Mod VII: Anesthesia for Vaginal Delivery Flashcards
Anesthesia for Vaginal Delivery
What’s the goal of Anesthesia for Vaginal Delivery
The Control of Labor Pain
Anesthesia for Vaginal Delivery
In the 1st Stage of labor, what causes pain? which dermatomal level should be blocked?
Contraction of the uterus causes pain
Block T10 - L1 level to control this pain
Anesthesia for Vaginal Delivery
In the Second Stage of labor, what causes pain? which dermatomal level should be blocked?
Contraction of the uterus
Block T10 - L1
Anesthesia for Vaginal Delivery
In the Second Stage of labor, where does the pain from Birth originate? which dermatomal level should be blocked?
From birth canal
Block S2 - S4
Anesthesia for Vaginal Delivery - Control of Labor Pain
What are the Labor effects on mother?
Increased sympathetic nervous system activity
Increased plasma catecholamine levels
Increase in cardiac output
Increase in peripheral vascular resistance
Reduction in uteroplacental perfusion - As much as 50% in animal studies.
Analgesia may result in 50% decrease in catecholamine concentrations
Periods of hyperventilation versus hypoventilation
Leads to maternal and/or fetal hypoxemia
Analgesia abolished increases in oxygen consumption.
Psychological effects…
Vary bu cultures - stoic vs screaming during the differents stages of labor
Anesthesia for Vaginal Delivery - Control of Labor Pain
Increased sympathetic nervous system activity on the mother during labor manifest as:
Increased plasma catecholamine levels
Analgesia may result in 50% decrease in catecholamine concentrations
Increase in cardiac output
Increase in peripheral vascular resistance
Reduction in uteroplacental perfusion
As much as 50% in animal studies
Anesthesia for Vaginal Delivery - Control of Labor Pain
How does labor affect uteroplacental perfusion?
Reduction in uteroplacental perfusion
As much as 50% in animal studies
Regional Anesthesia - Effect on Labor and Delivery
The use of Regional Anesthesia during the First stage of labor is a/w Conflicting studies, including:
Prolongation of labor by 1-2 hours
Greater oxytocin administration
Regional Anesthesia - Effect on Labor and Delivery
The use of Regional Anesthesia during the First stage of labor is may be a/w Prolongation of labor by 1-2 hours and Greater oxytocin administration - Is this Enough to withhold pain relief?
Many OBs would like to hold off until active phase
Which doesn’t occur until the uterus is dilated to 5cm
However, it’s Unlikely the pt will wait that long due to discomfort of the mother
Regional Anesthesia - Effect on Labor and Delivery
How does the use of Regional Anesthesia during the Second stage of labor affect the pelvis?
Relaxation of the pelvic floor
Interferes with the internal rotation of the fetal head as they engage during birth
Some providers Dilute local preferably with opioid to reduce this phenomenon
High doses may increase the risk of instrumentation during the actual birth process
It’s up to you to find that appropriate balance of local to opioid mix
Regional Anesthesia - Effect on Labor and Delivery
The use of Regional Anesthesia during the Second stage of labor causes Relaxation of the pelvic floor, which interferes with the internal rotation of the fetal head as they engage during birth. How do some providers deal w/ this phenomenon?
Dilute local anesthetics preferably with opioids to reduce this phenomenon
Regional Anesthesia - Effect on Labor and Delivery
The use of Regional Anesthesia during the Second stage of labor causes Relaxation of the pelvic floor, which interferes with the internal rotation of the fetal head as they engage during birth. Some providers Dilute local preferably with opioid to reduce this phenomenon. What’s a risk of high dose opioids?
May increase the risk of instrumentation during the actual birth process
It’s up to you to find that appropriate balance of local to opioid mix
Epidural Preparation
Preanesthetic evaluation for Epidural anesthesia include:
Informed consent
Review of medical history
Physical exam with vital signs
G-Gravida=number of pregnancies
P-Para=number of pregnancies over 20 weeks
Epidural Preparation
A Preanesthetic evaluation for Epidural anesthesia reveals the following “2-0-0-2” - What does that mean?
2 pregnancies
0 premature births
0 abortions/miscarriages
2 living children
Epidural Preparation
Which Equipments must be readied for Epidural Preparation?
