Complications in Anesthesia — MCQs

Complications in Anesthesia Indian Medical PG Practice Questions and MCQs

Question 191: 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 192: A patient is undergoing surgery where anesthesia is maintained with halothane. The patient develops hyperthermia and muscle rigidity. Which of the following agents is most likely responsible?

A. Cisatracurium
B. D-tubocurarine
C. Rocuronium
D. Suxamethonium (Correct Answer)

Explanation: ***Suxamethonium*** - **Suxamethonium** (succinylcholine) is a depolarizing neuromuscular blocker that can trigger **malignant hyperthermia** in susceptible individuals, characterized by **hyperthermia** and **muscle rigidity**. - This adverse reaction occurs due to an uncontrolled release of calcium from the **sarcoplasmic reticulum** in skeletal muscle, leading to sustained muscle contraction and increased metabolism. *Cisatracurium* - **Cisatracurium** is a non-depolarizing neuromuscular blocker, which works by competing with acetylcholine at the **neuromuscular junction**. - It does not typically cause **malignant hyperthermia** and is less likely to be associated with hyperthermia or muscle rigidity as a direct side effect. *D-tubocurarine* - **D-tubocurarine** is a non-depolarizing neuromuscular blocker that causes muscle relaxation by blocking nicotinic acetylcholine receptors. - While it can cause **histamine release**, leading to hypotension and bronchospasm, it is not implicated in triggering **malignant hyperthermia**. *Rocuronium* - **Rocuronium** is a rapid-onset, intermediate-acting non-depolarizing neuromuscular blocker, used for muscle relaxation during surgery. - Like other non-depolarizing agents, it does not directly trigger **malignant hyperthermia** and is not associated with hyperthermia and muscle rigidity in this context.

Question 193: A 60 year old male patient was undergoing laparoscopic cholecystectomy. During the surgery, a sudden drop in EtCO2 to 8 mmHg was noted. His SpO2 became 90%, his blood pressure dropped to 80/50 mmHg, and peak airway pressure was 18 cm of H2O. What is the diagnosis?

A. Anaphylaxis
B. Malignant hyperthermia
C. Gas embolism (Correct Answer)
D. Pneumothorax

Explanation: ***Gas embolism*** - A sudden drop in **EtCO2** to 8 mmHg, **hypotension**, and **hypoxemia** during laparoscopic surgery are classic signs of a gas embolism, often from insufflated CO2 entering the bloodstream. - The drop in EtCO2 is due to a sudden decrease in pulmonary blood flow, preventing CO2 from reaching the lungs for exhalation. *Anaphylaxis* - While anaphylaxis can cause hypotension and hypoxemia, it typically presents with **bronchospasm** (increased peak airway pressure), **tachycardia**, and skin manifestations like **urticaria** or angioedema, which are not explicitly mentioned. - Anaphylaxis does not typically cause a drastic, sudden drop in EtCO2 to such low levels as seen with a gas embolism. *Malignant hyperthermia* - This condition is characterized by a rapid and sustained increase in **EtCO2**, **tachycardia**, muscle rigidity, and hyperthermia, which is the opposite of the EtCO2 findings here. - Malignant hyperthermia would lead to a significant elevation in metabolic CO2 production, not a sudden drop in EtCO2. *Pneumothorax* - A pneumothorax would typically present with **increased peak airway pressures**, **hypoxia**, and **hypotension**, but the EtCO2 would likely initially rise or remain stable before dropping due to decreased ventilation, not an acute drop to 8 mmHg. - The primary physiological issue in pneumothorax is lung collapse, leading to ventilation-perfusion mismatch, but not directly causing a sudden near-absence of exhaled CO2 in this manner.

Question 194: False statement about post-dural puncture headache (PDPH):

A. Commonly occipito-frontal in location
B. Onset of headache is usually 12-72 hours following procedure
C. Breach of dura
D. Headache is relieved in sitting standing position (Correct Answer)

Explanation: ***Headache is relieved in sitting standing position*** - This statement is **false** because a cardinal feature of PDPH is that the headache is **worse in the upright position** (sitting or standing) and **relieved by lying flat**. - The postural nature of the headache is due to the continued leakage of CSF, leading to reduced intracranial pressure, which is exacerbated by gravity when upright. *Commonly occipito-frontal in location* - PDPH typically presents as a headache that can be **holocranial**, **occipital**, or **frontal**, often radiating to the neck. - The location is due to changes in **intracranial pressure** affecting pain-sensitive structures like blood vessels and meninges. *Onset of headache is usually 12-72 hours following procedure* - The onset of PDPH is typically **delayed**, occurring in the vast majority of cases between **12 to 72 hours** after the dural puncture. - Although it can occur immediately or up to five days later, this delayed presentation is characteristic. *Breach of dura* - PDPH is a direct consequence of the intentional or accidental **breach of the dura mater** during procedures like spinal anesthesia or lumbar puncture. - This breach allows for continuous leakage of **cerebrospinal fluid (CSF)**, leading to a reduction in intracranial pressure, which causes the headache.

