Obstetrics Flashcards

Question 1

Q

Cardiovascular and respiratory changes associated with normal pregnancy?

Answer

A

CV

Increase CO
- highest CO right after delivery d/t autotransfusion of empty uterus that now contracts and release of aorta-caval compression (baby not on IVC now)

RISKY time for CV hx pts (ex: fixed valvular stenosis/pHTN) → huge sudden increase in CO

Decrease SVR, SBP
S1 and S3 toward end pregnant
Left axis deviation
Left ventricular hypertrophy
Aortacaval compression- uterus sitting on IVC → decreases BP
Hypercoaguble state - increase fibrinogen, factor 7
Gestational thrombocytopenia d/t hemodiluation

Respiratory

Decrease FRC, arterial CO2 tension
Increase mV, alveolar ventilation, O2 consumption, CO2 production, arterial O2 tension
Capillary engrogement causing difficult AW

Question 2

Q

Effects of pregnancy on:

plasma volume?

total blood volume?

hemoglobin?

fibrinogen?

serum cholinesterase activity?

Answer

A

plasma volume- increase 40-50%

total blood volume- increase 25-40%

hemoglobin- dilutional decrease. 11-12 g/dL normal in pregnancy

fibrinogen- increase 100%

serum cholinesterase activity- decrease 20-30%

Question 3

Q

Effect of pregnancy on blood volume/composition?

Answer

A

Increase intravascular fluid volume in 1st trimester

Rising progesterone levels → increased RAAS
more Na reabsorption → H2O retention

Albumin – 25 % dec

Total protein- 10% dec

decrease colloidal osmotic pressure

Plasma volume 50% increase→ prepare for BL during delivery

Blood volume normalize 6-9 Postpartum

Question 4

Q

What is the impact of aortocaval compression during pregnancy?

Answer

A

Uterus sitting on IVC → decrease BP

Supine hypoTN syndrome – decrease MAP > 15 mmHg w/ increase HR > 20bpm
CV sig changes:
- diaphoresis
- N/V
- mental status change
Tx: LUD position (elevate R hip 10-15 cm w/ wedge/tilt)- anyone after 20 wks
- Prevents hypoTN and increase fetal BF

Question 5

Q

Airway changes during pregnancy and anesthetic implications

Answer

A

Capillary engorgement
DAW
- Avoid instruments
- Most expert
- Small ETT
- Position optimal
- Decrease FRC… → reserve dec

Question 6

Q

Coagulation changes during pregnancy?

Answer

A

Hypercoagulable state → increase fibrinogen, factor 7
- Factor 11 & 13 decreased
- ATIII, Protein S- decreased
- Protein C- unchanged
Plt normal- but dec 10% d/t dilutional effect
Gestational thrombocytopenia -d/t hemodilution and rapid plt turnover
- r/o: ITP, hemolysis, elevated liver enzymes, HELLP → do TEG on at risk pt
- PLT usually not < 70k unless problem
Normal pregnancy: PT and aPTT decreased by 20%

Question 7

Q

What are the physiologic effects progesterone has on a pregnant mother?

Answer

A

Increase RAAS Activity –> increase BV –> increase CO
Vascular Muscle Relaxation –> decrease SVR & PVR –> increase BF
increase mV (Vt > RR) –> decrease PaCO2 –> Kidneys secrete Hco3 to preserve pH

Question 8

Q

Describe the stages of labor and the pain innervation associated with those stages.

Answer

A

Stages of Labor (3)

First
- Start: regular painful contractions
- End: complete cervical dilation
  - Length: ~ 2 - 20 hours
Second
- Start: complete cervical dilation
- End: birth
Third
- Start: Birth
- End: Placenta delivery
Fourth (New)
- Placenta to hemostatic stabilization

Labor Pain

1^st Stage - visceral
- Cervical distention and stretching of lower uterine segment
  - Latent phase: T10 – T12
  - Active Phase: T10 – L1
- Non-specific nociceptor – unmyelinated C fibers
  - Visceral afferent fibers travel w/ sympathetic nerve fibers to uterine & cervical plexus and then through hypogastric & aortic plexus
2^nd Stage – somatic
- Mediation:
  - Pudendal nerve (S2-4)
  - Somatic afferent fibers – myelinated A delta
    - Pain impulse from perineum, pelvic floor, vagina

Question 9

Q

Inhaled Anesthetics and pregnancy

Answer

A

N2O

Onset immediate
duration minutes
minimal effect on mother/fetus, may only be partially effective
Impact on B12 synthesis

VA:

MAC reduced up to 40% d/t progesterone

Question 10

Q

Regional anesthesia options for labor pain?

Answer

A

Spinal opioids alone
- Single vs intermittent injection
- Good in high-risk patients – cardiac patients
Local anesthetic +/- opioids
- Epidural
  - Local only vs. local + opioids
- Dural puncture epidural can inadvertently do CSE and do wet tap and do this technique unintentionally
  - Place epidural – puncture dura with spinal needle
  - Bolus epidural
    - Risks: typically these are result of wet-tap (unintentional tech)
Combined spinal epidural (CSE)
- frequent technique for quick analgesia and follow up with epidural for continued labor
- Walking epidural – low dose local +/- opioid intrathecal
- Thread epidural catheter – initiate epidural at later moment
  - Uses: quick analgesia and need bolus epidurals after
Saddle block – pudendal nerve (somatic pain)
- Bupivacaine 2.5 mg and fentanyl 25 mcg

DOSING: Decreased!

Neuraxial req reduced by 40% at term
Epidural veins distended
Volume of epidural fat increases
→ increases size of epidural space/volume of CSF in SA space → more spread

Question 11

Q

Considerations for fetal heart rate monitoring? tachycardia? Bradycardia?

Answer

A

Follow:
- Baseline HR (120-160 bpm)
- beat to beat variability
- FHR pattern
Baseline
- Normal varies between 120 -160 BPM
Fetal Tachycardia- fetal distress
- > 160 BPM
  - Fetal hypoxia
  - maternal fever
  - sympathomimetic drugs
  - fetal anemia
  - fetal cardiac anomalies
Fetal Bradycardia (more ominous)
- < 100 BPM
  - Fetal head compression
  - umbilical cord compression
  - sympatholytic drugs
  - prolonged hypoxia
  - fetal cardiac anomalies

Question 12

Q

What are some various fetal heart rate patterns?

Answer

A

A. Early Decelerations
- Fetal head compression → baroreceptor activation
- Uniform in nature – mirrors contraction
- ~ 10 – 40 beat/min –NOT associated w/ fetal distress
B. Late Decelerations
- Uteroplacental insufficiency
- Decrease FHR at or following peak of uterine contraction
- Decrease varies b/t 10 – 20 beats/min
- Gradual and smooth return to baseline
- can be concerning
C. Variable Decelerations
- Most common fetal pattern
  - Variable in onset, duration, and magnitude
    - > 30 BPM
- R/t cord compression
- Associated with: FETAL HYPOXIA
  - FHR declines < 60 BPM
  - lasts > 60 seconds
  - persists > 30 minutes
Late decels and ominous variable decels → emergent c/s

Question 13

Q

Category I, II, III FHR intepretation system?

