Analgesia for Labor and Vaginal delivery

Question 1

What are the qualities of the ideal anesthetic in OB?

Answer 1

• Effective and controllable analgesia
• maternal safety
• no weakening of maternal powers
• no alteration of maternal passages
• no depression of the passenger

Question 2

What are the analgesia options for labor and vaginal delivery?

Answer 2

• Non pharm
  
  • hypnosis, TENS, acupuncture, LaMaze, Hot water tubs
• Parental medications
  
  • poioids- meperidine, fentanyl, remifentanil
  • agonist-Antagonist drugs- Nubain, Stadol
  • Ketamine
  • Anxiolytics- midaz
• Neuraxial blocks
  
  • intrathecal opioids
  • epidural analgesia
• paracervical and pudendal blocks
• IA

Question 3

Meperidine

dose

onset

fetal exposure

metabolite

Answer 3

• Usual dose 25-50 mg IV, max dose < 100 mg IV total
• Onset 5-10 min; duration 3-4 hours
• Fetal exposure highest 2-3 hrs
  
  • crosses placental- causes fetal acidosis and neonatal resp depression
  • active metabolite normeperidine in neonate

Question 4

Is morphine an option?

Answer 4

• It is infrequently used
• linked to neonatal respiratory depression and somnolence
• leads to maternal sedation

Question 5

Fentanyl

dose

onset

problems

Answer 5

• High potence and short duration make it good for labor
• Dose 25-50 mcg IV (max 1 mcg/kg without neonatal depression)
• onset 3-5 min; duration 30-60 min
• Problems
  
  • potent maternal respiratory depression
  • cummulative effect over time
  • may affect newbord feeding

Question 6

Why isnt sufentanyl frequently used?

Answer 6

because of potency/maternal resp depression and neonatal bradycardia

Question 7

Remifentanil

dose IV and PCA

why is it better?

Answer 7

• IV bolus 0.4 mcg/kg q 1 min
• PCA bolus 0.25 mcg/kg then 0.05 mcg/kg/min, lockout 2 min, 4 hr limit 3 mg and background infusion of 0.025-0.05 mcg/kg/min
• Metabolism by blood esterases therefore maternal and neonatal accumulation low
• ultra short acting

Question 8

Why is butorphenol (Stadol) a good choice?

Dose?

Answer 8

• 1-2 mg IV or IM
  
  • duration 4 hours
• it is an Agonist-Antagonist; it has a “ceiling effect” on resp depression
• 5x as potent as morphine

Question 9

What is the other Agonist-Antagonist besides butorphanol?

Answer 9

• Nalbuphine (nubain)
• Dose: 5-10 mg IV, IM , or SQ
  
  • duration 6 hours
• causes less dysphoria than butorphanol
• less N/V than butorphenol
• similar sedation to butorphanol

Question 10

Midazolam dose?

Answer 10

0.5- 1 mg

to alleviate anxiety w/o causing detriment to parturient and fetus

Question 11

Ketamine

dose

SE

Answer 11

• 10-15 mg IV for intense analgesia for 10-15 min w/o causing problem to mom or fetus
• 25-50 mg (0.5 mg/kg) to supplement an incomplete neuraxial block during c/s
• at higher doses, dissociative anesthetic associated with emergence/delirium and hallucinations
• High dose can increase uterine tone

Question 12

What IA are used during labor? How?

Answer 12

• Goal:
  
  • pain relief while maintaining consciousness and protective laryngeal reflexes
• Self administered intermittently during contraction or continuously
• Entonox (50:50 N2O:O2 mixture)
• Sevo (0.8%)

Question 13

What are the regional techniques and other blocks used for labor and vaginal delivery?

Answer 13

• Regional
  
  • epidural- walking epidural
  • spinal
  • CSE
• Other blocks
  
  • paracervical block
  • pudendal block
  • local perineal infiltration

Question 14

What are some problems with epidural anesthesia?

Answer 14

• cessation or slowing of labor
• asymmetrical/patchy block
• dense motor block
• migration of catheteraccidental dural puncture
• accidental intravascular injection
• toxicity
• hypotension
• fetal compromise
• N/V

Question 15

What are some absolute contraindications of epidural or spinal anesthesia?

