Labour analgesia....

1. STAGES OF LABOUR
&
LABOUR ANALGESIA
Dr. IMRAN

2. Definition of Labour :-
‘LABOR can be defined as spontaneous
painful uterine contractions associated
with the effacement and dilatation of the
cervix and the descent of the presenting
part’

3. The parameters for normal labour are:
• Contractions once in every 3 minutes,
lasting 45 seconds
• Progressive dilatation of the cervix
• Progressive descent of the presenting
part
• Vertex presenting with the head flexed
and the occiput anterior

4. • Labour not lasting less than 4 hours
(precipitate) or longer than 18 hours
(prolonged)
• Delivery of a live healthy baby
• Delivery of a complete placenta and
membranes
• No complications.

5. Stages of Labour :-
Divided into 4 stages
- 1st Stage
-2nd Stage
-3rd Stage
-4th Stage

6. First stage of labour :-
- Interval between onset of labor and full cervical
dilatation
- 3 phases:-
Latent – period between onset of labor and point at
which a change in slope of rate of cervical dilatation is
noted.
Active – Greater rate of cervical dilatation and usually
begins around 3-4cm upto 8 cm.
Transistion– is from 8 cm. to 10 cm

7. - Pain from the first stage comes from uterine
contractions that cause effacement of the
cervicovaginal angle and dilation, distention,
stretching and tearing of the cervix and
perineum.
- The resulting pain is felt between the umbilicus
and pubes and across at the level of the top of
the sacrum.

8. - Pain impulses are carried in the visceral
afferent type C fibres accompanying the
sympathetic nerves.
- In early labor , only the lower thoracic
dermatomes (T11 to T12) are affected, but
with progressing cervical dilation, adjacent
dermatomes maybe involved and pain
referred from T10 to L1.

9. Second Stages of Labor :-
- Interval between full cervical dilatation and delivery
- Duration
Nulliparous – 3 hrs w/ epidural; 2 hrs w/o epidural
Multiparous – 2 hrs w/ epidural; 1 hr w/o epidural
- In 2nd stage the pain impulses are carried by the
pudendal nerves, composed of lower sacral fibres(S2 to
S4).

10. - During the 2nd stage of labor, the nociceptive
stimulation is from the fully dilated cervix
decreases, but the presenting part of the fetus
distends pain sensitive structures in the pelvis
and perineum.
- Some patients also report aching, burning, or
cramping in the thighs or legs, probably
reflecting secondary hyperalgesia involving the
L1 to L3 and S2 dermatomes.

11. Third Stage of Labour :-
- Delivery of the placenta and membranes
- Duration – maximum of 30 minutes

12. 4th STAGE of LABOUR-
It is a stage of observation for atleast one
hour after expulsion of the placenta.
Pain during the third and fourth stage of labor
reflects the noxious stimuli that have
previously accompanied fetal descent and
separation of the placenta.

13. Cervical Dilatation : Stages of Labour

14. LABOUR ANALGESIA

15. Labor analgesia- brief history
• The first labor analgesia-
James Young Simpson
• -professor of midwifery in
Edinburgh, Scotland, was
the first to use ether for
the relief of labor.
• -on Jan 19th , 1847, his 1st
Case, that of a young
Woman with rickets and a
Severely deformed pelvis.
• -the mother survived the
Complicated delivery pain-free.

16. John Snow
• Administered the historic
Chloroform to queen
Victoria for labor analgesia
Helping her delivering
8th & 9th child, prince
Leopold & princess Beatrice.
• The queen commented in
her journal ,”Dr Snow gave
that blessed chloroform and
the effect was soothing, quieting,
and delightful beyond measure”.

17. Do parturients require pain relief??

18. Labor pain its effects on various systems
• Cardiovascular system:
Increased SV, CI, SVR, CO, tachycardia,
hypertension & exaggerated hypertensive
response in PIH patients.
Painful and traumatic labor can also lead to
postpartum stress disorder.

19. Labor pain its effects on various
systems
Respiratory system:
• Hyperventilation hypocarbia
hypoventilation hypercarbia cycles.
• Oxygen dissociation curve is shifted to the
left due to respiratory alkalosis, thus
causing reduced oxygen delivery to the
fetus leading to maternal and fetal acid-
base imbalance.
• Increase in oxygen consumption,
decrease in oxygen delivery to the fetus.

20. Advantages of pain relief
1. Reduction in maternal plasma conc. of
catecholamine's.
2. Improved uteroplacental perfusion.
3. Uterine contractions become more
effective.
4. Blunts the hyper-hypoventilation cycles
and adverse hemodynamic response.
5. Beneficial in patients with cardiovascular
and respiratory problems, intracranial
vascular pathology.

