Exam 3: Anesthesia For Operative Delivery Flashcards
What is Macrosomia?
Fetus/Newborn w/ excessive birth weight
What is TOLAC?
Trial of Labor after Cesarean
they have had a c-section in the past and now they are going to try to labor for this one
What is VBAC?
Vaginal Birth after Cesarean
What is PPH?
Post-partum Hemorrhage
What is SAB?
Spontaneous Abortion
Or subarachnoid block.
What are indicators for operative vaginal delivery?
- Bad FHR variability
- Maternal exhaustion
- Arrested Descent
If a denser sensory block is necessary for operative vaginal delivery, what medications can be used?
Epidural:
- Lidocaine 2% 5-10mls
- 2-Chloroprocaine 2-3% 5-10mls
What is the most common majory surgery in the USA?
C-section
Maternal mortality is ____ times greater with a c-section vs vaginal delivery.
10x greater
What are anesthesia complications that can contribute to mortality in converting to a C-section from a vaginal birth?
- Pulmonary aspiration
- Edematous/friable airways causing failed intubation
- Inadequate ventilation requiring GETA
all of these things are related to anesthesia
What factors are contributing to an increased national rate of c-sections?
- ↑ maternal age
- Obesity
- Fetal macrosomia
- ↓ TOLAC attempts
- Fewer of instrumented vaginal deliveries.
- increased use of FHR monitoring
- concern for malpractice litigation
What would cause a change in the anesthesia plan for an unscheduled c-section?
Depends on:
- fetal condition
- urgency vs emergency delivery
- in situ epidural or not
- maternal comorbidities
- maternal wishes (too much anxiety for the mom)
What are the maternal indications for c-section?
What are the fetal indications for c-section?
What are the types of skin incisions?
- Low transverse incision: lower incidence of dehiscence and the least painful
- Low verticle/midline: rapid access and emergent access. increased incidence of umbilical hernia
What are the three different types of uterine c-section incisions?
- Low Transverse: lower risk of bladder injury, lower risk of uterine rupture and TOLAC possible
- Vertical: lower uterine segment, may be extended. Low risk for uterine rupture but >low transverse cut
- Classical: highest risk ~10% uterine rupture
With what type of c-section incision is TOLAC contraindicated?
Classical incision
With what type of c-section incision is TOLAC possible?
Low-Transverse Incision
Most common C-section complication
Hemorrhage!
More blood loss with GETA
the four T’s of hemorrhage risk from ACOG
- Tone
- Trauma
- Tissue (retaines products)
- Thrombin (coag status)
applies to c-section and vaginal delivery too
Why does GETA potentiate blood loss?
Due to GETA vasodilation.
Maternal Hormorrhage steps to take
- call for help and blood
- IV fluids open, albumin, warm products
- get more IV access
- Uterine tone
- baby out, pitocin going (10-20 units in bag)
- methergin and/or hemabate IM
- TXA 1 gram over 5 min
- check coag factors and calcium
Methergen is contraindicated with what maternal comorbidity?
High blood pressure (preeclampsia, HTN or gestational HTN)
Hemabate is contraindicated in what maternal comorbidity?
Asthma (Prostaglandins)
What things can the OB provider do to stop a hemorrhage? (just so we are familiiar with them)
- Bakri Balloon: balloon to tamponade uterus from inside
- Compression/B Lynch Suture: wrap around the uterus like a turkey
- Uterine artery ligation: source of bleeding - but that will effect future pregnancies
- Hysterectomy
What complications (other than hemorrhage) can happen in c-sections?
- Wound Infection
- Uterine/cervical lacerations
- Bladder damage
- Fetal damage
- Hysterectomy
What is the terminology for abnormal placental invasion of surrounding tissues?
Accreta → Increta → Percreta
Placenta implanting or growing through the uterus
all hands on deck with MTP likely if you know about it before hand always GETA
____ is when the placenta develops in such a way that it blocks the baby’s ability to exit out of the cervix & vagina.
Placenta Previa
What risk occurs with external cephalic version?
