Pocket ObGyn – Local Anesthenia in Obstetrics 
See Abbreviations

• Indications for local anesthetics

Skin infiltration for episiotomies/assisted deliveries (nonemergent settings), lacera- tion repair

Nerve blocks: Pudendal, paracervical (close proximity to large vessels ® higher potential for tox)

Spinal & epidural anesthesia

• In an emergent setting where access to general anesthesia will be delayed, local anesthetics may be administered in large amts to perform C/S, followed by general anesthesia when available

 

Figure 4.2 Pudendal block

Reprinted with permission from Beckmann CRB, Ling FW, Laube DW, et al. Obstetrics and Gynecology. 4th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2002.

NonPharmacologic Analgesia in Obstetrics

• Advantages: Empowering, few side effects, may improve overall satisfaction w/ labor experience
• Disadvantages: Incomplete relief, pts may perceive eventual pharm rx as failure
• Evid: Many nonpharmacologic methods have not been well studied

 

Nonpharmacologic analgesia methods
Method	Effect
Labor support	Decreased analgesic, shorter labor; more likely to have spont vaginal deliv; greater satisfaction. Should be continuous, one-to-one nursing (Cochrane Database Syst Rev 2011;2:C003766)
Breathing	Lack of evid for pain control, but may be calming
Touch, massage	Massage & casual touch ¯ anxiety, perception of pain (J Nurse Midwifery 1986;31:270)
Music	Improves satisfaction, decreases distress, may ¯ need for analgesia (Pain Manag Nurs 2003;4:54)
Hydrotherapy	No change in labor outcome or use of rescue analgesia; does delay request for analgesia by 30 min (BMJ 2004;328:314)
Hypnosis	Women using self-hypnosis may have significantly decreased use of epidural anesthesia, better satisfaction.Very limited evid; not all women can successfully use hypnosis (BR J Anaesth 2004;93:505)
Acupuncture	Does not provide adequate analgesia. No std; few trials
TENS	Not effective pain relief during labor when compared to placebo
Sterile water injections	Rationale of counter-irritation: Irritate nerves in dermatome of pain. May be useful for back pain a/w labor; however, no change in labor outcomes or use rescue analgesia. Disadvantage of acute somatic pain during injection (Cochrane Database Syst Review 2012)

General Anesthesia in Obstetrics

• Rarely indicated for vaginal deliv except for emergent, unanticipated procedures (eg, breech extraction, internal version, shoulder dystocia)
• In US, 10% of C/S are performed under general anesthesia (Anesthesiology 2005;103:645) Emergent (“crash”) C/Ss are the most common setting for general anesthesia Other situations include nonemergent C/S in a pt w/ absolute contraindications to

neuraxial anesthesia

Advantages: Rapid, complete anesthesia; ability to administer 100% oxygen

Disadvantages: Risk of difficult intubation; risk of aspiration; small risk of infant respiratory depression; anesthetics cause uterine atony, leading to more bld loss

•   Other uses:

Uterine inversion: Obstetric emergency where body of uterus inverts following deliv

Nitric oxide or halogenated anesthetics relax uterus & facilitate replacement. Nitroglycerine may be given IV/sublingually if delay in general anesthesia is anticipated.

Can be considered in cases of retained placenta due to bandl’s ring or head entrapment for breech extraction; must balance w/ risk of uterine atony

Postoperative Pain Management

• Post C/S pain include visceral (uterus) & somatic pain (abdominal wall).
• Multimodal rx regimens

Goals: (1) Adequate pain control, (2) ¯ opioids to ¯ assoc side effects such as N/V, ileus, sedation, & effects on infant via secretion of active compounds into breast milk

• Oral pain meds – preferred mgmt once pt is tolerating PO Opioids – carry above side effects

NSAIDs – important adjuvant therapy to reduce opioid exposure Esp effective on visceral pain from uterine involution

Also available as 12 h IV formulation (ketorolac) for up to 4 doses postop

Breast-feeding: Opioids & NSAIDs considered generally compatible w/ breast- feeding

Exception: Meperidine – prolonged infant sedation by active metabolite normeperidine

 

Postoperative pain management after cesarean section
Method	Advantages	Disadvantages
Epidural/spinal: Single dose long-acting opioid Morphine, morphine XR Fentanyl Sufentanil Hydromorphone	Better pain relief than PCA, less systemic side effects Long acting Can remove catheter after dose	Pruritus N/V Respiratory depression potential – need extended monitoring
PCEA	Same pain relief as above Decreased side effects Pt control ® less total drug used	Pruritus N/V Catheter must remain in place
Epidural/spinal: Addition of local anesthetic	¯ dose of opioid side effects	More motor blockade
Patient-controlled IV analgesia: PCA	Superior to IM opioid	Sedation – less w/ demand- only dosing
Wound infiltration Single injection or catheter left in wound	Decreased systemic effects Decreased total dose of analgesic used	No effect unless catheter left in wound for continued infiltration
Transversus abdominis plane block T6–L1 nerve root block w/ local anesthetic	Improves pain control in women who do not receive intrathecal morphine; less side effects (Can J Anesth 2012;59:766)	Requires postop procedure

•   Postpartum bilateral tubal ligation:

Avoid long-acting intrathecal/epidural opioid/local anesthetic if goal is discharge soon after procedure. Infiltration of skin, fallopian tubes w/ local anesthetic shown to ¯ total analgesic use, ­ time to analgesic use postoperatively. Sufentanil, bupivacaine, lidocaine all effective.

See Abbreviations