Complicated OB Part 1 Flashcards
What does ECV stand for?
- External Cephalic Version
- A maneuver to rotate the fetus to a better position for delivery.
- Converts breech/shoulder presentation to vertex
Define Antepartum
Conception to the onset of labor
Define Intrapartum
Onset of labor to delivery of the placenta
What does PPROM stand for?
Preterm Premature Rupture of Membrane
What does PPH stand for?
Post Partum Hemorrhage
What is the optimal timing to perform an ECV?
- 36-37 weeks
- Unlikely to revert back to breach presentation after 37 weeks
What agent is needed before attempting ECV?
- Tocolytic agent (Terbutaline/NTG)
- Tocolytic agents are drugs that can slow or stop uterine contractions during pregnancy to prevent preterm labor.
What maternal factor will decrease the rate of success of an ECV?
Maternal pain
What factors contribute to a successful ECV?
- Neuraxial analgesia/ anesthesia
- SAB w/ bupivacaine 2.5-7.5 mg w/ or w/o opioids
- CSE/ epidurals
- T6 dermatome level analgesia
Be prepare for urgent C-section d/t placental abruption, preterm labor, non-reassuring fetal heart tones
What is placenta previa?
When the cervical os is partially or totally covered by the placenta.
What are the four types of placenta previa?
- Low lying: does not infringe on cervical os
- Marginal: touches but not covering top of cervix
- Partial: partially covers cervix
- Complete: covers top of cervix completely
What are risk factors for placenta previa?
- Advanced maternal age
- Multiparity
- Hx of smoking
- Prev. C-section/ uterine sx
- Previous placenta previa
At what age is a woman considered to be advanced maternal age?
35
What is the most common way placenta previa is diagnosed?
- Transvaginal US assessment or MRI
- Measures distance from the placental edge to the internal os
Can placenta previa be assessed and diagnosed by a vaginal exam?
- No
- Difficult to assess with complete placenta previa
What is the classical sign of placenta previa?
- PAINLESS vaginal bleeding in 2nd/3rd trimester
- Bleeding may stop spontaneously
- May be sudden & severe
Anticipated management of placenta previa in a preterm if bleeding is controlled.
- Anticipate early delivery, but the priority is to maintain fetal viability inside the womb
- Administration of tocolytics (Tertbuline), decrease contractions
- Betamethasone to promote fetal lung maturity
Anticipated management of placenta previa in a preterm if bleeding is uncontrolled and ongoing.
C-section
Due to the high liability of obstetric anesthesia, explain the setup for a placenta previa exam.
- Double setup exam (examination and emergent C-section)
- All team members present
- Patient prepped for C-section delivery
- Vaginal exam performed in OR
Anesthesia Considerations for Antepartum Hemorrhage
- Early Pre-op
- Type & Cross
- 2 large bore IVs
- Fluid warmer
- Bair hugger
Define Abruptio Placentae
- Placental Abruption
- Premature separation of the placenta (complete/partial), causes bleeding from uterus and placenta
Placenta abruption will prevent _________ of vessels → results in continued bleeding and hematoma formation.
Constriction
Placental abruption will lead to reduced _______ d/t loss of placental-uterine surface area.
Gas Exchange
Reduce gas exchange from placental abruption will result in:
- Fetal distress → Fetal Asphyxia
- Bradycardia
- Late or variable decels
- Decrease/ absent variabilty
Risk Factors for Placental Abruption
- Advanced maternal age
- Multiparity
- HTN
- Cocaine Abuse
- Smoking
- Trauma
- Premature rupture of membranes
- Pre-eclampsia
- Chorioamnionitis
What is the classic sign for placental abruption?
- PAINFUL vaginal bleeding
- Hypertonic uterus (frequent contractions)
- Uterus tender to touch
- Vaginal bleeding absent d/t hemotoma in concealed abruption
- Couvelaire Uterus
What is a Couvelaire Uterus?
- Blood is forced through the uterine wall into the serosa.
- This bleeding can then force its way into the peritoneal cavity, causing the uterus to become rigid and tense.
What is the primary risk to the mother from placental abruption?
