Regional Anesthesia in ERAS — MCQs
Contraindication to neuraxial block is ?
At what age does a child typically know their full name?
During abdominal surgery under local anesthesia, the patient suddenly felt pain due to
What is the maximum concentration allowed for epidural block?
Calcified canal is explored with all of the given instruments except:
Interscalene approach to brachial plexus block does not provide optimal surgical anaesthesia in the area of distribution of which of the following nerve?
What is the mechanism of action of local anesthetics?
Which nerve is targeted in the nasociliary nerve block?
Which of the following techniques is appropriate for the reduction of the shoulder?
Most common cause of maternal mortality in spinal anesthesia is ?
Regional Anesthesia in ERAS Indian Medical PG Practice Questions and MCQs
Question 1: Contraindication to neuraxial block is ?
- A. Hypertension
- B. Renal disease
- C. Clotting disorders (Correct Answer)
- D. Diabetes
Explanation: ***Clotting disorders*** - **Coagulopathy** is a major contraindication to neuraxial block due to the risk of **spinal hematoma**, which can lead to neurological deficits. - This includes patients on **anticoagulants** or with conditions like **thrombocytopenia** or hemophilia. *Hypertension* - While uncontrolled **severe hypertension** may be a relative contraindication, mild to moderate hypertension is generally not. - Neuraxial blocks can sometimes even help manage hypertension by causing **vasodilation**. *Renal disease* - **Chronic renal disease** itself is not a contraindication to neuraxial blocks. - However, complications of renal disease, such as **uremic coagulopathy**, would be a contraindication. *Diabetes* - **Diabetes mellitus** is not a contraindication to neuraxial blockade. - In fact, it may be beneficial by improving **glucose control** compared to general anesthesia in surgical patients.
Question 2: At what age does a child typically know their full name?
- A. 15 months
- B. 24 months
- C. 36 months (Correct Answer)
- D. 48 months
Explanation: ***36 months*** - By **36 months old** (3 years), most children can clearly state their **full name** (first and last name) when asked. - This milestone indicates developing **self-awareness** and **language skills**. - This is a standard developmental milestone tested in CDC and AAP guidelines. *15 months* - At **15 months**, children typically know their **first name** and respond to it, but cannot state their full name. - Their language at this age often includes only a few single words with primarily receptive understanding. *24 months* - By **24 months** (2 years), children often use two-to-four-word sentences and can identify familiar objects and people. - While they know their first name and may start recognizing it, they usually cannot articulate their full name yet. *48 months* - At **48 months** (4 years), a child's language skills are much more advanced, and they can typically tell stories and engage in complex conversations. - Knowing their full name is an expected milestone that should have been achieved earlier, typically by 36 months.
Question 3: During abdominal surgery under local anesthesia, the patient suddenly felt pain due to
- A. Liver
- B. Parietal peritoneum (Correct Answer)
- C. Intestines
- D. Visceral peritoneum
Explanation: ***Parietal peritoneum*** - The **parietal peritoneum** is richly innervated by somatic nerves (**spinal nerves**), making it highly sensitive to pain, pressure, and temperature. - When stimulated during surgery, even under local anesthesia which might not completely block deeper somatic nerves or if the local block is inadequate, it can cause the patient to suddenly feel **sharp, localized pain**. *Liver* - The liver itself has very few pain receptors in its parenchyma; pain from the liver typically arises from stretching of its fibrous capsule (**Glisson's capsule**). - This pain is usually dull and poorly localized, not the sudden, sharp pain typically experienced during surgical manipulation. *Intestines* - The intestines are primarily innervated by the **autonomic nervous system** and are sensitive to distension and ischemia, causing visceral pain, which is typically dull, crampy, and poorly localized. - They are generally not sensitive to cutting or burning, which are common surgical manipulations. *Visceral peritoneum* - The **visceral peritoneum** covers abdominal organs and is innervated by the autonomic nervous system, similar to the organs it covers. - Like the intestines, it is sensitive to stretch and ischemia, producing diffuse, poorly localized visceral pain rather than sharp, localized pain from surgical incision or manipulation.
Question 4: What is the maximum concentration allowed for epidural block?
- A. Chlorprocaine (Correct Answer)
- B. Lidocaine
- C. Ropivacaine
- D. Bupivacaine
Explanation: ***Chlorprocaine*** - **Chlorprocaine** is an ester-type local anesthetic that can be safely used in higher concentrations for epidural blocks up to **3%**, due to its rapid hydrolysis by plasma pseudocholinesterase, leading to a very short half-life and reduced systemic toxicity. - Its rapid metabolism minimizes the risk of accumulation and systemic toxicity, making it a suitable choice when a dense block is needed and a short duration of action is acceptable. *Lidocaine* - **Lidocaine** is an amide-type local anesthetic commonly used in epidural blocks, but its maximum concentration for this application is typically limited to **2%** to avoid systemic toxicity. - Higher concentrations of lidocaine are associated with an increased risk of neurological and cardiovascular adverse effects. *Ropivacaine* - **Ropivacaine** is an amide-type local anesthetic that is less cardiotoxic than bupivacaine, with common concentrations for epidural use ranging from **0.2% to 1%**. - Its maximum concentration is significantly lower than chlorprocaine due to its longer duration of action and potential for systemic toxicity at higher doses. *Bupivacaine* - **Bupivacaine** is a potent amide-type local anesthetic with a high risk of cardiotoxicity, and its maximum concentration for epidural use is generally restricted to **0.5%** or even less for continuous infusions. - Using concentrations above this limit significantly increases the risk of severe cardiovascular complications, including arrhythmias and cardiac arrest.