Answer

A

Catergory 1:

All of the following:
- Baseline rate 110-160 bpm
- Baseline FHR variability moderate
- Late or variable decels- absent
- early decel present or absent
- accelerations: present or absent

Catergory 3:

Absent baseline FHR varaibility and any of the following:
- recurrent late decels
- recurrent varaibile decels
- bradycardia
- sinusoidal pattern
concerning and need to go to OR

Catergory 2: all FHR tracings not categorized as I or III.

Question 14

Q

Preop considerations for elective c-section (from coexist)

Answer

A

Preoperatively
- History/Physical
  - Airway evaluation
- Informed Consent
- LUD (left uterine displacement)
  - > 20 weeks – Aortic Caval Syndrome
- IV access (free flowing 18-16 gauge)
- Hydration (minimal 500 mL)
- Aspiration prophylaxis (bicitra, metoclopramide, ranitidine)
- Supplemental O2
- Anesthetic plan/ postoperative analgesia plan
Choice of anesthetic depends on
- Indications for surgery
- Degree of urgency
- Maternal status
- Condition of fetus
- Desires of the patient
  - Sometimes too emergent → put to sleep

Question 15

Q

Anesthetic plan for preop/induction emergent c-section? (coexist)

Answer

A

Preop assessment of airway
Large bore IV
Aspiration prophylaxis (Non-particulate antacid, H2-blocker, Reglan)
Monitors/suction/ emergency airway cart
Optimal airway positioning/ LUD
Preoxygenate! (3 min or longer)
Prep + drape –surgeon ready
RSI w/cricoid (10 N while awake; inc to 30 N after LOC) → start putting force before even asleep
Agents available
- Ketamine (used with maternal hypotensive crisis) 1 mg/kg
- Etomidate 0.3 mg/kg
- Propofol 2-2.5 mg/kg
- Succinylcholine 1-1.5 mg/kg
  - Preferred muscle relaxant
Smaller ETT- 6.0, 6.5
Glidescope

Question 16

Q

Intubation considerations for emergent c-section? What happens immediately following intubation?

Answer

A

Intubate
- Expect difficult intubation
- Proper positioning
- Short handled laryngoscope (Datta) recommended
- Use minimal amount of time; first attempt best attempt
- Smaller ETT 6.0 or 6.5
- Use caution…friable tissues and decreased airway size
Verify placement of ETT → tell surgeon!
- Then…Surgeon makes skin incision (after tube placement verified)
Ventilate with 50% O2/50% N2O & VA (~1 MAC) → overpressure!
- Don’t forget to turn on gas! Tremendous recall
Secure ETT, tape eyes, OGT
****Critical interval of 3 minutes between uterine incision and delivery of fetus
- Tremendous recall risk → medications waring down and youre busy (mom remembers)
Delivery of baby
- PCA pump (bc didn’t do spinal)
- As soon as baby is delivered→ can give Versed, Fent, etc.

Question 17

Q

What happens after delivery in emergent c-section (coexist)

Answer

A

AFTER DELIVERY:
- Reduce VA (.75 MAC) → may increase N2O to 70%, and give opioids and benzodiazepine
  - Reduce MAC → don’t want to vasodilate & bleed out
Possible NDMR
Delivery of placenta
Then can add oxytocin to IV → start contracting of uterus so that mom doesn’t hemorrhage
At end:
- Suction OGT
- Reverse NDMR if necessary
- Extubate AWAKE
  - Emergence and recovery is a critical period for anesthesia-related deaths from airway factors!

Question 18

Q

What is gestational hypertension?

Answer

A

Most frequent cause of HTN during pregnancy
Incidence:
- ~ 7% parturients
Characterizations:
- BP > 140/90 AFTER 20 wks gestation after previously normal BP
- - Without proteinuria
- Most cases develop > 37 weeks’ gestation
- Self-limiting: Resolves by 12 weeks postpartum
- ~ ¼ will develop preeclampsia
  - True diagnosis only made after delivery when chronic hypertension can be ruled out

Question 19

Q

What is chronic hypertension of pregnancy?

Answer

A

Systolic BP > 140 and/or diastolic BP > 90
- Starts before pregnancy or PRIOR to 20 weeks
Elevated blood pressure that fails to resolve after delivery
Consequences:
- Develops into preeclampsia ~ 1/5- ¼ affected patients
- Still an important risk factor for unfavorable maternal and fetal pregnancy outcomes

Question 20

Q

Describe the pathophysiological process assicated with developing preeclampsia

Answer

A

Unknown Exact pathogenic mechanism
- Hypothesis: Immune maladaptation → leads to inflammation
Focus on the placenta
- Delivery of placenta resolves preeclampsia
- Can occur in absence of a fetus (molar pregnancy)
2 stage disorder
- 1^st stage = asymptomatic
- 2^nd stage = symptomatic
1^st stage
- Impaired remodeling of spiral arteries
  - End branch of uterine artery that supplies placenta
- Normally
  - Cytotrophoblasts invade the spiral arteries changing them to low resistance and high flow vessels
    - Adrenergic denervation
- Preeclampsia
  - Invasion is incomplete leaving small and constricted vessels that are responsive to adrenergic stimuli
    - Not undergo necessary remodeling →
      - Leaves high pressure system
      - Responsive to adrenergic stimuli
2^nd Stage
- Widespread endothelial damage/dysfunction causing
  - plt aggregation, thrombocytopenia, hemolytic anemia, increase liver enzymes → HELLP
- HTN from:
  - Decrease production/sensitivity of vasodilatory substances → increase SVR → HTN
  - Increase sensitivity to vasocontrictor substances (Angiotensin, NE) –> vasospasm → dec GFR → dec aldosterone escape/Na & H20 retention → HTN
- Increase glomerular cap permeability and proteinuria → EDEMA
- Insufficient placental BF → leads to placental hypoxia→ IUGR
- Increased production of free radicals and lipid peroxides
- Imbalances
  - Vasoconstrictors: (thromboxane A2 = ⇧)
  - Vasodilators (prostacyclin’s = ⇩)
- Hypoxia →
  - increase antiangiogenic factors (sFlt-1 and soluble endoglin) factors → decrease vascular endothelial growth factors & placental growth factors.

Question 21

Q

What are diagnostic criteria for mild vs severe pre-eclampsia? Risk factors associated?

Answer

A

Mild:

BP > 140/90 after 20 wks gestation
Proteinuria
- 300 mg/24 hours
- 1+ on dipstick
- protein/creatine ratio > 0.3

Severe:

BP > 160/110
Proteinuria
- > 5g/24 hours
- >3+ on dipstick)
Thrombocytopenia
- platelet < 100,000
Serum creatinine
- > 1.1 mg/dl (or 2x’s baseline)
Pulmonary edema
New onset cerebral or visual disturbances
Impaired liver function
Epigastric pain
Intrauterine growth restriction

Coexisting diseases that increase r/f pre-e

Chronic renal disease
Lupus
Protein S deficiency
Increased pulse pressure during 1st trimester

Obstetric Factors

African American
Nulliparity
Advanced age (> 40)
Smoking
Obesity
Diabetes
Multiple gestation
History of pre-eclampsia

Question 22

Q

Pathologic alterations/complications per system in preeclampsia?

