Obstetric Anesthesia

Obstetric Anesthesia Indian Medical PG Question 1: Anesthesia of choice for cesarean section in severe preeclampsia:-

• A. Spinal (Correct Answer)
• B. GA
• C. Epidural
• D. Combined spinal-epidural (CSE)

Obstetric Anesthesia Explanation: ***Spinal*** - **Spinal anesthesia** is generally preferred in severe preeclampsia because it provides **rapid onset** of dense block, which can be critical for emergent cesarean sections. - It avoids the risks associated with general anesthesia in these patients, such as difficult intubation and exaggerated **hypertensive response** to laryngoscopy. *GA* - **General anesthesia (GA)** in severe preeclampsia carries increased risks due to **airway edema**, potential for difficult intubation, and significant **blood pressure fluctuations** during induction and intubation. - It can exacerbate the already compromised uteroplacental perfusion due to the sympathetic blockade and the potential for a **hypotensive episode**. *Epidural* - While generally safe in less severe preeclampsia, an **epidural** has a **slower onset** compared to spinal anesthesia, which may be a disadvantage in emergent situations. - The gradual sympathetic blockade with an epidural is often preferred to avoid sudden drops in blood pressure, but the delay in achieving a surgical block might not be acceptable in severe, unstable cases. *Combined spinal-epidural (CSE)* - **Combined spinal-epidural (CSE)** offers the rapid onset of a spinal block with the flexibility of an epidural catheter for prolonged anesthesia or postoperative pain control. - However, in cases of severe preeclampsia where **hemodynamic instability** is a major concern, the relatively larger dose of local anesthetic required for epidural component can lead to a more pronounced or rapid drop in blood pressure.

Obstetric Anesthesia Indian Medical PG Question 2: The fetal well-being can be assessed by all of the following, except

• A. non-stress test
• B. ultrasound
• C. contraction stress test
• D. Kleihauer-Betke test (Correct Answer)

Obstetric Anesthesia Explanation: ***Kleihauer-Betke test*** - The **Kleihauer-Betke test** is used to quantify the amount of **fetal hemoglobin** that has entered the maternal circulation, typically in cases of **fetomaternal hemorrhage**. - It does assess fetal red blood cells in maternal circulation but does not directly assess current fetal well-being in terms of **cardiac activity**, **movement**, or **oxygenation**. *non-stress test* - The **non-stress test (NST)** monitors **fetal heart rate (FHR)** accelerations in response to fetal movement as an indicator of adequate **fetal oxygenation** and **autonomic nervous system function**. - A **reactive NST** with appropriate accelerations is considered a sign of **fetal well-being**. *ultrasound* - **Ultrasound** is a versatile tool for assessing fetal well-being, providing information on **fetal growth**, **anatomy**, **amniotic fluid volume**, and **biophysical profile (BPP)**. - The BPP, which includes ultrasound observations of **fetal breathing**, **movement**, **muscle tone**, and **amniotic fluid volume**, along with an **NST**, offers a comprehensive assessment of fetal status. *contraction stress test* - The **contraction stress test (CST)** evaluates the response of the **fetal heart rate** to uterine contractions, which temporarily reduce placental blood flow. - A **negative CST** (no late decelerations) indicates good **fetal oxygen reserve** and is a reliable sign of **fetal well-being**.

Obstetric Anesthesia Indian Medical PG Question 3: What is the anesthesia of choice for cesarean section in patients with severe pre-eclampsia?

• A. Epidural
• B. GA
• C. Spinal+epidural
• D. Spinal (Correct Answer)

Obstetric Anesthesia Explanation: ***Spinal*** - **Spinal anesthesia** is generally preferred due to its **rapid onset**, effective block, and minimal fetal exposure to drugs, which is crucial in pre-eclampsia where maternal and fetal well-being are compromised. - It provides **hemodynamic stability** and avoids the risks associated with general anesthesia in patients with severe pre-eclampsia, such as difficult airway and exaggerated pressor response to intubation. *GA* - **General anesthesia** is associated with significant maternal risks in severe pre-eclampsia, including a higher incidence of **difficult or failed intubation**, severe **hypertension** during intubation, and aspiration risks. - There is also a greater potential for **fetal depression** due to anesthetic drug transfer across the placenta. *Epidural* - While an **epidural** can be used, its **slower onset** and the need for incremental dosing make it less ideal for urgent cesarean sections compared to the rapid onset of spinal anesthesia. - It also carries a higher risk of **intravascular injection** and systemic toxicity if local anesthetics are inadvertently administered into the bloodstream. *Spinal+epidural* - A **combined spinal-epidural (CSE)** offers both rapid onset (from the spinal component) and flexibility for prolonged surgical time or post-operative pain control (from the epidural component). - However, in cases of severe pre-eclampsia, the **complexity of the procedure** and the potential for a larger drop in blood pressure with a combined block might be less favorable than a simple spinal, especially if time is critical.