Question 195: Malignant hyperthermia is due to

A. Isoflurane
B. Halothane
C. Scoline
D. All of the options (Correct Answer)

Explanation: ***All of the options*** - Malignant hyperthermia is a rare, **life-threatening condition** triggered by exposure to certain anesthetic agents, including **volatile inhalational anesthetics** (like isoflurane and halothane) and the **depolarizing muscle relaxant succinylcholine (scoline)**. - The condition is characterized by a rapid, uncontrollable increase in body temperature, muscle rigidity, and metabolic acidosis due to an uncontrolled release of **calcium** from the sarcoplasmic reticulum in muscle cells. *Isoflurane* - **Isoflurane** is a **volatile inhalational anesthetic** known to be a potent trigger for malignant hyperthermia in susceptible individuals. - It works by affecting ion channels in nerve cells, but in MH-susceptible individuals, it can induce massive calcium release in skeletal muscle. *Halothane* - **Halothane**, another **volatile inhalational anesthetic**, was historically one of the most common triggers for malignant hyperthermia. - While it is less commonly used today due to its potential for liver toxicity and cardiac arrhythmias, it remains a significant trigger for MH. *Scoline* - **Scoline** (also known as **succinylcholine**) is a **depolarizing muscle relaxant** and is a well-known trigger for malignant hyperthermia. - It acts on acetylcholine receptors, causing initial muscle fasciculations followed by prolonged relaxation, but in MH-susceptible patients, it can initiate an uncontrolled calcium release in muscle cells.

Question 196: All the following cause malignant hyperpyrexia except?

A. Methoxyflurane
B. N20 (Correct Answer)
C. Isoflurane
D. Halothane

Explanation: ***N2O*** - **Nitrous oxide (N2O)**, or laughing gas, is an inhaled anesthetic that does not trigger **malignant hyperthermia (MH)**. - It is often used as a carrier gas or adjunct during anesthesia, even in patients susceptible to MH, as it does not affect **ryanodine receptors**. *Methoxyflurane* - **Methoxyflurane** is a volatile inhaled anesthetic known to trigger **malignant hyperthermia (MH)** in susceptible individuals. - It causes an uncontrolled release of **calcium** from the sarcoplasmic reticulum in muscle cells, leading to severe hypermetabolism. *Isoflurane* - **Isoflurane** is a commonly used volatile inhaled anesthetic that can induce **malignant hyperthermia (MH)** in genetically predisposed individuals. - Like other volatile agents, it activates **ryanodine receptors** in skeletal muscle, leading to excessive muscle contraction and heat production. *Halothane* - **Halothane** is a potent volatile inhaled anesthetic historically associated with a high incidence of triggering **malignant hyperthermia (MH)**. - Its use has largely been replaced by newer agents due to concerns about MH and **hepatotoxicity**.

Question 197: Drug causing malignant hyperthermia:(Asked twice in the exam)

A. Thiopentone
B. Propofol
C. Cisatracurium
D. Suxamethonium (Correct Answer)

Explanation: ***Suxamethonium*** - **Suxamethonium** (succinylcholine) is a potent trigger for **malignant hyperthermia** (MH) in susceptible individuals due to its depolarizing action on skeletal muscle. - MH is a pharmacogenetic disorder characterized by a rapid and uncontrolled increase in **skeletal muscle metabolism**, leading to severe hyperthermia, muscle rigidity, and acidosis. *Thiopentone* - **Thiopentone** is an intravenous anesthetic that acts as a GABA-A receptor agonist, primarily causing central nervous system depression. - It is **not associated** with triggering malignant hyperthermia. *Propofol* - **Propofol** is a widely used intravenous anesthetic known for its rapid onset and recovery. - It is **not a known trigger** for malignant hyperthermia and is often considered a safe alternative for susceptible patients. *Cisatracurium* - **Cisatracurium** is a nondepolarizing neuromuscular blocker that competitively antagonizes acetylcholine at the neuromuscular junction. - It does **not trigger malignant hyperthermia** and is frequently used in patients with a history of MH.

Question 198: Which of the following is not seen in scoline apnea?

