUR ANALGESIA

2. STAGES OF LABOUR
• The first stage begins with the onset of uterine contractions and ends with the
complete dilation of the cervix.(cervical stage)
• The second stage of labour begins with the complete dilation of the cervix and ends
with the birth of the baby. (pelvic stage )
• The third stage begins with the birth of the baby and ends with the delivery of the
placenta.(placental stage)

3. MECHANISM OF LABOUR PAIN : THE FIRST
STAGE

4. PATHWAY OF THE FIRST STAGE OF
LABOUR

5. SUPRASPINAL PROJECTIONS

6. ANAESTHETIC IMPLICATIONS
• pain during the first stage of labour is amenable to blockade of peripheral afferents
(by para cervical block, paravertebral sympathetic nerve block, or epidural block of
the T10-L1 dermatomes)
• or to blockade of spinal cord transmission of pain by intrathecal injection of local
anaesthetics or opioids.

7. PAIN IN THE SECOND STAGE OF LABOUR
• Pain during the second stage of labour reflects the activation of the same afferents
activated during the first stage of labour plus afferents that innervate the vaginal
surface of the cervix, the vagina, and the perineum.
• course through the pudendal nerve with DRG at S2-S4, a
• the pain specific to the second stage of labour is precisely localized to the vagina
and perineum, and it is somatic in nature

8. ANAESTHETIC IMPLICATION
• Implications of the anatomic basis for the pain of the second stage of labour are that
analgesia can be obtained by
• a combination of methods used to treat the pain of the first stage plus
• pudendal nerve block
• or extension of epidural blockade from T10 to S4.

9. EFFECT OF LABOUR PAIN ON THE MOTHER
Effects on the labour process
• .Provision of analgesia decreases plasma concentrations of epinephrine and its beta-adrenergic
tocolytic effect on the myometrium.
• Ferguson's reflex involves neural input from ascending spinal tracts (especially from
sacral sensory input) to the mid- brain, thereby resulting in enhanced oxytocin
release. Some advocate that regional analgesia can inhibit this reflex and prolong
labour, especially the second stage.

10. CARDIAC EFFECTS
• Effective analgesia results in large (50%) decreases in catecholamine concentrations
in maternal blood.
• By contrast, regional anaesthetic techniques do not alter neonatal concentrations of
catecholamines, which are thought to be important to adaptation to extrauterine
life.

11. RESPIRATORY EFFECTS

12. EFFECT ON THE FETUS
labour pain can affect multiple systems that determine uteroplacental perfusion:
• uterine contraction frequency and intensity, by the effect of pain on the release of
oxytocin and epinephrine;
• uterine artery vasoconstriction, by the effect of pain on the release of
norepinephrine and epinephrine; and
• maternal oxy haemoglobin desaturation, which may result from intermittent
hyperventilation followed by hypoventilation .

13. METHODS OF LABOUR ANALGESIA

14. NON PHARMACOLOGICAL TECHNIQUES

15. SYSTEMIC PHARMACOLOGICAL
TECHNIQUES : OPIOIDS

16. NON OPIOIDS AND OTHER SEDATIVES

17. INHALATIONAL ANALGESIA
Nitrous oxide-administered in the form of Entonox
The pros
• Analgesic action
• No effect on uterine contraction
The cons
• Inadequate analgesia
• Possibility of diffusion hypoxia after its administration
• Possibility of neonatal respiratory depression

18. HALOGENATED INHALATIONAL AGENTS
• Dose dependant uterine muscle relaxation
• concern regarding pollution of the labour and delivery environment with waste
anaesthetic gases;
• incomplete analgesia
• the potential for maternal amnesia
• the potential for the loss of protective airway reflexes and pulmonary aspiration of
gastric contents.

19. INDICATION
• the ACOG and the ASA have stated that “in the absence of a medical
contraindication, maternal request is a sufficient medical indication for pain relief
during labour”
• Early epidural anaesthesia…………benefits versus risks.