Obstetric Anesthesia Indian Medical PG Question 4: Which volatile anesthetic agent is MOST commonly recognized for its clinically significant tocolytic effects in obstetric anesthesia?

• A. Isoflurane (Correct Answer)
• B. Sevoflurane
• C. Nitrous oxide
• D. Desflurane

Obstetric Anesthesia Explanation: ***Isoflurane*** - **Isoflurane** is well-known for its potent dose-dependent uterine relaxation (tocolytic) properties, which can be clinically useful during obstetric procedures requiring uterine quiescence, such as manual placenta removal or fetal manipulation. - This effect is due to its ability to decrease the frequency and intensity of uterine contractions by relaxing myometrial smooth muscle. *Sevoflurane* - While sevoflurane does possess uterine relaxant properties, its tocolytic effect is generally considered less potent compared to isoflurane at equipotent doses. - It is frequently favored for maintenance of anesthesia in obstetrics due to its rapid onset and offset, but its uterine relaxation is often less pronounced than that of isoflurane. *Desflurane* - Desflurane also causes dose-dependent uterine relaxation, but its tocolytic effects are not typically considered as significant or as commonly utilized for specific uterine relaxation needs as isoflurane. - Its rapid pharmacokinetics make it suitable for obstetric anesthesia, but its uterine effects are generally in line with other volatile agents, with isoflurane having a more pronounced reputation for tocolysis. *Nitrous oxide* - **Nitrous oxide** has minimal to no direct significant uterine relaxant (tocolytic) effects, making it a common choice for analgesia during labor in sub-anesthetic concentrations. - It does not cause the widespread smooth muscle relaxation observed with potent volatile agents, hence is not used for obstetric scenarios requiring uterine quiescence.

Obstetric Anesthesia Indian Medical PG Question 5: The Anaesthesia technique of choice in severely preeclamptic women for cesarean delivery -

• A. Spinal Anaesthesia (Correct Answer)
• B. General Anaesthesia
• C. Epidural Anaesthesia
• D. Pudendal block

Obstetric Anesthesia Explanation: ***Spinal Anaesthesia*** - **Spinal anaesthesia** is generally preferred due to its rapid onset, excellent muscle relaxation, and better hemodynamic stability compared to general anaesthesia when careful fluid management is in place. - It avoids the risks associated with **difficult airway management** and aspiration in preeclamptic patients and minimizes fetal drug exposure. *General Anaesthesia* - **General anaesthesia** carries a higher risk of **rapid, unpredictable increases in blood pressure** during tracheal intubation and extubation, which can be dangerous in preeclampsia with an already compromised cardiovascular system. - It is associated with increased risks of **aspiration**, **difficult airway**, and **postoperative respiratory complications** in preeclamptic women. *Epidural Anaesthesia* - While generally safe, **epidural anaesthesia** has a slower onset compared to spinal anaesthesia, which may not be ideal in emergency situations requiring rapid delivery. - The titration of an epidural can be more challenging in patients with severe preeclampsia, where rapid changes in blood pressure need careful management. *Pudendal block* - A **pudendal block** provides local anaesthesia to the perineum, vulva, and lower vagina. - It is used for pain relief during vaginal delivery and is unsuitable for a **cesarean section**, which requires anaesthesia of the abdominal wall and uterus.

Obstetric Anesthesia Indian Medical PG Question 6: Most common cause of maternal mortality in spinal anesthesia is ?