- Hypovolemia
- Hemorrhagic Shock
Consumptive coagulopathy is caused by:
- Activation of circulating plasminogen
- Placental thromboplastin
How is Placental Abruption diagnosed?
- Clinical presentation (painful vaginal bleeding)
- US guidance
OB treatment of Placental Abruption depends on what factors?
- Amount of blood loss
- Fetal status
Regarding volume status and circulation, placental abruption can result in these three problems.
- Massive blood loss
- Coagulopathy
- Uterine Atony
What are the most common causes of uterine rupture?
- Trauma
- Uterine scar from previous C-section
- Rapid progression of labor
- Prolonged labor w/ induction (Pitocin)
- Weakened uterine musculature (high gravida)
- Forcep-assisted delivery
Uterine rupture is most commonly associated with ____________.
TOLAC (Trial of Labor after Cesarean)
Uterine rupture at this site will result with the most significant morbidity/ mortality.
- Rupture at a uterine incision scar.
- This site is more vascular and is also the place of placental implantation
What is the most consistent clinical feature of uterine rupture?
Signs and symptoms of uterine rupture.
- Fetal bradycardia (most consistent feature)
- Vaginal bleed
- Severe abdominal pain (tearing)
- Shoulder pain
- Hypotension
How much is uterine blood flow at term?
700-900 mL/min
Uterine rupture requires ___________ operative delivery.
Emergent
Anesthesia management of uterine rupture.
- Situational, but GETA most common
- In situ epidural
- SAB not likely d/t problematic FHT/ hemorrhage
- Maternal status (hypovolemia/ change in LOC)
- Blood/ fluid warmer
- Get Help
What is the most common cause of maternal mortality worldwide?
Postpartum Hemorrhage
Differentiate b/w primary and secondary PPH.
- Primary: PPH within 24 hours of delivery. Higher maternal morbidity and mortality.
- Secondary: 24 hours - 6 weeks postpartum (slow bleeds → septic)
ACOG Definition of PPH
- Blood loss > 1000 mL
- Blood loss w/ signs and sx of hypovolemia within 24h of delivery
Causes of PPH
- Uterine atony (80%, most common)
- Retained placenta
- Cervical/ vaginal lacerations
What is the cause of uterine atony?
Failed release of endogenous uterotonic agents
What are the uterotonic agents?
- Oxytocin
- Prostaglandin
Uterine atony symptoms
- Soft, boggy, oversized, and poorly contracting uterus
- Painless vaginal bleeding
- Atonic uterus may hold >1000 mL of blood
- Tachycardia/ Hypotension → Hypovolemia
Uterine Atony management
- Prevention first, then treatment
- Active management in 3rd stage of labor
- Uterine massage
- Oxytocin administration
First-line treatment for uterine atony?
Oxytocin (Pitocin) - synthetic agent
Half-life of oxytocin
3-5 minutes
Dosing of Oxytocin for active management of 3rd stage of labor and prevention of uterine atony. Option 1
- 20 U in 1000 mL NS
- Bolus 1000 mL over 30 minutes
- Give a second bag at a maintenance dose at 125 mL/hr
Dosing of Oxytocin for active management of 3rd stage of labor and prevention of uterine atony. Option 2
- 30 U in 500 mL NS
- Bolus 334 mL over 30 minutes
- Maintenance dose at 95 mL/hr
Dosing of Oxytocin for active management of 3rd stage of labor and prevention of uterine atony. Option 3
- 10 units IM
Dosing of Oxytocin for active management of 3rd stage of labor and prevention of uterine atony. Option 4 (Rule of 3)
- 3 units IV loading dose over 20-30 seconds
- Initiate infusion 3 units/hr ( x 5 hrs)
- Assess uterine q 3 minutes
- Inadequate uterine tone → give 3 units IV rescue dose
- May repeat rescue dose x 1
Dosing of Oxytocin for active management of 3rd stage of labor and prevention of uterine atony. Option 5
- 30 units in 500 mL
- Infuse 300 mL/hr (18U/hr) - prevention of atony
- Infuse 600 mL/hr (36U/hr) - management of atony
- May increase to 900 mL/hr (54U/hr)
What are side effects associated with Oxytocin?