Answer

A

Neurological
- Headache, Visual disturbances
- Hyperreflexia
- Seizures (*eclampsia)
- Cerebral edema
Cardiovascular
- Increased BP
- Decreased intravascular volume (d/t contraction of vascular space)
- Increased arteriolar resistance
- Heart failure
Respiratory
- Pharyngeal and laryngeal edema → airway management difficult
  - Potentially WORSE d/t Na/H2O retention
- Pulmonary edema
Hepatic:
- impaired fx/elevated enzymes
- Hematomas/Ruptures
Renal:
- Proteinuria
- Na retention
- GFR decrease
- increase serum uric acid
Heme:
- Coagulopathy
  - Thrombocytopenia (both)
    - Quantitative: number
    - Qualitative: function
  - Platelet dysfunction
  - Prolonged PTT
    - *risk of cerebral hemorrhage → so need to tx HTN
      - Tx: (SBP >160) w/ labetolol, Hydralazine, nifedipine

Question 23

Q

General managmenet of preeclampsia?

Answer

A

Lots of overlap between obstetricians and anesthesia
General Overview (4)
- Timing of delivery
  - R/o regional technique d/t coagulopathy?
- Fetal and maternal surveillance
- Treatment of hypertension
- Seizure prophylaxis

Question 24

Q

Timing of Delivery for Preeclampsia

Answer

A

Timing of delivery
- Delivery only cure
  - > 37 weeks
    - Induction of labor
  - > 34 weeks with severe symptoms
  - < 34 weeks
    - Expectant management
    - Delay delivery for 24 – 48 hours
    - Administer steroids to facilitate fetal lung function
      - Ex: betamethasone- mature fetal lungs
    - Should be undertaken at facilities with neonatal and maternal intensive care resources

Question 25

Q

What does surveillance of Preeclampsia involve?

*Preop testing for patient with preeclampsia*

Answer

A

Ex: renal, liver
Laboratory
- CBC
  - PLT count (most important)
  - > 100,000
  - < 100,000 – additional tests
    - PT/PTT/INR
- Chemistry
- Urine protein/creatinine
- LFTs
- Uric acid testing – conflicting evidence

Question 26

Q

What are some guidelines for treatment of HTN in preeclampsia?

1st line and 2nd line therapies?

Answer

A

Control BP- important
- Considerations:
  - Rapid maternal perfusion pressure changes can adversely affect uteroplacental perfusion pressure
    - → uteroplacental perfusion pressure form arteries are already maximally dilated
    - *If drop BP rapidly → negatively affect perfusion to placenta
Targets:
- 15 – 25% reduction BP
  - Initial BP > 160 (labetalol, Hydralazine, nifedipine)
- Systolic: 120 – 160 mmHg
- Diastolic: 80 – 105 mmHg
1st line agents:
- Labetalol
  - Crosses placenta but does NOT cause fetal bradycardia
  - B:A of 7:1
  - Dose:
    - 1^st: 20 mg IV
    - 2^nd: 40 mg q10min
      - Max: 220 mg
- Hydralazine
  - MOA: Potent direct vasodilator
    - decreases MAP and SVR
    - increasing HR and CO
  - Dose: 5 mg IV q20 minutes
    - Max: 20 mg
2nd Line Agents:
- Nifedipine
  - Dose: 10 mg PO q20 min
    - Max: 50 mg
- Nicardipine
  - Dose: 1– 6 mg/hr
  - CAUTION:
    - Combo Ca+ blockers + Mg 
      - profound hypoTN
      - myocardial depression

Question 27

Q

What meds should you use with caution in patients with preeclampsia?

Answer

A

Methergine- any form of HTN in peripartum period
- Lead to HTN crisis
Sensitive to exogenous and endogenous catecholamines (adrenergic agents)
Magnesium- utilized for preeclampsia
- Leads to uterine atony → increased PP bleeding

Question 28

Q

Seizure prophylaxis in preeclampsia?

Side effects?

Answer

A

Magnesium Sulfate
- Bolus: 4 – 6 grams over 10 - 30 minutes
- Maintenance of 1 -2 gm’s/hour
  - Continued for 24 hours following delivery
- Maternal Side-effects:
  - flushing, HA, dizziness
  - skeletal muscle weakness, decreased deep tendon reflex
  - respiratory depression
  - hypotension
  - pulmonary edema
  - uterine atony (pp) → increase bleeding risk
- Fetal side effects:
  - neonatal hypotonia
  - respiratory depression

Question 29

Q

What is normal serum magenisum?

Therapeutic level for preeclampsia?

When are EKG changes seen?

Loss of DTR with Mg level?

Respiratory arrest?

Cardiac arrest?

Treatment for mg toxicity?

Answer

A

Normal: 1.7 – 2.4 mg/dl
Therapeutic: 5 – 9 mg/dl (prevent szs)
EKG changes: 6 – 12 mg/dl
Loss of DTR: 11 – 12 mg/dl
Respiratory arrest: 15 – 20 mg/dl
Cardiac arrest: > 25 mg/dl
Treatment- Mag toxicity
- Calcium gluconate: 1 gm over 10 minutes
- Calcium chloride: 300 mg over 10 minutes
  - Ex: stop mag → admin Ca → monitor for EKG changes

Question 30

Q

Labor pain managment and considerations for preeclamptic patient (not c/s)

Answer

A

Labor Management – neuraxial (CLE or CSE)
- Preferred method of pain control
  - Recommendation → EARLY placement
    - Ex: analgesia → dec level catecholamines/stress hormones circulating → increase uterine BF, less CV effects
- Advantages:
  - Provision of high quality analgesia
  - Decreased levels of catecholamines and stress hormones
  - Conversion of analgesia to anesthesia - avoids general anesthesia
  - Increase uterine blood flow
Considerations:
- Coagulation status (Plt**)
  - > 100,000 = traditional level
  - > 80,000 = currently acceptable w/o other risk factors
  - < 50,000 = unacceptable risk
  - 50,000 – 80,000
    - risk vs benefits of regional vs. general anesthesia
    - Platelet count trends over last 24 – 48 hours
      - If platelet count is decreasing – may want to place epidural catheter early
  - Coexisting coagulopathies
    - Evaluate
      - Coagulation studies
      - LFTs
      - TEG and platelet function analysis
  - Platelet count < 100,000 mm3
    - Chestnut Recommendations:
      - Most skilled provider
      - Single shot technique
      - Use of a flexible, wire-embedded epidural catheter
        * Less trauma
      - Monitor S/S of neurological complication (ex: epidural hematoma)
      - Check plt count before removal
        * NEED: > 75 – 80,000 BEFORE REMOVING
      - Imaging studies should be obtained immediately if question to neuro fx
        * CT
        * MRI
- Intravascular volume status
  - Contracted intravascular space → need volume prior to placement
    - BUT restrictive management- 250 ml bolus good
- HypoTN tx
  - tx promply
- Vasopressor use
  - Exaggerated response to endo/exogenous catecholamines (in preeclamptic pts)- careful titration
    - Small doses!!
      - Ephedrine (5 – 10 mg)
      - Phenylephrine (25 – 50 mcg)