Question 5: Calcified canal is explored with all of the given instruments except:
- A. 10 K file (Correct Answer)
- B. 6 K file
- C. C+ file
- D. Profinder
Explanation: ***10 K file*** - **#10 K-files** are typically used for initial negotiation of **larger, more accessible canals**, not for exploring highly calcified or severely constricted canals. - Their larger diameter (0.10 mm) makes them too stiff and prone to ledge formation or perforation in extremely calcified areas. *6 K file* - **#6 K-files** are extremely small and flexible (0.06 mm in diameter), making them ideal for initial penetration through tight, calcified canal orifices. - Their fine tip and flexibility help in navigating complex anatomy and overcoming initial resistance without causing iatrogenic damage. *C+ file* - **C+ files** are specifically designed for calcified or severely curved canals due to their **stiffer shaft, non-cutting tip**, and improved resistance to buckling. - They are offered in multiple diameters, including very small sizes like 06 and 08, which are suitable for initial exploration of challenging canal anatomy. *Profinder* - **ProFinder files** are specialized stainless steel hand files with a **triangular cross-section** and non-cutting tip, designed for initial negotiation of difficult and calcified canals. - Their enhanced tip design and shaft stiffness facilitate easy insertion into tight orifices and help maintain the canal pathway.
Question 6: Interscalene approach to brachial plexus block does not provide optimal surgical anaesthesia in the area of distribution of which of the following nerve?
- A. Median
- B. Musculocutaneous
- C. Radial
- D. Ulnar (Correct Answer)
Explanation: ***Ulnar*** - The **ulnar nerve** (C8-T1) emerges from the lower trunk of the brachial plexus. During an **interscalene block**, the local anesthetic is typically deposited at the level of the roots and trunks (C5-C7), which is superior to the origin of the lower trunk that gives rise to the ulnar nerve. - Due to the **cephalad spread** of the local anesthetic from an interscalene block, the **C8 and T1** nerve roots (and thus the ulnar nerve) are often not adequately blocked, leading to suboptimal anesthesia in its distribution. *Median* - The **median nerve** (C5-T1) originates from the lateral and medial cords, which are typically well-covered by the spread of local anesthetic in an interscalene block due to its formation from the middle and upper trunks. - Optimal anesthesia in the distribution of the median nerve is generally achieved with an interscalene block, as its nerve roots are within the targeted antegrade spread. *Musculocutaneous* - The **musculocutaneous nerve** (C5-C7) arises from the lateral cord, which is formed by the upper and middle trunks. These structures are reliably blocked during an interscalene approach. - Sensory and motor functions of the musculocutaneous nerve, such as **biceps contraction** and lateral forearm sensation, are usually well anesthetized. *Radial* - The **radial nerve** (C5-T1) is a branch of the posterior cord, which receives fibers from all three trunks. Its upper and middle trunk components are generally well-blocked by an interscalene approach. - While complete anesthesia of the entire brachial plexus can be variable, the radial nerve is more consistently affected by an interscalene block than the ulnar nerve due to its more extensive proximal root contributions which are within the typical spread.
Question 7: What is the mechanism of action of local anesthetics?
- A. Block chloride channels
- B. Block calcium channels
- C. Block sodium channels (Correct Answer)
- D. Block potassium channels
Explanation: ***Block sodium channels*** - Local anesthetics work by **reversibly binding** to the alpha subunit of **voltage-gated sodium channels** on the neuronal membrane. - This binding prevents the influx of sodium ions, thereby inhibiting the **depolarization** of the neuron and **propagation of action potentials**. *Block chloride channels* - **Chloride channels** are primarily involved in **hyperpolarization** or stabilization of the resting membrane potential, and their blockade is not the primary mechanism of local anesthesia. - Drugs like **benzodiazepines** modulate GABA-gated chloride channels for their anxiolytic and sedative effects. *Block calcium channels* - **Calcium channels** are important for neurotransmitter release and muscle contraction, but their blockade is not the way local anesthetics exert their effects. - **Calcium channel blockers** are used in cardiovascular medicine (e.g., diltiazem, verapamil) to reduce heart rate and blood pressure. *Block potassium channels* - **Potassium channels** are crucial for repolarization of the neuronal membrane and maintaining the resting potential. - While some toxins block potassium channels, it is not the principal mechanism by which **local anesthetics** achieve their nerve blocking effect.
Question 8: Which nerve is targeted in the nasociliary nerve block?
- A. Greater palatine nerve
- B. Sphenopalatine nerve
- C. Anterior ethmoidal nerve
- D. Nasociliary nerve (Correct Answer)
Explanation: ***Nasociliary nerve*** - A nasociliary nerve block specifically targets the **nasociliary nerve** itself. - This block is used to anesthetize the sensory innervation of structures supplied by the nasociliary nerve, such as parts of the **nasal cavity**, **eyeball**, and **skin of the nose**. *Greater palatine nerve* - The **greater palatine nerve** supplies sensation to the posterior hard palate and is targeted in a **greater palatine nerve block**. - This nerve is a branch of the **maxillary nerve** and is primarily involved in dental and palatal anesthesia. *Sphenopalatine nerve* - The **sphenopalatine nerve**, or pterygopalatine ganglion, contains sensory fibers for the nasal cavity, palate, and pharynx, and its block is distinct from a nasociliary block. - A **sphenopalatine ganglion block** is mainly used for conditions like cluster headaches and facial pain, not for direct eyeball sensation. *Anterior ethmoidal nerve* - The **anterior ethmoidal nerve** is a branch of the nasociliary nerve, but a nasociliary nerve block targets the main trunk, which includes all its branches. - While the anterior ethmoidal nerve supplies the anterior part of the nasal septum and lateral wall, it is a **component** of the nasociliary innervation rather than the sole target.
Question 9: 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 10: 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.
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