20. CONTRAINDCATIONS
• Patient refusal or inability to cooperate
• Increased intracranial pressure secondary to a mass lesion
• Skin or soft tissue infection at the site of needle placement
• Frank coagulopathy
• Uncorrected maternal hypovolemia (e.g., haemorrhage)

21. BENEFITS OF EPIDURAL ANALGESIA
• Epidural analgesia may facilitate an atraumatic vaginal breech delivery, the vaginal
delivery of twin infants, and vaginal delivery of a preterm infant
• By providing effective pain relief, epidural analgesia facilitates the control of blood
pressure in pre-ecclamptic women
• Epidural analgesia also blunts the hemodynamic effects of uterine contractions
(e.g., sudden increase in preload) and the associated pain response.
• Prevents hypoventilation hyperventilation syndrome

22. ADMINISTRATION OF EPIDURAL ANALGESIA
FOR LABOR: TECHNIQUE
• 1. Informed consent is obtained, and the obstetrician is consulted.
• 2. Monitoring includes the following:
• Blood pressure every 1 to 2 minutes for 15 minutes after giving a bolus of local
anaesthetic
• Continuous maternal heart rate monitoring during and after administration of the
block.
• Continuous fetal heart rate monitoring during and after the procedure and
• Continual verbal communication.

23. • 3. The patient is hydrated with 500 mL of Ringer's lactate solution.
• 4. The patient assumes a lateral decubitus or sitting position.
• 5. The epidural space is identified with a loss-of-resistance technique.
• 6. The epidural catheter is threaded 3 to 5 cm into the epidural space.
• 7. A test dose of 3 mL of 1.5% lidocaine with 1:200,000 epinephrine is injected after
careful aspiration and after a uterine contraction (to minimize the chance of
confusing tachycardia that results from pain with tachycardia as a result of
intravenous injection of the test dose).

24. • 8. If the test dose is negative, one or two 5-mL doses of 0.25% bupivacaine are
injected to achieve a cephalad sensory level of approximately T10.
9. After 15 to 20 minutes, the block is assessed by means of loss of sensation to cold
or pinprick
• 10. The patient is cared for in the lateral or semi lateral position to avoid aortocaval
compression

25. • .
• 11. Subsequently, maternal blood pressure is measured every 5 to 15 minutes. The
fetal heart rate is monitored continuously.
• 12. The level of analgesia and the intensity of motor block are assessed every 1 to 2
hours.

26. CHOICE OF LOCAL ANAESTHETIC:
BUPIVACAINE
• dilute solutions of bupivacaine produces excellent sensory analgesia with minimal
motor blockade. A 0.125% solution is often adequate during early labour, and a
0.25% solution is effective during active labour in most patients
• Bupivacaine is highly protein bound, which limits trans placental transfer.
• The umbilical vein :maternal vein concentration ratio is approximately 0.3.
• the reports of FHR decelerations after bupivacaine did not demonstrate adverse
neonatal outcome

27. ROPIVACAINE
• It is difficult to justify the increased cost of ropivacaine without clear patient benefit.
• There is no definitive evidence of increased patient safety or decreased motor block
when ropivacaine is used to provide epidural analgesia in labouring women,
• and there is no significant difference between ropivacaine and bupivacaine in
obstetric or neonatal outcome

28. LEVOBUPIVACAINE
• preclinical and clinical studies have suggested that levo bupivacaine has less
potential for cardio toxicity.
• However this is still to be proved by conclusive studies

29. LIGNOCAINE
• Lower quality of analgesia
• epidural administration of lidocaine during labour was associated with abnormal
neonatal neurobehavioral
• At delivery, the umbilical vein : maternal vein lidocaine concentration ratio is
approximately twice that of bupivacaine.

30. OPIOIDS
• epidural administration of a local anaesthetic alone can provide adequate analgesia
throughout labour, but the concentration of local anaesthetic needed to maintain
analgesia often results in significant motor block.
• Epidural administration of an opioid alone provides moderate analgesia during
early labour, but the dose needed to maintain analgesia is accompanied by
significant side effects (e.g., pruritus, nausea, perhaps neonatal depression).

31. CHOICE OF OPIOIDS
• lipid-soluble opioids are superior to morphine when used in combination with a local
anaesthetic for epidural analgesia in labouring women. three lipid-soluble opioids—
fentanyl, sufentanil, and alfentanil—may be combined with a local anaesthetics.
• sufentanil may provide slightly better analgesia with slightly less neonatal
neurobehavioral depression.

32. MAINTENANCE OF EPIDURAL ANALGESIA
• Intermittent top up doses
• Continuous epidural infusion
• Patient controlled epidural analgesia

33. SPINAL ANALGESIA FOR LABOUR :SINGLE
SHOT TECHNIQUE
• a single-shot subarachnoid injection of local anaesthetic is not suitable for the first
stage of labour.
• A single-shot injection has a finite duration,
• and multiple injections result in an increased risk of post dural puncture headache
(PDPH).