Question 31

Q

Preanesthetic considerations for preeclamptic patient undergoing elective c-section

Answer

A

ALWAYS do AW evaluation - generalized edema, DAW

same neuraxial considerations:

Coagulation status (Plt**)
- > 100,000 = traditional level
- > 80,000 = currently acceptable w/o other risk factors
- < 50,000 = unacceptable risk
- 50,000 – 80,000
  - risk vs benefits of regional vs. general anesthesia
  - Platelet count trends over last 24 – 48 hours
  - If platelet count is decreasing – may want to place epidural catheter early
- If Coexisting coagulopathies (evaluate)
  - Coagulation studies
  - LFTs
  - TEG and platelet function analysis
  - Platelet count < 100,000 mm3
    Chestnut Recommendations:
    - 1. Most skilled provider
    - 1. Single shot technique
    - 1. Use of a flexible, wire-embedded epidural catheter
        * Less trauma
    - 1. Monitor S/S of neurological complication (ex: epidural hematoma)
    - 1. Check plt count before removal
        * NEED: > 75 – 80,000 BEFORE REMOVING
    - 1. Imaging studies should be obtained immediately if question to neuro fx
        * CT
        * MRI
Intravascular volume status
- Contracted intravascular space → need volume prior to placement
  - BUT restrictive management- 250 ml bolus good
HypoTN tx
Vasopressor use
- Exaggerated response to endo/exogenous catecholamines (in preeclamptic pts)- careful titration
- Small doses!!
  - Ephedrine (5 – 10 mg)
  - Phenylephrine (25 – 50 mcg)

Question 32

Q

C-section with general anesthesia considerations for preeclamptic patient

Answer

A

Airway
- Generalized edema → DAW
- Increased vascularity of Nasopharynx
  - Tissue swollen/friable → tendency to bleed
Hemodynamic Monitoring
- Noninvasive blood
  - Mild and uncomplicated severe
- A-line- for sick/uncontrolled HTN
  - Need for frequent ABG measurement
  - Continuous monitoring during induction/emergence in poorly controlled hypertension
  - Calculated systolic pressure variation
- Central- severe
  - Careful considerations and placement
- TEE- severe
Useful technique for assessing cardiopulmonary status
AW swollen/vascular as is → CAREFUL w/ probe
Hypertensive response to laryngoscopy
- *Laryngoscopy most sympathetic response!
- < 160/110 before induction and extubation
  - Maintain:
    - 140 - 160/90-100 throughout
  - Tx: HTN
    - Labetalol
    - Remifentanil (0.5 mcg/kg)
      - Good drug: esterases fetus already mature → able to metabolize at same rate as mom

Question 33

Q

General Anesthesia c-section plan for patient with preeclampsia

Answer

A

General Anesthesia
- Airway considerations
  - Edema
- Hypertensive response to laryngoscopy
  - *Laryngoscopy most sympathetic response!
- < 160/110 before induction and extubation
- Maintain:
  - 140 - 160/90-100 throughout
- Tx: HTN
  - Labetalol
  - Remifentanil (0.5 mcg/kg)
    - Good drug: esterases fetus already mature → able to metabolize at same rate as mom
Muscle relaxants
- Continue muscle relaxants throughout surgery
- Considerations:
  - Very small doses
  - Monitor with nerve stimulator
    - Esp w/ Mag admin → decrease muscle tone/delay NMF
  - NM & Mag
    - Steriodal: DOA and potency increased
      - Ex: rocuronium, vecuronium, and mivacurium
    - Succinulcholine: DOA NOT affected by magnesium
- Reversal agents – including sugammadex is acceptable
(Chestnut Chapter 35; Box 35.5)
1. Place radial arterial line if BP severe
2. Verify difficult airway equipment & smaller sized tubes available (6.0, 6.5)
3. Administration of H2 blocker or reglan 30 – 60 minutes before
4. Sodium citrate 30 ml’s prior to induction
5. De-nitrogenate
6. Labetalol 10 mg iv boluses to get BP to <160/110
7. Monitor FHR- s/s fetal distress
8. Consider remifentanil 0.5 mcg/kg or other adjuncts to help blunt
9. RSI with Propofol/succinylcholine or etomidate/succinylcholine
10. Maintain with ½ MAC volatile and 50% N2O
After delivery →
- Decrease VA
- Admin:
  - Benzo- Versed
  - Opioid
  - Propofol

Small doses of opioids and avoid muscle relaxants if possible (bc Mag)
Reverse muscle relaxants and administer more labetalol/hydralazine to prevent hypertension on extubation

Question 34

Q

What are some risk factors for eclampsia?

s/s eclampsia?

Answer

A

Life threatening emergency
Most often occurs 2^nd half of pregnancy
- > 20 wks gestation
Risk factors:
- young maternal age
- nulliparity
- multiple gestation
- pre-existing HTN
- preeclampsia
80% develop premonitory signs:
- Headache
- visual disturbances
- photophobia
- altered mental status
- epigastric pain
- Seizure
  - Abrupt onset of facial twitching → then tonic phase → followed by clonic phase (often with apnea)
    - ~ lasts about 1 minute

Question 35

Q

Complications of eclampsia

Answer

A

Aspiration
cerebral hemorrhage
kidney failure
cardiac arrest
placental abruption
extreme prematurity

Question 36

Q

Treatment of eclampsia

Answer

A

Stop the convulsions
- Benzodiazepine
- Propofol
- Magnesium
Establish an airway
Turn patient to left side
Administer 100% oxygen
Apply VS monitors - frequent assessment
Check BP frequently – control hypertension (DBP < 110 mmHg)
- Labetolol
- Hydralazine
- Nifedipine
Ensure adequate IV access
Ensure adequate ventilation/oxygenation
Maintain circulation
Deliver the baby expeditiously

Question 37

Q

Describe anesthetic plan for cesarean delivery for patient with eclampsia (stable vs unstable)

Answer

A

Stable
- Epidural and spinal acceptable
Unstable
- GA preferred
- Techniques for patients with increased intracranial pressure
  - Propofol- positive effects on cerebral BF
  - Maintain cerebral perfusion pressure
    - MAP – ICP (MAP up, ICP down)
  - Avoid anything decreasing CPP
    - Hypoxemia
    - Hypoventilation
    - hyperglycemia
- Persistent neurological evaluations

Question 38

Q

Describe HELLP syndrome and the pathophysiological processes involved

Answer

A

Defined:
- Hemolysis
- Elevated levels of liver enzyme
- Low platelets
  - Maybe a variant of severe preeclampsia
Associated with: DIC, abruption, pulmonary edema, acute renal failure, liver failure, sepsis, & death
- 70% deliver pre-term
Hemolysis
- Microangiopathic hemolytic anemia
- Abnormal peripheral blood smear
  - Schistocytes
  - burr cells
  - echinocytes
- Bilirubin > 1.2 mg/dl
Elevated Liver Enzymes
- AST > 70 IU/L
- LDH > 600 IU/L
Low Platelets
- < 100,000
- Platelet transfusion
  - < 20,000 or significant bleeding in all paturients
  - < 40,00 scheduled for cesarean section
Rupture of subcapsular hematoma of liver (possibility)
- Life threatening complication of HELLP syndrome
- S/S:
  - abdominal pain
  - N/V
  - Headache
  - enlarged liver
  - hypotension
- Dx - Ultrasound or CT scan
- Tx – emergency surgery
  - volume resuscitation
  - coagulation management

Question 39

Q

What are some reasons why pregnancy has increased bleeding and clotting risk?