- Tachycardia
- Hypotension
- Coronary vasoconstriction / myocardial ischemia
- Hyponatremia
- Seizures → coma
What is the second line agent for uterine atony?
Methylergonovine (Methergine) - Ergot Alkaloid
What receptors does Methergine work on?
- Partial agonist at alpha-adrenergic receptor
- Tryptaminergic receptor
- Dopaminergic receptor
Dose of Methergine
0.2 mg Intramuscular (medication needs to be refrigerated)
NOT GIVEN IV, you will kill your patient
Onset time for Methergine
Duration of action.
- Onset: 10 minutes
- Duration: 2-4 hours
How often can you repeat Methergine dose?
- May repeat as early as 2 hours
- May repeat up to 4 times to a max dose of 0.8 mg
Contraindication of Methergine
- HTN
- Pre-eclampsia
- Peripheral vascular disease
- Ischemic heart diseae
What are the cardiovascular effects of Methergine?
- Vasoconstriction
- HTN
What are the neuro effects of Methergine?
- CVA
- Seizures
What are the GI effects of Methergine?
- N/V
Management of HTN secondary to Methergine administration
- NTG
- Sodium Nitropursside
What is the third-line agent for uterine atony?
Carboprost (Hemabate)
When would you want to use Hemabate over Methergine?
- If the patient has existing hypertension
- Pre-eclampsia
- Cardiac Disease
What is the dosage for Hemabate?
250 mcg IM or intrauterine q 15-90 mins
Max dose of 2 mg
Medication needs to be refrigerated
Cardiovascular effects of Hemabate?
↑ SVR
Pulmonary effects of Hemabate?
- Bronchospasm
- V/Q Mismatch
- Shunt
- Hypoxia
- ↑ PVR
What two drugs used to treat uterine atony must be refrigerated?
- Methergine
- Hemabate
Which drug used to treat atony has primarily cardiovascular complications?
Methergine
Which drug used to treat atony has primarily pulmonary complications?
Hemabate
What type of patients would you want to avoid giving Hemabate to?
- Cautious use in patients with reactive airway disease (asthma)
- Pt w/ cardiac disease
- Pulmonary HTN
What is Misoprostol (Cytotec) used for?
- Induce Labor
- Uterotonic agent and treatment of PPH
MOA of Cytotec
Prostaglandin E1 Analogue
Dose of Cytotec
Route of Administration (most common)
Side Effects
- Dose: 600-1000 mcg
- Route: Vaginal
- SE: N/V/Diarrhea
What are medical devices used to manage PPH?
- Bakri Balloon: Intrauterine balloon tamponade
- Jada System: Vacuum, induces physiologic uterine contraction
When is the placenta considered “retained”?
Failure to deliver placenta completely within 30 minutes of delivery
Risk for _______ increases if the interval b/w delivery and placenta is >30 minutes.
PPH
Treatment for Retained Placenta
- Manular removal by OB provider (painful, needs relaxation, spinal)
- Treat uterine atony/hemorrhage
Anesthesia Management of Removal of Retained Placenta
- BZD + Ketamine (0.1 mg/kg)
- In situ epidural (convert to anesthetic epidural)
- GETA
What are ways to induce uterine relaxation?
- Nitroglycerin 25-50 mcg IV
- Nitroglycerin spray
- VA - dose-dependent decrease in uterine tone
Spinal Anesthesia Dosing Chart
Epidural Anesthesia Dosing Chart
Define Placenta Accreta
Placenta invades uterine wall
Define Placenta Increta
Placenta invades the myometrium
Define Placenta Percreta
- Placenta through myometrium into serosa
- May invade adjacent organs
Factors that will increase the risk of placenta accreta?
- Hx of C-section
- Placenta previa with/without uterine sx
- Hx of myomectomy
- Asherman syndrome (scar tissues that form inside uterus/cervix)
- Maternal age > 35
How is Placenta Accreta diagnosed?
