Regional Anesthesia — MCQs

Regional Anesthesia Indian Medical PG Practice Questions and MCQs

Question 151: Which anesthetic modality is to be avoided in sickle cell disease?

A. Intravenous Regional Anaesthesia (Correct Answer)
B. Spinal Anaesthesia
C. Brachial Plexus Block
D. General Anesthesia

Explanation: ***Intravenous Regional Anaesthesia*** - Intravenous regional anesthesia (IVRA), also known as a **Bier block**, involves injecting local anesthetic into an extremity isolated by a tourniquet; removal of the tourniquet rapidly introduces the local anesthetic into the systemic circulation. - In patients with **sickle cell disease**, the **venous stasis** and **acidosis** induced by the tourniquet and ischemia can precipitate **sickling crises** and **thrombosis** within the isolated limb. *Spinal Anaesthesia* - Spinal anesthesia is generally considered safe in sickle cell patients, as it leads to **sympathectomy** and **vasodilation**, which can improve blood flow and oxygenation. - Careful attention to **fluid balance** and **blood pressure maintenance** is crucial to prevent hypovolemia and hypotension. *General Anesthesia* - General anesthesia can be used in sickle cell patients, provided there is meticulous management of **oxygenation**, **hydration**, and **temperature** to prevent a sickle cell crisis. - It requires careful monitoring of **end-tidal CO2** and arterial blood gases to avoid hypoxia and acidosis. *Brachial Plexus Block* - Peripheral nerve blocks like a **brachial plexus block** are generally safe and often preferred in sickle cell patients, as they provide effective analgesia without systemic hemodynamic changes. - The local anesthetic does not significantly alter the systemic circulation or oxygenation, reducing the risk of a **sickling crisis**.

Question 152: 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 153: Which approach of brachial plexus block targets cords of the brachial plexus:-

A. Infraclavicular (Correct Answer)
B. Supraclavicular
C. Axillary
D. All of the options

Explanation: ***Infraclavicular*** - The **infraclavicular approach** targets the brachial plexus at the level of the **cords**, which lie deep to the pectoralis muscles and medial to the coracoid process. - This block is particularly useful for surgeries involving the **distal upper limb**, as it blocks all divisions of the cords. *Supraclavicular* - The **supraclavicular approach** targets the brachial plexus at the level of the **trunks**, specifically where they emerge between the anterior and middle scalene muscles. - While it provides good anesthesia for the entire upper limb, it is proximal to the cord level. *Axillary* - The **axillary approach** targets the terminal nerves (e.g., median, ulnar, radial, musculocutaneous) after the brachial plexus has divided into individual nerves in the **axilla**. - This block is distal to the cords and is often used for surgeries of the forearm and hand. *All of the options* - This option is incorrect because only the **infraclavicular approach** specifically targets the cords of the brachial plexus. - The other approaches target either the trunks (supraclavicular) or the terminal nerves (axillary).

Question 154: In a patient with sickle cell trait, which mode of anesthesia should be avoided?

A. Brachial plexus block infraclavicular approach
B. Supraclavicular brachial plexus block
C. Brachial plexus block axillary approach
D. IVRA (intravenous regional anesthesia) (Correct Answer)

Explanation: ***IVRA (intravenous regional anesthesia)*** - **IVRA** involves injecting a local anesthetic into an isolated limb, which can lead to **stasis** and **hypoxia** if the tourniquet is left on too long or if the block is incomplete. - In patients with **sickle cell trait**, these conditions predispose to **sickling crises**, as the red blood cells deform under low oxygen tension, obstructing blood flow and causing tissue damage. *Brachial plexus block infraclavicular approach* - This regional anesthetic technique involves injecting local anesthetic around the brachial plexus nerves, which does not typically lead to **ischemia** or **stasis** in the extremity. - It maintains normal blood flow, thereby avoiding the triggers for **sickling** seen in sickle cell trait patients. *Supraclavicular brachial plexus block* - Similar to other brachial plexus blocks, the supraclavicular approach provides anesthesia without compromising **blood flow** to the limb. - As long as proper technique is used and no **vascular compromise** occurs, it is generally safe for patients with sickle cell trait. *Brachial plexus block axillary approach* - The axillary approach to the brachial plexus block is another regional technique that provides excellent anesthesia to the arm and hand. - It does not induce **hypoxia** or **vascular stasis** in the limb, making it a safer option for patients with sickle cell trait compared to IVRA.

Question 155: IVRA is contraindicated in -

A. Sickle cell disease (Correct Answer)
B. Cancer of hematogenous system
C. Coagulopathy
D. Hypertension

Explanation: ***Sickle cell disease*** - **Intravenous regional anesthesia (IVRA)** involves injecting local anesthetic into an isolated limb, which can lead to **stasis** and **ischemia** when the tourniquet is inflated. - In sickle cell disease, **hypoxia** and **acidosis** from stasis can precipitate or worsen a **sickle cell crisis**, leading to severe pain and potential organ damage. *Cancer of the hematogenous system* - While certain cancers of the hematogenous system might indirectly affect anesthetic choice, there is **no direct contraindication** for IVRA in these conditions. - Local anesthetics used in IVRA do not typically interfere with the systemic treatment or progression of hematological malignancies. *Coagulopathy* - Coagulopathy is a relative contraindication to regional anesthesia due to the risk of **hematoma formation** if a nerve block is performed or if there is trauma during venipuncture. - However, IVRA primarily uses **intravenous access**, and the major risk is generally not hematoma due to bleeding at the injection site but rather systemic effects if the tourniquet fails. *Hypertension* - **Hypertension** itself is not a contraindication for IVRA. - While local anesthetics, if they escape the tourniquet, can cause systemic effects, properly performed IVRA has minimal systemic absorption until the tourniquet is released.

