Analgesia for Labor and Vaginal delivery Flashcards
What are the qualities of the ideal anesthetic in OB?
- Effective and controllable analgesia
- maternal safety
- no weakening of maternal powers
- no alteration of maternal passages
- no depression of the passenger
What are the analgesia options for labor and vaginal delivery?
- 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
Meperidine
dose
onset
fetal exposure
metabolite
- 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
Is morphine an option?
- It is infrequently used
- linked to neonatal respiratory depression and somnolence
- leads to maternal sedation
Fentanyl
dose
onset
problems
- 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
Why isnt sufentanyl frequently used?
because of potency/maternal resp depression and neonatal bradycardia
Remifentanil
dose IV and PCA
why is it better?
- 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
Why is butorphenol (Stadol) a good choice?
Dose?
- 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
What is the other Agonist-Antagonist besides butorphanol?
- 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
Midazolam dose?
0.5- 1 mg
to alleviate anxiety w/o causing detriment to parturient and fetus
Ketamine
dose
SE
- 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
What IA are used during labor? How?
- 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%)
What are the regional techniques and other blocks used for labor and vaginal delivery?
- Regional
- epidural- walking epidural
- spinal
- CSE
- Other blocks
- paracervical block
- pudendal block
- local perineal infiltration
What are some problems with epidural anesthesia?
- 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
What are some absolute contraindications of epidural or spinal anesthesia?
- refusal
- no resuscitative equipment
- increased ICP
- hypotension/instability
- coagulopathy
- infection at site
- untreated bacteremia
- severe stenotic valvular heart lesions
What shuold you do to prepare for an epidural placement?
- informed consent
- monitor vital signs, FHR, contractions
- fluid load
- supplemental oxygen
- ? labs
where do you insert an epidural for labor?
below L2
What is the technique for epidural placement?
- 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
How do you manage an epidural?
- 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
When is a Spinal indicated?
advantages and disadvantages?
- 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
What are some side effects of neuraxial opioids?
- pruritis
- N/V
- urinary retention
- drowsiness
- resp dep
- fetal bradycardia
Why would you consider a combined spinal/epidural?
- 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
How should you manage Neuraxil analgesia?
- 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
What level do you need blocked for a C-section?
T4
may affect cardiac accelerators
What level do you need blocked for the first stage of labor?
3rd stage?
T-10
sacral region
What is the significance of a numb little finger?
C-8 block
All cardioaccelerator fibers are blocked
What is the significance of a numb inner aspect of arm and forearm
T1 & T2 block
Some degree are cardiac accelerators are blocked
What is the significance of numbness at the niple line?
T4-T5
possibility of cardiac accelerator block
What is the significance of numbness at the umbilicus?
T10
sympathetic blockade is limited to lower limbs
What are some side effects of LA toxicity?
first signs progressing to later/more significant
- circumoral numbness
- tinnitus
- vision changes
- slurred speech
- muscle twitching
- irrational conversation
- unconsciousness
- Grand Mal confulsion
- Coma
- apnea
How to treat LA toxicity?
- 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
What are the symptoms for postdural puncture?
treatment?
- 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
How is an epidural blood patch done?
- 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
