Regional Anesthesia in Children — MCQs
In a patient with sickle cell trait, which mode of anesthesia should be avoided?
A patient presented with rigidity, tremors, and trismus after being administered an anesthetic agent. Which anesthetic agent is most likely to have been administered?
In spinal anesthesia, the needle is pierced up to which space?
Inhalational anesthetic with highest respiratory irritation is:-
In a 2 months old infant undergoing surgery for biliary atresia, you would avoid one of the following anaesthetic -
The most appropriate circuit for ventilating a spontaneously breathing infant during anesthesia is –
A young male was administered regional anesthesia with 0.25% bupivacaine. The patient became unresponsive, and the pulse became unrecordable. What is the best management in this situation?
Where is the local anesthetic introduced in spinal anesthesia?
To give a field block, the LA should be deposited near
A two month old infant has undergone a major surgical procedure. Regarding postoperative pain relief which one of the following is recommended:
Regional Anesthesia in Children Indian Medical PG Practice Questions and MCQs
Question 1: 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 2: 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 3: In spinal anesthesia, the needle is pierced up to which space?
- A. Subarachnoid space (Correct Answer)
- B. Intrathecal space
- C. Epidural space
- D. Subdural space
Explanation: ***Subarachnoid space*** - In **spinal anesthesia**, the anesthetic agent is injected directly into the **cerebrospinal fluid (CSF)**, which is located in the subarachnoid space. - This space is targeted to achieve rapid and widespread blockade of spinal nerves, leading to anesthesia and paralysis below the level of injection. *Epidural space* - The **epidural space** is located outside the **dura mater** and contains fat and blood vessels; it is targeted in **epidural anesthesia**, not spinal anesthesia. - Anesthetic agents in the epidural space provide a slower onset and a more segmental block compared to spinal anesthesia. *Intrathecal space* - The term **intrathecal space** broadly refers to the space containing CSF, which includes the subarachnoid space, but is a less precise anatomical term for the site of injection in spinal anesthesia. - While technically correct in referring to an injection into the CSF, "subarachnoid space" is the specific anatomical term for where the needle tip rests. *Subdural space* - The **subdural space** is a potential space between the **dura mater** and the **arachnoid mater**; it is not the intended target for either spinal or epidural anesthesia. - Accidental injection into the subdural space during spinal or epidural procedures can lead to an unpredictable block with delayed onset and variable spread.
Question 4: Inhalational anesthetic with highest respiratory irritation is:-
- A. Desflurane (Correct Answer)
- B. Halothane
- C. Nitrous oxide
- D. Sevoflurane
Explanation: ***Desflurane*** - **Desflurane** has the highest **pungency** among common inhalational anesthetics, leading to significant respiratory irritation. - This irritation can manifest as **coughing**, **laryngospasm**, and **bronchospasm**, particularly during induction. *Halothane* - **Halothane** is a less pungent anesthetic and is generally well-tolerated by the respiratory system. - It was historically known for its **bronchodilating properties**, making it less irritating than Desflurane. *Nitrous oxide* - **Nitrous oxide** is a gaseous anesthetic with a very low solubility and virtually no respiratory irritant properties. - It is often used as a carrier gas and is known for its quick onset and offset without causing airway reactivity. *Sevoflurane* - **Sevoflurane** is known for its sweet smell and is considered a non-pungent agent, making it suitable for inhalational induction, especially in children. - It causes minimal respiratory irritation and has **bronchodilating effects**, which are beneficial in patients with reactive airway disease.