↑ risk of uterine rupture
What is the preferred anesthetic technique for a c-section?
Neuraxial Anesthesia
Previous c-sections indicates an increased risk of ____.
bleeding
The C-section is high risk if….
i.e. 2nd IV and blood on hold
- Previous C-sections
- Multiparity
- Multiple Gestation
- Classical Incision
- Anemia
- Maternal comorbidities
- Abnormal Placental implantation (acreta or worse likely will need central line)
What sensations are normal even with a spinal anesthetic?
- pushing, pulling, tugging, & pressure
- possibility of nausea
Support person cannot come back during spinal - only when the pt is fully draped
Which two drugs need to be stocked and ready to go in the OB operating room?
Propofol & Succinylcholine
Be ready to RSI.
What three medications are given to prevent (or diminish consequences) aspiration in parturients?
- Famotidine 20mg IV
- Metoclopramide 10mg IV
- Na⁺ Citrate (Bicitra) 30mLs PO
What type of drug is famotidine?
H2 receptor antagonist that decreases gastric acid production.
What is the onset, peak and dose of famotidine?
Onset: 30 min
Peak: 60 - 90 min
Dose: 20mg
How does metoclopramide work?
- ↓ stomach volume via increased motility.
- increased LES tone
- ↓ N/V
Dopamine D2 antagonist and mixed serotonin antagonist 5HT3 and 5HT4
When should metoclopramide be administered?
15-30 min prior to anesthesia start
What type of drug is Bicitra?
Non-particulate antacid that decreases gastric acidity to > 6 pH for 1 hour
When should Bicitra be administered?
20-30 min before going to the OR. But usually they are drinking it as you are rolling down the hall
Decreases Mendelson’s syndrome risk substantially
What antibiotic given to parturients should be administered slowly due to risk of N/V?
Azithromyicin (500mg IV)
What monitoring equipment is necessary before spinal placement?
At minimum:
- FHT
- Mom’s BP
- Pulse oximetry
Why is versed “discouraged” but not contraindicated?
- Crosses placenta & sedates baby
- Amnestic effects on bonding
Is oxygen necessary for an elective c-section?
Not necessarily (but is typically done).
Sometimes intercostal muscles are numb and its hard to feel yourself breathing, so sometimes O2 can help them feel better
What is an ideal spinal dose of morphine?
100 - 150mcg
What is an ideal spinal dose of Fentanyl?
5 - 10mcg
What is an ideal dose of epidural morphine?
3-5mg
What are some disadvantages to C-section?
- N/V
- Diaphragm stimulated
- HoTN
What causes referred shoulder/chest pain during a c-section?
Uterus being pulled out
How is the diaphragm stimulated during a c-section?
Irrigation can stimulate the diaphragm & cause N/V, cold, pain sensations.
What reflex can be activated during a c-section?
Bezold Jarisch Reflex
What are the triad of symptoms associated with the Bezold-Jarisch Reflex?
- Vasodilation
- Hypotension
- Bradycardia
What causes the Bezold-Jarisch reflex?
Mechanoreceptors sensing a hyperdynamic LV w/ low preload.
Which drug can be administered to prevent the bezold-jarisch reflex associated with a spinal block?
Glycopyrrolate 0.2mg
-or-
Ondansetron 4mg
Antagonizes 5HT-3 receptors & prevents activation of BJR.
What position should a patient be in after a spinal block?
Slight (10°) head up
Bed can also be tilted left for slight LUD.
Which colloid has an increased risk for anaphylaxis?
Hetastarch
What is the IM dose of ephedrine for hypotension?
25-50mg IM
What acid-base imbalance of the umbilical artery can be caused by ephedrine?
Metabolic Acidosis
Which of the following readily crosses the placenta:
Ephedrine
Phenylephrine
Ephedrine
Hyperbaric Lidocaine (5%) is not commonly seen due to risk of ____.
TNS
Transient Neurologic Syndrome (leg & back pain 24-48 hrs after spinal).
We want our spinal anesthetic to reach what sensory level?
