Advanced | Obstetric Anesthesia Part I Flashcards
Which of the following is INACCURATE during term pregnancy:
A. gastric emptying is not delayed during pregnancy or early labor
B. BP should be monitored frequently (every 2 to 3 minutes) after the induction of neuraxial
anesthesia
C. Cardiac output is highest immediately post partum
D. Flow volume loop is decreased
E. Arterial CO2 tension is increased
E. Arterial CO2 tension is increased
A 30-year-old woman underwent emergency cesarean delivery under general anesthesia at 36 weeks’ gestation because of preeclampsia. Two hours after the operation, she is still intubated and apneic and cannot be aroused. Deep tendon reflexes are 1+. With mechanical ventilation at an FiO2 of 0.4, PaO2 is 130 mmHg, PaCO2 is 32 mmHg, pH is 7.45, and base excess is -0.6. The most likely cause is
(A) hypovolemic shock
(B) intracerebral hemorrhage
(C) nitroprusside toxicity
(D) overdose of magnesium sulfate
(E) pituitary necrosis
(B) intracerebral hemorrhage
- The deep tendon reflex score is low normal to hyporeflexia which means the dose of Mg Sulfate is not the culprit.
- PaCO2 of 32 is a clue that this could be a blunting of the hypoxia drive which could be attributed to a possible stroke-related complication of pre-eclampsia.
Hypotension after spinal anesthesia is common due to sympathetic blockade. Which of the following agents results in LESS fetal acidosis:
A. Phenylephrine
B. Ephedrine
C. Norepinephrine
D. Epinephrine
A. Phenylephrine
Phenylephrine is equally efficacious to ephedrine for treating maternal hypotension and results in less fetal acidosis; thus, phenylephrine is
preferred for the prevention and treatment of neuraxial anesthesia-induced
hypotension in pregnancy.
Which of the following is MOST likely to represent an abnormal finding in a woman at 38 weeks gestation?
A. Left axis deviation on ECG
B. Pulmonary artery occlusion pressure of 22 mmHg
C. Mild tricuspid regurgitation
D. Presence of a 3rd heart sound on auscultation
B. Pulmonary artery occlusion pressure of 22 mmHg
- The acceptable normal PAOP is 4 -12 mmHg which means 22 is an elevated PAOP.
All the other choices are normal physiologic changes during pregnancy.
In cases of hypotension induced by spinal anesthesia, norepinephrine can be administered as an IV bolus at which of the following doses?
A. 6ug
B. 2ug
C. 4ug
D. 8 ug
A. 6ug
Because phenylephrine may result in reflex bradycardia and decreased CO, some experts have proposed using norepinephrine to prevent and treat hypotension due to its β-adrenergic agonist effects.
The relative potency of norepinephrine to phenylephrine is approximately 11:1, and thus the
suggested dose of IV bolus norepinephrine for this indication is 6 μg.
Barash | 9th edit
Normal pregnancy is associated with a decrease in each of the following EXCEPT
(A) expiratory reserve volume
(B) FEV1/FVC ratio
(C) functional residual capacity
(D) thoracic compliance
(E) vital capacity
(B) FEV1/FVC ratio
- FEV1/FVC ratio should have NO SIGNIFICANT change during pregnancy period.
- Thoracic compliance is decreased due to increased in diaphragm excursion and decreased Chest wall excursion.
- VITAL CAPACITY is NOT changed
- FRC and ERV are both decreased during pregnancy
What is the underlying cause of this CTG tracing?
A. Head compression
B. Uteroplacental insufficiency
C. Cord compression
D. Fetal acidosis
A. Head compression
This shows EARLY DECELERATIONS
Early Deceleration > Head compression
Variable Deceleration > Cord Compression
Late Deceleration > Uteroplacental insufficiency
What is the underlying cause of this CTG tracing?
A. Head compression
B. Uteroplacental insufficiency
C. Cord compression
D. Fetal acidosis
B. Uteroplacental insufficiency
This shows LATE DECELERATIONS
Early Deceleration > Head compression
Variable Deceleration > Cord Compression
Late Deceleration > Uteroplacental Insufficiency
A category I fetal heart rate has:
A. Minimal variability +/- early decelerations
B. Moderate variability +/- early decelerations
B. moderate variability ± early decelerations
NORMAL ACID BASE status
Peak effect of Betamethasone:
A. 24 hrs
B. 48 hrs
C. 12 hrs
B. 48 hrs
TRUE or FALSE
Continuous epidural infusion of lidocaine is associated with a higher incidence of ‘Tachyphylaxis.’