A. It occurs due to deficiency of acetylcholinesterase (Correct Answer)
B. It is due to succinylcholine
C. Patients usually do not die of scoline apnea if they are properly managed
D. It can be inherited

Explanation: ***It occurs due to deficiency of acetylcholinesterase*** - **Scoline apnea** is caused by a deficiency of **pseudocholinesterase (butyrylcholinesterase)**, not acetylcholinesterase. - **Pseudocholinesterase** is responsible for metabolizing **succinylcholine**, while acetylcholinesterase breaks down acetylcholine at the neuromuscular junction. *It is due to succinylcholine* - **Scoline apnea** is indeed triggered by the administration of **succinylcholine** in individuals with a genetic defect in **pseudocholinesterase**. - Without proper metabolism by pseudocholinesterase, succinylcholine prolongs its action, leading to prolonged neuromuscular blockade. *Patients usually do not die of scoline apnea if they are properly managed* - With appropriate management, which involves **mechanical ventilation** until the succinylcholine is metabolized, patients typically recover fully from scoline apnea. - The primary risk is respiratory failure due to prolonged paralysis, which can be managed by supportive care. *It can be inherited* - The deficiency of **pseudocholinesterase** that causes scoline apnea is an **autosomal recessive inherited disorder**. - Genetic testing can identify individuals who are at risk for this condition.

Question 199: Anaesthetic death rate more than what level calls for scrutiny of staff or equipment?

A. 1 in 500
B. 1 in 5000 (Correct Answer)
C. 1 in 1000
D. None of the options

Explanation: ***1 in 5000*** - Historically, an anaesthetic death rate exceeding **1 in 5,000** was considered a benchmark for initiating scrutiny into staffing, equipment, and protocols. - This threshold indicates a potential systemic issue rather than isolated incidents, necessitating a thorough review to ensure **patient safety**. *1 in 500* - A death rate of **1 in 500** is significantly higher than accepted norms for anaesthesia and would be considered an exceptionally alarming rate, indicating severe and immediate concerns about safety. - This rate would suggest a widespread and critical failure in care, far exceeding the threshold for mere "scrutiny." *1 in 1000* - While concerning, a death rate of **1 in 1,000** is still much higher than the point at which detailed scrutiny is typically triggered for anaesthetic practice. - Modern anaesthesia aims for much lower mortality rates, so even this figure would warrant investigation but doesn't precisely match the historical threshold for concern. *None of the options* - The option is incorrect because **1 in 5000** is indeed a recognized threshold that historically prompted scrutiny of anaesthetic practice. - This standard has been an important reference point, although modern practice strives for even lower mortality rates.

Question 200: Problems which may result from hypotensive anesthesia include:

A. Deep vein thrombosis
B. Reactionary hemorrhage
C. Retraction anemia
D. All of the options (Correct Answer)

Explanation: ***All of the options*** - Hypotensive anesthesia is a technique used to reduce **blood pressure** during surgery, aiming to decrease **blood loss** and improve the **surgical field visibility**. - While beneficial, it carries inherent risks including **deep vein thrombosis (DVT), reactionary hemorrhage**, and complications like **retraction anemia** if not managed properly. *Deep vein thrombosis (DVT)* - While hypotension might seem to reduce the risk by lowering **blood flow velocity**, prolonged immobility and potential for **venous stasis** during any surgery, especially under hypotension, can increase DVT risk. - The combination of **endothelial dysfunction** and **hypercoagulability** often seen in surgical patients, coupled with reduced peripheral blood flow due to hypotension, can contribute to DVT formation. *Reactionary hemorrhage* - This is a common post-operative complication where bleeding restarts hours after surgery. With hypotensive anesthesia, **blood vessels** are constricted and may not be actively bleeding during the surgery. - As the patient's **blood pressure** returns to normal post-operatively, these previously undetected bleeds can manifest as significant **hemorrhage** due to the increased pressure. *Retraction anemia* - This term is less commonly used in medical literature. However, it likely refers to the complications arising from prolonged tissue retraction during surgery, which, when combined with reduced **perfusion** from hypotensive anesthesia, can lead to **tissue ischemia** or damage akin to anemia in the affected area. - The reduced **oxygen delivery** to tissues during hypotensive states, especially when further compromised by retraction, may result in localized tissue injury or contribute to systemic complications if severe or prolonged.

Practice by Chapter

Adverse Drug Reactions

Practice Questions

Anaphylaxis and Allergic Reactions

Practice Questions

Malignant Hyperthermia

Practice Questions

Local Anesthetic Toxicity

Practice Questions

Perioperative Cardiac Complications

Practice Questions

Pulmonary Complications

Practice Questions

Awareness Under General Anesthesia

Practice Questions

Neurological Complications

Practice Questions

Postoperative Visual Loss

Practice Questions

Perioperative Renal Dysfunction

Practice Questions

Transfusion-Related Complications

Practice Questions

Risk Management and Prevention

Practice Questions

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