Regional Anesthesia — MCQs

Regional Anesthesia Indian Medical PG Practice Questions and MCQs

Question 191: What is the most effective method to prevent hypotension following spinal anesthesia?

A. Using small size needle
B. Preloading with crystalloids
C. Preloading with colloids
D. None of the above (Correct Answer)

Explanation: ***None of the above*** - The effectiveness of preloading with crystalloids or colloids in preventing **spinal anesthesia-induced hypotension** has been largely disproven or found to be minimal in many studies. - The most effective strategy involves **judicious fluid administration** and prompt use of **vasopressors** (e.g., phenylephrine, ephedrine) to maintain blood pressure, rather than relying solely on preloading. *Preloading with colloids* - While colloids expand intravascular volume more effectively than crystalloids, studies have shown **limited clinical benefit** in preventing hypotension after spinal anesthesia. - Their use is often associated with **higher costs** and potential adverse effects compared to crystalloids. *Using small size needle* - The size of the needle used for spinal anesthesia primarily influences the incidence of **post-dural puncture headache**, not hypotension. - A smaller needle size is associated with a **lower risk of headache** but does not prevent the vasodilatory effects of spinal anesthesia that cause hypotension. *Preloading with crystalloids* - **Crystalloids** rapidly redistribute into the extravascular space, making their effect on intravascular volume and prevention of hypotension largely transient and **ineffective**. - Current evidence suggests that **crystalloid preloading** does not consistently reduce the incidence or severity of hypotension following spinal anesthesia.

Question 192: Where is the drug injected during epidural anaesthesia?

A. Outside the dura (Correct Answer)
B. Inside the duramater
C. Inside arachnoidmater
D. Inside piamater

Explanation: ***Outside the dura*** - Epidural anaesthesia involves injecting the drug into the **epidural space**, which is located **outside the dura mater**. - This space contains fat, connective tissue, and blood vessels, allowing the anaesthetic to diffuse to the spinal nerves. *Inside the duramater* - Injecting inside the dura mater would place the drug into the **subdural space**, which is not the target for epidural anaesthesia. - This approach is associated with a higher risk of complications and is not the intended site for an epidural block. *Inside arachnoidmater* - The arachnoid mater is a middle layer of the meninges; injecting here is not the standard for epidural anaesthesia. - This would typically involve puncturing both the dura and arachnoid, potentially leading to a **spinal block** rather than an epidural. *Inside piamater* - The pia mater is the innermost meningeal layer, directly covering the spinal cord; injection here would be intrathecal. - This site is reserved for **spinal anaesthesia** (subarachnoid block) and carries different physiological effects and risks compared to epidural anaesthesia.

Question 193: For which of the following surgeries is a supraclavicular block most commonly used?

A. Brachial plexus surgery
B. Shoulder surgery
C. Wrist surgery
D. Elbow surgery (Correct Answer)

Explanation: ***Elbow surgery*** - A **supraclavicular block** effectively anesthetizes the entire upper extremity distal to the shoulder, making it ideal for procedures involving the **elbow**, forearm, and hand. - This block targets the **trunks of the brachial plexus** as they pass over the first rib, providing comprehensive coverage for elbow surgeries. *Shoulder surgery* - While it anesthetizes the upper extremity distal to the shoulder, it typically does not adequately cover the **shoulder joint itself**, as the suprascapular nerve and axillary nerve branches to the shoulder often arise more proximally. - **Interscalene blocks** are generally preferred for shoulder joint surgeries due to their more proximal spread and better pain control for shoulder-specific procedures. *Wrist surgery* - Although providing excellent anesthesia for wrist surgery, a **supraclavicular block** is often considered more extensive than necessary, given the potential for more distal, less invasive blocks (e.g., **axillary blocks** or specific nerve blocks at the wrist) that carry fewer risks. - Simpler, more targeted blocks might be chosen to minimize the risk of complications associated with a supraclavicular approach, such as **pneumothorax**. *Brachial plexus surgery* - A supraclavicular block is used to anesthetize the brachial plexus; it is generally not performed *for* brachial plexus surgery itself, but rather to provide surgical anesthesia for procedures *distal* to the shoulder. - Surgery on the brachial plexus often requires general anesthesia and careful nerve identification, rather than regional block for the plexus itself.

Question 194: Which of the following statements about post-dural puncture headache is incorrect?

