Obstetric Anesthesia Practice Questions

Q: Internal podalic version is typically performed under which type of anesthesia?

General anesthesia. **Explanation:** **Internal Podalic Version (IPV)** is an obstetric maneuver used to convert a non-vertex presentation (usually a transverse lie of a second twin) into a breech presentation by reaching into the uterus, grasping the feet, and pulling them through the cervix. **Why General Anesthesia (GA) is correct:** The primary requirement for a successful IPV is **profound uterine relaxation**. A contracted uterus tightly encircling the fetus makes manipulation impossible and significantly increases the risk of uterine rupture. GA using **volatile inhalational agents** (like Halothane, Isoflurane, or Sevoflurane) at high concentrations provides rapid and reliable uterine relaxation (tocolysis), allowing the obstetrician to reach the feet and turn the fetus safely. **Why other options are incorrect:** * **Pudendal Block:** This only provides anesthesia to the perineum and vagina. It offers no pain relief for intrauterine manipulation and zero uterine relaxation. * **Intravenous Diazepam:** While it provides sedation and minimal skeletal muscle relaxation, it does not relax the smooth muscles of the uterus. * **Spinal Anesthesia:** While excellent for pain relief, neuraxial blocks (Spinal/Epidural) do not provide uterine relaxation. In fact, they may increase uterine tone due to sympathetic blockade, making version more difficult. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for Rapid Relaxation:** If GA is not used, **IV Nitroglycerin (NTG)** is the pharmacological agent of choice for rapid, short-acting uterine relaxation during obstetric emergencies. * **Twin Delivery:** IPV is most commonly indicated for the **delivery of the second twin** in a transverse lie. * **Uterine Relaxants in Anesthesia:** Halogenated inhalational agents are potent uterine relaxants; this is beneficial for IPV but a disadvantage during the third stage of labor as it can lead to **Postpartum Hemorrhage (PPH)** due to uterine atony.

Q: In a pregnant female, there is decreased requirement of the spinal anaesthetic agent because of all of the following physiological changes except?

Exaggerated lumbar lordosis. **Explanation:** In pregnancy, the dose requirement for spinal anesthesia is reduced by approximately **25-30%**. This reduction is driven by both mechanical and biochemical factors. **Why "Exaggerated Lumbar Lordosis" is the correct answer:** While pregnant women do develop exaggerated lumbar lordosis to compensate for the shifting center of gravity, this anatomical change **does not decrease the dose requirement**. In fact, severe lordosis can technically make the performance of a spinal block more challenging, but it has no direct physiological effect on the potency or spread of the anesthetic drug within the CSF. **Analysis of Incorrect Options (Factors that DO decrease dose requirement):** * **Decreased volume of subarachnoid space & Engorgement of epidural veins:** As the uterus grows, it causes inferior vena cava (IVC) compression. This leads to blood being shunted into the internal vertebral venous plexus (Batson’s plexus), causing **epidural vein engorgement**. These swollen veins encroach upon the subarachnoid and epidural spaces, reducing their volume. Consequently, a smaller volume of local anesthetic results in a higher cephalad spread. * **Increased sensitivity of the nerves:** Hormonal changes, specifically increased **progesterone** levels, enhance the sensitivity of neuronal membranes to local anesthetics. This biochemical shift means less drug is needed to achieve the same level of nerve block. **High-Yield Clinical Pearls for NEET-PG:** * **MAC Reduction:** The Minimum Alveolar Concentration (MAC) for inhalational agents is also decreased by ~30-40% in pregnancy due to progesterone's sedative effects. * **CSF Pressure:** While the volume of CSF is decreased, the baseline CSF pressure remains unchanged; however, it may rise during labor pains (contractions). * **Aortocaval Compression:** Always remember the "Left Lateral Tilt" to prevent supine hypotension syndrome during anesthesia.

Q: Which of the following drugs does not cross the blood-placental barrier?

Glycopyrrolate. **Explanation:** The transfer of drugs across the blood-placental barrier is primarily determined by the drug's molecular weight, lipid solubility, and ionization state. Drugs that are **highly ionized** and **polar** do not cross the placenta easily. **1. Why Glycopyrrolate is the Correct Answer:** Glycopyrrolate is a **quaternary ammonium compound**. Due to its quaternary structure, it is highly ionized and possesses low lipid solubility. This prevents it from crossing the blood-brain barrier (BBB) and, more importantly in this context, the **blood-placental barrier**. Therefore, it does not cause fetal tachycardia or other systemic effects in the fetus. **2. Why the Other Options are Incorrect:** * **Atropine, Physostigmine, and Hyoscine (Scopolamine):** These are all **tertiary amines**. Tertiary amines are non-ionized and highly lipid-soluble, allowing them to readily cross both the blood-brain barrier and the placental barrier. * **Atropine** is known to cause fetal tachycardia after maternal administration. * **Physostigmine** is the only anticholinesterase that crosses the BBB (used in atropine toxicity), unlike Neostigmine (a quaternary amine). **Clinical Pearls for NEET-PG:** * **Mnemonic "He Is Not Going":** Drugs that do **NOT** cross the placenta: **H**eparin, **I**nsulin, **N**eostigmine, **G**lycopyrrolate (also includes Succinylcholine and Vecuronium/Rocuranium). * **Anticholinesterases:** Neostigmine (quaternary) does not cross the placenta, but its counterpart Atropine (tertiary) does. This is why Glycopyrrolate is the preferred anticholinergic to pair with Neostigmine in obstetric reversals to maintain fetal heart rate stability. * Most anesthetic induction agents (Thiopentone, Propofol) and opioids **do** cross the placenta.