Answer 15

• refusal
• no resuscitative equipment
• increased ICP
• hypotension/instability
• coagulopathy
• infection at site
• untreated bacteremia
• severe stenotic valvular heart lesions

Question 16

What shuold you do to prepare for an epidural placement?

Answer 16

• informed consent
• monitor vital signs, FHR, contractions
• fluid load
• supplemental oxygen
• ? labs

Question 17

where do you insert an epidural for labor?

Answer 17

below L2

Question 18

What is the technique for epidural placement?

Answer 18

• Parturient should be in active labor with cervical dilation about 4 cm- bigger is too late
• sitting or lateral position
• BP q 2 min
• insert below L2
• Insert catheter 4-6 cm
  
  • this is deeper than normal because of movement during labor

Question 19

How do you manage an epidural?

Answer 19

• place test dose to make sure it is not subarachnoid or intravascular
• administer bolus
  
  • do not start continuous infusion until satisfactory block is obtained to at least T-10 level
  • continuouse infusion (CLE) is used to maintain the block, not elevate or intensify

Question 20

When is a Spinal indicated?

advantages and disadvantages?

Answer 20

• very early labor
• distressed parturient to enable epidural placement under controlled conditions
• instrumental deliveries
• when epidural analgesia not possible
• Advantage: rapid onset
• disadvantage: lacks flexibility, finite duration

Question 21

What are some side effects of neuraxial opioids?

Answer 21

• pruritis
• N/V
• urinary retention
• drowsiness
• resp dep
• fetal bradycardia

Question 22

Why would you consider a combined spinal/epidural?

Answer 22

• spinal is rapid and effective analgesia
• epidural is prolonged and can convert to surgical anesthesia
• Adv: greater sensory block, minimal motor block
• dis: increased frequency of nonreassuring FHR tracing and fetal bradycardia

Question 23

How should you manage Neuraxil analgesia?

Answer 23

• monitor the level of the block q 1 hr
• monitor mother VS/FHR
• monitor contractions
• monitor mother’s LOC
• look for signs of toxicity
• keep LUD/ avoid supine
• treat hypotension

Question 24

What level do you need blocked for a C-section?

Answer 24

T4

may affect cardiac accelerators

Question 25

What level do you need blocked for the first stage of labor? 3rd stage?

Answer 25

T-10 sacral region

Question 26

What is the significance of a numb little finger?

Answer 26

C-8 block All cardioaccelerator fibers are blocked

Question 27

What is the significance of a numb inner aspect of arm and forearm

Answer 27

T1 & T2 block Some degree are cardiac accelerators are blocked

Question 28

What is the significance of numbness at the niple line?

Answer 28

T4-T5 possibility of cardiac accelerator block

Question 29

What is the significance of numbness at the umbilicus?

Answer 29

T10 sympathetic blockade is limited to lower limbs

Question 30

What are some side effects of LA toxicity? first signs progressing to later/more significant

Answer 30

* circumoral numbness * tinnitus * vision changes * slurred speech * muscle twitching * irrational conversation * unconsciousness * Grand Mal confulsion * Coma * apnea

Question 31

How to treat LA toxicity?

Answer 31

* 100% O2 and intubate if necessary * barbituates or benzos if seizing * support BP with IVF and pressors * CPR * treat bradycardia with atropine * **intralipids** * consider delivery of fetus

Question 32

What are the symptoms for postdural puncture? treatment?

Answer 32

* HA with stiff neck and photophobia * onset may be 1-2 days * treatment * bedrest * over the counter analgesics * hydration * caffeine( 300 mg oral or IV) * Epidural blood patch

Question 33

How is an epidural blood patch done?

Answer 33

* place Tuohy needle into epidural space, preferably at same interspace * assistant draws 15-20 ml of venous blood from pt * inject blood into epidural space * remove Tuohy needle * bedrest 1 hr * then light activites for few hours * effective in 90% of patients * can perform 2nd patch