TRUE
TRUE or FALSE
Being pregnant doesn’t increase the risk of developing PDPH.
FALSE
Pregnant is PDPH risk!
By virtue of age and sex, pregnant patients are at HIGHER risk for developing PDPH
In addition, after delivery, reduced pressure in the epidural space may increase the risk of cerebrospinal fluid leakage through a dural puncture, and estrogen withdrawal after delivery of the placenta may exacerbate vascular headaches.
Meningitis is a rare complication after spinal or epidural anesthesia. If clinically suspected, the most common pathogen is:
A. staph. aureus
B. strep. viridans
C. staph. epidermidis
B. strep. viridans
Infections are rare; epidural abscess is usually
caused by skin contaminants and meningitis by contamination of drugs or needles with clinicians’ nasopharyngeal flora (streptococcus viridans).
At the ER, you called a code blue on a full term G2P1001. The resuscitation measures failed after several attempts and the OB decided to do a perimortem cesarean section. When is the golden period to perform perimortem CS?
A. within 5 minutes of the cardiac arrest
B. within 2 minutes of the cardiac arrest
C. CS hysterectomy should be done within 30 mins after the arrest
A. within 5 minutes of the cardiac arrest
In the event of maternal cardiac arrest, cardiopulmonary resuscitation should be initiated immediately.
If return of spontaneous circulation is not achieved with the usual resuscitation measures, perimortem
cesarean delivery should be performed, ideally within 5 minutes of the cardiac arrest.
The patient should not be moved to an operating room to perform the hysterotomy, as this wastes valuable time. Rather, the delivery should be performed at the site of the arrest.
Which of the following drugs does NOT pass the placenta easily?
A. Etomidate
B. Ephedrine
C. Atropine
D. Glycopyrrolate
D. Glycopyrrolate
Magnesium sulfate (MgSO4 ) is used as an anticonvulsant in patients with preeclampsia and for fetal neuroprotection and sometimes for short-term tocolysis. MgSO4 may produce any of the following effects EXCEPT:
A. Sedation
B. Respiratory paralysis
C. Inhibition of acetylcholine (ACh) release at the myoneural
junction
D. Hypertension when used with nifedipine
D. Hypertension when used with nifedipine - FALSE NOTION
Because magnesium antagonizes the effects of α-adrenergic agonists, ephedrine is usually preferred over phenylephrine if a vasopressor is needed to restore blood pressure, along with fluids, after a neuraxial blockade. When a calcium channel blocker, such as nifedipine, is administered along with magnesium, greater hypotension has resulted.
Cardiac output increases dramatically during pregnancy and delivery. When will the cardiac output returns to nonpregnant values in a postpartum state?
A. 12 hours
B. 1 day
C. 2 weeks
D. 6 months
C. 2 weeks
Each uterine contraction increases the cardiac output by about:
A. 10 -25%
B. 5%
C. 30 - 40%
A. 10 -25%
What is therapeutic range of Magnesium Sulfate:
A. 4 to 8 mEq/L
B. 10 mEq/L
C. 2 - 3 mEq/L
D. 15 - 20 mEq/L
A. 4 to 8 mEq/L
With increasing serum levels, loss of deep tendon reflexes occurs at 10 mEq/L (12 mg/dL),
respiratory paralysis occurs at 15 mEq/L (18 mg/dL), and cardiac arrest at greater than 25 mEq/L (> 30 mg/dL) can occur.
Magnesium decreases the release of ACh at the myoneural junction and decreases the sensitivity of the motor endplate to ACh. This can produce marked potentiation of nondepolarizing muscle relaxants.
Magnesium sulfate (MgSO4 ) is used as an anticonvulsant in patients with preeclampsia and for fetal neuroprotection and sometimes for short-term
tocolysis. MgSO4 may produce any of the following effects EXCEPT
A. Sedation
B. Respiratory paralysis
C. Inhibition of acetylcholine (ACh) release at the myoneural
junction
D. Hypertension when used with nifedipine
D. Hypertension when used with nifedipine
Magnesium inhibits the presynaptic release of acetylcholine
at the neuromuscular junction, decreases the sensitivity
of the postsynaptic receptor to acetylcholine, and depresses
the excitability of the muscle fiber membrane
Even though succinylcholine mimics acetylcholine at the
nerve terminal, the onset and duration of a single intubating
dose is not prolonged when administered concurrently with a
magnesium sulfate infusion; a routine intubating dose of 1
to 1.5 mg/kg should be used during rapid-sequence induction
of anesthesia
Which of the following is considered the therapeutic dose of Mg Sulfate in the context of Hypertensive pregnancy?