T4
What is the most common local anesthetic used for spinals?
0.75% bupivacaine (hyperbaric)
Do spinally administered opioids increase or decrease PONV occurrence?
Decrease
Attenuates some of the sensations that trigger N/V
What is the dose of Fentanyl for SAB?
10 - 25mcg
Is early or late respiratory depression seen with fentanyl?
early
What is the dose of morphine for SAB?
100 - 150mcg
What is the onset and duration for morphine administered spinally?
Onset: 30 - 60 min
Duration: 12 - 24 hrs
Will respiratory depression be seen earlier or later with morphine administered via SAB?
Later (6-18 hrs after!)
How is the pruritus associated with SAB morphine treated?
Nalbuphine or Butorphanol
Naloxone or Naltrexone
it is not histamine related, so benadryl won’t work - but it will make them sleepy
What is the dose of an “epi wash”?
0.1 - 0.2mg epinephrine administered in a SAB.
What is the purpose of an “epi wash”?
Can prolong block by 15% or more
What dose of Precedex is utilized in spinals?
5-10 mcg
What is the purpose of spinally administered Precedex?
- Prolongs sensory & motor blockade
- Post-op pain control
- Minimizes shivering
What are the adverse effects associated with spinally administered dexmedetomidine?
Bradycardia & Hypotension
Epidural medication doses are approximately ____ times that of spinal doses.
5 - 10 x
Are spinals or epidurals better for C-sections?
Spinals (more reliable and dense)
Epidural can also be “patchy”
What VAA can be added to a patient with an epidural who is undergoing an unplanned C-section?
N₂O
IV anesthetics such as ______ or ______ are commonly used as adjuncts to epidurals for patients undergoing unplanned c-section.
ketamine ; precedex
2% Lidocaine is just as fast as chloroprocaine when what additive is added to it?
Na⁺ Bicarbonate
What dose of 1% Lidocaine is utilized for spinal blocks for c-sections?
Trick Question. Concentrations less than 2% Lidocaine are inadequate for c-section anesthetics.
What metabolizes chloroprocaine?
Pseudocholinesterases
What drug can decrease the efficacy of epidural morphine? Why?
2-Chloroprocaine
Antagonizes μ and κ opioid receptors
Which dose of bupivacaine IS NOT utilized in epidurals?
0.75% is only for spinals
What dosage of bupivacaine is used for epidurals?
0.5%
What dosage of ropivacaine is common for epidurals?
0.5%
Compare the cardiac toxicity profiles of ropivacaine & bupivacaine?
Ropivacaine is less cardiotoxic than bupivacaine
Between fentanyl and morphine, which opioid administered spinally provides for a more dense block?
Fentanyl
What ratio of dexmedetomidine to LA is typically used in epidurals?
4-5 mcg of precedex for each 1mL of LA.
Ex. 20mL of LA + 80 to 100mcg Precedex
How does Na⁺ bicarb helps speed up onset?
Shifts local anesthetic to more non-ionized state.
very useful speeding up epidural to avoid GETA.
Your patient has an epidural in place and is being converted from a normal labor to a c-section. The epidural is unilateral, how can this be fixed?
Replaced the catheter if possible
Your patient has an epidural in place and is being converted from a normal labor to a c-section. The epidural is patchy, how can this be fixed?
- Supplement w/ adjuncts (ex. 50mcg Fentanyl)
How much local anesthetic will you typically use to “top off” an epidural for a c-section?
10 - 15mls to extend the level up to T4
Always assess the level
What is the Allis Test?
Pinch patient with clamps to assess quality of epidural anesthesia.
- If the patient can’t feel clamps then you’re good for surgical incision.
Why should your epidural dosing be less with a combined spinal epidural (CSE) ?
Hole through dura mater can result in medication going from epidural to spinal space.
What are four reasons that one might have to convert to general anesthesia for a c-section?
- Fetal Distress
- Maternal Hemmorrhage w/ hypovolemia
- Neuraxial Anesthetic not possible
- failed block or pt not tolerating block
What are some reasons that neuraxial anesthesia may not be possible for c-section patients?
