Obstetrics Anesthesia Power Point prepared by Natnael Dechasa, who is an outstanding and gold medalist graduate of applied human nutrition at Bahir Dar University in 2022.

1. OBSTETRICAL ANESTHESIA
NATNAEL DECHASA (MSc .)

2. ANALGESIA FOR LABOR AND DELIVERY
Contents/outline/
• Where is the pain coming from?
• Is pain bad in labor?
• What are analgesic options ?
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3. PAIN OF CHILDBIRTH
Nociceptive pathways involved
 T10 – L1 during labor &
 S2-S4 for delivery
NB#
10 ml of lignocaine 1% is
injected into the episiotomy by
injection around it.
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4. PAIN OF CHILDBIRTH…
Psychological stress can cause:
increased levels of catecholamines & hyperventilation
These may result in decreased uterine blood flow leading to hypoxia and
acidosis in the fetus.
NB#
Catecholamines are important neurohormone in stress responses.
High levels cause high blood pressure which can lead to headaches, sweating,
pounding of the heart, pain in the chest, and anxiety.
E.g. Dopamine, epinephrine (adrenaline)
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5. FACTORS AFFECTING PAIN PERCEPTION IN LABOR
• Mental preparation
• Family support
• Medical support
• Cultural expectations
• Underlying mental status
• Parity
• Size and presentation of the fetus
• Maternal pelvic anatomy
• Duration of labor
• Medications
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6. ANALGESIA FOR LABOR AND DELIVERY
• Non-medication
• Inhalational
• Parenteral
• Regional
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7. ANALGESIA- NON MEDICATION OPTIONS
• Hypnosis
• Breathing exercises
• White Noise/ Music
• Massage/ walking
• Water bath
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8. HYPNOBIRTHING
• The laboring person uses positive affirmations, suggestions, and
visualizations to relax their body, guide their thoughts, and control
breathing.
• This can be done through self-hypnosis or by receiving assistance from a
hypnotherapist.
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9. BREATHING EXERCISES
• Put one hand on your belly just below your ribs and the other hand on your chest.
• Take a deep breath in through your nose, and let your belly push your hand out.
Your chest should not move.
• Breathe out through pursed lips as if you were whistling.
• Do this breathing in between or during contractions.
•
• st.
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10. WHITE NOISE/ MUSIC
• Audio analgesia, or using music, white noise or environmental sounds like
waves crashing, boosts mood, reduces anxiety and stress, and can lessen
pain during labor.
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11. MASSAGE & WALKING
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12. WATER BATHING
 Warm water immersion in labour can diminish stress hormones (catecholamines)
and reduce pain by increasing the body's production of pain relievers
(endorphins).
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13. RARELY …USED
Aromatherapy,
• Essential oils can help reduce sensations of labor pain,
as well as nausea, vomiting, and headaches.
Acupuncture.
• It's used to promote labor, ease labor pain, and reduce obstruction.
• Acupuncture can be especially helpful to ripen the cervix, release oxytocin,
and encourage a more natural, efficient labor.
Others…
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14. INHALATION MEDICATIONS/#/
• Nitronox: 50:50 mixture of oxygen and nitrous oxide
• Low dose Isoflurane in oxygen.
Advantages: on demand delivery, relatively safe
Disadvantages: variable efficacy, nausea, drowsiness, neonatal
depression
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15. LOCAL ANESTHETICS
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16.  Good for the pain of cervical dilation phase but no help for the
perineum
 3-5cc in each site( always aspirate 1st)
 Complications are lacerations, intravascular injection, Parametrial
hematoma, abscess, and hypotension
Fetal complications of para cervical block
Up to 70% get bradycardic (last 2-10min)
PARA CERVICAL BLOCK
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17. PARA CERVICAL BLOCK
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18. PUDENDAL BLOCK
• Transvaginally or transperineal
• Use a needle guide (Iowa trumpet)
• 7-10cc each side of lidocaine1% or chlorprocaine 2%
• For pelvic outlet manipulations(2nd stage)
Complications of Pudendal blocks
Systemic toxicity(IV)
Vaginal laceration
Vaginal or ischiorectal hematoma
Retro psoas or sub gluteal abscess
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19. PUDENDAL BLOCK
 7-10cc each side of lidocaine1% or chlorprocaine 2%
To relieve pain during the second (pushing) stage of labour, an injection called
a pudendal block can be given through the vaginal wall and into the pudendal
nerve in the pelvis.