A. 4 to 8 mEq/L
B. 2 to 4 mEq/L
C. 8 to 12 mEq/L
A. 4 to 8 mEq/L
A 24-year-old primiparous woman is undergoing an elective cesarean section (breech position). After prehydration with 1500 mL of saline, a spinal
anesthetic is performed; 5 minutes later, the blood pressure is noted to be 80/40 mm Hg and the heart rate is 110 beats/min.
The BEST treatment (best fetal pH) after ensuring that adequate left uterine displacement is performed would be:
A. Phenylephrine
B. Ephedrine
C. Epinephrine
D. 1000 mL 5% dextrose in lactated Ringer solution
A. Phenylephrine
In this patient who has left uterine displacement, adequate IV hydration, and a heart rate of 110
beats/min, phenylephrine would be the preferred vasopressor. If the mother has hypotension with bradycardia, ephedrine might be a better choice.
Epinephrine is rarely needed but should be available and used when there is severe hypotension that is not responsive to phenylephrine or ephedrine, especially when there is associated fetal bradycardia.
What is the P50 of fetal hemoglobin at term?
A. 12 mm Hg
B. 18 mm Hg
C. 24 mm Hg
D. 30 mm Hg
B. 18 mm Hg
A 32-year-old parturient with a history of spinal fusion, severe asthma, and hypertension (blood pressure 180/110) is brought to the operating room wheezing. She needs an emergency cesarean section under general anesthesia
for a prolapsed umbilical cord.
Which of the following induction agents would be MOST appropriate for her induction?
A. Sevoflurane
B. Midazolam
C. Ketamine
D. Propofol
D. Propofol
When inducing general anesthesia in an asthmatic
patient, it is imperative to establish an adequate depth of anesthesia before placing an endotracheal tube. If the patient is “light,” then severe bronchospasm may occur. In patients with asthma, IV induction will work with ketamine or propofol
Ketamine is considered by many as the induction
agent of choice due to its mild bronchodilator properties, but because propofol (also a good induction agent in asthmatic patients) does not
stimulate the cardiovascular system as ketamine does, propofol would be preferred in this patient with hypertensive disorders of pregnancy.
The following are proposed mechanisms of action for corticosteroids in asthma patient EXCEPT:
A. Decreases in cellular infiltration and mediator release
B. Reduction in airway permeability
C. Upregulation of the
beta-adrenergic system
D. Direct relaxation of airway smooth muscles
D. Direct relaxation of airway smooth muscles - This is the MOA of theophylline.
Proposed mechanisms of action for corticosteroids are:
(1) decreases in cellular infiltration and mediator release
(2) reduction in airway permeability
(3) upregulation of the beta-adrenergic system.
- Unlike bronchodilators, corticosteroids not only reduce airway sensitivity to a constrictor stimulus but also decrease the maximal extent of airway narrowing, a feature that may predict severity of an acute asthmatic episode.
Chestnut’s OB Anesthesia | 6th edition
Arterial oxyhemoglobin desaturation develops more rapidly following apnea in a pregnant patient at term than in a nonpregnant patient with a large intra-abdominal tumor. Which of the following findings in pregnancy is the most likely cause?
(A) Higher cardiac output
(B) Higher oxygen consumption
(C) Larger anatomic dead space
(D) Smaller blood volume
(E) Smaller functional residual capacity
(B) Higher oxygen consumption
Gravid uterine blood flow is:
(A) autoregulated
(B) decreased by normotensive epidural analgesia
(C) decreased by uterine contractions
(D) increased with an increase in maternal Pa02
(E) unaffected by alpha-adrenergic agonists
(C) decreased by uterine contractions
Which of the following is a manifestation of preeclampsia?
(A) Hypovolemia
(B) Increased colloid osmotic pressure
(C) Natriuresis
(D) Resistance to catecholamines
(E) Thrombocytosis
(A) Hypovolemia
Each of the following factors decreases uterine blood flow EXCEPT
(A) aortocaval compression
(B) hypocarbia
(C) hypoxia
(D) sympathetic block
(E) uterine contractions
(C) hypoxia
An asymptomatic 38-year-old woman is scheduled for elective cesarean delivery. The preoperative EKG shows left axis deviation that was not present one year ago. The most appropriate next step is to:
(A) postpone the procedure and consult a cardiologist
(B) postpone the procedure and obtain an echocardiogram
(C) proceed with the procedure after administration of digitalis
(D) proceed with the procedure but avoid inhalational agents
(E) proceed without intervention since this is a normal finding
(E) proceed without intervention since this is a normal finding
Which of the following is MOST likely to be DECREASED in a healthy ASA II parturient at 36 weeks AOG?