21. Reasons for treating labor pain.
• Exhaustion and pain of labor can result in
failure of progression of labor.
• Failure of progression can cause maternal
exhaustion and / or foetal distress.
• The personal experience of extreme pain during
labor or delivery is related to the occurrence of
postnatal depression
• (Ferber et al 2005, Hiltunen et al 2004).

22. Techniques of labor analgesia
• Non-pharmacological
1. Psycho prophylaxis
2. Touch massage
3. Water bath
4. Hydrotherapy
5. Bio-feed back
6. TENS-transcutaneous electric nerve
stimulation
7. Hypnotherapy
8. Acupuncture

23. Pharmacological
• Systemic analgesia
1. Pethedine
2. Fentanyl
3. Remifentanyl
4. Tramadol
5. Morphine
#NSAID’s are not recommended

24. • Inhalational methods
1. Entonox
2. Sevox
3. PCIA- patient controlled inhalational
analgesia.
• Regional anesthesia
1. Epidural analgesia.
2. Combined spinal epidural analgesia.
3. Continuous spinal analgesia.
4. Subarachnoid block.

25. • Non pharmacological methods….
Developed in the soviet union in 1954 by
A. Nikolayev.
Psychoprophylaxis involves :-
1. Deep breathing during each contraction.
2. Stroking of sections of the abdomen
combined with deep breathing.
3. Pressure applied to “pin prevention points
“ along the back and the medial surface
of the anterior superior iliac spine.

26. • Hypnosis….
Benefits - shorter first stage of labor.
- less medication.
- more frequent spontaneous
deliveries.
- highly susceptible, hypnotically
treated women had lower
depression scores after birth.

27. • Acupuncture
Background:
1. Chi(qi) energy runs along 12
meridians(channels).
2. Two forms of energy, yin and yang, must
be in balance .
3. Imbalances causes disease and pain.
4. Inserting needles into accupuncture
points, which lie on the meridians, and
gently vibrating them can reestablish
balance.

28. • According to clinical studies…
- some pain relief is obtained.
- 40 to 80% laboring women requested
additional analgesia.
- occasionally associated with shorter 1st
stage.
- maternal response is usually positive.

29. TENS
• The use of TENS in modern medicine
derives from the gate control theory of pain.
- Cells in the posterior horn of the spinal grey
mater have a gating function.
- Activity in low threshold, large afferent
fibres(not conducting pain) “closes the gate”
and blocks conduction in afferent pain fibres
to the pain pathways.
- TENS is thought to work by a combination of
increasing the release of endogenous
opiates and closing the pain gate.

30. • TENS stimulator is a dual output device.
• Each output varies in both amplitude and
rate.
• Amplitude varies from 0 to 220 V.
• Frequency ranges from 40 to 150hz.
• Two pairs of silicon electrodes are placed
paravertebrally.
1. T10 to L1 spinal levels
2. S2 to S4 spinal levels.

31. • Upper level :The amplitude and frequency
are adjusted until the patient is aware of a
tingling sensation, this background
sensation is maintained continuously.
• Lower level :the amplitude and frequency
are set at higher than the upper level.
Electrodes are stimulated from the
beginning until 30 seconds after each
contraction.

32. • Efficacy of TENS –
1. Usually provides some pain relief during
1st stage.
2. Decreased need of narcotic.
3. May shorten 1st stage.
4. Less effective in 2nd stage.
5. Over 70% of parturient’s find TENS
helpful and request it for subsequent
labor.

33. Systemic analgesics in obstetrics
• Systemic drugs have been in use for labor
pain since 1847.
• Existing data suggest that the provide little
significant analgesia.
• PCA, has the advantage of better pain relief
with lower dosage.
- Less risk of maternal respiratory depression.
- Less placental transfer of drugs.
- Less nausea and vomiting.
- Greater patient satisfaction.

34. Meperidine (pethidine) :
• Dose- (every 2 to 4 hrs);25 to 50mg IV, 50
to 100mgIM.
• Onset –within 5 min. after IV inj. & 45min
after IM.
• Pharmacokinetics (IV inj.)
- Remains detectable throughout labor,
appears in fetal blood within 90sec, half-
life : 2.5hrs in mother & 23hrs in neonate.

35. • Major side effects are N& V, maternal
sedation, dose related depression of
ventilation, orthostatic hypotension,& the
potential for neonatal depression.
Desaturation episodes (SpO2 between 70 to
90%) in about 50% of women (Reed et al
1989, Minnich et al 1990).
Elimination of Pethidine from the bodies of
both mother and child (63hrs)is relatively
slow.