Resuscitation equipment
Always check emergency airway equipment
- Supplemental oxygen
Epidural Preparation
Monitors for Epidural Preparation:
BP
Pulse oximeter
FHR—pre and post but not mandatory during
[FHR monitoring is not mandatory during Epidural placement but is ideal]
Epidural Preparation
IV access and Fluids for Epidural Preparation:
18g IV catheter
Access is very important in case of need for resuscitation
AT LEAST 500cc fluids prior to placement
To combat potential hypotension usually a/w epidural placement
Epidural Preparation
Position for Epidural Preparation:
Sitting
(preferred!!!)
Lateral
(left lateral preferred)
Epidural Preparation
What’s the puprose of performing a test dose after epidural placement?
Allows recognition of intravenous or subarachnoid placement
Uses a mixture Lidocaine with epinephrine as test dose
Look for s/s of intravenous or subarachnoid placement
Epidural Preparation
What do you do when you are uncertain as to the result of the test dose?
Try another test dose, or
“Replace the catheter”; this is the safest thing to do
Epidural Preparation
The four Local Anesthetics commonly used for Epidural Preparation include:
Bupivacaine
Ropivicaine
Lidocaine
2% or 3% -Chloroprocaine
Epidural Preparation
Why is Bupivacaine the most often used Epidural LA?
B/c it has limited placental transfer
d/t being Highly protein bound
Epidural Preparation
What are Bupivacaine’s onset and peak times? How how long does it provide analgesia?
Onset 5-10 minutes, Peak 20 minutes
8-10 mls provides 2 hours of analgesia (DOA)
Epidural Preparation
Which is Less cardiodepressant and arrhythmogenic
A. Ropivicaine
B. Bupivacaine
A. Ropivicaine
B. Bupivacaine
Epidural Preparation
Which is LA is more potent?
A. Ropivicaine
B. Bupivacaine
A. Ropivicaine
B. Bupivacaine
Ropivicaine 40% less potent than Bupivacaine
Epidural Preparation
Which is LA is a/w a Higher cost?
A. Ropivicaine
B. Bupivacaine
A. Ropivicaine
B. Bupivacaine
Epidural Preparation
What’s the DOA of Lidocaine? How does lidocaine’s DOA compares to Bupivacaine’s?
Lidocaine => 1-1.5 hours (DOA)
Epidural Preparation
How does Lidocaine’s analegesic effect compares to Bupivacaine’s?
Lidocaine may not equal analgesia provided by bupivacaine
Epidural Preparation
2% or 3% Chloroprocaine is an Ester LA with rapid onset of action - What’s its DOA?
2% or 3% -Chloroprocaine => 40 minutes block duration
Epidural Preparation
How does 2% or 3% Chloroprocaine affect epidural bupivacaine and opioids?
Diminishes the effect of epidural bupivacaine and opioids
Epidural Preparation
What are the two different classes of LA?
Amides
All amide local anesthetics contain an “i” in the name. For example, lidocaine,mepivacaine, prilocaine, bupivacaine, ropivacaine, and levo-bupivacaine all contain an “i” before the “-caine”
Esters
Esters such as procaine, chloroprocaine, and tetracaine do not contain an “i” before the “-caine”.
Epidural Preparation
What’s the drug of choice if you need immediate onset of epidural?
2% or 3% -Chloroprocaine
Indicated for a pt where the epidural was put in late, and you anticipate that labor will start w/in minutes, or
Pt w/ multiple gestations
If you have more time, use Bupivacaine!!!
Maintenance of Epidural Analgesia
Intermittent Bolus - are these typically necessary?
Yes
Administer PRN
Maintenance of Epidural Analgesia - Intermittent Bolus
What must you always complete prior to administration of an Intermittent Bolus of epidural LA?
Patient assessment
Document it!!!!
Maintenance of Epidural Analgesia - Intermittent Bolus
Why is it important to Aspirate first and titrate slowly prior to Intermittent Bolus for Maintenance of Epidural Analgesia?
To ensure that the catheter hasn’t migrated to a different level or to a vein
Maintenance of Epidural Analgesia
What are the Benefits of Maintenance of Epidural Analgesia w/ a Continuous Infusion over intermittent boluses?
Maintenance of a stable level of analgesia
More stable maternal heart rate and blood pressure
Decreased risk of hypotension (b/c no labile drug infusions)
Less frequent need for bolus
Maintenance of Epidural Analgesia
During Maintenance of Epidural Analgesia via Continuous Infusion you must continue to look for Signs of migration into which spaces?
Vascular space & Subarachnoid space
Maintenance of Epidural Analgesia
During Maintenance of Epidural Analgesia via Continuous Infusion which assessments must you still complete every 1-2 hours?