A. Total RBC volume
B. Tidal volume
C. IRV (inspiratory reserve volume)
D. Serum creatinine
D. Serum creatinine
Which of the following is most likely to decrease uterine tone?
(A) Administration of isoflurane 1%
(B) Administration of nitrous oxide 50%
(C) Intravascular injection of 5 ml of 0.5% bupivacaine
(D) Intravenous administration of ketamine 2 mg/kg
(E) Paracervical block with 20 ml of 1% lidocaine
(A) Administration of isoflurane 1%
Which of the following is MOST likely an indication of a RENAL pathology in 36 weeks parturient?
A. Hydronephrosis
B. Elevated creatinine clearance
C. Creatinine elevation 2 times than normal
D. Elevated Aldosterone
C. Creatinine elevation 2 times than normal
A 30 year old is 18 weeks pregnant. She underwent ‘E’ non-obstetric surgery and NMB agent was used. In your plan to reverse the effect of NMB, which of the following will MOST likely result in FETAL BRADYCARDIA?
A. Neostigmine + Atropine
B. Neostigmine + Glycopyrrolate
C. Edrophonium + Atropine
D. Edrophonium + Glycopyrrolate
B. Neostigmine + Glycopyrrolate
Neostigmine plus atropine is the best reversal agent for this case because Atropine will cross the placenta. In contrast to glycopyrrolate which is a quaternary compound, it will not cross the placenta thus will not oppose the effect of neostigmine which will eventually lead to fetal bradycardia.
A woman is in labor at 40 weeks’ gestation and the fetus is in breech presentation. Which of the following will provide adequate uterine relaxation for vaginal delivery?
(A) Spinal anesthesia
(B) Epidural anesthesia
(C) Halothane anesthesia
(D) Pudendal nerve block
(E) Magnesium sulfate
(C) Halothane anesthesia
Administration of succinylcholine 1 mg/kg to a pregnant woman rarely causes fetal neuromuscular blockade. Which characteristic of succinylcholine best explains this phenomenon?
(A) High protein binding
(B) Ionization
(C) Lack of passive placental diffusion
(D) Lipid solubility
(E) Metabolism in the fetal liver
(B) Ionization
The degree of ionization is also important because only the nonionized form of the drug crosses the placental membrane.
- The degree of ionization depends on the pKa of the drug and the pH of maternal
blood.
Which of the following is the most likely effect of administration of magnesium sulfate in a patient with preeclampsia?
(A) Decreased motor end-plate sensitivity to acetylcholine
(B) Decreased uteroplacental blood flow
(C) Increased platelet aggregation
(D) Increased systemic vascular resistance
(E) Inhibited acetylcholinesterase
(A) Decreased motor end-plate sensitivity to acetylcholine
A 28-year-old woman receives a lumbar epidural anesthetic for uncomplicated labor and delivery. During removal of the catheter, 1 cm breaks off and remains in her back. After informing the patient, the most appropriate management is
(A) no intervention unless symptoms occur
(B) prophylactic antibiotics
(C) epidural corticosteroids
(D) dye contrast study of the epidural space
(E) neurosurgical exploration
(A) no intervention unless symptoms occur
ABA Question
To eliminate involuntary expulsive effort with contraction in the second stage of labor, a nerve block must include at least
(A) T6-T12
(B) T4-S5
(C) T8-L2
(D) L1-S2
(E) S2-S4
(E) S2-S4
Following maternal epidural injection, fetal exposure to chloroprocaine is lower than fetal exposure to bupivacaine for which of the following reasons?
(A) Chloroprocaine is metabolized by plasma cholinesterase
(B) Chloroprocaine is more protein bound
(C) Chloroprocaine is not readily absorbed from the epidural space
(D) The ionized fraction of chloroprocaine in the fetal circulation is smaller
(E) The pKa of chloroprocaine is less than that of bupivacaine
(A) Chloroprocaine is metabolized by plasma cholinesterase
In the majority of cases, fetal heart rate decelerations in a variable pattern are associated with:
(A) decreased uteroplacental perfusion
(B) fetal head compression during contractions
(C) umbilical cord compression
(D) low Apgar scores at birth
(E) low neurobehavioral scores eight hours post partum
(C) umbilical cord compression
Administration of magnesium sulfate for treatment of preeclampsia results in a decreased dose requirement for each of the following drugs EXCEPT:
(A) bupivacaine
(B) halothane
(C) midazolam
(D) succinylcholine
(E) vecuronium
(A) bupivacaine
The elimination half-life of amide local anesthetic agents is relatively long, so repeated injections may lead to accumulation in the maternal plasma. In contrast, 2-chloroprocaine, an ester local anesthetic, undergoes rapid enzymatic hydrolysis in the presence of pseudocholinesterase and does not accumulate.