Q: Which of the drugs must be available in a labor room when administering narcotics for pain management?

Naloxone. **Explanation:** **Correct Answer: B. Naloxone** **Medical Concept:** Narcotics (opioids) used for labor analgesia, such as pethidine or morphine, readily cross the placental barrier. While they provide maternal pain relief, they can cause **neonatal respiratory depression** if the baby is delivered shortly after administration. **Naloxone** is a specific opioid antagonist that competitively binds to mu-opioid receptors, reversing the effects of narcotics. It is mandatory to have Naloxone available in the labor room to manage potential respiratory depression in the newborn (Neonatal Resuscitation) or accidental maternal overdose. **Analysis of Incorrect Options:** * **A. Fentanyl:** This is a potent short-acting synthetic opioid used *for* analgesia (often in epidurals). It is the cause of potential depression, not the rescue medication. * **C. Pheniramine:** This is an antihistamine (H1 blocker). While it may be used to treat opioid-induced pruritus (itching), it has no role in reversing respiratory depression. * **D. Morphine:** This is a long-acting opioid analgesic. Administering it would worsen the respiratory depression caused by other narcotics. **High-Yield Clinical Pearls for NEET-PG:** * **Naloxone Dosage:** In neonates, the standard dose is **0.1 mg/kg** administered IV or IM. * **Duration of Action:** Naloxone has a shorter half-life than most narcotics. Therefore, the patient must be monitored closely for **"renarcotization"** (recurrence of respiratory depression) as the antagonist wears off. * **Pethidine (Meperidine):** Historically the most common systemic opioid in labor; its metabolite (normeperidine) has a long half-life and can cause prolonged neonatal sedation. * **Contraindication:** Avoid Naloxone in neonates born to opioid-dependent mothers, as it can precipitate acute, life-threatening withdrawal seizures.

Question 1

For operative vaginal delivery, what is the level of sensory block needed to cover pain?

Accepted Answer

S2-S4

Answer

T10-L1

Answer

T10-S1

Answer

L1-S1

Question 2

What is the best method of analgesia for a 25-year-old primigravida with mitral stenosis and mitral regurgitation who desires a normal delivery?

Accepted Answer

Neuraxial blockade analgesia

Answer

Inhalational analgesia

Answer

Intravenous opioids

Answer

Spinal anesthesia

Question 3

What is true about epidural anesthesia in pregnancy?

Accepted Answer

Decreases venous return

Answer

Given through the subarachnoid space

Answer

Increases cardiac output

Answer

Causes venous pooling

Question 4

Internal podalic version is typically performed under which type of anesthesia?

Accepted Answer

General anesthesia

Answer

Pudendal block

Answer

Intravenous diazepam

Answer

Spinal anesthesia

Question 5

In a pregnant female, there is decreased requirement of the spinal anaesthetic agent because of all of the following physiological changes except?

Accepted Answer

Exaggerated lumbar lordosis

Answer

Decreased volume of the subarachnoid space

Answer

Engorgement of epidural veins

Answer

Increased sensitivity of the nerves to the anaesthetic agent

Question 6

Which of the following drugs does not cross the blood-placental barrier?

Accepted Answer

Glycopyrrolate

Answer

Atropine

Answer

Physostigmine

Answer

Hyoscine hydrobromide

Question 7

Which of the drugs must be available in a labor room when administering narcotics for pain management?

Accepted Answer

Naloxone

Answer

Fentanyl

Answer

Pheniramine

Answer

Morphine

Question 8

A 26-year old primigravida with severe rheumatic heart disease (mitral stenosis with mitral regurgitation) is in early labour. The obstetrician wants to try a normal labour. Which of the following is the ideal intervention for labour analgesia?

Accepted Answer

Neuraxial analgesia

Answer

Parenteral opioids

Answer

Inhalational analgesia

Answer

Spinal anaesthesia

Question 9

A patient with mitral stenosis is in labor and desires analgesia for a normal delivery. Which form of anesthesia is most appropriate for her?

Accepted Answer

Epidural Anesthesia

Answer

Inhalational Anesthesia

Answer

Spinal Anesthesia

Answer

Opioids

Question 10

A 20-year-old G1P0 female at 40 weeks of gestation presents to the labor room with rupture of membranes and early onset of labor. She is extremely anxious with peripheral IV placement and begins to hyperventilate. If allowed to continue hyperventilation, what will occur?

Accepted Answer

Decreased maternal uterine artery flow

Answer

Decreased maternal arterial pH

Answer

Increased placental perfusion

Answer

Increased fetal arterial pH

Obstetric Anesthesia — MCQs

Obstetric Anesthesia — MCQs

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