Answer

A

Thrombocytopenia- 10% pregnancies
Etologies:
- > 20 wks → sign of HELLP
- Typically benign → Gestational Thrombocytopenia
Plts
- Normal: Plts # decrease 10%
- Threshold
  - ~100,000 safe (varies)
  - 70-100,000
  - NO < 50,000
- Coexisting bleeding disorders → increased risk
  - Ex: VWF Deficiency → risk of peripartum hemorrhage
Increased risk of clotting
- DVT/PE → d/t hormone changes
  - Preexisting factor 5 leiden, Protein S/C/AT/Antiphospholipid deficiencies → increase risk clotting
    - Tx: anticoag therapy → impacts delivery plan

Question 40

Q

Describe the pathology of placenta previa, classification types, risk factors, diagnosis, tx

Answer

A

Present if placenta implants in advance of presenting part of fetus
- (placenta partially or totally covers cervix)
- Dx: (Miller)
  - Placenta low in uterus
  - in front of presenting fetus
  - Either covering or encroaching on cervical os
Classifications:
- Marginal
  - Lies close to, but does not cover the cervical os
- Partial
  - Partially covers the cervical os
- Complete
  - Placenta completely covers cervical os
Considerations:
- *Can impair uterine contractions –> risk for high blood loss
Risk factors
- Previous cesarean section (prior scar tissue)
- Prior placental previa
- Multiparity
- advanced maternal age
- assisted pregnancy
- smoking
Diagnosis:
- Painless vaginal bleeding during the 2^nd or 3^rd semester
  - Self-limited
- Transvaginal ultrasound
- Digital or speculum exam requires “double set-up”
OB Management
- Bed rest
- Between 24 and 34 weeks – betamethasone
  - → accelerate fetal lung maturity/surfactant development
- C-Section delivery

Question 41

Q

Preop considerations for management of placenta previa?

Answer

A

All patients admitted with vaginal bleeding should be evaluated by anesthesia on arrival to the labor deck
Increased risk for intraoperative BL
- Placenta maybe injured during incision
- Lower uterine segment may not contract as well
Increased risk for placenta accreta
- Prepare for massive BL
  - T&C
  - 2 large bore IV’s
  - fluid warmer
  - blood tubing
  - rapid infuser
  - invasive monitoring equipment (a-line)

Question 42

Q

Intraoperative managment of placenta previa

Answer

A

Choice of anesthetic technique depends on:
- urgency of delivery
- maternal vital signs
- pregnancy history
Without active bleeding & normal vital signs
- Epidural or CSE acceptable (one RCT showed epidural superior to GA)
Active bleeding or altered vital signs (d/t prolonged bleeding)
- RSI- CV instability
- Induction agent based on hemodynamic status
  - Low dose Propofol or etomidate & ketamine all have been used
- Maintenance
  - Depends on hemodynamic status
  - Benzodiazepine/ketamine vs nitrous/volatile
- Bleeding management (Uterotonics)
  - Oxytocin
  - Hemabate
  - Methergine
  - D/C VA if bleeding continues
    - → Increase N2O [] + midaz or low dose Propofol/ketamine infusion
  - Activate massive transfusion protocol

Question 43

Q

What is placenta abruption? s/s?

Answer

A

Defined:
- Complete or partial separation of placenta from the uterine wall (decidua basalis) > 20 wks gestation but before delivery of fetus
- S/S:
  - Vaginal bleeding
    - Significant BL trapped behind placenta (remain in uterus)
      - → Coagulopathy!!
  - PAINFUL/tenderness w/ examination
  - Coagulopathies
  - hypotension
  - increased uterine activity
- Fetal compromise occurs
  - Loss of placental surface area
    - → Oxygen tissue exchanging surfaces area reduced → fetal distress
      - Non-reassuring FHR
      - Bradycardia
      - loss of variability
Risk factors:
- advanced maternal age
- Chorioamnionitis
- PROM
- Hx of abruption
- multiparity
- preeclampsia
- hypertension
- substance abuse- cocaine *
- ETOH/tobacco use
- direct/indirect trauma *

Question 44

Q

Management of placenta abruption?

Answer

A

Delivery of infant and placenta

Degree of compromise determines timing and route
- Expectant
- Vaginal
- Emergent cesarean section
Anesthesia Management
- Labor
  - Epidural
- Cesarean delivery
  - Stable – adequate volume resuscitation and normal coagulation
    - Epidural, Spinal, CSE
  - Severe ( >50% placenta detached) – fetal death rate approaches 50%
    - Crash GA
      - ketamine/etomidate and succinylcholine
    - Multiple large bore IV’s – place a-line/CVP
    - Volume resuscitation – 1:1:1 ratio
    - Monitor for DIC
      - PT/INR, PTT
      - CF
    - Monitor for uterine atony (uterotonics*)

Question 45

Q

What is uterine rupture?

Answer

A

Uterine wall defect with maternal hemorrhage and/or fetal compromise
- require emergency C-section or postpartum laparotomy(after delivery)
  - Disastrous for mother and fetus
Conditions associated rupture
- Obstetric:
  - Prior uterine surgery
  - induction of labor
  - high dose oxytocin
  - Trial of labor after cesarean (TOLAC)
    - Scar dehiscence
- Trauma:
  - OB:
    - Forceps application
    - internal podalic version
    - excessive fundal pressure
  - Non-OB: Blunt or penetrating trauma
Diagnosis
- Abnormal FHR and fetal distress – most common sign
- Abdominal pain (sudden & severe), abnormal FHR, and vaginal bleeding (<9%)
- Hypotension, vaginal bleeding, change in uterine contour, and changes in contraction pattern – cessation of labor
- Breakthrough pain and need for frequent redosing of neuraxial labor
Obstetric Management
- Antepartum – emergent laparotomy with delivery
- Uterine repair
- Arterial ligation – may not control bleeding and delay definitive treatment
- Hysterectomy

Question 46

Q

What is placenta accreta?

Classifications?

And factors increasing risk for developing placenta accreta?

