Anesthesia for Labor, Vaginal, and C/S deliveries Flashcards
What is the first stage of labor and delivery?
onset of uterine contractions to complete cervical dilation, includes ischemic pain of uterine contraction and visceral pain from T10-L1
What is the second stage of labor and delivery?
complete cervical dilation to delivery of fetus, includes somatic pain from fetal descent from S2-S4
What is the third stage of labor and delivery?
delivery of placenta
What are the goals for pain relief during labor and delivery?
- decreased sense of uterine contraction and of fetal descent
- preservation of pressure sensation to facilitate expulsive efforts
- minimal motor block to improve effectiveness of expulsive efforts
- inform mom that pressure and pain are not the same thing and pressure is good for baby and her
What inhalation agents are used for labor and delivery?
Nitrous oxide
- commonly used in UK
- valuable for brief analgesia such as for emergent forceps
- increased sensitivity of parturient makes it esp. effective
Volatiles agents
Does epidural analgesia change the rate of cervical dilation?
don’t know, there’s research that states it increases and decreases cervical dilation
What are the types of analgesia that can be used for labor and delivery?
- local anesthetics
- opioids
- adjuvants
- CLE/SAB/CSE
What local anesthetics can be used?
Bupivacaine (Marcaine, Sensorcaine)
Lidocaine (Xylocaine)
2-Chloroprocaine (Nescaine)
Ropivacaine
What opioids can be used?
Fentanyl
Sufentanil
Morphine
Meperidine
What are some adjuvants that can be used?
alpha 2 receptor agonists
epinephrine - used to prolong spinal anesthetics
Ketamine - good for spotty spinal/epidural
Nubain/Stadol - good for reversing heavy-handed narcotics
Naloxone/Nelmefene - good for reversing effects of intrathecal narcotics such as itching
Barbituates and tranquilizers (used in remote practices)
What are some CV physiologic effects of epidural/intrathecal analgesia?
Sympathetic block - veno and arteriodilation with decreased venous return and decreased afterload, hypotension with reflex tachycardia
Bradycardia with high block
What are respiratory effects of epidural/intrathecal analgesia?
- no significant effect if level kept low (
What are some fetal effects from epidural/intrathecal analgesia?
- decreased uteroplacental perfusion can result from prolonged maternal hypotension which can cause fetal acidosis
What are some fetal effects from all the drugs that can be given for analgesia?
- principal concern is sedation and respiratory depression from opioids, timing is important so don’t administer them too close to delivery
- transient FHR abnormalities have been reported after initial epidural and subarachnoid dose
What are some advantages of intrathecal opioids?
- ease of administration
- faster onset than epidural
- typically results in no motor blockade
- typically results in no alteration of vital signs
- effects are reversible for both mother and fetus
- often used in conjunction with CLE (CSE)
What are some disadvantages of intrathecal opioids?
- morphine has long latency and unsatisfactory for second stage of labor
- brief latency with most that do not last throughout first stage
- possibility of PDPH
- side effects that include respiratory depression, urticaria, N/V, urinary retention
What are the effects of intrathecal opioids on labor?
- no apparent effect on progress of labor when intrathecal opiates administered alone or with small amount of bupivacaine (exception of meperidine)
- more beneficial in use in some cardiac patients and for early or late use in labor
- no effect on uteroplacental perfusion
What are the opioids that can be given intrathecally?
fentanyl
sufenta
duramorph
meperidine
What is the onset and duration of fentanyl intrathecally?
- Fast onset within 5 minutes
- Provides analgesia anywhere from 1-3 hours
- Smaller incidence of side effects when compared with MSO4
What is the onset and duration of sufenta?
- Fast onset (within 5 minutes)
- Duration of action anywhere from 1-4 hours
- Analgesia more profound in reported cases than with fentanyl
What is the onset/characteristics/dose of intrathecal morphine?
- Dose 0.1-0.3 mg
- Slow onset (45-60 minutes)
- Typically not adequate to provide analgesia during entire labor
What is the onset/characteristics of intrathecal meperidine?
- onset of action within 10 minutes
- local anesthetic property
- higher incidence of nausea and motor blockade
- can be used to provide surgical anesthesia
What should you remember when combining intrathecal LA with opioids?
- effective and controllable analgesia
- maternal safety
- no weakening of maternal POWERS
- no alteration of maternal PASSAGES
- no depression of the PASSENGER
What is the most frequent combination of intrathecal LA and opioids?
PF isobaric bupivacaine 2.5 mg (small dose) with 20-25 mcg Fentanyl or 10-15 mcg Sufenta
What are some advantages of combining small dose LA with opioids?
