Obstetrics

2.

A healthy girl is born with APGAR scores of 9 and 9. Which of following blood gases would you expect to see drawn from her umbilical artery at the time of birth?

7.4 / 40 / 171 / 24
7.26 / 52 / 17 / 22
7.1 / 81 / 28 / 28
7.21 / 55 / 103 / 22

Correct Answer

A. 7.26 / 52 / 17 / 22

Explanation

Babies are expected to have some degree of acidosis immediately after they are born because the uterine contractions interrupt their blood supply repeatedly.

pH 7.26 (7.05- 7.38)
pCO2 55.0 (37-80)
O2 17 (6 - 30)

http://www.ajog.org/article/S0002-9378(96)70214-4/abstract
http://www.k2ms.com/documents/UmbilicalCordBloodSamplingEDCIndepthWeb2013.pdf

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3.

A 32-year old Nigerian immigrant who is 37 weeks pregnant by ultrasound presents to the Labor and Delivery triage complaining of blurred vision. Her chart reveals she is pregnant with twins and has a history of focal segmental glomerulonephritis from HIV. Her initial BP is 190/115 mmHg, and a urine dipstick is 3+ for protein. You place an 18 gauge IV and a radial arterial line, and after giving her a 4g Magnesium Sulfate (MgSO4) bolus, you start a labetalol drip for blood pressure control along with a steady MgSO4 infusion. You also place an epidural without acute complications. Six hours later you are called because the patient has become drowsy. Her vital signs are: 135/80, 80, 6, 99.8 F, and 95% on 2L nasal cannula. Fetal monitoring of her twins is reassuring, and she is arousable to sternal rub. The best management is which of the following:

Atropine 0.5g IVP
Calcium Gluconate 1g IVP
Delivery by emergent Caesarian section
Bolus 1L of Lactate Ringers
Narcan 0.4mg IVP initial dose and maximum of 2mg cumulative dose
Flumazenil 0.5mg IVP initial dose and maximum 3mg cumulative dose
None of the above

Correct Answer

A. Calcium Gluconate 1g IVP

Explanation

This patient presents with signs and symptoms of severe Preeclampsia, and she received the correct treatment with: 1. Magnesium Sulfate (MgSO4) for seizure prophylaxis and 2. Labetalol for blood pressure control. In the setting of damaged kidneys, the renal clearance decreases dramatically, and patients can experience Magnesium toxicity. This patient's increased sedation and respiratory depression are early signs. Late signs of magnesium include heart blocks even complete cardiac arrest.

Calcium Gluconate is initial treatment of magnesium toxicity as it stabilizes the myocardium. Diuretics and sometimes dialysis are definitive therapy.

Question contributed by MMaloney MD.

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1

4.

Which of the spinal levels below is the lowest location for a blockade that would impede the cardioaccelerator fibers?

T1
T3
T4
T6
T7

Correct Answer

A. T4

Explanation

Sympathetic fibers from T1-T4 innervate the heart, so a spinal or epidural from T4 upward block that innervation and could cause a very dangerous bradycardia.

Barah, Clinical Anesthesia, 6th Edition, Chapter 37: Spinal and Epidural Anesthesia, pg. 947.

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5.

The fetal heart monitor result above is thought to be caused by which of the following:

Fetal head compression
Umbilical cord compression
Uteroplacental insufficiency
None of the above

Correct Answer

A. Uteroplacental insufficiency

Explanation

This fetal heart monitor shows a classic "late deceleration," which means that after the uterus contracts the fetal heart rate drops. This happens because a uterine contraction interrupts blood flow across the placenta. During a normal delivery, the baby has enough reserve that it can tolerate this momentary lapse in blood flow, but when the baby is already hypoxic, hypercarbic, and acidotic, it response to the contraction by decreasing the heart rate. The heart consumes the most oxygen in the fetus, so slowing the rate prolongs survival on a lower oxygen supply.

Sweha A and Hacker T, Interpretation of the Electric Fetal Heart Rate During Labor, Journal of the American Family Physician, 1999 May 1; 59(9): 2487-2500.

available at: http://www.aafp.org/afp/1999/0501/p2487.html

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6.

The fetal heart monitor result above is thought to be caused by which of the following:

Fetal head compression
Umbilical cord compression
Uteroplacental insufficiency
Fetal hypoxia and acidosis
None of the above

Correct Answer

A. Umbilical cord compression

Explanation

This fetal heart monitor shows a contraction and a heart rate deceleration that do not start or stop at the same time. This is a called a "variable deceleration," and it is thought to be caused by compression of the umbilical cord.

Sweha A and Hacker T, Interpretation of the Electric Fetal Heart Rate During Labor, Journal of the American Family Physician, 1999 May 1; 59(9): 2487-2500.

available at: http://www.aafp.org/afp/1999/0501/p2487.html

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1

7.

