Mod VII: Anesthesia for Cesarean Section Flashcards
Anesthesia for Cesarean Section
What’s the rate of Cesarean Section in the US?
Exceeds 30% in the U.S.
Anesthesia for Cesarean Section
Reasons for Cesarean Section are variable and include:
Repeat C/S (classical)
Malpresentation
(Breech presentation)
Placental abnormalities
(<strong>Placenta abruptio</strong> where the placenta is separating from the uterine wall - <strong>Placenta previa</strong> where part of the placenta is in the birth canal)
Transverse position
Fetal distress
Maternal distress
Anesthesia for Cesarean Section
What’s the classical reason for having a C-section?
Repeat C/S
This is because any scaring in the uterus is a potential weak spot for possible uterus rupture
This is a serious concern if subsequent vaginal delivery is attempted after C/S
VBAC: Vaginal Birth After C-section
Be familiar with this
Many obstetrician don’t like them
VBACs are a/w a higher incidence of emergency C-sections
Anesthesia for Cesarean Section
Comorbidities a/w Cesarean Section include:
Obesity - Diabetes - HTN
(Chronic - PIH - Preeclampsia)
Cardiac abnormalities
Anesthesia for Cesarean Section
Picture showing a pt being prepped for c-section
Picture showing a pt being prepped for c-section
Anesthesia for Cesarean Section
Types of incisions seen with C-section
Horizontal incision
(also known as the Fenestone incison is the most common)
Vertical incision
Anesthesia for Cesarean Section
Graphical representation of C-section after incision has been made and the uterus is accessed
Graphical representation of C-section after incision has been made and the uterus is accessed
The physician will insert fingers inside and pull appart the uterus and then deliver the fetus
Anesthesia for Cesarean Section
Picture showing pressure being applied to upper part of the uterus to deliver fetus
MD will usually place a large amount of pressure on the upper part of the uterus to deliver the fetus via the uterine incision
Be prepared; this can be really uncomfortable for the mother
Anesthesia for Cesarean Section
Picture showing clamping and cutting of the umbilical cord after delivery
Picture showing clamping and cutting of the umbilical cord after delivery
Following this, the infant/neonate is passed on to a different team that will care for the infant/neonate as a separate pt
Cesarean Section (C-S) and Anesthesia
What are anesthetic options for c/s
Use epidural if already in place
(appropriate for pts who attempted a vaginal birth and had a failure to progress, or became destressed)
Use of spinal anesthesia
(placed while the pt is still on the table and right before they lay down to have the c/s)
General Anesthesia
Cesarean Section (C-S) and Anesthesia
Anesthesia alone is the cause of 3-12 % maternal deaths -This is usually due to:
Failed intubation
Failed ventilation and oxygenation
Aspiration
Cesarean Section (C-S) and Anesthesia
What is the best type of anesthesia for C-Section in light of the above?
Anything that avoids the pt’s airway
Avoid General anesthesia at all costs!!!
Cesarean Section (C-S) and Anesthesia
What’s probably the most popular and most commonly used type of anesthesia for Cesarean Section?
Spinal Anesthesia for C-S
Cesarean Section (C-S) and Anesthesia
What are the Pros of Spinal Anesthesia for C-S?
Technical ease of administration (vs epidural or GA)
Rapid, dense anesthesia block
Low fetal exposure
Maternal alertness
Presence of coparent
Cesarean Section (C-S) and Anesthesia
What are the Cons of Spinal Anesthesia for C-S?
Hypotension
Prolonged recovery time
Limited usefulness in emergencies
(b/c no time to place the pt in spinal position - in which case you would use existing epidural if available or will just move to a GA)
Cesarean Section (C-S) and Anesthesia
T/F: Monitors are required during Spinal Anesthesia for C-S
True
Spinal Anesthesia for C-S
Premedication for Spinal Anesthesia for C-S includes:
Anxiety – usually verbal only
Hypotension prophylaxis
Bacitra
Metoclopramide-if nausea or recent food ingestion
Spinal Anesthesia for C-S
Fluids management considerations for Spinal Anesthesia for C-S includes:
Administer Crystalloid vs. Colloid
Be aware of HTN, hypovolemic, preeclamptic
Spinal Anesthesia for C-S
A what level is Spinal Anesthesia for C-S placed?
T4
Spinal Anesthesia for C-S
Which drug combinations and dosings are used for Spinal Anesthesia for C-S?
Lidocaine 60-75 mg = 45-75 minutes
Epinephrine 100-200 mcg (to increase block duration)
Choice of a Narcotic
10-25 mcg fentanyl, or
5-10 mcg sufentanil, or
100-250 mcg morphine (Duramorph)
Spinal Anesthesia for C-S
Wha’s the most common drug combination and dosing used for Spinal Anesthesia for C-S?
Lidocaine 60-75 mg = 45-75 minutes
Epinephrine 100-200 mcg (to increase block duration)
10-25 mcg fentanyl
Spinal Anesthesia for C-S
Bupivacaine is the most favored LA for spinal Anesthesia for C-S - How is it administered?