34. CONTINUOUS SPINAL ANALGESIA
• placed through an 18- or 19-gauge needle. Very small (e.g., 28- to 32-gauge)
catheters
• were developed for insertion through small (e.g., 22- to 26-gauge) spinal needles.
• Unfortunately , several cases of cauda equina syndrome (associated with the use of
spinal micro catheters during surgery in non pregnant patients) prompted the Food
and Drug Administration to remove these micro catheters from the market.

35. SADDLE BLOCK
• advantageous in the patient with a preterm fetus or a vaginal breech presentation.
In these cases, dense perineal relaxation may facilitate an atraumatic vaginal
delivery.
• A saddle block also provides excellent anaesthesia for an outlet/low forceps delivery..
• The block is administered with the patient in the sitting position to promote caudal
spread of the hyperbaric local anaesthetic,
• we administer the local anaesthetic immediately after a uterine contraction to
decrease the likelihood of an unexpected high block

36. COMPLICATIONS OF NEURAXIAL OPIOIDS
• Neurotoxicity
• Sensory changes
• Nausea and vomiting
• Pruritus
• Respiratory depression
• Urinary retention
• Delayed gastric emptying
• Recrudescence of herpes simplex virus infection

37. FETAL OUTCOME OF NEURAXIAL OPIOIDS
• The indirect fetal effects of epidural and intrathecal opioids may be more significant.
• the mother has severe respiratory depression and hypoxemia, fetal hypoxemia and
hypoxia will
• follow.
• More common is the occurrence of fetal bradycardia after intrathecal
administration of a lipid-soluble opioid.
• Direct fetal effects may include intrapartum effects on the FHR as well as possible
respiratory depression after delivery.

38. TREATMENT
• fetal bradycardia
• fetal resuscitation in utero.
(1) relief of aortocaval compression;
(2) discontinuation of intravenous oxytocin;
(3) administration of supplemental oxygen;
(4) treatment of maternal hypotension, if present; and

39. COMPLICATIONS OF NEURAXIAL
ANALGESIA
• Hypotension
• Inadequate analgesia
• Intravenous injection of local anaesthetic
• Unintentional dural puncture
• Unexpected high block
• Extensive motor block
• Urinary retention
• backache

40. THE CAUSES OF A HIGH BLOCK

41. NEONATAL OUTCOME OF NEURAXIAL
ANALGESIA
• Expectant mothers can be reassured that, although epidural analgesia may be
associated with some short term maternal side effects, it does not exacerbate fetal
acidosis, and if anything, may partially protect the fetus from fetal hypoxia.

42. INFUSION REGIMENS

43. COMBINED SPINAL EPIDURAL BLOCK
• Combined spinal-epidural anaesthesia: Intrathecal injection of 2.5 to 5 mg
bupivacaine followed by placement of an epidural catheter for use if the spinal
anaesthesia is insufficient

44. OTHER TECHNIQUES FOR LABOUR
ANALGESIA:PARACERVICAL BLOCK

45. MATERNAL COMPLICATIONS
• Vasovagal syncope
• Laceration of the vaginal mucosa
• Systemic local anaesthetic toxicity
• Parametrial hematoma
• Postpartum neuropathy
• Paracervical, retropsoal, and subgluteal abscess

46. FETAL COMPLICATIONS
• Fetal bradycardia
Possible causes
• Reflex Bradycardia
• Direct Fetal Central Nervous System and Myocardial Depression
• Increased Uterine Activity
• Uterine and/or Umbilical Artery Vasoconstriction
• Injection of local anaesthetic into fetal scalp leading to systemic toxicity

47. • 1. Perform paracervical block only in healthy parturients at term
• 2. Continuously monitor the FHR and uterine activity before, during, and after
performance of paracervical block.
• 3. Do not perform paracervical block when the cervix is dilated 8 cm or more.
• 4. Establish intravenous access before performing paracervical block.
• 5. Maintain left uterine displacement while performing the block.
• 6. Limit the depth of injection to approximately 3 mm.

48. LUMBAR SYMPATHETIC BLOCK
• Adequate analgesia for first stage of labour
• interrupts the transmission of pain impulses from the cervix and lower uterine
segment to the spinal cord
• Modest hypotension occurs in 5% to 15% of patients
• systemic local anaesthetic toxicity, total spinal anaesthesia, retroperitoneal
hematoma, Horner's syndrome, and postdural puncture headache (PDPH).

49. OTHER TECHNIQUES
• Pudendal nerve block
• Perineal infiltration