Question 156: 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 157: First fibres to be blocked in spinal anaesthesia is:

A. Sensory fibres
B. Motor nerves
C. Sympathetic preganglionic (Correct Answer)
D. Efferent motor nerves

Explanation: ***Sympathetic preganglionic*** - **Sympathetic preganglionic fibers** are generally the **smallest** and **unmyelinated** or **lightly myelinated**, making them most susceptible to local anesthetic blockade. - Their blockade leads to **vasodilation** and a potential drop in blood pressure, which is often the first physiological sign of spinal anesthesia taking effect. *Sensory fibres* - While sensory fibers are blocked in spinal anesthesia, they are typically **larger diameter** than sympathetic preganglionic fibers and require a higher concentration or longer exposure to be fully blocked. - The onset of sensory blockade, though rapid, usually follows the initial sympathetic blockade. *Motor nerves* - **Motor nerves** are among the **largest diameter** and **heavily myelinated** nerve fibers, making them the most resistant to local anesthetic blockade. - Motor paralysis is usually the last effect to manifest as the spinal block deepens. *Efferent motor nerves* - This option refers to the same set of fibers as "Motor nerves," which are **large and myelinated**, requiring a greater degree of blockade than sympathetic preganglionic fibers. - Their blockade is responsible for the skeletal muscle relaxation observed in spinal anesthesia, but this effect occurs later than sympathetic blockade.

Question 158: In spinal anaesthesia, which of the following statements about the segmental levels of blockade is correct?

A. The sympathetic block occurs at a higher level than the sensory block. (Correct Answer)
B. The sympathetic block occurs at a lower level than the sensory block.
C. The sympathetic, motor, and sensory blocks occur at the same level.
D. The motor block occurs at a higher level than the sensory block.

Explanation: ***The sympathetic block occurs at a higher level than the sensory block.*** - **Sympathetic nerve fibers** are smaller and less myelinated than sensory fibers, making them more susceptible to local anaesthetic agents and thus blocking at a **higher dermatomal level**. - This differential blockade is important clinically, as a higher sympathetic block can lead to more significant **hypotension** and **bradycardia**. *The sympathetic block occurs at a lower level than the sensory block.* - This statement is incorrect because the **small, unmyelinated sympathetic fibers** are precisely what make them more vulnerable and therefore blocked at a *higher* level than sensory fibers. - If sympathetic block occurred at a lower level, the cardiovascular effects would be less pronounced for a given sensory level. *The sympathetic, motor, and sensory blocks occur at the same level.* - This is incorrect as **differential blockade** is a well-established phenomenon in spinal anaesthesia, reflecting the varying susceptibility of different nerve fiber types to local anaesthetics. - **Motor fibers** are generally larger and more myelinated, requiring higher concentrations or longer exposure to achieve blockade, unlike sympathetic fibers. *The motor block occurs at a higher level than the sensory block.* - This is incorrect; the **motor block** usually occurs at a *lower* level than the sensory block, or at best, at the same level. - **Motor fibers** (Aα fibers) are thicker and more heavily myelinated, making them the most resistant to local anaesthetics compared to sensory (Aδ, C fibers) and sympathetic (B fibers) fibers.

Question 159: High spinal anaesthesia is characterized by:

A. Hypertension, tachycardia
B. Hypotension, bradycardia (Correct Answer)
C. Hypertension, bradycardia
D. Hypotension, tachycardia

Explanation: ***Hypotension, bradycardia*** - High spinal anesthesia blocks the **sympathetic nervous system**, leading to **vasodilation** below the level of blockade and redistribution of blood, causing **hypotension**. - The blockade of **cardioaccelerator fibers** (T1-T4) can result in a loss of sympathetic tone to the heart, leading to **bradycardia**. *Hypertension, tachycardia* - This combination is more typical of a **pain response** or a systemic release of catecholamines, not the direct effect of high spinal anesthesia. - High spinal anesthesia primarily causes a decrease in sympathetic tone, which would counteract hypertension and tachycardia. *Hypertension, bradycardia* - This combination is sometimes seen in conditions like **Cushing's reflex** due to increased intracranial pressure, which is unrelated to spinal anesthesia. - The primary effect of high spinal anesthesia on blood pressure is hypotension, not hypertension. *Hypotension, tachycardia* - While hypotension is a feature of high spinal anesthesia, **tachycardia** is less common as the sympathetic blockade often extends to the cardioaccelerator fibers, leading to bradycardia. - Tachycardia in this context might indicate an **inadequate block** or a compensatory response to hypovolemia not directly caused by the anesthetic.

Question 160: 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.

Practice by Chapter

Neuraxial Anatomy

Practice Questions

Spinal Anesthesia

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Epidural Anesthesia

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Combined Spinal-Epidural Anesthesia

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Peripheral Nerve Blocks: Upper Extremity

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Peripheral Nerve Blocks: Lower Extremity

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Truncal Blocks

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Ultrasound-Guided Regional Anesthesia

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Complications of Regional Anesthesia

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Regional Anesthesia in Pediatric Patients

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Regional Anesthesia in Obstetrics

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Continuous Peripheral Nerve Catheters

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