• A. Allergy to local anesthesia
• B. Nerve injury
• C. Hypotension (Correct Answer)
• D. High block

Obstetric Anesthesia Explanation: ***Hypotension*** - **Profound hypotension** due to sympathetic blockade is the most common cause of maternal mortality in spinal anesthesia. - This can lead to **decreased placental perfusion**, fetal distress, and maternal cardiovascular collapse if not promptly managed. *Allergy to local anesthesia* - True allergic reactions to local anesthetics are **extremely rare**, especially to ester-type anesthetics used in spinal anesthesia. - While possible, it is not the most common cause of maternal mortality. *Nerve injury* - **Direct nerve injury** during spinal anesthesia is a rare complication, usually resulting in localized neurological deficits rather than mortality. - It does not represent the primary cause of maternal death. *High block* - A **high spinal block** can cause severe hypotension and respiratory compromise, which can lead to mortality. - However, the underlying mechanism for the life-threatening aspects of a high block is often **severe hypotension** and subsequent cardiovascular collapse.

Obstetric Anesthesia Indian Medical PG Question 7: During induction of anesthesia, after thiopentone injection patient develops discoloration of hand. All are true about this condition and its management except:

• A. Immediately remove the needle from the vessel (Correct Answer)
• B. Inject lignocaine
• C. Dilute heparin
• D. Intra-arterial thrombolysis

Obstetric Anesthesia Explanation: ***Immediately remove the needle from the vessel*** - This is an **incorrect** management step for accidental intra-arterial injection of thiopentone because removing the needle can lead to **vasospasm** and further compromise blood flow. - The needle should be left in place to facilitate administration of vasodilator and antispasmodic agents, helping to mitigate the damage. *Inject lignocaine* - **Intra-arterial lignocaine** (without adrenaline) is a crucial step to induce vasodilation and alleviate pain caused by the irritation and arterial spasm. - This helps to restore blood flow and prevent further tissue ischemia. *Dilute heparin* - Administering **dilute heparin** directly into the artery helps to prevent or treat **thrombosis**, a common complication of intra-arterial injection of irritant substances like thiopentone. - Thiopentone's high pH can cause endothelial damage, leading to clot formation and further reducing perfusion. *Intra-arterial thrombolysis* - If conservative measures fail and there is evidence of severe ischemia or thrombosis, **intra-arterial thrombolysis** with agents like urokinase or streptokinase may be considered. - This highly invasive procedure aims to dissolve existing clots and restore arterial patency to salvage tissue.

Obstetric Anesthesia Indian Medical PG Question 8: A patient presents with malignant hyperthermia and metabolic acidosis. Immediate treatment should be started with:

• A. Intravenous fluids
• B. Sodium bicarbonate
• C. Paracetamol
• D. Intravenous Dantrolene (Correct Answer)

Obstetric Anesthesia Explanation: ***Intravenous Dantrolene*** - **Dantrolene** is the specific and primary treatment for **malignant hyperthermia** as it acts directly on the **ryanodine receptor** to inhibit calcium release from the sarcoplasmic reticulum, relaxing skeletal muscle. - Its prompt administration is crucial in reversing the life-threatening metabolic and physiological derangements associated with this condition, including **hyperthermia** and **metabolic acidosis**. *Intravenous fluids* - While **intravenous fluids** are important for maintaining hydration and supporting renal function in patients with **malignant hyperthermia**, they are a supportive measure, not the definitive treatment. - They primarily address complications like **dehydration** and **rhabdomyolysis**, but do not directly treat the underlying pathophysiology of excessive calcium release. *Sodium bicarbonate* - **Sodium bicarbonate** may be used to correct severe **metabolic acidosis**, which can be a consequence of **malignant hyperthermia**. - However, treating the acidosis without addressing the primary cause (malignant hyperthermia) by administering dantrolene is insufficient and will not stop the progression of the syndrome. *Paracetamol* - **Paracetamol (acetaminophen)** is an antipyretic often used for fever reduction, but it is entirely ineffective in treating the rapid and severe hyperthermia of **malignant hyperthermia**. - The temperature dysregulation in malignant hyperthermia is caused by uncontrolled muscle metabolism, not a response to typical antipyretics, and thus paracetamol would provide no therapeutic benefit.

