Regional Anesthesia in Obstetrics — MCQs
Anesthesia of choice for cesarean section in severe preeclampsia:-
Which local anesthetic is considered the most cardiotoxic?
Which of the following is FALSE about ropivacaine?
What is the name of the nerve block technique shown in the image?
All are absolute contraindications for regional anesthesia EXCEPT:
Which of the following techniques is appropriate for the reduction of the shoulder?
80-year-old patient is admitted for open reduction and internal fixation of a fracture of the femur. Which one of the following techniques is the ideal anesthetic technique for this patient?
Most common cause of maternal mortality in spinal anesthesia is ?
A patient is placed in the **lateral decubitus position** (lying on their side with knees drawn toward the chest and the spine flexed/arched outward) before the procedure. This position is maintained during which of the following types of anaesthesia?
Which block is described as regional anesthesia of the arm:-
Regional Anesthesia in Obstetrics Indian Medical PG Practice Questions and MCQs
Question 1: Anesthesia of choice for cesarean section in severe preeclampsia:-
- A. Spinal (Correct Answer)
- B. GA
- C. Epidural
- D. Combined spinal-epidural (CSE)
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.
Question 2: Which local anesthetic is considered the most cardiotoxic?
- A. Procaine
- B. Prilocaine
- C. Ropivacaine
- D. Bupivacaine (Correct Answer)
Explanation: ***Bupivacaine*** - **Bupivacaine** is an amide-type local anesthetic associated with significant **cardiotoxicity** due to its high lipid solubility and slow dissociation from cardiac sodium channels. - This can lead to severe **arrhythmias** and myocardial depression, making it particularly dangerous in systemic overdose. *Procaine* - **Procaine** is an ester-type local anesthetic with a relatively low potential for cardiotoxicity. - Its rapid metabolism by **plasma pseudocholinesterase** limits systemic exposure and reduces the risk of cardiac effects. *Prilocaine* - **Prilocaine** is an amide-type local anesthetic that is generally less cardiotoxic than bupivacaine. - Its primary concern is the potential to cause **methemoglobinemia** at higher doses, a side effect not directly related to cardiotoxicity. *Ropivacaine* - **Ropivacaine** is an amide-type local anesthetic developed as an alternative to bupivacaine with a reduced cardiotoxicity profile. - It exhibits a more favorable **therapeutic index** for cardiac effects due to its chemical structure and faster dissociation from cardiac sodium channels.
Question 3: Which of the following is FALSE about ropivacaine?
- A. More cardiotoxic than lignocaine
- B. Contains only R enantiomer (Correct Answer)
- C. Less cardiotoxic than bupivacaine
- D. Onset of action is faster than bupivacaine
Explanation: ***Contains only R enantiomer*** - Ropivacaine is a **pure S-enantiomer** (S-(-)-enantiomer) preparation, NOT the R-enantiomer. - This single enantiomer formulation contributes to its **reduced cardiotoxicity** and improved safety profile compared to racemic bupivacaine. - The statement "contains only R enantiomer" is **FALSE** - this is the correct answer. *Less cardiotoxic than bupivacaine* - Ropivacaine has **lower lipid solubility** and faster dissociation from cardiac sodium channels compared to bupivacaine. - This results in **significantly reduced cardiotoxicity**, making it safer for large-volume regional blocks. - This statement is **TRUE**. *More cardiotoxic than lignocaine* - Ropivacaine is indeed **more cardiotoxic than lidocaine** due to its greater potency and longer duration of action. - Amide local anesthetics with higher potency (bupivacaine > ropivacaine > lidocaine) carry greater cardiac risk. - This statement is **TRUE**. *Onset of action is faster than bupivacaine* - Ropivacaine and bupivacaine have **similar onset times** (10-15 minutes for epidural/nerve blocks). - Both have similar pKa values (ropivacaine 8.1, bupivacaine 8.1), resulting in comparable onset characteristics. - While ropivacaine may have marginally faster onset in some contexts, clinically they are considered equivalent. - This statement is generally **FALSE or equivocal**, making it potentially the second-best answer, but the R-enantiomer statement is definitively false.
Question 4: What is the name of the nerve block technique shown in the image?
