This document discusses pain pathways and methods of pain management during labor and caesarean section. It describes how the uterus and cervix receive nerve supply during different stages of labor. The ideal analgesic for labor should provide rapid and effective pain relief with no side effects to the mother or fetus. Methods of labor analgesia discussed include non-pharmacological techniques, parenteral drugs like pethidine, inhalation of nitrous oxide, and regional techniques like epidural analgesia. Epidural analgesia is described as the most effective form of pain relief but it requires careful administration and monitoring to avoid problems.

1. Painless labor
Dr. Mohamed Ibrahem El said
Lecturer of Anesthesia
Zagazig university

2. PAIN PATHWAYS IN LABOUR AND
CAESAREAN SECTION
• The afferent nerve supply of the
uterus and cervix is via A8 and C
fibers that accompany the
thoraco-lumbar and sacral
sympathetic outflows.
• First stage of labor = uterus and
the cervix = T10, 11, 12 and LI.
• Pain of distension of the birth
canal and perineum = S2-S4
nerves.
• Caesarean section = block T4 +
the sacral roots (S1-S5).

3. Pain
↓ Placental blood flow.
less effective uterine
contractions
↑ Catecholamine  ↑
myocardial work and arterial
pressure + peripheral VC.
↑ adreno-cortical
hormones  electrolyte,
carbohydrate and protein
metabolism.
The ideal analgesic
The ideal analgesic 
Rapid-onset
Effective pain relief in 1st and
2nd stages
No side-effects to mother or
fetus
Preserve mother's ability to
strain.

4. LABOUR ANALGESIA
• non-pharmacological
• Parenteral
• inhalation
• Regional.
Non-pharmacological analgesia
• Birth preparation classes
• Environment and the management of labor
• Transcutaneous electrical nerve stimulation (TENS)
• Hypnosis

5. Parenteral (systemic) analgesia pethidine
• Many opioids  pethidine, morphine …..
Pethidine 
• Two doses of 100 mg.
• Intramuscular injection  maximum effect after 1 h.
• The analgesic effects are variable
Adverse effects on mother
 Maternal sedation
 Nausea and vomiting
 Dysphoria
 Inhibition of gastric
emptying.
Adverse effects on the fetus as it
freely crosses the placenta
 CTG abnormalities and
 Respiratory depression
 Neurobehavioural
depression

6. Inhalation analgesia Nitrous oxide
• The ideal inhalation agent 
• Good analgesic in sub-anesthetic doses.
• Rapid onset of action and recovery and not accumulate.
• Nitrous oxide is relatively insoluble in blood and has
these properties.
• Isonox 50% nitrous oxide and 50% oxygen with 0.2%
isoflurane.
• Entonox 50% nitrous oxide and 50% oxygen under
pressure in a cylinder
• Entonox  on-demand valve with a face mask or
mouthpiece.
• Although Entonox is a reasonably effective analgesic,
many women feel faint and nauseated and may vomit or
become out of control.

7. Regional analgesia for labor
• The most effective form of analgesia in labor.
• 90% women  complete or near-complete pain relief.
• it is invasive and require careful monitoring.
Contraindications to epidural
analgesia in labor
 Maternal refusal
 Bleeding disorders
 Sepsis in the lumbar area and
systemic sepsis
 Local infection epidural
abscess.
 systemic infection or systemic
inflammatory response syndrome
(SIRS)
Indications for epidural analgesia
 Maternal request
 Occipitoposterior presentation
 pre-eclampsia
 Prematurity or IUGR
 Intrauterine death
 Induction of labor
 Instrumental or caesarean delivery likely
Previous caesarean delivery
 Presence of significant concurrent disease
(e.g. heart disease,diabetes, hypertension)
 Twin pregnancy

8. Dose
1 - Test dose+ maintenance
test dose small dose of local anesthetic 2 ml 2% lidocaine or 3 ml
0.5% bupivacaine to check for inadvertent intrathecal or vascular
placement Hypotension or profound motor block
Maintenance  0.1% bupivacaine/fentanyl 2 ug /ml may be used.
2- Boluses from the start
A 15 ml bolus 0.1% bupivacaine/fentanyl 2 ug /ml 15 mg bupivacaine
in total.
Bupivacaine 0.25% given in 10 ml boluses has been standard practice
10-15 ml boluses 0.1% bupivacaine/fentanyl 2 ug /ml in
The lower concentration  ↓hypotension + ↑ ability to walk.
The disadvantage of boluses is the possibility of intermittent pain if
top-ups are not administered at appropriate intervals.

9. 3 - Continuous infusion by syringe pump. 0.1%
bupivacaine/fentanyl 2 ug /ml  a rate of 10 ml/ h.
4 - Patient-controlled epidural analgesia (PCEA).
Initial bolus dose 0.1% bupivacaine/fentanyl 2 ug /ml
and maintaining analgesia by allowing the patient to
self-administer boluses of analgesic solution as
required by depressing a button on a special
computer-controlled volumetric syringe. There may or
may not be a low-dose background infusion.
The advantage  more control to the patient and
reduced total analgesic consumption

10. Problems maintaining epidural analgesia
• Epidural is not effective.
• If the epidural is not providing good analgesia within 15-20 min
with 15 ml 0.1% bupivacaine/fentanyl 2 ug /ml or 10 ml of 0.25%
bupivacaine, the catheter is probably not in the epidural space
and it should be withdrawn and re-sited.
• Missed segment or unilateral block. Groin pain is
the most common manifestation  small bolus,
e.g. 5 ml of 0.25% bupivacaine.
• Hypotension. exclude aortocaval compression+
Intravenous fluids + ephedrine

11. CSE for labour and the 'walking' epidural
• intrathecal injection of 1 ml 0.25% bupivacaine with 25
ug fentanyl is given.
• rapid-onset analgesia (< 5 min) and approximately 70%
of patients
• have normal or near-normal leg power such that they
may walk.
• commencing with a 15 ml bolus of bupivacaine 0.1%
bupivacaine/fentanyl 2 ug /ml without a test dose, as
described above. potentially making walking hazardous.
• The medicolegal position of the anesthetist in the
event of a fall of a parturient during a walking epidural
is unclear.

12. Thank you