- US/MRI
- If the patient has placenta previa, likely to have accreta
Obstetric Treatment of Placenta Accreta
- Area and Depth determine tx
- Definitive approach is a cesarean hysterectomy
- Preop placement of ureteral stents optional (this will help identify the ureters)
Anesthetic Management of Placenta Accreta
- GETA to protect the airway
- Fluid warmer, Rapid transfuser
- Forced air warmer
- MTP
- Be prepared for coagulopathy
- Get help
Describe the four degrees of uterine inversion
- 1st degree: Uterus is inverted inside the abdomen
- 2nd degree: Uterus occludes cervical ox
- 3rd degree: Uterus protrudes through cervical os
- 4th degree: Complete inversion, fully protruding through cervix
What factors will increase the risk of uterine inversion?
- Overzealous fundal pressure
- Umbilical cord traction
- Uterine anomalies
- Uterine atony
- Placenta accreta
Signs and symptoms associated with uterine inversion
- Severe hemorrhage
- Vagal-mediated bradycardia (consider glycopyrrolate)
Uterine inversion treatment
- Discontinue uterotonic administration
- OB promptly replaces uterus
- Requires uterine relaxation by anesthesia w/ NTG 200-250 mcg IV or sublingual
- Volatile anesthetics
- Transfusion
What is the definitive treatment for unresponsive PPH?
- Peripartum Hysterectomy
Biggest cause of hysterectomy: Uterine atony, Placenta Accreta, Increase number of C-sections
Peripartum hysterectomy is challenging d/t what factors?
- Large uterus
- Increased blood flow (700-900 mL/min)
- Engorged blood vessels
- > 40% of patients require PRBCs
- Mortality 25x higher in peripartum vs non-peripartum hysterectomy
During a peripartum hysterectomy, why will the surgeon manually compress the aorta?
- Decreases blood flow to pelvis
- Potentially life-saving in catastrophic OB hemorrhage
This will increase the risk of Lactic acidosis and hemodynamic instability when compression released
Anesthesia Management of Peripartum Hysterectomy
- Pain & N/V due to intraperitoneal manipulation
- Neuraxial (T4 sensory)
- IV Sedation
- GETA is the best option for increase EBL
- Large fluid shifts → airway edema
Hemorrhage: When to Transfuse?
- Consider overall picture
- Tachycardia
- Decreased pulse pressure
- Tachypnea
- Decreased UOP
- Altered mental status
- Most providers transfuse for HGB of 7.0– 8.0 g/dL
Parturient can tolerate EBL of ~ ____% of blood volume w/o symptoms or change in vital signs
15%
What is a late sign of hemorrhage?
Hypotension
Late sign d/t increased blood volume with pregnancy
Risks of transfusion
- TACO, TRALI, TRIM
- Bacterial contamination & transfusion reaction
- Hypothermia & hypocalcemia
- Hyperkalemia
TACO: Transfusion-Associated Circulatory Overload
TRALI: Transfusion-Related Acute Lung Injury
TRIM: Transfusion-Related Immunomodulation
How much will 1 PRBC increase a patient’s Hgb?
Increases Hgb by 1 mg/dL in a hemodynamically stable patient
FFP is 1 pack per ________ kg of body weight as initial dose
20 mL/kg
Cryoprecipitate is important to transfuse because __________ rapidly gets consumed during a hemorrhage
Fibrinogen
Fibrinogen level should be maintained at this level
> 150-200 mg/dL
When to transfuse platelets
- Plt <50,000
- If EBL > 5000 mL
- Consumptive coagulopathy
How much does 1 pack of platelets increase plt level?
5000-10000 mm3
How does large volume of crystalloid transfusion affect blood level.
Dilutional Thrombocytopenia
What can elevated levels of D-dimer & plasmin-antiplasmin complexes indicate?
Fibrinolysis
Treatment for Fibrinolysis
- Tranexamic Acid (TXA)- Antifibrinolytic
- Tx of PPH-associated coagulopathy
- 1 gm IV within 3 hrs of PPH recognition
- Repeat 1 gm IV in 30 minutes if bleeding continues
- Consider 2 gm IV initial dosing
Recombinant Activated Factor VIIa will have direct activation of __________.
Factor X to Xa
Recombinant Activated Factor VIIa enhances ______ and ________.
platelet aggregation and adhesion
Why is Recombinant Activated Factor VIIa not recommended for routine use in OB?
- Concern for increased thromboembolic events
- Extremely expensive
What does TOLAC stand for?
