Analgesia and Anesthesia in Obstetrics SUPER VISED BY ; ASIS.PROF.MOHAMMED AL-KHATIM Done by :Eman Abdullah AL- otibi
Dec 26, 2015
Analgesia and Anesthesia in
ObstetricsSUPER VISED BY;
ASIS.PROF.MOHAMMED AL-KHATIM
Done by :Eman Abdullah AL- otibi
Objective:
1-Introduction about anesthesia in pregnancy 2-Uterine innervations and Pain pathway3- list the different types ,uses ,complications ,contraindications and Factors determining the choice of anesthesia. 4-special considerations while using anesthesia in labor including cardiovascular diseases and uterine inversion
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.
Definition: Anesthesia: is the absence of all
sensation ,including pain,touch,temperature,and pressure.
Analgesia: is the absence of nociceptive stimuli ,with the preservation of motor &touch sensation.
Ideal :allow the patient to participant in her labor and delivery .
Pain pathway:1-During first stage of labor(visceral pain): *Visceral pain produced by distention of
the uterous &cervix and ischemia of the uterine and cervical Tissue
* Pain signal traverse T10 to L12-During second stage of labor(visceral+
somatic)* Distention of the vagina ,perineum and
pelvic floor* Pain signals traverse the pudendal
nerve ( S2 to S4)* more somatic pain
Type of anesthesia &analgesia:
1-non pharmacological 2-pharmacological
-#Non pharmacological :use In a highly motivated patients this may be all that they require
1-relaxation and concentration on breathing2-Massage - including aromatherapy
3-Acupuncture and acupressure4 -audioanalgesia.
5-maternal movement and positioning.#Pharmacological:
1-local injection2-periphral nerve block
3-regional (epidural, spinal)4-systemic(IV, IM ,inhalation)
•5-general anesthesia
A)Local injection: (field bloke)
*indication: Used before episiotomies &for repair of episiotomies or tears that occur during and after
delivery
* Advantage : no systemic complication if administered correctly
* Complication: (rare) systemic complication - toxicity may cause hypotension, arrhythmia and
seizures.
(The maximum dose of lidocaine should be 4.5mg\kg per dose)
Commonly used agent include lidocaine (1% to 2%) or 2-chloroprocaine (1% to 3%) which provide anthesia
20 -40 mint...
B)Peripheral nerve block (pudendal, paracervical)
*indication:
- Paracervical block used in →-first stage of labor in patient in which the
epidural or spinal contraindicated - rarely used today duo 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 compromise (rarely occur)
♠maternal toxicity from rapid absorption of the drug
C)regional(epidural, spinal)
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.
Application
(CSE )Combined spinal epidural The needle-through-needle approach.
A single bolus of opiod,perhaps with local anesthetic into subarachanoid 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 .
loss of pain sensation occurs below the T8 to T10 levels, with varying degrees of motor blockage.
Indications:1-1st stage of labor.(preferred method of birth control)
2 -difficulty with intubation.3 -a history of malignant hyperthermia.
4 -CVS or respiratory disorders.5 -preeclampsia.
Advantage :
provide effective anesthesia &yet allows patient to participates in her labor &delivery.
*Complication:
1-Infection:meningitis ,epidural abscess
2-Neurological complication :
♦ Spinal headache: -may result in up to 70% of patient .
- ttt 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
.
3-drug-related complication:
♦Systemic toxicity: tinnitus, disorientation, and seizures.
CV symptoms include hypotension,
Cardiac arrest.
♦ High spinal: result in a more cranial progression of anesthesia.
♦ Motor bloc
4-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).☻ttt with IV fluids or small dose of ephedrine (5mg)
5-Fetal complication:♦ Malpresentation
) not clearly known increase risk of shoulder dystocia(
6-complication in labor;♦ Instrumentation
♦ prolongation of second stage of labor.
*contraindication: 1-patient's refusal
2-Uncorrected/untreated coagulopathy→ hematoma
3-Skin infection of the lower back→ meningitis.4-Bacteremia →meningitis.
5-Hypotension/hypovolemia6-↑intracranial pressure →herniation of
cerebral content through foramen magnum
D)Systemic (IV, IM, inhalation)
-Use opiods (morphine, mepridine),or mixed opiod agonist –antagonist(butorphanole).
- Have very limited efficacy for the relief of labor pain.- They work best in the first stage of labor.
*Indication based on maternal request*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.
E)-General anesthesia
Indication: ☻In urgent situation (shoulder dystocia,
head entrapment)☻ If there is contraindication to regional
anesthesia.
Advantage:♦Rapid onset of uterine relaxation occurs, which
is desirable with management of uterine inversion, internal/external cephalic version, or
fetal entrapment..
**Complication:1-Fetal side effect (respiratory
depression)→oxygenation, naloxone, intubation after delivery.
2-Uterine bleeding →managed by pitocin.3-Risk with intubation increase risk of aspiration
and hypoxia. 4 -Drug related complications: Potential side
effects of the intrathecal opioids include maternal respiratory depression and hypoxemia.
During the first stage of labor : visceral pain is mollified by the preferred use of regional anesthesia
♠During vaginal delivery the goal is block nociceptive pathway while preserve motor function
By☺ local anesthesia or peripheral nerve blocks . After delivery (post partum ) by oral analgesics.
♠During C.S:1 -better use regional anesthesia (safe, effective, and allows the mother to
interact with the baby soon after the delivery )2 -general anesthesia renders the patient unconscious and unable to
experience the moment of birth and is used in urgent situation..3 -local anesthesia can be used by the obstetrician who is familiar with
maximal doses.
Postoperative pain managementSystemic administration or continuation of the epidural Eventually tranitioned to oral pain medication..
#Special consideration: Cardiovascular diseases:
Regurgitant lesions : Regional anesthesia is better compared to general anesthesia, because It will Improve the blood supply.Stenotic lesions:The general anesthesia will be better compared to the regional one ,
because the regional anesthesia will further augments the hypotension. -Hypertension:
We have to balance Regional anesthesia will lead to more hypotension
Uterine inversion :Usually halothane is used to do relaxation, then we will evert the uterus .
Factors determining the choice of anesthesia1-fittness and condition of the mother2-type and duration of the condition .
3-condition of the fetus.4 -presence of contraindications.5 -opinion of the anesthesiologist
Summary :
Definition:Analgesia ,Anesthesia
Type of anesthesia &analgesia 1-non pharmacological
2-pharmacological
Reference