- minimal motor blockade
- minimal alteration of vital signs
- can be given at any stage of labor
What is a disadvantage of giving a combination of intrathecal LA with opioids?
all side effects associated with intrathecal opioids
What helps your determine which type of LA to choose?
dependent on when and for what reason block is induced, typically given for immediate analgesia as needed in forceps delivery or if extensive repairs are needed
What LA and doses can be used for a saddle block?
Lidocaine 30-35 mg
Tetracaine 3 mg
Bupivacaine 7.5 mg
Why would you use a vasoconstrictor with LA?
- potentiates lidocaine and tetracaine
- no effect on bupivacaine
- LA properties
- use carefully with pre-existing HTN
What monitoring do you do with a spinal/epidural?
- fetal heart rate monitoring (cont.)
- uterine contraction monitoring (cont.)
- blood pressure monitoring (q5min for first 30 min then 15 min thereafter)
- pulse ox (first 30 mins)
- verbal (cont.)
- respiratory rate and heart rate
- anesthetic level monitoring
What is the epidural level and duration dependent on?
dose, volume, and concentration of LA
presence or absence of epi
What is the level and duration of an epidural not dependent on?
- weight, height, age, and rate of injection
- baricity of LA
- maternal position (although can have some influence)
What are opioids that can be used in an epidural?
fentanyl
duramorph
sufenta
What LA are used in epidurals?
chloroprocaine (rapid onset and short duration)
lidocaine (intermediate onset and duration)
bupivacaine (slow onset and prolonged duration)
ropivacaine being used more now
What are the 2 epidural techniques?
segmental block
continuous block
What is a segmental block epidural technique?
intermittent injections to isolate specific segments
What is a complete block epidural technique?
- intermittent or continuous infusions
- more stable depth of analgesia
- lower blood concentrations seen with continuous
- lower risk or complete spinal with continuous
- lower blood concentrations if migration of catheter
- lower incidence of hypotension
What is the loading dose and starting infusion rate for an epidural?
use loading dose to achieve level of analgesia and then start infusion of 8-12 mL/hr
At what level do you want a block before initiating continuous infusion?
at least T10-L1
How often should epidurals be monitored?
Check level carefully for first 30 min then hourly rounds on patients to check vital signs and level of block and note on anesthesia record
What are some of the effects on labor that can be caused by an epidural block?
- slow progression of labor
- cessation of labor
- can disrupt uteroplacental perfusion due to hypotension
- fetal hypoxia/asphyxia
- somnolence/hypoxemia
- nausea/vomiting
What are some problems with epidural analgesia?
- asymmetrical sensory block
- diminishing analgesia
- dense motor block
- patchy block
- migration of catheter
- LA toxicity
- hypotension
- maternal and fetal compromise
What do you monitor during epidural analgesia?
- vital signs
- fetal heart rate
- contractions
- level of block
- level of maternal consciousness/awareness
- oxygenation
- urinary output (lose sensation of when bladder is full)
What are some complications of epidural analgesia?
- inadvertent dural puncture
- subdural injection
- massive epidural analgesia
- vital signs
- inadvertent intravascular injection
What are characteristics of PDPH?
- positional, occurs when mom sitting up
- frontal to occiput
- visual disturbances
- nausea
- time
What is the treatment for PDPH?
- bedrest
- fluids
- caffeine
- theo-dur
- epidural blood patch
What can cause backaches and are they common?
- not common
- dependent on technique
- dependent on skill of practitioner
- studies show no increase in incidence when compared to normal labor
What are some obstetrical causes of neurological complications?
- prolapsed intervertebral disk (from exertional efforts causing spinal root compression)
- L4-L5 compression from descending head or use of forceps (see foot drop, hypothesia of foot and calf, quadriceps weakness)
- femoral nerve (L2-L4) injured from lithotomy position (see knee problems and quadriceps paralysis)
- LFC (L2-L3) injured during lithotomy and c-section, see transient numbness of thigh
- sciatic nerve (L4-S3) can be injured during lithotomy, see pain that radiates from gluteal to foot and inability to flex the leg
- obturator (L2-L4) injured with lithotomy causing weakness or paralysis of thigh adductors
- common peroneal nerve (L4-S2) injured during lithotomy position due to prolonged compression of lateral aspect of knee, lose ability to assume the erect position with foot drop
- saphenous nerve (L2-L4) injured during lithotomy position, loss of sensation over the medial aspect of the foot and anteriomedial aspect of the lower portion of leg
What are anesthesia related causes of neurological complications following spinal/epidural for analgesia?