Bupivacaine: 7.5-15 mg => 60-120 mins of analgesia
+ Choice of Narcotic
Fentanyl 10-25 mcg, or
Sufentanil 5-10 mcg
Spinal Anesthesia for C-S
You are to administer 12 mg of Of 0.75% bupivacaine + 20 mcg fentanyl+/- duramorph 0.1 - 0.2 mg. How many cc of drugs will you administer?
1.) Determine how many mg of bupivacaine are in 0.75% bupivacaine, vs. 0.25%, vs 0.5%
0.75% bupivacaine = 7.5mg/mL
0.25% bupivacaine = 2.5mg/mL
0.5% bupivacaine = 5.0mg/mL
2.) How many cc are in 20 mcg fentanyl
Fentanyl 50 mcg/mL
3.) How many cc are in 0.1-0.2 mg od duramorph
Duramorph is available in 0.5mg/mL and 1mg/mL
Possible math problems on the exam
Spinal Anesthesia for C-S
After dosing Spinal Anesthesia for C-S, what next?
Return pt supine with slight LUD (Left Uterine Displacement)
Spinal Anesthesia for C-S
What are Symptoms of High level effects of Spinal Anesthesia for C-S on breathing that you must be aware of after placing your spinal?
Decreased intercostals movement
Thoracic proprioception
(they feel like they are not breathing even when they are; which is uncomforatble)
Cephalad displacement of abdomen
(esp. in the supine position)
Fundal pressure by surgeons
Spinal Anesthesia for C-S
What are potential compliations of Spinal anesthesia?
Hypotension
Tx w/ Ephedrine - Phenylephrine
High spinal
Tx w/ Prompt intervention, resuscitation, ABCs
Failed spinal, patchy block
Tx: Redo spinal (if time allows)
Tx: Supplement with nitrous or ketamine boluses
Tx: Convert to a GA (worst case scenario)
Spinal Anesthesia for C-S
Which drugs are used to treat Hypotension resulting from spinal anesthesia?
Ephedrine - Phenylephrine
Spinal Anesthesia for C-S
How is “High spinal” resulting from spinal anesthesia treated?
Prompt intervention
Resuscitation
ABCs
Spinal Anesthesia for C-S
How is Failed spinal or patchy block resulting from spinal anesthesia treated?
Redo spinal (if time allows)
Supplement with nitrous or ketamine boluses
Convert to a GA (worst case scenario)
Epidural Anesthesia for C-S
What are advantages of using Epidural Anesthesia over spinal anesthesia for C-S?
Epidural Anesthesia for C-S
Could use incremental dosing
Extension from labor period
(no need looking for another access)
Less intense motor blockade
(Less likely to impair ventilation (pulmonary, twins)
Less occurrence of PDPH
Epidural Anesthesia for C-S
Which provides a more intense motor blockade?
A. Spinal
B. Epidural
A. Spinal
B. Epidural
Epidural Anesthesia for C-S
Which is associated with Less occurrence of PDPH?
A. Spinal
B. Epidural
A. Spinal
B. Epidural
Epidural Anesthesia for C-S
What are disadvantages of Epidural Anesthesia for C-S?
Not as dense as spinal
Not suitable for emergencies
(use it if already inplace in case of emergency - If none in place, it takes more skill and time to place an epidural than it takes to place a spinal)
Dural puncture with medication delivery, which could require
Intubation - PPV - Maternal resuscitation, fluids, vasopressors - Prompt delivery if necessary
Epidural Anesthesia for C-S
Patient preparation for placement Epidural Anesthesia for C-S includes:
Monitors
Fluids 15-20 ml/kg
Bicitra 30 ml
Epidural Anesthesia for C-S
Pt should be returned to which position after Epidural placement?
Supine with LUD
Epidural Anesthesia for C-S
Which drug combinations and dosing are commonly used for Epidural Anesthesia for C-S?
2% Lidocaine with epi
Epi 5 mcg/ml
Epi Decrease absorption LA
(by constricting the arteries and reducing the amount of LA that’s washed away
Epi Increase intensity of block
2 or 3% Chloroprocaine
Very rapid onset
40-50 min duration
Sometimes will cover a patchy block
(Appropriate if the pt they can still “feel” something!!!)
Epidural Anesthesia for C-S
T/F: Complications of Epidural Anesthesia for C-S are Similar to spinal
True
Combined Spinal-Epidural Anesthesia for C-S
Why is the combined Spinal & Epidural Anesthesia for C-S becoming increasingly popular?
Advantages of spinal with epidural back up
This means that you could start w/ a spinal but runout of time
Your only option then will be to convert to a GA
You could avoid GA if you have an epidural in place
In which case you would just dose through the epidural
Combined Spinal-Epidural Anesthesia for C-S
Which technique is used for the combined Spinal-Epidural Anesthesia for C-S?
Needle-through-needle
Tuohy needle + spinal needle inside Tuohy needle
(1) You would inject the medication into the subarachnoid space
(2) Then you would tread the epidural catheter in the epidural space
Requires Longer spinal needle, special kits
General Anesthesia for C-S
When is General Anesthesia indicated for C-S?