- A. Intra-arterial anesthesia (Correct Answer)
- B. Bier's block
- C. Regional anesthesia
- D. Axillary block
Explanation: ***Intra-arterial anesthesia*** - The image shows a **cannula inserted directly into an artery**, indicated by the blood reflux and the context of anesthesia, suggesting direct drug delivery into the arterial system. - This method is used for specific types of regional pain management or diagnostic procedures where direct arterial access is required for **localized drug distribution**. *Bier's block* - A Bier's block, or **intravenous regional anesthesia**, involves injecting local anesthetic into a **vein** in an extremity after it has been exsanguinated and isolated by a tourniquet. - The image clearly shows a **bright red blood flash**, characteristic of arterial cannulation, not venous. *Regional anesthesia* - This is a broad term referring to the **anesthesia of a specific region** of the body and encompasses various techniques. - While intra-arterial anesthesia is a type of regional anesthesia, "regional anesthesia" itself is too general to specifically describe the technique shown. *Axillary block* - An **axillary block** is a type of peripheral nerve block targeting the brachial plexus in the axilla to anesthetize the arm. - The image does not depict the axillary region or the characteristic needle placement for an axillary block; instead, it shows direct vascular access.
Question 5: All are absolute contraindications for regional anesthesia EXCEPT:
- A. Lack of resuscitation facilities
- B. INR > 2 in ophthalmic procedures (Correct Answer)
- C. Infection at injection site
- D. Patient refusal
Explanation: ***INR > 2 in ophthalmic procedures*** - While a high INR (international normalized ratio) indicates increased bleeding risk, an INR > 2 is generally considered a **relative contraindication** for most regional anesthesia procedures, especially in ophthalmic cases where the risk of significant hemorrhage might be lower compared to deeper blocks. - The decision to proceed often depends on the specific procedure, patient's overall condition, and a careful risk-benefit analysis, rather than being an absolute bar. *Lack of resuscitation facilities* - The absence of proper **resuscitation equipment and trained personnel** is an absolute contraindication for regional anesthesia, as serious complications (e.g., local anesthetic systemic toxicity, respiratory depression) can occur, requiring immediate intervention. - Performing regional anesthesia in such a setting puts the patient at extreme risk of irreversible harm or death in the event of an adverse reaction. *Infection at injection site* - Performing regional anesthesia through an infected area carries a high risk of introducing bacteria into deeper tissues, including the **neuraxial space** or surrounding nerves, leading to serious complications like **abscess formation, meningitis, or osteomyelitis**. - This is an **absolute contraindication** to prevent the spread of infection. *Patient refusal* - **Informed consent** is a fundamental ethical and legal principle in medicine; a competent patient's refusal to undergo a procedure, including regional anesthesia, must always be respected. - Proceeding against a patient's wishes constitutes **assault and battery** and is an absolute contraindication for any medical intervention.
Question 6: Which of the following techniques is appropriate for the reduction of the shoulder?
- A. Spinal anesthesia
- B. Interscalene block (Correct Answer)
- C. Axillary brachial block
- D. Bier block
Explanation: ***Interscalene block*** - An **interscalene block** targets the brachial plexus at the level of the neck, providing excellent anesthesia for shoulder procedures. - This technique effectively blocks the nerves innervating the shoulder joint, allowing for **muscle relaxation** and pain control necessary for reduction. *Spinal anesthesia* - **Spinal anesthesia** provides anesthesia to the lower body and is primarily used for procedures below the waist. - It does not provide adequate **analgesia or muscle relaxation** for a shoulder reduction. *Axillary brachial block* - An **axillary brachial block** anesthetizes the distal arm and hand, but it often spares the more proximal shoulder innervation. - While useful for forearm and hand surgery, it typically does not provide sufficient **anesthesia for the shoulder** joint itself. *Bier block* - A **Bier block**, or intravenous regional anesthesia, is suitable for procedures on the distal extremities, such as the hand or foot. - It involves tourniquet inflation and intravenous injection of local anesthetic, making it **unsuitable for shoulder reduction** due to the large muscle mass and proximal location.
Question 7: 80-year-old patient is admitted for open reduction and internal fixation of a fracture of the femur. Which one of the following techniques is the ideal anesthetic technique for this patient?