- prolonged neural blockade (delayed recovery more pronounced with high concentrations of bupivacaine and tetracaine)
- bladder dysfunction
- shivering and shaking
- Horner’s syndrome
- Nerve root trauma
- Cauda equina syndrome/adhesive arachnoiditis
- epidural abcess/hematoma
What are anesthetic goals for regional anesthesia for a c-section?
- fetal safety
- maternal comfort
- no adverse impact on mode and/or duration of delivery
- no adverse impact on “birth experience”
What level do you want for regional anesthesia for a c-section?
T4
What types of regional anesthesia are available for c-section?
spinal/SAB
epidural (lumbar or caudal)
What are positioning considerations for a c-section?
- aortocaval compression
- left uterine displacement
- avoid systemic hypotension
- maintenance of uterine blood flow
What are problems with spinal anesthesia for c-section?
- hypotension
- n/v
- headache
- technical problems (large patients)
What premeds should you give before doing spinal/epidural anesthesia for a c-section?
30 mL NaCitrate PO
10 mg reglan
volume expansion and pre-load with crystalloid
What size and type of needle can you use to administer spinal anesthesia for a c-section?
25-27 g Sprotte or Whitacre
What is the concentration and dose of tetracaine for spinal anesthesia before a c-section?
1% Tetracaine in 10% dextrose
90-120 minutes
65” - 14 mg
What is the concentration and dose of bupivacaine for a spinal before a c-section?
0.75% bupivacaine in 8.5% dextrose
90-120 minutes
65” - 1.6 mL or 12 mg
What is the dose for opioids you can add to a spinal for postoperative analgesia following a c-section?
Fentanyl 25 mcg
MSO4 200 mcg
What are contraindications to spinal anesthesia for a c-section?
- severe maternal bleeding
- severe maternal hypotension
- coagulation disorders
- neurological disorders
- patient refusal
- short stature and morbidly obese
- sepsis in local area or generalized
What are advantages of epidural anesthesia for c-sections?
- less incidence and severity of maternal hypotension
- avoidance of dural puncture
- with catheter placement it can be redosed and give opioids
What are disadvantages of epidural anesthesia for c-sections?
- increased complexity of technique with greater incidence of failure
- slower onset (not used for emergent cases unless already in place )
- need for much larger amts of LA which can potentiate LAST
How much volume of LA do you need to give in an epidural for a c-section to achieve at least a T4 level?
about 20 mL
What concentration of bupivacaine can you use in an epidural for a c-section and how long will it last?
bupivacaine 0.5%
75-90 mins
What concentration of chloroprocaine can you use in an epidural for a c-section and how long will it last?
chloroprocaine 3%
35-40 mins
What concentration of lidocaine can you use in an epidural for a c-section and how long will it last?
lidocaine 2%
75-90 mins
What can you add to an epidural to speed the onset for a c-section?
NaBicarb
What are contraindications to epidural anesthesia?
- severe maternal hypotension
- coagulation disorders
- some forms of neurological disorders
- patient refusal
- technical problems
- sepsis, local or generalized
Can you use 0.75% Bupivacaine for an anesthesia epidural?
no, causes cardiac and CNS toxicity
What are some complications of chloroprocaine?
- arachnoiditis
- diminishing analgesia
- effect on bupivacaine
What are some differences between spinal and epidural anesthesia for c-sections?
- spinal more profound block
- epidural easier to control block height
- epidural better control of hemodynamics
- epidural opioids have less systemic side effects
What are other anesthetic blocks you can do for labor and delivery?
caudal block
paracervical block - manages visceral pain in 1st stage
pudendal block - manages somatic pain during 2nd stage
What are some indications for general anesthesia for a c-section?
- patient refusal of regional anesthesia
- fetal emergencies (abruption, prolapsed cord, etc)
- certain neuromuscular diseases - particularly with neurologic compromise
What are advantages of general anesthesia for a c-section?
- speed of induction
- reliability
- reproducibility
- controllability
- avoidance of hypotension
What are some disadvantages of general anesthesia for a c-section?
- possibility of maternal aspiration
- airway management
- narcotization of the neonate
- maternal awareness during light and general anesthesia (no midaz or narcs until cord is clamped)
What are complications of general anesthesia for a c-section?
- maternal aspiration
- maternal awareness
- anticholinergics
- airway management (dec. FRC)
Which causes more cardiovascular depression, regional or general anesthesia for c-sections?
regional