Question 5: In a 2 months old infant undergoing surgery for biliary atresia, you would avoid one of the following anaesthetic -
- A. Propofol
- B. Halothane (Correct Answer)
- C. Thiopentone
- D. Sevoflurane
Explanation: ***Halothane*** - **Halothane** is a potent hepatotoxic agent and should be avoided in patients with **biliary atresia** or other liver conditions. - Its metabolism can lead to the formation of **toxic metabolites** that can worsen pre-existing liver dysfunction. *Propofol* - **Propofol** is primarily metabolized by the liver, but its hepatic clearance is generally **high** and less dependent on liver function than some other anesthetics. - It is often used for induction and maintenance of anesthesia in patients with liver disease, with **dose adjustments** as needed. *Thiopentone* - **Thiopentone** (thiopental) is an ultra-short-acting barbiturate primarily eliminated by **hepatic metabolism**. - While it has a good safety profile for liver disease compared to halothane, careful **dose titration** is needed due to potential for prolonged effects with severe hepatic impairment. *Sevoflurane* - **Sevoflurane** is an inhalation anesthetic with minimal hepatic metabolism and a low potential for hepatotoxicity. - It is often considered a **preferred agent** in patients with liver disease due to its favorable metabolic profile.
Question 6: The most appropriate circuit for ventilating a spontaneously breathing infant during anesthesia is –
- A. Jackson Rees modification of Ayres T piece (Correct Answer)
- B. Mapleson A or Magill's circuit
- C. Mapleson C or Waters to and frocanister
- D. Bain circuit
Explanation: ***Jackson Rees modification of Ayres T piece*** - This circuit is ideal for spontaneously breathing infants due to its **low resistance** and minimal dead space, which is crucial for their small tidal volumes and high respiratory rates. - The open-ended expiratory limb allows for scavenging of anesthetic gases and minimizes the risk of **rebreathing CO2** and barotrauma. *Mapleson A or Magill's circuit* - The Mapleson A circuit is highly efficient for **spontaneous ventilation** in adults, as it prevents rebreathing with low fresh gas flow rates. - However, its relatively high resistance and larger dead space make it **unsuitable for infants** due to their fragile respiratory mechanics. *Mapleson C or Waters to and fro canister* - The Mapleson C circuit is primarily used for **controlled ventilation** or manual ventilation for short periods due to its compact nature. - The Waters to and fro canister incorporates a CO2 absorber, but both systems have significant **mechanical dead space** and higher resistance compared to the Jackson Rees, making them inappropriate for spontaneously breathing infants. *Bain circuit* - The Bain circuit is a coaxial Mapleson D system, often used for both spontaneous and controlled ventilation in adults and older children due to its **portability** and effective CO2 washout with appropriate fresh gas flow. - However, for infants, even with its advantages, the fresh gas flow required to prevent rebreathing can be higher than ideal, and its slightly higher resistance makes the Jackson Rees more suitable for **spontaneously breathing neonates**.
Question 7: A young male was administered regional anesthesia with 0.25% bupivacaine. The patient became unresponsive, and the pulse became unrecordable. What is the best management in this situation?
- A. ECPR with calcium
- B. ECPR with dobutamine
- C. ECPR with 20% intralipid (Correct Answer)
- D. ECPR with sodium bicarbonate
Explanation: ***ECPR with 20% intralipid*** - The scenario describes **Local Anesthetic Systemic Toxicity (LAST)**, likely due to bupivacaine, leading to cardiovascular collapse. - **Intralipid 20%** is the first-line treatment for LAST-induced cardiovascular toxicity, as it acts as a lipid sink for the lipophilic local anesthetic. *ECPR with calcium* - While calcium may be used in certain cardiac arrest scenarios, it is **not the primary treatment for bupivacaine-induced cardiovascular collapse** and LAST. - Calcium might offer some cardiac support but does not directly neutralize the local anesthetic's toxic effects. *ECPR with dobutamine* - **Dobutamine is an inotropic agent** used to improve cardiac contractility but is not indicated as a primary rescue therapy for severe LAST. - It would not address the underlying toxicity caused by bupivacaine and could potentially worsen the situation by increasing myocardial oxygen demand without reversing toxin effects. *ECPR with sodium bicarbonate* - **Sodium bicarbonate** is used to treat metabolic acidosis and can be beneficial in certain drug overdoses to enhance excretion or stabilize cardiac membranes. - However, it is **not the primary or most effective treatment for bupivacaine-induced LAST** and cardiovascular collapse compared to lipid emulsion therapy.
Question 8: Where is the local anesthetic introduced in spinal anesthesia?