A. A thin bore needle is less likely to cause it.
B. It is more common in females.
C. Using a beveled edge needle parallel to the long axis of the spine can help prevent it.
D. The timing of ambulation has no effect on its incidence. (Correct Answer)

Explanation: ***The timing of ambulation has no effect on its incidence.*** - This statement is **incorrect** because while previously thought to reduce the incidence, early ambulation does not significantly alter the risk of developing a **post-dural puncture headache (PDPH)**. - However, the absence of an effect on incidence does not mean that ambulation is completely irrelevant; it has been shown to cause more intense pain related to the headache when occurring in some individuals. *A thin bore needle is less likely to cause it.* - This statement is **correct**. Using a **smaller gauge (thin bore) needle** causes a smaller dural tear, which reduces the leakage of cerebrospinal fluid and thus lowers the risk of PDPH. - The size of the needle is a primary determinant of the incidence of PDPH. *It is more common in females.* - This statement is **correct**. **Females**, particularly those who are pregnant or in the postpartum period, have a higher incidence of PDPH compared to males. - Hormonal factors and differences in dural elasticity are thought to contribute to this increased susceptibility. *Using a beveled edge needle parallel to the long axis of the spine can help prevent it.* - This statement is **correct**. Inserting a **beveled needle parallel** to the longitudinal dural fibers spreads them apart rather than cutting across them, which can reduce the size of the dural tear. - This technique minimizes cerebrospinal fluid leakage and, consequently, the risk of PDPH.

Question 195: What is the typical duration of a post spinal headache?

A. 10 minutes
B. 1 hour
C. 1 week (Correct Answer)
D. 10 days

Explanation: ***1 week*** - A post-dural puncture headache (PDPH) typically resolves spontaneously within **1 week**, although it can persist longer in some cases. - While supportive care is often sufficient, interventions like an **epidural blood patch** may be considered for severe or persistent symptoms. *10 minutes* - This duration is far too short for a typical **post-dural puncture headache**, which is a recognized complication and tends to last much longer. - Headaches lasting only minutes are more likely related to simple **hypotension** or other transient issues rather than cerebrospinal fluid leakage. *1 hour* - An hour is generally too short for a true **post-dural puncture headache**, which is characterized by a persistent CSF leak and positional pain. - Headaches resolving within an hour are often benign and not indicative of a significant dural puncture. *10 days* - While a **post-dural puncture headache** can occasionally last this long, 10 days is generally considered on the longer end of the typical duration. - If a headache persists this long, especially with severe symptoms, further evaluation or intervention might be considered.

Question 196: Which nerve is commonly tested to assess the adequacy of anaesthesia?

A. Radial nerve
B. Mandibular nerve
C. Median Nerve
D. Ulnar Nerve (Correct Answer)

Explanation: ***Ulnar Nerve*** - The **ulnar nerve** is commonly used in clinical practice to assess the adequacy of neuromuscular blockade because it is a **superficial nerve** that is easily accessible and stimulated. - Stimulation typically occurs at the wrist, and the muscular response (adduction of the thumb or fifth finger twitch) is readily visible and quantifiable via a **train-of-four (TOF) monitor**. *Median Nerve* - While the median nerve can be stimulated, it is **less commonly used** for routine monitoring of neuromuscular blockade compared to the ulnar nerve. - Its stimulation may cause **unwanted deep muscle twitches** which are harder to observe and quantify. *Radial nerve* - The radial nerve is generally **not preferred for routine neuromuscular monitoring** because stimulating it can lead to more diffuse muscle contractions and inconsistent responses, making assessment less reliable. - Its motor response, primarily wrist and finger extension, is **more complex downstream** than the simple adduction of the thumb/fifth finger. *Mandibular nerve* - The mandibular nerve is a branch of the **trigeminal nerve** and controls muscles of mastication; it is **not used for assessing general anaesthesia** or neuromuscular blockade. - Testing this nerve would be relevant for conditions affecting the head and neck, not for monitoring muscular paralysis during surgery.

Question 197: Post dural puncture headache usually presents within ?

A. 0-6 Hrs
B. 6-12 Hrs
C. 12-72 Hrs (Correct Answer)
D. 72-96 Hrs

Explanation: ***12-72 Hrs*** - The onset of a **post-dural puncture headache (PDPH)** typically occurs within **12 to 72 hours** after the dural puncture. - This delay is thought to be related to the time it takes for significant **cerebrospinal fluid (CSF) leakage** and corresponding intracranial hypotension to develop. *0-6 Hrs* - Headaches presenting within this timeframe are less likely to be true **PDPH** as the typical latency period for significant CSF leakage and its symptomatic effects hasn't usually manifested. - Such early headaches might be due to other causes like **anxiety**, **dehydration**, or mild irritation from the procedure. *6-12 Hrs* - While possible, onset within this timeframe is less common than the 12-72 hour window for **classic PDPH**. - Moderate **CSF leakage** might lead to symptoms in some individuals, but the vast majority present later. *72-96 Hrs* - Although PDPH can persist for days or even weeks, its **onset** is significantly less common in this range. - A headache beginning this late may prompt consideration of other differential diagnoses, though late-onset PDPH is not unheard of.