- Outright refusal
- Infection
- Coagulopathy / thrombocytopenia
Does GETA increase or decrease maternal mortality?
Increase
Is it beneficial for the mother to go to sleep and not remember anything?
Trick question: There is actually a greater risk of recall if you put the laboring mother to sleep
- because no versed until baby is out and you want the gas lower (gas makes the uterus boggy)
How does GETA affect apgar scores?
↓ Apgar scores associated with GETA
What is the dose of succinylcholine?
1 - 1.5 mg/kg
What induction agents are used for emergent c-sections?
Propofol + Succ
Truly RSI (better to give more sux than less, you really want them down)
What size ETT is used for c-sections?
6 - 7 mm ETT (remember that airway is friable & edematous)
What other tube is placed (other than ETT) for a GETA c-section?
orogastric tube (suction out the stomach)
In regards to a c-section delivery, when is pitocin/oxytocin started?
AFTER delivery
Needs to be announced to whole room that its being started.
Less VAA = ____ uterine tone.
increased (results in less bleeding)
What is MAC value decreased to after delivery of the baby?
0.5 - 0.75 MAC
consider N2O so you can decrease VAA
Opioids are given ____ delivery in order to decrease risk of neonate respiratory depression.
After.
What paralytic is used after Succinylcholine has worn off?
Trick question. Use VAA to drive muscle relaxation
Maternal hypocapnia results in what oxygenation change for the fetus?
↓ O₂ delivery due to leftward oxyhemoglobin dissociation curve shift.
Maternal hypercapnia results in bradycardia or tachycardia?
Tachycardia
What would cause you to do a deep extubation on a parturient patient?
Trick Question. Extubate patient awake. Still considered a full stomach.
What are the three drugs used to treat uterine atony?
- Pitocin
- Methergine (methylergonovine)
- Hemabate (Carboprost)
What symptoms from a Pitocin drip would prompt you to slow the infusion?
Hypotension & flushing
slow the infusion if they experience this
When is Pitocin started after delivery?
What dosage is used?
- After umbilical cord is cut
- 20units in NS bag (drip in slowly)
What is the dose of Methergine (methylergonovine)?
0.2 mg IV/IM
Methergine (methylergonovine) is contraindicated/caution in what maternal comorbidity?
Hypertension
What class of agent is methergine?
Ergot Alkaloid (only one of this class)
What is the dose of Carboprost (Hemabate)?
250mcg IM
What drug is given if a patient is still bleeding after Pitocin administration?
Carboprost (Hemabate)
What medical condition would make you cautious in giving Hemabate?
Asthma (prostaglandin)
What factors associated with C-sections result in PONV?
- Hypotension
- Surgical Stimulation
- Uterotonics
How does hypotension result in PONV?
- Cerebral hypoperfusion → medullary vomiting center stimulation
- Gut ischemia → emetogenic substances released from intestines
Why does surgical stimulation result in PONV?
VAGAL Stimulation
- Uterine exteriorization
- Intra-abdominal manipulation
- Periotneal tract stimulation
What meds specific to OB result in N/V?
- Uterotonics/antibiotics
- oxytocin: r/t hypotension
- ergot alkaloids (methergen): interact with D2 and 5HT3 receptors
- hemabate: stimulate GI smooth muscles causing diarrhea
GETA for emergent c-section results in a very high risk for ____ and ____.
recall / hemorrhage
What drug can be given to help prevent recall in emergent c-sections? When is this given?
2mg Midazolam as soon as the baby is out.
Ketamine is good too per Bailey
Is it better to have block that is too high or too low?
too high
Can supplement w/ O₂
What should anesthesia do if a block is excessively high? (loss of consciousness, loss of respiratory drive, refractory HoTN)
Convert to GETA
Shaking during or after the C-section
- Very common and hard to control because its hormonal
- meperidine or fentanyl may help
- precedex may help (some evidence)
- distraction or squeezing a towel works!