Answer

A

When placenta abnormally adheres to uterus
Types: (3)
- Placenta accreta vera – uterine wall
  - Adherence of the basal plate directly to the uterine myometrium without an intervening decidual layer
  - Miller: Abnormal adherence to myometrium w. absent decidual line of separation (w/o entering decidual layer)
- Placenta increta- uterine muscle
  - When the chronic villi invade the myometrium
  - Miller: Abnormal implantation and growth of placenta into myometrium
- Placenta percreta- through
  - Invasion through the myometrium into the serosa and adjacent organs
  - Miller: Growth of placenta through uterine wall (myometrium) with placental implantation onto surrounding tissue (bladder, bowel, ovaries, etc)
Risks:
- Mirrors the cesarean section rate
- Previous cesarean delivery or other uterine surgery increase the risk
# C/S deliveries → Increase risk!!
- 0 = 3%
- 1 = 11%
- 2 = 40%
- 3 = 61%
4 or > = 67%

Question 47

Q

What is the labor mgmt plan for patient with placenta accreta syndrome?

Answer

A

Plan:
- Planned preterm c/s and hysterectomy with placenta left in situ
  - → removing likely to initiate massive hemorrhage
- Goal: Gestation > 34 weeks
- Most often at institutions that manage complex OB patients
However must be prepared for emergency delivery and hysterectomy at any institution the care for parturients
- Crash GA
  - RSI
- Blood loss can be massive
- Prepare for massive transfusion- T&C
- Efforts to stop bleeding:
  - Internal iliac artery balloon catheters
  - resuscitative endovascular balloon occlusion of aorta

Question 48

Q

What is retained placenta?

Conesequence?

Anesthesia interventions?

Answer

A

Placenta that has not undergone expulsion w/in 30 min of birth
- whole placenta
- placenta parts
Consequences: post-partum hemorrhage
Therapy:
- Epidural = top up +/- conscious sedation
- Intravenous = nitroglycerine 1 mcg/kg
  - May also try sublingual spray 400 mcg
- GA with high dose volatiles
All the risks that go with general anesthesia

Question 49

Q

What is uterine inversion? Risk factors? S/S?

Answer

A

The uterus inverts through the cervix into the vagina
- Rare – 1: 2,000 – 10,000 deliveries
Risk factors:
- Pulling on the umbilical cord
- uterine atony
- placenta previa
- connective tissue disorders
S/S:
- postpartum hemorrhage
- hypotension
- *Bradycardia – traction on uterine ligament
Tx: Immediate uterine relaxation followed by uterine contraction
- Nitroglycerine
  - 50 – 200 mcg IV
  - 400 mcg sublingual
- GETA with high dose VA
- Monitor fluid volume status
  - Uterine contraction
    - Oxytocin
    - Hemabate
    - methergine

Question 50

Q

What is normal blood loss during vaginal delivery? c section?

What defines post partum hemorrhage?

Answer

A

Normal Blood Loss
- Vaginal delivery = 500 ml
- Cesarean section = 800 – 1000 ml’s
  - Well tolerated d/t physiological increase plasma volume (compensates)
Post-partum hemorrhage
- American College of Obstetrician and Gynecologists
  - > 1,000 ml’s
  - Signs and symptoms of hypovolemia
  - Within 24 hours of birth
  - US rate = 3%
    - Most common cause of maternal mortality world wide

Question 51

Q

What is the most common cause of postpartum hemorrhage and risk factors associated?

Answer

A

Most common cause of severe post-partum hemorrhage
- 80% of cases
Patho:
- Uterine atony results from inability of uterus to contract and constrict uterine vessels
Risk factors: (Chestnut- box 37.3)
- OB:
  - Multiple gestation
  - Polyhydramnios
  - high parity
  - prolonged labor
  - choriamnionitis
  - induced/augmented labor
  - c-section
- Maternal:
  - advanced maternal age
  - hypertension
  - diabetes
- Other:
  - tocolytic drugs – slows down labor
    - ex: Magnesium
  - high VA []

Question 52

Q

Explain the drugs that are administered to treat/prevent uterine atony? MOA, Dose, SE

Other therapies to combat uterine atony?

Answer

A

Oxytocin (Pitocin)
- First line drug therapy for uterine atony prophylaxis
- MOA: increasing Ca [] inside muscle cells that control contraction of uterus. Increased Ca increases contraction of uterus
- Synthetic preparation of oxytocin w/ 6 minute half life
- Rapidly metabolized by the liver and cleared in the urine and bile
- Dosage:
  - 20 units/L crystalloid @ 200 – 500 ml/hour – (uncomplicated c/s)
    - can double if ineffective 40 Units
  - Some newer protocols:
    - Ex: 3 unit boluses of oxytocin, rest on infusion pump
      - 3 units bolus (slow)
      - 3 doses total
      - 3 units/hr
- Side Effects:
  - Vasodilation
  - Hypotension
  - Tachycardia
  - coronary vasoconstriction (don’t push large doses)
  - hyponatremia (with large dosages)

Uterine Atony Treatment ***

Ergot alkaloids
- Methylergonovine or ergonovine (methergine)
  - Dose: 0.2 mg IM Q 30 minutes x’s 1
  - Relative contraindications:
    - Hypertensive
    - CAD
    - preeclampsia
  - Side effects: Nausea/vomiting, increased blood pressure, chest pain, blurred vision and headache, seizure,
Prostaglandins
- 15-Methylprostaglandin (carboprost) – Hemabate
  - Dose: 0.25 mg Q 15 min to 2 mg
  - Relative contraindications:
    - Reactive airway disease (asthma)
    - pulmonary hypertension
    - hypoxemia
  - Side effects: Bronchoconstriction, nausea, vomiting, diarrhea,
- Misoprostol
  - Dose: 600 – 1000 mcg PR
  - Relative contraindications: None
Side effects: fever, chills, nausea, vomiting, & diarrhea
Others
1. Manual message
2. Intrauterine balloon tamponade
3. Uterine compression sutures
4. Embolization of arteries supplying the uterus
5. Cesarean hysterectomy

Question 53

Q

Describe the different stages of uterine atony and the treatment associated with each stage.

