Regional Anesthesia in Pediatric Patients — MCQs
Child with aspiration risk needs emergency surgery. Best induction sequence is:
What is the preferred concentration range of lidocaine for topical anesthesia?
Which block is described as regional anesthesia of the arm:-
Which of the following is not an amide local anesthetic?
Anesthesia of choice for induction in children among the following is:
A patient presented with rigidity, tremors, and trismus after being administered an anesthetic agent. Which anesthetic agent is most likely to have been administered?
What is the maximum concentration allowed for epidural block?
Which of the following inhalation anesthetic agents is hepatotoxic?
Percentage of adrenaline with lignocaine for local infiltration is?
All are absolute contraindications for regional anesthesia EXCEPT:
Regional Anesthesia in Pediatric Patients Indian Medical PG Practice Questions and MCQs
Question 1: Child with aspiration risk needs emergency surgery. Best induction sequence is:
- A. Preoxygenation-ketamine-succinylcholine
- B. Sevoflurane-propofol-succinylcholine
- C. Midazolam-propofol-rocuronium
- D. Preoxygenation-propofol-succinylcholine (Correct Answer)
Explanation: ***Preoxygenation-propofol-succinylcholine*** - This sequence describes a **rapid sequence intubation (RSI)**, which is the preferred method for patients at high risk of aspiration, including children needing emergency surgery with an unknown fasting status. - **Preoxygenation** provides an oxygen reserve during the apneic period, **propofol** offers rapid induction with good hemodynamic stability, and **succinylcholine** provides fast-onset, short-acting neuromuscular blockade, crucial for preventing aspiration. *Preoxygenation-ketamine-succinylcholine* - While preoxygenation and succinylcholine are appropriate for RSI, **ketamine** may not be the optimal choice for a child with aspiration risk due to its potential to increase secretions and maintain laryngeal reflexes, which could complicate intubation. - Ketamine can also cause **emergence delirium** in some children, making it less favorable for a smooth anesthetic course compared to propofol. *Sevoflurane-propofol-succinylcholine* - **Sevoflurane** is an inhaled anesthetic often used for mask induction in children due to its non-pungent odor and rapid onset. However, it is generally **not suitable for RSI** in patients with aspiration risk as it has a slower induction time compared to intravenous agents and can cause coughing or laryngospasm. - Using both sevoflurane and propofol for induction in an RSI scenario is redundant and prolongs the induction phase, increasing aspiration risk. *Midazolam-propofol-rocuronium* - **Midazolam** is a benzodiazepine used for anxiolysis and sedation but has a **slower onset** and longer duration of action compared to propofol for rapid induction. - **Rocuronium** is a non-depolarizing neuromuscular blocker with a slower onset of action than succinylcholine, making it less ideal for RSI where immediate paralysis for intubation is critical to prevent aspiration.
Question 2: What is the preferred concentration range of lidocaine for topical anesthesia?
- A. 2-4% (Correct Answer)
- B. 7-12%
- C. 12-15%
- D. <2%
Explanation: ***Correct Option: 2-4%*** - **Lidocaine** is an **amide-type local anesthetic** commonly used for topical anesthesia to numb localized areas before minor procedures. - The **preferred concentration range for topical application is 2-4%**, which provides effective anesthesia with an acceptable safety profile. - **2% lidocaine gel/cream** is commonly used for skin and genital mucosa. - **4% lidocaine** is standard for oral and respiratory mucous membranes. - **5% lidocaine patches** are used for post-herpetic neuralgia. - This concentration range balances **clinical efficacy** with **minimal systemic toxicity risk**. *Incorrect Option: <2%* - Concentrations below **2%** are generally **suboptimal** for achieving significant topical anesthesia. - These lower concentrations result in **insufficient pain relief** or require longer application times. - While 0.5-1% solutions exist, they are primarily used for infiltration anesthesia, not topical application. *Incorrect Option: 7-12%* - Concentrations in the **7-12%** range are **too high** for routine topical use and increase the risk of **systemic toxicity**. - These concentrations are not standard in clinical practice for general topical anesthesia. - Higher concentrations increase absorption without proportional improvement in efficacy. *Incorrect Option: 12-15%* - Concentrations in the **12-15%** range are **excessively high** and pose substantial **risk of systemic absorption and toxicity**. - Such high concentrations are **not recommended** for topical anesthesia in clinical practice. - Even 10% sprays (used for oropharyngeal anesthesia) require strict dose limitations to prevent toxicity.
Question 3: 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.
Question 4: Which of the following is not an amide local anesthetic?
- A. Prilocaine
- B. Bupivacaine
- C. Lignocaine
- D. Cocaine (Correct Answer)
Explanation: ***Cocaine*** - **Cocaine** is an **ester-type** local anesthetic, not an amide. Ester local anesthetics are characterized by an **ester bond** in their chemical structure. - It works by blocking nerve impulse transmission and also by **inhibiting norepinephrine reuptake**, contributing to its vasoconstrictive and stimulatory effects. *Lignocaine* - **Lignocaine** (also known as **lidocaine**) is an **amide-type** local anesthetic, characterized by an **amide bond** in its chemical structure. - Amide local anesthetics are generally more stable and have a longer duration of action compared to ester types. *Prilocaine* - **Prilocaine** is an **amide-type** local anesthetic, commonly used in dentistry and for regional anesthesia. - Its amide structure contributes to its stability and intermediate duration of action. *Bupivacaine* - **Bupivacaine** is an **amide-type** local anesthetic known for its relatively long duration of action and potency. - It is often used for epidural anesthesia and nerve blocks due to its prolonged effect.