- A. Dura and pia
- B. Between ligamentum flavum and dura
- C. Directly into cord
- D. Subarachnoid space (Correct Answer)
Explanation: ***Subarachnoid space*** - In **spinal anesthesia**, the local anesthetic is injected directly into the **subarachnoid space**, which contains **cerebrospinal fluid (CSF)** and surrounds the spinal cord. - This allows the anesthetic to directly block nerve roots, producing rapid and profound **sensory and motor blockade**. *Dura and pia* - The **dura mater** is the outermost membrane covering the spinal cord, and the **pia mater** is the innermost. The anesthetic is injected *between* the arachnoid and pia, not directly into these membranes. - Injecting into the dura itself would be an **intradural injection** but not the target for spinal anesthesia, and injecting into the pia is not feasible or desired. *Between ligamentum flavum and dura* - This describes the **epidural space**, which is where **epidural anesthesia** is administered. - While it's a common regional anesthetic technique, it is distinct from **spinal anesthesia** due to the different site of drug delivery and resulting pharmacological effects. *Directly into cord* - Injecting anesthetic directly into the **spinal cord** would cause severe and potentially irreversible neurological damage. - This is a highly dangerous and avoided procedure in all forms of regional anesthesia.
Question 9: To give a field block, the LA should be deposited near
- A. Main trunk
- B. Small nerve endings
- C. Periodontal ligament
- D. Large branch of peripheral nerve (Correct Answer)
Explanation: ***Large branch of peripheral nerve*** - A **field block** involves depositing local anesthetic near a larger sensory nerve branch to anesthetize a wider area of tissue distal to the injection site. - This method effectively blocks nerve impulses before they innervate smaller nerve endings, providing a broader area of numbing compared to infiltration. *Main trunk* - Depositing local anesthetic near the **main nerve trunk** (e.g., inferior alveolar nerve block) represents a **nerve block**, not a field block. - Nerve blocks aim to anesthetize an entire region supplied by that major nerve, which is usually more extensive than a field block. *Small nerve endings* - Injecting local anesthetic near **small nerve endings** is characteristic of **local infiltration** anesthesia. - This method provides localized anesthesia to a small, circumscribed area, which is less extensive than a field block. *Periodontal ligament* - Injecting into the **periodontal ligament** is a specific technique called an **intraligamentary injection**, primarily used for single-tooth anesthesia. - This method targets the dental nerve fibers entering the apex of the tooth and is not a field block.
Question 10: A two month old infant has undergone a major surgical procedure. Regarding postoperative pain relief which one of the following is recommended:
- A. Spinal narcotics intrathecal route
- B. Intravenous narcotic infusion in lower dosage (Correct Answer)
- C. Only paracetamol suppository is adequate
- D. No medication is needed as infant does not feel pain after surgery due to immaturity of nervous system
Explanation: ***Intravenous narcotic infusion in lower dosage*** - **Intravenous narcotic infusion** provides continuous pain relief and allows for careful titration of the dose, which is crucial in infants due to their developing metabolism and increased sensitivity to opioids. - Lower dosages are recommended because infants have a **reduced capacity for drug metabolism** and excretion, making them more susceptible to side effects like respiratory depression. *Spinal narcotics intrathecal route* - While effective, the **intrathecal route** carries risks such as neurotoxicity and spinal cord injury, which are particularly concerning in infants due to their small size and developing neural structures. - The **pharmacokinetics** of intrathecal narcotics can also be unpredictable in infants, leading to potential for delayed respiratory depression. *Only paracetamol suppository is adequate* - For **major surgical procedures**, a single agent like **paracetamol** is typically insufficient to manage severe postoperative pain effectively. - While paracetamol is a useful adjunct, it lacks the potent analgesic effects of opioids needed for comprehensive pain control after significant surgery. *No medication is needed as infant does not feel pain after surgery due to immaturity of nervous system* - This statement is **incorrect** and a dangerous misconception; infants, even neonates, have a **fully developed pain pathway**, perceive pain, and require appropriate analgesia. - The **pain response** in infants can be more exaggerated due to an immature inhibitory pain system, necessitating careful and effective pain management.
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