Which of the following statements concerning the use of epidural opioids during labor is TRUE?
(A) Fentanyl decreases the concentration of epidural bupivacaine required for satisfactory analgesia
(B) Fentanyl is an effective analgesic for the second stage of labor
(C) Sufentanil is an unsatisfactory analgesic for labor
(D) The addition of epinephrine to morphine prolongs the duration of analgesia
(E) The duration of analgesia with fentanyl is six to ten hours
(A) Fentanyl decreases the concentration of epidural bupivacaine required for satisfactory analgesia
In patients with pregnancy-induced hypertension, magnesium sulfate is most likely to:
(A) decrease maternal heart rate
(B) decrease sensitivity to relaxants
(C) decrease succinylcholine-induced fasciculations
(D) prevent hypokalemia
(E) produce fetal bradycardia
(C) decrease succinylcholine-induced fasciculations
The low fetal/maternal plasma ratio of bupivacaine compared with lidocaine is due to:
(A) fetal tissue binding
(B) fetal plasma protein binding
(C) maternal plasma protein binding
(D) ionization in maternal blood
(E) ionization in fetal blood
(C) maternal plasma protein binding
Which of the following statements concerning diabetes mellitus in pregnancy is TRUE?
(A) Beta-mimetic tocolytics cause maternal hypoglycemia
(B) Epidural anesthesia produces hyperglycemia
(C) Fetal insulin secretion is suppressed
(D) Maternal insulin does not cross the placenta
(E) Maternal insulin resistance develops abruptly after delivery
(D) Maternal insulin does not cross the placenta
During therapy for eclampsia, toxic blood levels of magnesium sulfate can be distinguished from therapeutic levels by the presence of:
(A) diminished knee jerk reflex
(B) a widened QRS complex on EKG
(C) fetal tachycardia
(D) maternal drowsiness
(E) uterine rigidity
(B) a widened QRS complex on EKG
A 25-year-old woman is admitted to the hospital in the early stages of labor at term. Initial hematocrit is 33%. Which of the following is the most likely cause of the hematocrit value?
(A) Decreased erythropoietin activity
(B) Destruction of erythrocytes by the placenta
(C) Early placental abruption
(D) Increased plasma volume
(E) Iron deficiency
(D) Increased plasma volume
The red blood cell volume increases in response to elevated erythropoietin concentration and the erythropoietic effects of
progesterone, prolactin, and placental lactogen.
- The increase in plasma volume exceeds the increase in red blood cell volume, resulting in the physiologic anemia of pregnancy.
Chestnut OB Anesthesia | 6th edit
Which of the following drugs is LEAST likely to cross the placenta?
(A) Lidocaine
(B) Meperidine
(C) Midazolam
(D) Thiopental
(E) Vecuronium
(E) Vecuronium
Chestnut OB Anesthesia | 6th edit
Which of the following drugs administered to a parturient eliminates fetal heart rate variability?
(A) Atropine
(B) Ephedrine
(C) Hydralazine
(D) Magnesium sulfate
(E) Terbutaline
(A) Atropine
A multiparous 24-year-old woman sustains an amniotic fluid embolism during general anesthesia. The LEAST likely clinical finding is:
(A) increased end-tidal carbon dioxide tension
(B) increased uterine bleeding
(C) jugular venous distention
(D) ST and T wave abnormalities on ECG
(E) wheezing
(A) increased end-tidal carbon dioxide tension
Uterine blood flow is:
(A) autoregulated in normal unanesthetized parturients
(B) decreased by the addition of epinephrine 1:200,000 to lidocaine administered epidurally
(C) decreased by intravenous infusion of ritodrine in unanesthetized parturients
(D) increased by administration of magnesium sulfate to patients with preeclampsia
(E) unchanged after paracervical injection of lidocaine without epinephrine
(D) increased by administration of magnesium sulfate to patients with preeclampsia
During the first stage of labor, the pain of uterine contractions and cervical dilatation is transmitted via the spinal cord segments
(A) T6 to L1
(B) T6 to S5
(C) T10 to L1
(D) T10 to S1
(E) T10 to S5
(C) T10 to L1
Which of the following anesthetic techniques is most appropriate for a woman in the second stage of labor?
(A) Epidural opioids
(B) Local infiltration of the perineum
(C) Lumbar sympathetic block
(D) Paracervical nerve block
(E) Pudendal nerve block
(E) Pudendal nerve block