Trial of Labor after Cesarean
What is the success rate of TOLAC?
60-80%
Decrease popularity d/t legal concerns
What are the eligibility requirements for TOLAC?
- 1-2 previous C-sections
- Risk of uterine rupture 0.8-1.8%
- Low transverse or low vertical incision
Anesthesia management of TOLAC
- Neuraxial analgesia- Early placement
- May facilitate successful VBAC
Early epidural placement for TOLAC does not delay diagnosis of __________-
uterine rupture
Preterm labor and delivery is defined as labor between _____ and _______ weeks of gestation.
20 to 36 6/7 weeks gestation
Infant survivability > 90% after _______ weeks gestation
30 weeks
Predictive lab factors of preterm labor
Elevated Fetal fibronectin (fFN)
What is fetal fibronectin?
Basement membrane glycoprotein produced by fetal membranes used to indicate maturity
What are the effects of corticosteroids on preterm labor?
- Decreased respiratory distress syndrome
- Decreased intraventricular hemorrhage
- Decreased death with preterm delivery
Which corticoid steroids are used in preterm labor?
- Betamethasone
- Dexamethasone
Betamethasone dose for preterm labor
12 mg IM every 24 hours x 2
Dexamethasone dose for preterm labor
6 mg IM every 12 hours x 4
What is used for neuroprotection of the fetus during preterm labor?
Magnesium Sulfate will decrease the incidence of cerebral palsy and death
What tocolytics (anti-contractions) are used for pre-term labor?
Terbutaline (Beta-adrenergic agonist )
Stimulate β2-adrenergic receptors on uterine smooth muscle, leading to muscle relaxation and inhibition of contractions.
What are the effects of Terbutaline on the Uterus?
Relaxes smooth muscles and prevents contractions
What are the maternal side effects of terbutaline?
- Dysrhythmias
- Pulmonary edema
- Hypotension & tachycardia
Anesthesia consideration of administering terbutaline
- Preferentially delay ~ 15 mins for maternal HR to decrease
- Cautious use of hydration d/t risk of pulmonary edema
What is the most common NSAID administered for preterm labor?
Indomethacin
Indomethacin works by inhibiting COX. COX is crucial for the synthesis of prostaglandins, which play a significant role in initiating and sustaining uterine contractions. By reducing prostaglandin production, indomethacin helps to decrease uterine contractility and delay labor.
Why are NSAIDs administered in preterm labor??
Nonsteroidal anti-inflammatory drugs (NSAIDs), such as indomethacin, are used during preterm labor primarily because of their ability to inhibit the production of prostaglandins, which play a key role in initiating and sustaining labor contractions.
MOA of Indomethacin
Inhibit cyclooxygenase → prevent the synthesis of prostaglandins from arachidonic acid → decrease contractions
Side Effects of Indomethacin
- Nausea
- Heartburn
MOA of Magnesium Sulfate for preterm labor
- Competitive antagonist of calcium
- Reduces calcium influx into uterine myocyte
- Limits release of ACh @ NM endplate
- Reduces the sensitivity of the NM endplate to ACh
Side Effects of Magnesium Sulfate
- Flushing
- Sedation
- Chest pain
- Blurred vision
- Hypotension
- Pulmonary edema
What are the effects of Hypermagnesemia?
- Abnormal neuromuscular function
- Decreased or absent deep tendon reflexes
- Abolishes compensatory response to hemorrhage
Anesthetic consideration for magnesium sulfate administration
- Monitor renal function and mag level
- Assess DTR
- Mag potentiate neuraxial agents, decrease spinal/epidural dose
- Potentiate action of depolarizing and NDMR
- Avoid defasciculating dose of NDMR
Magnesium Sulfate dose
- 2-4 gm loading dose
- 1-2 gram/hour
Most of the time magnesium is initated d/t HTN or pre-eclampsia.
Does magnesium readily cross the placenta?
Yes
Look for muscular weakness in the baby after delivery and decrease WOB
What is a normal magnesium level?
What is the therapeutic range?
- Normal = 1.7 – 2.4 mg/dL
- Therapeutic range for pre-eclampsia or pre-term labor = 5-9 mg/dL