Question 5: Anesthesia of choice for induction in children among the following is:
- A. Isoflurane
- B. Sevoflurane (Correct Answer)
- C. Halothane
- D. Desflurane
Explanation: ***Sevoflurane*** - **Sevoflurane** is the anesthetic of choice for induction in children due to its **low pungency**, which reduces the likelihood of coughing and laryngospasm. - It has a relatively **rapid onset of action** and allows for a smooth, inhalation induction, making it well-tolerated by pediatric patients. *Isoflurane* - **Isoflurane** has a **pungent odor** and is known to cause a higher incidence of airway irritation, coughing, and breath-holding, making it less suitable for mask induction in children. - It also has a **slower onset** compared to sevoflurane, which can prolong the induction process. *Halothane* - **Halothane** was previously used for pediatric induction but is largely uncommonly used today due to its association with **hepatotoxicity** (halothane hepatitis) and cardiac arrhythmias. - While it has a relatively pleasant odor, its significant side effect profile makes it a less desirable option now. *Desflurane* - **Desflurane** is very **pungent** and frequently causes airway irritation, coughing, and laryngospasm, making it unsuitable for mask induction in children. - It also has a **low potency** compared to other volatile anesthetics, requiring higher concentrations that can exacerbate airway complications.
Question 6: A patient presented with rigidity, tremors, and trismus after being administered an anesthetic agent. Which anesthetic agent is most likely to have been administered?
- A. Halothane (Correct Answer)
- B. Nitrous Oxide (N2O)
- C. Thiopentone sodium
- D. Etomidate
Explanation: ***Halothane*** - The combination of **rigidity**, **tremors**, and **trismus** after an anesthetic agent suggests **malignant hyperthermia (MH)**, a rare but life-threatening inherited condition. - **Halothane (and other volatile anesthetics)**, along with succinylcholine, are known triggers for malignant hyperthermia. *Nitrous Oxide (N2O)* - While an anesthetic agent, **nitrous oxide** is not a known trigger for **malignant hyperthermia**. - It works by modulating **NMDA receptors** and does not typically cause rigidity, tremors, or trismus as a side effect. *Thiopentone sodium* - **Thiopentone sodium** is a **barbiturate** anesthetic and is not associated with triggering **malignant hyperthermia**. - Its effects primarily involve potentiation of **GABA-A receptors**, leading to sedation and hypnosis. *Etomidate* - **Etomidate** is a short-acting intravenous anesthetic that is not a known trigger for **malignant hyperthermia**. - It is typically associated with minimal cardiovascular depression but can cause **adrenocortical suppression** with prolonged use.
Question 7: 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 8: Which of the following inhalation anesthetic agents is hepatotoxic?
- A. Halothane (Correct Answer)
- B. Sevoflurane
- C. Isoflurane
- D. Desflurane
Explanation: ***Halothane*** - **Halothane** is known for its potential to cause **halothane hepatitis**, a severe and sometimes fatal form of liver damage. - This toxicity is typically due to the formation of reactive metabolites during its metabolism, which can lead to immune-mediated liver injury. *Sevoflurane* - **Sevoflurane** is generally considered to have a very low risk of hepatotoxicity. - While it can produce a small amount of inorganic fluoride, which was a concern with older halogenated anesthetics, its metabolic profile makes it much safer for the liver compared to halothane. *Isoflurane* - **Isoflurane** is metabolized to a very small extent (less than 0.2%), significantly reducing the risk of generating toxic metabolites that could harm the liver. - It is commonly used in clinical practice due to its favorable safety profile, including minimal hepatotoxicity. *Desflurane* - **Desflurane** has an even lower metabolism rate than Isoflurane, making it one of the safest inhaled anesthetics in terms of liver toxicity. - Its rapid onset and offset properties, coupled with its minimal metabolism, contribute to its low potential for hepatotoxic effects.
Question 9: Percentage of adrenaline with lignocaine for local infiltration is?
- A. 1:1000
- B. 1:10000
- C. 1:50000 (Correct Answer)
- D. 1:200000
Explanation: ***1:50000*** - This concentration of **adrenaline (epinephrine)** is commonly used with **lignocaine (lidocaine)** for local infiltration to prolong the anesthetic effect and reduce bleeding. - At this concentration, adrenaline acts as a **vasoconstrictor**, decreasing systemic absorption of lignocaine and allowing a higher dose locally. *1:1000* - This concentration of adrenaline is typically used for the treatment of **anaphylaxis** and is considered too high for local infiltration with lignocaine. - Using such a high concentration locally can lead to severe **vasoconstriction**, tissue ischemia, and systemic side effects like **tachycardia** and **hypertension**. *1:10000* - This concentration is too strong for routine local infiltration and is usually reserved for **cardiac arrest** protocols or severe anaphylaxis when administered intravenously. - It would carry a significant risk of **tissue damage** and systemic effects if used for local infiltration. *1:200000* - While sometimes used, **1:50000** is generally the more common and effective concentration for achieving **hemostasis** and prolonging anesthesia during local infiltration. - A 1:200000 concentration provides a lesser degree of **vasoconstriction**, potentially leading to less prolonged local anesthetic effect and reduced bleeding control compared to 1:50000.
Question 10: 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.
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