Catheter position
Quality of block and labor progression
Sensory level/Intensity of motor block
Maternal BP/Fetal heart rate tracing
Document these on the record
Maintenance of Epidural Analgesia
During Maintenance of Epidural Analgesia via Continuous Infusion which Equipment will you need?
Pump specific for epidural infusion
Tubing specific for epidural infusion
Be sure epidural tag on tubing to prevent accidental “IV” injection into epidural space
Sterile preparation of local anesthetic—remember preservative free solutions
Epidural Techniques
A popular epidural techinique uses a combination of which two drugs?
Bupivacaine + Narcotic (Fentanyl)
Loading dose of Bupivacaine => 0.25% 5-10 ml +
Fentanyl 5-10 mcg/ml
Begin infusion
0.125% bupivacaine
1-2 mcg/ml fentanyl
Rate of 8-15 ml/hr
Adjust rate according to maternal response
Intermittent dosing may be required
Labor Analgesia Second Stage
Pain in Second Stage of labor is a/w Pain Impulses from which dermatomes?
S2-S4
Pain Impulses from dermatomes may not be covered by epidural
Could be source of breakthrough pain impulses
Usually happens during the very late stages of labor when the fetus is engaged to be delivered
The pt at this point need more analgesia than motor blockade
Labor Analgesia Second Stage
How is Pain in Second Stage of labor d/t Pain Impulses from dermatomes S2-S4 managed?
Epidural dosing may need alteration at this point
More analgesia, less motor block
Bolus dosing may be necessary
May need to inject a “delivery dose”
Be cautious with combination LA and blood loss r/t hypotension.
Anesthesia for Vaginal Delivery
What are potential Complications of Epidural anesthesia?
Hypotension
Inadequate analgesia
Dural Puncture
Pruritis
Respiratory Depression
Epidural Complications
The primary Epidural Complication is Hypotension - How do we combat it?
Crystalloids
Position to left-lateral position
Supplemental oxygen
5-10mg ephedrine
Phenylephrine when maternal HR elevated
Epidural Complications
What are possible causes of Inadequate analgesia from epidural?
Type of catheter
Depth of placement
Epidural failure rate is 1.5-5%
Epidural Complications
What’s the % risk of Dural Puncture?
1 - 8%
Skill dependent
Epidural Complications
What are your options if you experience a Dural Puncture?
Move to another space
Consider Continuous spinal
Epidural Complications
What question should you anwer first if you encouter Pruritis (itching) during epidural?
Is it Histamine mediated?
Epidural Complications
Epidural Complications
What’s the Treatment for pruritis?
Small doses of naloxone (usual treatment)
If severe then 0.4 naloxone in 100 cc NS infused over an hour
Nalbuphine (Partial opioid agonist) 2.5 to 5 mg
Epidural Complications
Respiratory Depression a/w Epidural is dose related - As a result, how should you dose intrathecal fentanyl or sufentanil?
No more than 25 mcg fentanyl intrathecally
Or 10 mcg sufentanil
Epidural Complications
What’s the Rule of thumb for presentation of Respiratory Depression w/ epidural opioid administration - How does solubility of opioids affect order of presentation of respiratory depression?
Lipid soluble
Lipid soluble will present early depression (fentanyl, sufentanil) within 1-2 hours
Hydrophilic
Hydrophilic—will present late depression (morphine)
Rostral spread due to delayed absorption
6-12 hours
Post op orders important!!
Epidural Complications
Opioids with which solubility present early respiratory depression?
Lipid soluble
Lipid soluble will present early depression (fentanyl, sufentanil) within 1-2 hours
Epidural Complications
Why do Hydrophilic opioids (morphine) present late respiratory depression?
Rostral spread due to delayed absorption
Can take 6-12 hours
Take this into account when Considering Post op orders after epidural!!!
Epidural Take Home Points
Regional anesthesia may slightly increase length of labor - so why do we still use it?
Benefits outweigh this phenomenon
Epidural Take Home Points
There should not be an arbitrary set point for epidural placement - Why not?
Epidural should be individualized based on how the pt is feeling and how she is able to tolerate the labor process
Epidural Take Home Points
Which drug concentrations should be utilized for epidural?
Diluted concentrations of epidural or neuraxial drugs should be utilized
Epidural Take Home Points
Why is important to EDUCATE parturients about pain control?
Some think they’re not supposed to feel a thing or not to move
Educate them on what to expect