36. Morphine:-
- Placental transfer is rapid
- Mother: uterus reactiveness↓
orthostatic hypotension
nausea
vomiting
delayed gastric emptying
- Fetus: respiratory depression

37. • Synthetic opoids such as fentanyl, alfentanil,
& remifentanil are more potent than
meperidine; however their use in labor is
limited by their short duration of action.
• PCA device for remifentanil is programmed to
give a bolus of 20 microgm over 20 sec, with
a lockout time of 3min, and no background
infusion. Analgesia is reported as very good
by the mothers.
• These offer an advantage when analgesia of
rapid onset but short duration is
necessary(e.g., with forceps application).

38. • Opoid agonist-antagonist of the
phenanthrene series, such as Butorphanol
and nalbuphine , have the proposed benefit
of lower incidence of N&V, dysphoria, as well
as a “ceiling effect” on depression of
ventilation.
• Butorphanol, 1 to 2 mg every 3 to 4 hrs, or
nalbuphine, 10 mg by IV or IM every 4 to 6
hrs are popular.
• These are biotransformed into inactive
metabolites and have a ceiling effect on
depression of ventilation.

39. 39
Fentanyl:-
• Most frequently used for parturient in
active labor.
• Administered in 2-3 divided doses of 25 μg
given 5 min apart.
• Peak analgesic effect = 5-6 min after each
IV injection. Duration = 30-60 min.

40. Tramadol :-
Placental transfer
No inhibiting uterine contraction
No Respiratory depression
Diazepam :-
Readily cross the placenta
Half-lives : 48 hours
Problems :sedation, hypotonia,
cyanosis, impaired
metabolic responses to stress.

41. Remifentanil Continuous infusion plus PCA bolus
administration
• More consistent results have been reported from
studies using a constant i.v. infusion at rates
between 0.025-0.05 mcg/kg/min combined with
rescue PCA bolus doses of 0.25-0.5 mcg/kg.
• These studies report good analgesia, no neonatal
respiratory depression, and incidence and severity
of desaturation incidents equivalent to Pethidine
Blair et al 2005, Roelants et al 2001 .

42. Opoid antagonist
• Opoid antagonist has been administered
in three ways:
1) To the mother with each dose of opoid,
2) To the mother 10 to 15 min before
delivery.
3) To the neonate immediately after delivery.
• Dose : adults, initial dose is 0.4mg IV.
neonates, 0.1mg/kg IV or IM.

43. Inhalational methods for labor
analgesia
• Inhalational analgesia refers to the
inhalation of sub-anesthetic concentrations
of anesthetic agents to provide pain relief
for labor &/or delivery.

44. Entonox
• Entonox is premixed 1:1 nitrous oxide with
oxygen.
• It is manufactured utilizing the Poynting
effect, by which gaseous oxygen is
bubbled through liquid nitrous oxide with
vaporization of the liquid to form a
gaseous mixture.
• Three sizes of cylinders are available:
500,2000, & 5000liters of gas.

45. • At temperatures above -7degrees C, both
nitrous and oxygen remain in the gaseous
phase.
• Most use of entonox is with intermittent “on-
demand” systems, reflecting the non
continuous nature of labor pain.
• Usually a two stage pressure reducing valve
is used.

46. Technique….
1. Instruct the parturient in the technique.
She needs to be aware that she can feel
dizzy or nauseated.
2. Establish IV access, pulseoximetry
should be applied.
3. Inhalation should begin 30sec before the
next contraction & cease when the
contraction start to recede.
4. The pt. should take slow deep breaths,
and concentrate on her breathing.

47. 6. Maintain verbal contact with the pt. and
be reassuring.
6. During 2nd stage of labor, 2-3 deep
breaths should be taken before each
push.
7. The obstetrician should consider
pudendal block or infiltration of the
perineum with local anesthetics for
additional analgesia.

48. - Other agents like 0.2 -0.25% isoflurane
with entonox have been used successfully.
- Desflurane & sevoflurane(sevox) have
low blood-gas solubilities(0.42 & 0.69
respectively), which might make them
especially suited for intermittent inhalation.

49. • Sevoflurane :
1. 2-3% of sevoflurane with air-oxygen
mixture in labor.
2. 0.8% generally suffices.
3. Can be used where RA is
contraindicated.