Answer

A

Stage 1
- BL:
  - > 500 ml vaginal
  - > 1000 ml cesarean
- VS: Normal
- Labs: Normal
  - Place 100% oxygen
  - Start large bore IV
  - increase IV fluids
  - T/C 2 units
Stage 2
- BL:
  - > 1500 ml’s or
  - > 2 uterotonics
- VS: Normal
- Labs: Normal
  - Call for help
  - Start 2^nd large bore IV
  - Draw stat labs (CBC, coags, fibrinogen)
  - Obtain 2 units RBC’s and FFP (1:1) → anticipate OR if not there already
    - Type specific better than O-negative
- Provide analgesia
- Prepare OR
Stage 3
- BL:
  - > 1500 ml’s EBL
  - > 2 units PRBC’s admin
- VS/labs: abnormal
  - oliguria
    - Move to OR – mobilize additional resources
    - Initiate massive transfusion protocol
  - Fixed ratio transfusion (1:1:1)
  - Add cryoprecipitate, TXA, and calcium
    - TXA: crosses placenta
      - Recommendation: wait until cord clamped to admin
    - Cell salvage- possible
- Factor VIIa - not recommended for routine use
- Admin per TEG studies
Stage 4
Cardiovascular collapse
- Goals of Massive Transfusion
  - Lactate- Decrease
  - Base excess- Normalize
  - Hemoglobin: > 7 g/dl
  - Platelets: > 50,000/mm3
  - Fibrinogen: > 200 mg/dl
  - INR: < 1.5 times normal

Question 54

Q

What are the goals of massive transfusion in obstetrics

Answer

A

Goals of Massive Transfusion
- Lactate- Decrease
- Base excess- Normalize
- Hemoglobin: > 7 g/dl
- Platelets: > 50,000/mm3
- Fibrinogen: > 200 mg/dl
- INR: < 1.5 times normal

Question 55

Q

What are physiological changes seen in patients with multiple gestations?

Answer

A

Physiological changes
- Accelerate and exaggerate physiological changes of pregnancy
- Increased uterine size
- Pulmonary
  - Reduced TLC and FRC
  - Aspiration risk - Increased
  - Tracheal intubation (Difficult)- Increased
- CV
  - Additional 750 ml plasma volume increase
  - 20% greater increase in CO
    - SV 15%
    - HR 3%
  - Greater aortocaval compression

Question 56

Q

Anesthetic management for labor and vaginal delivery of twins

Answer

A

Labor & Vaginal Delivery
- Epidural – great flexibility and optimal analgesia
  - Low threshold to replace equivocal epidural
- Move to OR for delivery
  - Establish 2^nd large bore IV → increased risk for uterine atony and bleeding
- Be ready to convert epidural from analgesia to anesthesia- supplement
- In case of uterine inversion:
  - Nitroglycerin
    - 400 mcg sublingual or
    - 150 – 250 mcg IV
Vaginal Twin A/Operative Twin B
- Epidural = same as above
- May require rapid conversion to general anesthesia with high concentration of volatile anesthetic
Planned Cesarean Delivery
- Spinal vs CSE
- Mean umbilical venous/arterial lidocaine [] were 35 – 53% higher in twin newborns compared to singletons (increased sensitivity to LA)
  - Increased plasma volume combined with a decreased plasma protein volume
  - Clinical relevance of these findings remain unclear (Chestnut – Chapter 34)

Question 57

Q

Describe pharmacological treatments to prevent/treat preterm labor.

Answer

A

Regular contractions occurring b/t 20 – 37 wks gestationResult: dilation or effacement of cervix
Survivability depends on:
- gestational age
- maturity of organ systems
- weight
Treatments:
- Corticosteriods- accelerate fetal lung development
- Tocolytic agents (2)
  - 1. Magnesium- Ca antagonist = relaxes smooth muscle by turning off myosin light-chain kinase in vasculature, AW, uterus
    - Bolus: 4 – 6 grams over 10 - 30 minutes
    - Maintenance of 1 -2 gm’s/hour
      - Continued for 24 hours following delivery
      - Maternal Side-effects:
        
        CNS depression
        
        skeletal muscle weakness, decreased deep tendon reflex
        
        respiratory depression
        
        hypotension
        
        pulmonary edema
        
        uterine atony (pp) → increase bleeding risk
      - Fetal side effects:
        
        neonatal hypotonia
        
        respiratory depression
  - 2. Calcium channel blockers
    - Inhibit influx of calcium- inhibit Ca release from SR
      - Nifedipine PO
      - SE: Hypotension, flushing, dizziness, nausea
- Cyclooxygenase inhibitors (indomethacin)
  - Blocks arachidonic conversion
  - - Maternal SE: N/V
      - Fetal SE:
        
        constriction of ductus arteriosus
        
        pulmonary HTN
        
        renal dysfunction
        
        intraventricular hemorrhage
        Maternal SE: Nausea/vomiting
- Beta-2 agonists (Terbutaline)
  - Smooth muscle relaxation (increase CAMP – activates protein kinase – inactivating myosin light chain kinase – decreasing contraction)
    - SE: Tachycardia, cerebral vasospasm, chest pain, arrhythmias, palpitations, hyperglycemia, hypokalemia, pulmonary edema
    - Fetal SE: tachycardia, hypoglycemia, hypocalcemia & hypotension
- Delivery

Question 58

Q

Describe pathological process of amniotic fluid embolism

Answer

A

Appears to be a systemic inflammatory response associated with inappropriate release of endogenous inflammatory mediators and platelet activation
Exact trigger is unknown
A rare pathologic fetal antigen
Usual antigen presented in an unusual way – amount, timing, or frequency of entry into circulation
Fetal cells, lanugo hair, and mucin into the maternal pelvic vasculature is a common event
- However, pulmonary artery aspirates of patients without AFE have shown fetal material in it
Systemic inflammatory response:
- arachidonic acid metabolites like thromboxane, prostaglandins, leukotrienes, and endothelins.
- Fetal squamous cells release tissue factor which activates platelets to release thromboxane and serotonin
- –> Sudden onset of cardiovascular arrest or both hypotension and respiratory arrest

Question 59

Q

Describe risk factors and s/s of an amniotic fluid embolism

Answer

A

US Amniotic Fluid Embolism Registry Entry Criteria

Acute Hypotension or cardiac arrest
Acute hypoxia (dyspnea, cyanosis, or respiratory arrest)
Onset during labor, cesarean delivery, dilation & evacuation, or within 30 minutes post partum
Absence of an alternative explanation of the observed signs and symptoms

Risk factors

Older age
Abnormal placenta
Placental abruption
Eclampsia
Multiple gestation
Induction of labor
Operative delivery

S/S:

Prior to delivery:
- Seizure, LOC, and profound dyspnea (maternal symptoms BEFORE fetal decels)
At Delivery:
- Acute CV collapse
- Pulmonary HTN
  - RV dilation
  - decreased CO
  - profound V/Q mismatch
  - ABG’s 30 minutes on 100% FiO2 = < 30 mmHg
- Cardiovascular
  - Vary:
    - ST segment/T wave abnormalities
    - arrhythmias or asystole
  - ECHO:
    - RV → akinetic, progressive dilation
      - RV dilation → leads
        
        decreased LV fx
        
        decreased CO
- Massive hemorrhage & DIC
- Thrombocytopenia and significant hypofibrinogenemia

Question 60

Q

Describe the treatment plan associated with an Amniotic fluid embolism

Answer

A

1. Maintain Oxygenation
  * Intubate and administer 100% oxygen
1. Hemodynamic Support
  * Place a-line and central line as necessary
  * Administer fluids and vasopressors as necessary
  - Ensure left uterine displacement
    * TEE to guide fluid replacement therapy
    * Chest compressions as needed
1. Correction of coagulation
  * Activate massive transfusion protocol
  * Serial laboratory assessments
  * Coagulopathy support:
  - TXA
  - recombinant Factor VIIa
  - prothrombin complex concentrates
  - fibrinogen concentrate