- A. Local infiltration
- B. Regional anesthesia (Correct Answer)
- C. General anesthesia
- D. Paracervical block
Explanation: ***Regional anesthesia*** - **Regional anesthesia** offers advantages in elderly patients undergoing hip fracture repair, including reduced risks of **postoperative cognitive dysfunction** and **cardiovascular complications**. - It provides **effective pain control** during and after surgery, potentially leading to faster recovery and fewer opioid-related side effects. *Local infiltration* - **Local infiltration** alone is typically inadequate for surgical pain control during an **open reduction and internal fixation of a fractured femur**. - It would not provide sufficient **muscle relaxation** or **sensory block** for such an invasive procedure. *General anesthesia* - While an option, **general anesthesia** in an 80-year-old patient carries a higher risk of **postoperative delirium** and **cardiopulmonary complications** compared to regional techniques. - It may also prolong recovery time and increase the need for **postoperative ventilation**. *Paracervical block* - A **paracervical block** is primarily used for **gynecological procedures**, such as cervical dilation and uterine procedures, due to its localized anesthetic effect around the cervix. - It is completely unsuitable for **femur fracture surgery**, as it would not provide any pain relief or surgical anesthesia to the lower limb.
Question 8: 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
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.
Question 9: A patient is placed in the **lateral decubitus position** (lying on their side with knees drawn toward the chest and the spine flexed/arched outward) before the procedure. This position is maintained during which of the following types of anaesthesia?
- A. Spinal anaesthesia (Correct Answer)
- B. Bier's block
- C. Caudal anaesthesia
- D. Stellate block
Explanation: ***Spinal anaesthesia*** - The **lateral decubitus position** with flexed spine and knees drawn to chest maximally opens the **intervertebral spaces**, facilitating needle insertion into the **subarachnoid space**. - This **fetal position** increases the distance between spinous processes, making identification of anatomical landmarks easier for **lumbar puncture**. *Bier's block* - Requires the patient in **supine position** with the affected limb elevated to achieve **exsanguination** before tourniquet application. - The procedure involves **intravenous injection** into a peripheral vein of the isolated limb, not spinal positioning. *Caudal anaesthesia* - Typically performed in **prone position** or **jack-knife position** to provide optimal access to the **sacral hiatus**. - The lateral decubitus position does NOT facilitate access to the **caudal epidural space** through the sacrococcygeal membrane. *Stellate block* - Requires **supine position** with slight **neck extension** to access the **anterior paratracheal space** at C6-C7 level. - The lateral decubitus position would make identification of **cervical landmarks** and **carotid artery** extremely difficult and unsafe.
Question 10: Which block is described as regional anesthesia of the arm:-
- A. Interscalene block
- B. Infraclavicular block
- C. Axillary block
- D. Supraclavicular brachial plexus block (Correct Answer)
Explanation: ***Supraclavicular brachial plexus block*** - The **supraclavicular block** targets the **trunks of the brachial plexus** as they exit the scalene muscles, providing comprehensive anesthesia to the entire upper limb, including the shoulder, arm, forearm, and hand. - This block is particularly effective for procedures involving the arm due to its proximal location within the brachial plexus, covering multiple nerve distributions. *Interscalene block* - An **interscalene block** primarily targets the **roots or trunks of the brachial plexus** and is typically used for shoulder and upper arm surgery, but may spare the ulnar nerve. - While it anesthetizes the arm, it is primarily chosen for more proximal procedures and may not provide complete distal arm anesthesia compared to the supraclavicular approach. *Infraclavicular block* - An **infraclavicular block** targets the **cords of the brachial plexus** and is suitable for procedures involving the elbow, forearm, and hand, providing good coverage for these areas. - While it does anesthetize the distal arm, it is more distal than the supraclavicular block and may not provide full coverage for the entire upper arm and shoulder. *Axillary block* - An **axillary block** targets the **terminal branches of the brachial plexus** in the axilla, mainly anesthetizing the forearm and hand. - This block is often used for procedures distal to the elbow and provides less comprehensive coverage for the entire upper arm and shoulder compared to more proximal blocks.
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