50. Regional anesthesia for labor
• Central neuraxial blockade, the GOLD
STANDARD(combined spinal epidural).
• Indications –
a) maternal request.
b) PIH/PE/eclampsia.
c) Parturient with co-existing medical
problems:
resp- asthma, CNS-AVM’s,
aneurysm,anemia, sickle cell disease.

51. Contraindications :
a) Patients refusal.
b) Allergy to amide local anesthetics.
c) Local skin infection.
d) Frank coagulopathy.
Relative contraindications:
a) Uncorrected maternal hypovolemia
b) Progressive neurological disease.
c) Gross spinal deformity.
d) Increased ICP secondary to mass lesion.

52. TECHNIQUES OF Central neuraxial
blocks
• Continuous epidural analgesia
• Patient-controlled epidural analgesia (PCEA)
• Combination of the above two techniques
• Combined spinal-epidural analgesia (CSE)
• Spinal opiates
• Intermittent epidural bolus injections
• Continuous spinal analgesia

53. Epidural Analgesia
• The American College of Obstetricians and
Gynecologists and the American Society of
Anesthesiologists have collectively published
the opinion that "maternal request is sufficient
justification for pain relief during labor"
ACOG committee opinion. Pain relief during labor. No. 231, February
2000.Obstet Gynecol 2000;95:1

54. Mandatory prerequisites before
siting an epidural
i. Informed consent
ii. Resuscitation equipment checked and kept
ready.
iii. Detailed PAC.
iv. Good venous access.
v. Hydration is not mandatory.
vi. Coagulation profile – in PE pt’s, recent count
done within 6hrs prior to procedure is
preferred. Trend analysis is always better
than absolute single value.

55. • Position – lateral is preferred in women
with active labor. Sitting is preferred in
obese parturient.
• Space L3-L4, L2-L3 or L4-L5 can be
chosen.
• Midline approach is better as it is least
vascular.
• Air or saline can be used for epidural
space identification.

56. Recent update
• Localization of epidural space using
ultrasound.
• Electrical stimulation by Tsui needle.
• Pharmacological advances:
-local anesthetics: ropivacaine &
levobupivacaine.
-narcotics: fentanyl, sufentanil,& remifentanil.
-adjuvants: clonidine & neostigmine.

57. • Technological advances:
- Availability of mobile CEI pumps:
PCEA/PCIV pumps.
- Spinal micro-catheters at the moment are
used only in FDA approved centers, and
the preliminary results of their use are
promising.

58. Advantages of Epidural Analgesia
- Provides superior pain relief
- 90% to 95% are satisfied with epidural
analgesia.
- Facilitates patient cooperation during labor
and delivery
- Decreases maternal hyperventilation
- Avoids opioid-induced maternal and neonatal
respiratory depression

59. - Extend the duration of block to match the duration of
labor
- Provides anesthesia for episiotomy or forceps delivery
- Allows extension of anesthesia for cesarean delivery
- Facilitates delivery of twins, delivery of preterm infants
and vaginal breech delivery
- Blunts hemodynamic effects of uterine contractions:
beneficial for patients with preeclampsia, mitral
stenosis, spinal cord injury, intracranial neuro-vascular
lesions.

60. CHOICE OF LOCAL ANESTHETIC
Ideal local anesthetic should have:----
• Rapid onset with minimal motor block
• Minimal risk of maternal toxicity
• Negligible effects on uterine activity and
uteroplacental perfusion
• Limited uteroplacental transfer
• Long duration of action

61. Suggested regimes for maintaining a
regional block
Low dose mixtures:
• Bupivacaine:0.1%+fentanyl 2micg/ml.
• Bupivacaine:0.1%+sufentanil 0.5-
1micg/ml.
Ultralow dose:
• Bupivacaine:0.0625%+fentanyl 2 micg/ml.
• Bupivacaine:0.0625%+sufentanil 0.5-
1micg/ml.

62. CONTINUOUS EPIDURAL INFUSION
• 0.0625% bupivacaine + fentanyl 2.5 μg/ ml at 12 ml/hr
(early labor) + demand dose: 4 ml q 15 min
• 0.125% bupivacaine + fentanyl 2 μg/ml at 8 ml/hr
(advanced labor) + demand dose : 3 ml q 15 min

63. LOCAL ANESTHETICS
Continuous infusion:
Bupivacaine: 0.0625%-0.25%-8 -15 ml/hr
Ropivacaine: 0.125%-0.25%- 6 -12 ml/hr
Lidocaine: 0.5%-1% -8-15 ml/hr
2-chloroprocaine 0.75% -27 ml/hr
Intermittent bolus injections:
Bupivacaine: 0.125%-0.375%, 5-10 ml, duration:1-2hr
Ropivacaine: 0.125%-0.25%, 5-10 ml, duration: 1-2 hr
Lidocaine: 0.75%-1.5%, 5-10 ml, duration: 1-1.5 hr
2 chloroprocaine 1-2%, 5-10 ml, duration: 0.75-1 hr

64. • Evidence is presented that intermittent boluses of local
anesthetic in labor are more effective than continuous
infusions.
P. D. W. Fettes et al.(Br J Anaesth, 97:359–364, 2006)
Intermittent vs Continuous Administration of
Epidural Ropivacaine With Fentanyl for
Analgesia During Labour.