TREATMENT:

A-OK regimen
- Atropine 1 mg- anticholinergic
  - Blocks vagal reflex → blocks systemic hypoTN
- Ondansetron 8 mg- serotonin antagonist
  - Blocks serotonin pathway → ultimately decrease pulm vasoconstriction
- Ketorlac 30 mg- nonselective COX inhib
  - Blocks thromboxane → blocks release of inflam mediators
    *

Question 61

Q

S/S, patho, tx of Amniotic Fluid Embolism (miller)

Answer

A

S/S:
- Pulm:
  - Resp Distress
  - Hypoxia
  - Dyspnea
  - Cough
  - PHTN
- CV:
  - CV collapse
  - HypoTN
  - DIC
  - Cyanosis
  - Fetal brady
  - Bradycardia
- Neuro:
  - Altered mental status
Patho:
- Unknown anaphylactoid rx
  - Previously thought squamous cells in maternal pulm circ → but present in healthy moms pp
Tx: early recognition and aggressive resuscitation
- Oxygenation
- Hemodynamic support
- Coagulopathy correction

Question 62

Q

Fetal considerations during non-OB surgery in paturitent patient?

Answer

A

Teratogenicity
- Most structural abnormalities result from exposure during organogenesis
  - 31 – 71 days after first day of last menstrual period
- Physiological derangements
- Diagnostic procedures
- Drugs
  - No anesthetic agents is proven teratogenic in humans
  - Most anesthesia providers AVOID:
    - Nitrous oxide (inhibits methionine synthase)
    - Benzodiazepines – cleft lip/palate risk

Question 63

Q

Anesthetic considerations for non-OB surgery

Answer

A

Preoperative
- Multi-disciplinary team available
- Good airway exam (multiple different plans)
- Pharmacological prophylaxis against acid aspiration (H2 blocker, reglan, bicitria)
  - > 12 weeks
Choice of Anesthesia
- Local
- Regional
- Neuraxial
- General – only if necessary (avoid if can)
Monitoring
- When fetus is viable (20 -24 weeks) and technically feasible
- OB provider available for diagnosis and intervention
Prevention of compression
- Beginning at 18 -20 weeks
- Good left uterus displacement
  - When mom supine → significant hypoTN
Anesthesia management
- De-nitrogenation
  - d/t dec FRC
- RSI with cricoid pressure
- Volatile, muscle relaxants, opioids, and reversals acceptable
- No difference in maternal/fetal outcomes based on anesthetic agents
- Maintain PaCO2 in normal pregnancy range
  - 28 – 32 mmHg
- Avoid hypoxemia, hypotension, acidosis and hyperventilation
- Use low pneumoperitoneum pressure and Trendelenburg position
- Avoid NSAIDS – close PDA

Question 64

Q

What is TOLAC?

C/I? Risk?

Answer

A

Trial of Labor After Cesarean Section
C-section rate was 32% in 2016
Trial
- Based on c-section type (classic vs low transverse)
- 60 – 80% successful
Contraindications
- Multiple gestations, two previous sections, severe preeclampsia, obesity, previous stalled labor
Risk
- Uterine rupture
- Uterine atony
- Blood transfusions

Answer 65

A

Intra-amniotic infection
S/S
- Maternal leukocytosis
- Maternal tachycardia
- Fetal tachycardia
- Uterine tenderness
- Foul smelling odor
Tx
- Antibiotics
- Delivery

Answer 66

A

Affects up to 1.6% of all pregnancies
Leading non-obstetric cause of maternal mortality
Optimal management begins at conception
- Consult cardiology early
  - Most already know about
- Tailor anesthetic plan to exact lesion
Regional anesthesia is good
- Analgesia = decrease pain and lowers catecholamine release
  - Epidural = slow onset – easier to maintain hemodynamic parameters
    - better choice
- Carful fluid administration
Always provide supplemental oxygen
SBE prophylaxis = consult with OB

Answer 67

A

Occurs in about 3% of pregnancies
Blood sugar goal: 60 -120 mg/dl
Problems:
- placental insufficiency
- preeclampsia
- hypertension
No evidence that one anesthetic technique is superior to another
Consequences:
- Maternal: DKA, HHNC, hypoglycemia, macro/microvascular disease, stiff joint syndrome, diabetic nephropathy,
- Fetal: large for gestational age (shoulder dystocia/birth trauma) and structural malformations

Answer 68

A

Higher rates of chronic hypertension, gestational diabetes, preeclampsia and UTI
Increased risk of premature labor, low birth weight, fetal/neonatal demise
Increased cesarean section rates, post partum hemorrhage, and hospital stays
Good preanesthetic evaluation
- Particular to airway evaluation
- Have multiple airway adjunct available
Establish IV access early
Apply supplemental O2
Establish epidural early – high failure rate
- LA → lower dose req (smaller epidural space)
- Ensure LUD

Answer 69

A

Tobacco
- Most common abused substance in pregnancy = 18%
- Nicotine causes vasoconstriction and may decrease placental blood flow and oxygenation
- Associated with miscarriages, IUGR, placental previa, abruptio placentae, preterm delivery & SIDS.
Alcohol
- 9% of pregnant women between 15 - 44 report drinking in the past month
- Associated with liver disease, coagulopathy, cardiomyopathy, and esophageal varices
  - Fetal alcohol syndrome – 33% of heavy drinkers
- Acute intoxication:
  - GETA w/ RSI and aspiration prophylaxis
- May also undergo acute alcohol withdrawal during the intrapartum or postpartum period = 6 to 48 hours after cessation
  - Nausea, vomiting, tachycardia, tremors, agitation, hallucinations and seizures
Opioids
- Multiple effects on mother and fetus
  - Increased risk:
    - Preeclampsia
    - bleeding
    - increased opioid requirements
- Continue opioids through peripartum course
- Monitor neonates for abstinence syndrome
Cocaine
- Consequences:
  - 1st trimester = congenital anomalies
  - 2^nd/ 3^rd = premature labor, IUGR, placental insufficiency, or placental abruption
- Considerations:
  - HTN Tx: Direct vasodilators (avoid CV and CNS complications)
  - HypoTN tx: direct acting agents
    - Ex: phenylephrine
- GA:
  - may be a/w uncontrolled HTN, tachycardia, dysrhythmias
- Chronic use: a/w thrombocytopenia
- Abuse Requirement
  - Chronic = decrease MAC
  - Acute use = increase MAC
Marijuana
- Frequently used = 4.7%
- Readily crosses the placenta – however, no know effects
- Preterm labor and IUGR can occur
- Long term users = increased secretions, impaired cough & potentially increased airway reactivity
Amphetamines
- Leads to indirect sympathetic stimulation (serotonin, norepi & dopamine)
  - Vasoconstriction with labile blood pressure and tachycardia
- Both neuraxial and general anesthesia have been used
- Acute use may increase risk for urgent cesarean section under general anesthesia
  - Treat like acute cocaine use