Fetal distress
Maternal emergency
Acute hypovolemia
Significant coagulopathy
(preventing from doing a neuraxial technique)
Inadequate regional anesthesia
(the block is just too patchy and the pt cannot tolerate the pain)
Maternal refusal of regional anesthesia*
You want to avoid a GA in an obstetric pt if at all possible!!!
General Anesthesia for C-S
The biggest disadvantage of General Anesthesia for C-S is Difficult airway - How should you prepare for it?
Careful exam
Difficult airway cart
(have LMAs and intubating adjuncts available)
Awake fiberoptic
Stubby intubating handles
(make sure they are not on the way as you try to intubate the pt)
Refer to Box 77-3 and Figure 77-4 in Miller’s Anesthesia
General Anesthesia for C-S
What’s the Suggested Sequence for General Anesthesia for Cesarean Section?
- Administer a nonparticulate oral antacid (sodium citrate) before induction of anesthesia with consideration for metoclopramide or a histamine-2 blocker
- Place standard monitors, maintain left uterine displacement, and ensure suction, airway equipment, and appropriate drugs are readily available.
- Ensure the patient has a working intravenous catheter and start an infusion of crystalloid solution.
- If time permits (nonemergent), administer prophylactic antibiotics and participate in time-out checklist.
- Preoxygenate/denitrogenate patient for more than 3 minutes or 4 maximal (vital capacity) breaths over 30 seconds with 100% oxygen.
- When the surgeon is ready and patient prepared, an assistant should apply cricoid pressure (and maintain until the position of the endotracheal tube is verified).*
- Notify and confirm with the surgeon that the patient is ready for induction of anesthesia.
- Administer induction agent and muscle relaxant in rapid sequence, wait 30 to 60 seconds, and then initiate direct laryngoscopy for tracheal intubation. Consider using etomidate or ketamine if concern for hypotension exists.
- After confirming endotracheal tube placement, communicate to surgeon to proceed with incision.
- Administer 50% nitrous oxide in oxygen with 0.5 to 0.75 minimum alveolar concentration (MAC) of a halogenated anesthetic.
- Adjust minute ventilation to maintain normocarbia (end-tidal carbon dioxide 30 to 32 mm Hg).
- After delivery, anesthesia may be augmented by administering opioids, barbiturates, or propofol while continuing the volatile anesthetic. Additional muscle relaxant may be considered if necessary.
- Administer oxytocin and assess uterine tone.
- Extubate the trachea when the patient is awake and following commands and neuromuscular blockade is fully reversed.
General Anesthesia for C-S
How would you address Aspiration risk a/w General Anesthesia for C-S?
Prophylactic pharmacologic intervention
RSI
General Anesthesia for C-S
How would you address Placental transfer of drugs a/w General Anesthesia for C-S?
Ensure surgeon limits Uterus-Drug (U-D) time < 3 minutes
(Do not induce until the surgeon is ready to cut - From the time you induce, the surgeon must try to get a clamp on the umbilical cord w/in 3 minutes)
General Anesthesia for C-S
What are some psychosocial disadvantages of General Anesthesia for C-S?
Decreased maternal-fetal bonding
(mother asleep)
Absence of coparent
(not allowed in the room during GA)
General Anesthesia for C-S
What does a typical General Anesthesia Plan for C-S include?
Clear antacid, H2 antagonist, metoclopramide
LUD
Monitors
Denitrogenation
Cricoid Pressure
Propofol, succinylcholine
Intubation*
(use smaller than calculated tube size b/c tracheal edema)
Confirm breath sounds
Tell the surgeon to cut
Run the case w/ 0.5 MAC of volatile agent with 30- 50% nitrous
Muscle relaxation
(must take into consideration if the pt has been of MgSO4 which accentuates the effects of muscle relaxants)
General Anesthesia for C-S
Which drug is administered once the fetus has been delivered? what should you watch for during administration of this drug?
Oxytocin 20 U in 1000 cc LR, wide open
Watch for hypotension
General Anesthesia for C-S
Which drugs are administered post delivery for anxyolysis and analgesia?
Versed 2 mg
Fentanyl 1-2 mcg/kg
Morphine 0.1 mg/kg
General Anesthesia for C-S
What are required reversals and other precautions prior to extubation following General Anesthesia for C-S?
NMB reversal
Thorough suction
Extubation when airway reflexes intact
General Anesthesia for C-S
A uterus that is still spongy feely after the fetus and placenta have delivered is dubbed:
“Boggy uterus”
General Anesthesia for C-S
Intrauterine administration of which drugs would you anticpipate if “Boggy uterus” is present?
OB surgeon may want Pitocin for intrauterine injection
Methylergonovine 0.2 mg IM (IV rare) (Methergine)
Carboprost tromethamine (Hemabate)
Effects of Anesthesia on Fetus and Neonate
How can we prevent fetal hypoxemia and acidosis that are often d/t anesthesia?
LUD
Ensure adequate maternal oxygenation
Avoid maternal hyperventilation
Avoid excessive dose of anesthetic agents
Treat hypotension promptly
U-D interval of less than 3 minutes is optimal