65. Walking epidural
• Criteria:
a) Patient should be of low risk.
b) Grand multies, history of precipitate labor ,
PE/epileptics should not be ambulated.
c) Ensure that no motor block exists.
d) Mothers should feel confident enough to
ambulate.
e) Mothers should remain in bed rest for atleast
30min following CSE/epidural during which
FHR,PR,BP are monitored.
f) FHR should be normal.
g) Approval from anaesthesiologist and
obstetrician is a must.
h) A nurse should always accompany the
parturient.

66. Epidural Complications
Early
• IV toxicity
• LA toxicity
• Hypotension
• High block/total spinal
• Extensive motor block
• Fetal effects
• Urinary retention
• Labour progress
• Mode of delivery
Late
• PDPH
• Neurological injury
• Epidural abscess
• Epidural hematoma
• Back pain

67. Combined Spinal Epidural Analgesia
(CSE) For Labor And Delivery
Needle-through-needle technique

69. CSE locking devices
Portex CSEcure
Eldor Needle /
Espocan spinal-
epidural needle

70. • Women in severe pain
• Late first-stage labor
• Malpresentations
• Second-stage fetal distress
• Unsatisfactory epidurals (previous labor)
• Obese women
Indications For CSE

71. CSE ADVANTAGES
Rapid Onset of Analgesia
• Analgesia is often nearly complete before the
epidural cath. is taped up and the tray discarded
• Hepner Can J Anaesth 2000
• Nickells Anaesth 2000

72. CSE ADVANTAGES
Better Blocks
• Quality of analgesia is improved by CSE
• Norris retrospectively compared epidural and CSE
techniques in 1661 women who received either
technique and found a lower incidence of failed blocks
and a greater incidence of bilateral symmetrical
analgesia with CSE.
Norris MC .Anesth Analg 1995;79:529-37

73. CSE ADVANTAGES
Better Patient Satisfaction
An Updated Report by the American Society of
Anesthesiologists Task Force on Obstetric Anesthesia
Anesthesiology 2007; 106:843–63
• Several studies have found better patient satisfaction
scores with CSE vs. conventional epidural.
• Others have found no difference, but none have found
better satisfaction with conventional epidural analgesia

74. CSE ADVANTAGES
Better in Difficult Backs
An Updated Report by the American Society of
Anesthesiologists Task Force on Obstetric
Anesthesia
Anesthesiology 2007; 106:843–63
CSE has been associated with improved
chances of adequate analgesia in parturients
with scoliosis or other causes of a difficult back.

75. CSE ADVANTAGES
Less Motor Block
• CSE associated with less total LA use for a given
degree of analgesia
• Adding opioids decreases motor block.

76. CSE and Progress of Labor
Tsen et al. reported faster initial cervical dilation and
shorter time from induction of analgesia to full cervical
dilation among women receiving CSE analgesia vs
epidural analgesia.
Tsen L.C,Thue BDatta S: Anesthesiology 2001;91;920-5
Two large randomized trials have confirmed an increase
in the spontaneous vaginal delivery rate with CSE vs.
conventional epidural analgesia.

77. CSE Complications
• Fetal bradycardia/FHR changes
(50% greater than epidural)
• Pruritus
• Infection
• Neurotrauma
• Other side effects

78. Regional Techniques:
First Stage :- Paracervical block
Was used in 5-12% of parturients
in the early 1980’s.
Use has decreased because of fetal complications and the
increased use of epidural analgesia.
It interrupts pain transmission between T10 and L1.
Fetal bradycardia is the most significant risk

79. Second stage :-
Pudendal block
It blocks the sacral nerves from S2 to S4, which
transmit somatic nerve impulses.
Bilateral pudendal nerve blocks provide satisfactory
analgesia for spontaneous vaginal delivery, outlet
forceps and vacuum extraction.
Disadvantage: incomplete analgesia @ time of
delivery, since pain of uterine contraction is unaffected