Analgesics

1. ANALGESIA
AND
ANESTHESIA IN
OBS-GYN
Tohouri Grace Gre Osso
IM-638
Topic 10

2. INTRODUCTION
• Labor and delivery is a time of intense pain, which is often influenced by the
psychological ,emotional , social, cultural , and physiological state of the
parturient .multiple methods of alleviating pain are currently available during
the birthing process.
• Anesthesia: is the absence of all sensation ,including pain, touch, temperature

3. Factors determining the choice of anesthesia
• fittness and condition of the mother
• type and duration of the condition.
• condition of the fetus.
• presence of contraindications.
• opinion of the anesthesiologist

4. Non-Phamacological
Used in highly motivated patients and the following may be all that they require
:
 Relaxation in warm water during first stage can lead to sense of well being
and concentration on breathing
 Massage - including aromatherapy
 Acupuncture and acupressure
 Audio analgesia
 Material movement and positioning
 Trans cutaneous electrical nerve stimulation
(TENS); it blocks pain fibers in the posterior ganglia of the spinal cord (the
gate theory)

5. Pharmacological
Local injection: (field block)
to induce the absence of sensation in a specific part of the
body.
• Indication: Used before episiotomies & for
repair of episiotomies or tears that occur
delivery
• Advantage : no systemic complication if
administered correctly
• Complication: (rare) systemic complication -
toxicity may cause hypotension, arrhythmia
• (The maximum dose of lidocaine should be
dose) Commonly used agent include lidocaine
chloroprocaine (1% to 3%).

6. Peripheral nerve block (pudendal,
paracervical)
• indication:
Paracervical block used in first stage of labor in patient in which the epidural
or spinal contraindicated ,it is rarely used today due to fetal adverse effect.
Pudendal block used as supplemental during second stage of labor if
epidural has not provide adequate analgesia to the sacral nerves. - Also use
in lower forceps.
• Advantages: highly effective and provide an alternative method of pain
control .
• Complication: IV injection→ hematoma ,infection; Para cervical block→ fetal
bradycardia is a common side effect (15%); Pudendal block→ fetal
bradycardia (rarely occur); maternal toxicity from rapid absorption of the
drug

7. Regional (epidural, spinal)
• Application
Epidural
1- introduce a catheter into epidural space through a needle usually into the
mid-lumber region . 2- The catheter is then secured to the patient's back with
adhesive tape. 3- Medication is administered via the epidural route using
continuous infusion pumps. 4- A test dose may be given to ensure the correct
position of catheter.
(CSE)Combined spinal epidural
The needle-through-needle approach.
A single bolus of opioid, perhaps with local anesthetic into subarachnoid
space, in addition to an epidural catheter placement in the lumbar epidural
space.This method combine a rapid onset of action of spinal with epidural to
provide long-lasting throughout the labor and delivery process.
Hyperbaric bupivacaine (5-10 mg) or lignocaine (25-50 mg) is used.

8. Technique of epidural analgesia
• IV infusion of crystalloids (hartmanns or N/S) prior to insertion of 500-1000cc preload to prevent hypotension,
Catheter inserted at L2-L3 or L4-L5 interspace in the epidural space which contain blood vessels and nerve roots.
Then small dose is shot into the catheter using drug bupivacaine if no effect on sensation in the lower limb the
catheter is in correct space wait for 5 minutes and then complete the dose
• While if there is leg weakness and vasodilationso the catheter is in the suarachnoid space (spinal) if we give the
normal dose it causes complete motor and respiratory paralysis
• Keep the patient later position never supine, cheque blood pressure if hypotension occur give IV fluid and may
need ephedrine (vasoconstrictor)
• The regional analgesia is maintained by intermittent or continuos infusion

9. • Indications: 1st stage of labor.(preferred method of birth control),
difficulty with intubation, history of malignant hyperthermia, CVS or
preeclampsia.
• Advantage :provide effective anesthesia & yet allows patient to
delivery
• Contraindication:
patient's refusal, Uncorrected/untreated coagulopathy-> hematoma,
lower back -> meningitis, Bacteremia -›meningitis,
pressure -> herniation of cerebral content through foramen magnum

10. Complications of CSE
Infection: meningitis epidural abscess
Neurological complication:
• Spinal headache: -may result in up to
70% of patient.
• Tx: include analgesics, supine
positioning, hydration
• Obstetric nerve palsies:
the commonly injured nerves include
lumbosacral trunk, lateral Coetaneous
nerve, femoral nerve, and common
peroneal.
• back pain
Drug-related complication:
• Systemic toxicity: tinnitus, disorientation,
and seizures.
CV symptoms include hypotension,
Cardiac arrest.
• Hypotension: (because dilatation of
vascular beds decrease in venous return)
become significant if clinical sign are shown
in the mother (light-headedness Or
fetus(bradycardia).
• Tx: with IV fluids or small dose of
ephedrine (5mg)
• Fetal complication: Malpresentatio (not
clearly known increase risk of shoulder
dystocia)
• Complication in labor; Instrumentation,
prolongation of second stage of labor.

11. Systemic (IV, IM, inhalation)
• Opioids (morphine, mepridine),or mixed opioids agonist –antagonist
(butorphanole).
Have very limited efficacy for the relief of labor pain. They work best in the
first stage of labor.
o Indication based on maternal request
o Complication:
• Mother & fetus respiratory depression(cross placenta barrier),
• If there is continuous sign of respiratory depression→ repeated dose of
naloxone are indicated.
• Fentanyl & nalbuphine have the shortest neonatal half-lives of the commonly
used.

12. General Anesthesia
General anaesthesia or general anesthesia is a medically induced loss of consciousness that renders the patient
unarousable even with painful stimuli.
• Indication: URGENT SITUATION (shoulder dystocia, head entrapment), if there is contraindication to regional
contraindication to regional anesthesia.
• Advantage: Rapid onset of uterine relaxation occurs, which is desirable with management of uterine inversion,
of uterine inversion, internal/external cephalic version, or fetal entrapment.
• Complication:
o Fetal side effect (respiratory depression) -> oxygenation, naloxone, intubation after delivery.
o Uterine bleeding -managed by pitocin/oxytocin
o Risk with intubation increase risk of aspiration and hypoxia.
o Drug related complications: Potential side effects of the intrathecal opioids include maternal respiratory depression and
hypoxemia.