Question 198: What is a contraindication to performing a neuraxial block?

A. Renal disease
B. Clotting disorders (Correct Answer)
C. Hypertension
D. Diabetes

Explanation: ***Clotting disorders*** - **Coagulopathy** or **anticoagulation** significantly increases the risk of **epidural hematoma**, which can lead to spinal cord compression and permanent neurological damage. - The procedure involves puncturing blood vessels, and impaired clotting could result in uncontrolled bleeding into the epidural or intrathecal space. *Hypertension* - While careful management of blood pressure is needed before and during a neuraxial block, **controlled hypertension** is not an absolute contraindication. - Severe or uncontrolled hypertension may be a concern due to increased risk of hemodynamic instability but doesn't preclude the procedure itself. *Renal disease* - **Chronic renal disease** itself is not a direct contraindication, though it might impact drug clearance if local anesthetics are used in large doses. - However, severe renal disease can be associated with coagulopathies, which would then become the primary contraindication. *Diabetes* - **Diabetes mellitus** is generally not a contraindication to neuraxial blocks. - Careful monitoring of blood glucose is necessary, but the condition itself does not increase the specific risks associated with the procedure.

Question 199: Drug of choice for Bier's block ?

A. Bupivacaine
B. Etidocaine
C. Ropivacaine
D. Lidocaine (Correct Answer)

Explanation: ***Lidocaine*** - **Lidocaine** is the preferred local anesthetic for **Bier's block** (intravenous regional anesthesia) due to its rapid onset and good safety profile. - Its relatively short duration of action and **minimal cardiotoxicity** upon systemic release are favorable for this technique. *Bupivacaine* - **Bupivacaine** has a **longer duration of action** and is associated with a higher risk of **cardiotoxicity** when inadvertently delivered systemically, making it less suitable for Bier's block. - Its use in Bier's block is generally avoided due to the potential for significant adverse events if the tourniquet malfunctions or is released prematurely. *Etidocaine* - **Etidocaine** is a potent, **long-acting local anesthetic** with a similar toxicity profile to bupivacaine, making it less ideal for Bier's block. - Its prolonged action and higher potential for systemic toxicity make it less favorable for a procedure where rapid washout and lower systemic risk are desired. *Ropivacaine* - **Ropivacaine** is an amide-type local anesthetic with a similar efficacy to bupivacaine but with a **lower potential for cardiotoxicity**. - While safer than bupivacaine, **lidocaine** is still generally preferred for Bier's block due to its established safety record, faster onset, and lower cost.

Question 200: Which of the following cannot be given by epidural anaesthesia?

A. Morphine
B. Remifentanil (Correct Answer)
C. Alfentanil
D. Fentanyl

Explanation: ***Remifentanil*** - **Remifentanil** is specifically designed for **intravenous administration** and is rapidly metabolized by plasma esterases, making it unsuitable for epidural use. - Due to its short half-life and rapid metabolism, epidural administration would provide inconsistent and fleeting analgesia, and its breakdown products are not inert in the epidural space, potentially causing **neurotoxicity**. *Morphine* - **Morphine** is a commonly used opioid for **epidural analgesia** due to its hydrophilicity, allowing for prolonged action in the cerebrospinal fluid. - It provides effective **postoperative pain relief** and has a relatively slow onset but long duration of action when administered epidurally. *Alfentanil* - **Alfentanil** is a synthetic opioid that has been used for **epidural analgesia**, though less commonly than fentanyl or sufentanil, sometimes in conjunction with local anesthetics. - It has a faster onset and shorter duration of action compared to morphine, but still provides effective **analgesia** when administered epidurally. *Fentanyl* - **Fentanyl** is a widely used lipophilic opioid for **epidural analgesia**, often combined with local anesthetics, for both surgical and obstetric pain. - Its lipophilicity allows for rapid absorption and a relatively quick onset of action, providing effective **segmental analgesia**.

Practice by Chapter

Neuraxial Anatomy

Practice Questions

Spinal Anesthesia

Practice Questions

Epidural Anesthesia

Practice Questions

Combined Spinal-Epidural Anesthesia

Practice Questions

Peripheral Nerve Blocks: Upper Extremity

Practice Questions

Peripheral Nerve Blocks: Lower Extremity

Practice Questions

Truncal Blocks

Practice Questions

Ultrasound-Guided Regional Anesthesia

Practice Questions

Complications of Regional Anesthesia

Practice Questions

Regional Anesthesia in Pediatric Patients

Practice Questions

Regional Anesthesia in Obstetrics

Practice Questions

Continuous Peripheral Nerve Catheters

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free