The fetal heart monitor result above is thought to be caused by which of the following:

Fetal head compression
Umbilical cord compression
Fetal hypoxia
Uteroplacental insufficiency

Correct Answer

A. Fetal head compression

Explanation

This fetal heart monitor (FHM) shows a classic "early deceleration." This means that as the uterus contracts (shown by the increased pressure of the bottom line), the fetal heart rate decreases along with it. Likewise, as the contraction resolves the fetal heart rate returns to baseline.

The thinking is that the compression on the baby's head causes a vagal response in the fetal heart.

Sweha A and Hacker T, Interpretation of the Electric Fetal Heart Rate During Labor, Journal of the American Family Physician, 1999 May 1; 59(9): 2487-2500.

available at: http://www.aafp.org/afp/1999/0501/p2487.html

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8.

Which of the following is the leading cause of maternal death in the US?

General anesthesia (failed intubation or aspiration)
Hemorrhage
Pulmonary embolism
Infection
Pregnancy-induced hypertension

Correct Answer

A. Pregnancy-induced hypertension

Explanation

While childbirth is normally associated with blood loss (500ml in vaginal birth and approximately 1L in a c-section), the blood loss can be more significant especially with a placental abruption, uterine rupture, uterine atony, DIC, or high-grade laceration. While blood loss remains the leading cause of maternal death worldwide, pregnancy-induced hypertension (PIH) is more deadly in the US more recently.

Berg CJ, et al. Obstetrics and Gynecology 2010; 116:1302-1309.

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9.

The distance from the skin to the epidural space correlates with which of the following factors: 1. Age 2. Height 3. BMI

1, 3
2, 3
1, 2, 3
3

Correct Answer

A. 3

Explanation

The only factor that is consistently associated with a change in the distance from the skin to the epidural space is a patient's BMI. While some studies indicate that race has a correlation also, the evidence for this is still controversial.

Ravi K et al, Distance from Skin to Epidural Space: Correlation to Body Mass Index (BMI), Journal of Anesthesia and Clinical Pharmacology, 2011 Jan;27(1):39-42.

article available at: http://www.ncbi.nlm.nih.gov/pubmed/21804704

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10.

Which of the following lab values increases in a normal pregnancy?

Hemoglobin
Creatinine
PaCO2
Fibrinogen
Platelets
Bicarbonate
None of the above

Correct Answer

A. Fibrinogen

Explanation

A list of the physiologic changes of a normal pregnancy includes:

1. Increased blood volume ( >8 L at term)
2. Increased cardiac output (peaks immediately after delivery)
3. Dilutional anemia (normal Hb = 12
4. Increased respiratory rate (PaCO2 is approximately 30)
5. Decreased Bicarbonate (compensates for respiratory alkalosis)
6. Decreased FRC
7. Hypercoaguable state with increased fibrinogen, Factors VII, VIII, IX, X, XII
8. Increased GFR and creatinine clearance

As fibrinogen should be significantly increased in pregnancy, when it is low it is an ominous sign of possible DIC.

Miller's Anesthesia, Chapter 69: Anesthesia for Obstetrics, 2009.

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11.

A 23 yo F who is G1P0 presents at 39 weeks with 3cm dilation. She has no medical problems and has never had surgery before. Which tests should she have prior to the delivery?

CBC
CMP
Type and Screen
PT/ PTT
None of the above

Correct Answer

A. None of the above

Explanation

According to the ASA Task Force on Obstetric Anesthesia, CBC is only indicated when there is history of bleeding or clotting disorder or if there is clinical suspicion. Type and Screen

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2

12.

Which of the following does not interfere with an epidural test dose?

Age > 60
Administration of beta blockers
General anesthesia
Administration of Midazolam

Correct Answer

A. Administration of Midazolam

Explanation

When an epidural is newly inserted or there is some uncertainty whether it is intravascular

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Obstetrics

Which of the following obstetric patients has the lowest risk for post-dural puncture headache?

Quiz Preview

A healthy girl is born with APGAR scores of 9 and 9. Which of following blood gases would you expect to see drawn from her umbilical artery at the time of birth?

Which of the spinal levels below is the lowest location for a blockade that would impede the cardioaccelerator fibers?

The fetal heart monitor result above is thought to be caused by which of the following:

The fetal heart monitor result above is thought to be caused by which of the following:

The fetal heart monitor result above is thought to be caused by which of the following:

Which of the following is the leading cause of maternal death in the US?

The distance from the skin to the epidural space correlates with which of the following factors: 1. Age 2. Height 3. BMI

Which of the following lab values increases in a normal pregnancy?

A 23 yo F who is G1P0 presents at 39 weeks with 3cm dilation. She has no medical problems and has never had surgery before. Which tests should she have prior to the delivery?

Which of the following does not interfere with an epidural test dose?