Obstetric Anesthesia Indian Medical PG Question 9: The most appropriate treatment for hypothermia during anesthesia is

• A. Treated with warm saline (Correct Answer)
• B. Mechanism of heat loss is conduction
• C. Occurs in all types of Anaesthesia
• D. Is beneficial to patients

Obstetric Anesthesia Explanation: ***Treated with warm saline*** - **Warm intravenous fluids**, particularly saline, are a primary and effective method for rewarming hypothermic patients during surgery. - This helps to directly transfer heat into the patient's core circulation and raise body temperature. *Mechanism of heat loss is conduction* - While **conduction** (heat loss to colder surfaces) is one mechanism of heat loss during anesthesia, **radiation** (heat loss to the environment) and **convection** (heat loss to moving air currents or blood) are often more significant. - Evaporation (from open surgical sites) also contributes substantially to heat loss. *Occurs in all types of Anaesthesia* - Hypothermia is a common complication of **general anesthesia** due to impaired thermoregulation, but it is less common or sometimes deliberately avoided in certain regional anesthesia techniques unless the patient is already cold. - The degree and likelihood of hypothermia vary depending on the type and duration of anesthesia, ambient temperature, and patient factors. *Is beneficial to patients* - **Hypothermia** is generally **detrimental** to most surgical patients, leading to complications like increased bleeding, impaired drug metabolism, prolonged recovery, and increased risk of wound infection. - Therapeutic hypothermia is only medically induced for specific conditions (e.g., post-cardiac arrest) and is not a general benefit during anesthesia.

Obstetric Anesthesia Indian Medical PG Question 10: What clinical sign is used to confirm the success of an epidural block?

• A. Inability to dorsiflex the foot
• B. Loss of sensation in the T10 dermatome (Correct Answer)
• C. Loss of resistance (used during block placement)
• D. Westphal's sign (diminished patellar reflex)

Obstetric Anesthesia Explanation: ***Loss of sensation in the T10 dermatome*** - The **T10 dermatome** is a common and reliable landmark for assessing the spread and effectiveness of an epidural block, especially for surgical procedures or labor analgesia impacting the abdominal and pelvic regions. - A successful epidural block should produce a **bilateral, symmetric sensory deficit** to pinprick or cold sensation within the target dermatomes, indicating proper anesthetic distribution. *Inability to dorsiflex the foot* - This symptom suggests a motor block primarily affecting the **deep peroneal nerve** (L4-L5 nerve roots), which would be a sign of a dense spinal block rather than a typical epidural, or an overly extensive epidural block, especially if it's bilateral. - While some motor weakness is expected with an epidural block, a complete inability to dorsiflex the foot is not the primary or most sensitive indicator of its success for general pain relief. *Loss of resistance (used during block placement)* - **Loss of resistance** is a technique used *during the placement* of an epidural needle to identify the epidural space (passing through the ligamentum flavum). - It is a procedural step for correct needle positioning, not a clinical sign used *after* injection to confirm the block's effect. *Westphal's sign (diminished patellar reflex)* - **Westphal's sign** refers to the absence or diminution of the patellar reflex (an L2-L4 reflex), which can indicate a neurological issue involving the quadriceps muscles or the femoral nerve pathway. - While a dense epidural block can affect motor function and reflexes, Westphal's sign is not typically used as the primary or most accurate indicator of a successful epidural block's sensory coverage.

Obstetric Anesthesia Flashcard 1 of 9

Question: A _____ is the preferred anesthetic technique for ensuring painless labor

Answer: lumbar epidural

Obstetric Anesthesia Flashcard 2 of 9

Question: _____ is the vasopressor of choice in pregnant patients developing hypotension following neuraxial anesthesia

Answer: Phenylephrine

Obstetric Anesthesia Flashcard 3 of 9

Question: What type of anesthesia offers the most benefit in a patient with post-partum hemorrhage?_____

Answer: General (inhalational) anesthesia

Obstetric Anesthesia Flashcard 4 of 9

Question: Which anesthetics have the most potent effect on uterine relaxation?_____

Answer: Halogenated anesthetics (halothane)

Obstetric Anesthesia Flashcard 5 of 9

Question: Which inhalational agent is the best uterine relaxant?_____

Answer: Halothane

Obstetric Anesthesia Flashcard 6 of 9

Question: In an obstetric emergency (eg. cord prolapse), the ideal anaesthetic of choice would be _____ anesthesia

Answer: general

Obstetric Anesthesia Flashcard 7 of 9

Question: Most common cause of death during GA in obstetrics is _____ syndrome

Answer: Mendelson s

Obstetric Anesthesia Flashcard 8 of 9

Question: _____ anesthesia is the first choice for most patients with preeclampsia during labor, vaginal delivery, and cesarean section

Answer: Epidural

Obstetric Anesthesia Flashcard 9 of 9

Question: The concentration of bupivacaine used in labour analgesia/walking-epidural is ____%.

Answer: 0.0625-0.1