24.preparation of delivery. obstetric aneshesia.

Question 1

what are the general guidelines of obstetric anesthesia?

Answer 1

Vaginal delivery → epidural anesthesia

Elective C-section → spinal anesthesia

Emergency C-section → general anesthesia

Question 2

what parenteral narcotics can be used?

Answer 2

Fentanyl and nalbuphine are most commonly used and have short neonatal half-lives;
remifentanil, an ultra-short-acting narcotic

work best in the early first stage of labor, when the pain is primarily visceral and less intense

Question 3

Pudendal nerve block

Answer 3

Anesthetizes somatic afferent nerve fibers entering the spinal cord at sacral segments S2-S4.

Question 4

what is the effect of a pudendal nerve block

Answer 4

relieving the perineal pain associated with the second stage of labor, as well as the pain of episiotomy and episiotomy repair.
It does not affect the ongoing pain of uterine contractions.

Question 5

Epidural anesthesia management

Answer 5

an initial bolus of local anesthetic (bupivacaine, ropivacaine, lidocaine), as well as narcotics (fentanyl) to achieve a T10 sensory level, followed by an infusion of a dilute solution of the same agents until delivery

Question 6

what is the goal of Lumbar epidural analgesia?

Answer 6

provide pain relief for the first and second stages of labor and, by injecting a higher concentration of local anesthetic, the block may be intensified and extended to provide surgical anesthesia for cesarean delivery or postpartum tubal ligation

Question 7

Combined spinal-epidural technique is used for?

Answer 7

rapid onset of analgesia and/or anesthesia and the prolonged administration capability of an epidural catheter.

Question 8

Potential side effects of epidural anesthesia

Answer 8

• Maternal hypotension (prevent by infusing 1 L of crystalloid solution before the procedure)
• Prolonged second stage of labor (by approx. 15 min’)
• Partial/complete motor block, may cause complete inability to push
• Maternal fever
• Headache (positional headache, worse with sitting or standing), usually resolves within 5-7 days
• Backache

Question 9

in what location is the spinal anesthesia performed?

Answer 9

below L1/L2 (cauda equina)
Injected to the subarachnoid space
(puncture through the dura mater)

Question 10

what type of anesthesia is a more denser block?

Answer 10

Spinal anesthesia

Question 11

what type of anesthesia has a slower onset of action?

Answer 11

Epidural anesthesia (15-20 min’)

spinal- 2-5 min’

Question 12

what type of anesthesia has a greater risk for post-dural puncture headache?

Answer 12

spinal anesthesia

Question 13

Hypotension is slower in..

Answer 13

epidural anesthesia

rapid in spinal

Question 14

in what location do we perform epidural anesthesia?

Answer 14

any level of the spinal cord
Injection to the epidural space
(between ligamentum flavum and dura mater)

Question 15

absolute contraindications to regional anesthesia

Answer 15

1. Patient refusal
2. Coagulopathy
3. Infection at needle insertion site
4. Severe hypovolemia with ongoing bleeding

Question 16

relative contraindications to regional anesthesia

Answer 16

Prior back surgery
Certain cardiac lesions (aortic stenosis)
Elevated ICP

Question 17

why is regional anesthesia is preferred for elective or urgent cesarean deliver (non-emergency)?

Answer 17

because the airways are maintained

Question 18

in what situations is General anesthesia employed?

Answer 18

(1) Extreme urgency and no preexisting epidural catheter
(2) There is a contraindication to regional anesthesia
(3) Regional anesthesia has failed (< 2% incidence)

Question 19

what induction agents are used for general anesthesia in emergent cesarean delivery?

Answer 19

Propofol (most common),
etomidate (when cardiovascular stability is particularly desirable), and ketamine (for patients with hypovolemia or asthma).

*All anesthetic agents that depress the maternal CNS can cross the placenta and depress the fetal CNS as well; this may result in newborn respiratory depression