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20. PERINEAL INFILTRATION
• Local infiltration of the perineum is a simple and commonly
used technique for providing pain relief for episiotomy &
repair of perineal lacerations
• Most common anesthetic
• Best choice is lidocaine
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21. EPIDURAL ANESTHESIA
 Best anesthesia for PIH
 More technically challenging
 Slower onset
 Need prior IV hydration
 Continuous monitoring of the FHR and contractions
 Used in SVDs & CS
 Used for CS when already placed for labor analgesia
 Placed at L2-3 or L3-4
 Continuous infusion better than boluses
 15mg/hrBupivicaine and Chlorprocaine have become the agents of
choice for epidural anesthesia (IV of either can cause cardiac collapse
and death
 Continuous infusion better than boluses
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22. EPIDURAL ANESTHESIA
Potential Complications:
• Hypotension
• Headache (approx 1:100)
• Transient backache ~24hrs
• Urinary retention
• Unintentional spinal injection
• Intravascular injection of
local anesthetic
• Neurological damage
• Infection
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23. ANEST…FOR CAESAREAN SECTION
Contents
• Preparation
• Preventing complications
• Choice of Anesthetic technique
• Effects on the fetus
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24. PREPARATION
• Premeds: antacid (sodium citrate)
• IV access and fluid bolus within 30 minutes of operating .
• Left lateral tilt with wedge under right pelvis
• Routine Monitors: pulse oximeter, fetal monitoring
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25. PREVENTING COMPLICATIONS
• Aspiration prophylaxis
• Detailed airway assessment
• Fluid resuscitation/left lateral tilt to prevent hypotension
• Safe practice for placement of neuraxial blocks.
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26. ANESTHETIC TECHNIQUES
• Local infiltration by surgeon
• Regional anesthesia: spinal, epidural, combined spinal-epidural
• General anesthesia
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27. LOCAL INFILTRATION
• Rarely performed
• Patient usually in extremis
• Surgery must be done via midline incision, gentle retraction, no
exteriorization of the uterus
• Usually done to supplement a regional technique if local
anesthetic toxicity not a concern
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28. SPINAL ANESTHESIA
 Administered in the
subdural space
 Simple to perform
 Rapid onset
 Single shot technique
 Profound neural block
 Technique of choice for caesarian section
 Considered to intersect the body of L4 or the L4-L5 intervertebral
space.
 In younger children, it passes through L5 –S1.
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29. SPINAL ANESTHESIA
Potential Complications:
• Hypotension
• Headache (rare ~1:100)
• Backache (temporary ~24hrs)
• Nausea/vomiting (secondary to BP, narcotics)
• Neurological damage (very rare)
• Anaphylaxis (very rare)
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30. COMBINED SPINAL-EPIDURAL
• Used when require the speed and density of a spinal anesthetic with
the flexibility of prolonging the block by supplemental increments of
local anesthesia via the epidural catheter
• Complications: as mentioned for spinals and epidurals
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31. LANDMARKS & ANATOMY
T7
T12-L1
L4
S2
The standard positions recommended for an
spinal anesthetic injection are
 Sitting and lateral decubitus positions with
an optimal flexion of the back.
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32. HIGH/TOTAL SPINAL
• Mechanism: Blockade of neuronal transmission in the cervical spinal cord
and brainstem.
• Risk Factors
• Prior Epidural
• Large spinal anesthetic dose
• Immediate supine positioning
• Increased intra-abdominal pressure (pregnancy and truncal obesity)
• Management: MOSTLY SUPPORTIVE!
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33. HEMODYNAMIC COMPROMISE
1. HYPOTENSION
• IV Fluid bolus
• Vasopressors: Ephedrine, phenylephrine
• Left lateral tilt
2. BRADYCARDIA
• Atropine 0.5mg IV, may repeat if necessary
• Epinephrine 50-100 mcg IV,preferred, especially if severe
hypotension or unresponsive to other vasopressors.
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34. GENERAL ANESTHESIA
Used when
• Patient refuses regional technique
• Regional technique is contraindicated
• Emergency C/S when there is inadequate/absent regional
analgesia and to delay will cause undue risk to the fetus /
mother
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35. GENERAL ANESTHESIA
• Complications:
• Failed intubation
• Failed ventilation causing death or neurological injury
• Awareness
• Aspiration pneumonia
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36. CHANGES DURING PREGNANCY & ANESTHETIC IMPLICATIONS
• AORTOCAVAL COMPRESSION
• Left uterine displacement AORTOCAVAL COMPRESSION
• RAPID DESATURATION
• If GA, need adequate
pre-oxygenation and rapid intubation
• DIFFICULT INTUBATION
• Use smaller Endotracheal tube.
• Optimize maternal positioning.
• ASPIRATION RISK
• Ideally patient is NPO during labor
• Administer premedication with clear antacid (e.g. sodium citrate PO)
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37. REFERENCE
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38. THANK YOU
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