General Anesthesia Practice Questions

Q: The inducing agent of choice in shock -

Ketamine. **Ketamine** * **Ketamine** is preferred in shock due to its sympathomimetic properties, which maintain or increase blood pressure and heart rate, thus preserving **cardiovascular stability**. * It also has minimal respiratory depression and bronchodilatory effects, making it safer for patients with compromised respiratory function. * The cardiovascular stimulating effects of ketamine helps maintain haemodynamic stability in shocked patients. It maintains cerebral autoregulation and perfusion of vital organs. *Isoflurane* * **Isoflurane** is an inhaled anesthetic that typically causes **dose-dependent myocardial depression** and **vasodilation**, which can worsen hypotension in a shock state. * It can significantly decrease systemic vascular resistance, thereby exacerbating the already compromised cardiovascular status of a shock patient. *Desflurane* * **Desflurane** is an inhaled anesthetic known for its rapid onset and offset but can cause a **significant increase in heart rate and blood pressure** upon rapid concentration changes, which may be detrimental in an unstable patient. * Like isoflurane, it also causes dose-dependent peripheral vasodilation and myocardial depression, which can worsen hypotension in patients in shock. *Thiopentone* * **Thiopentone** is a barbiturate that causes significant **myocardial depression** and **peripheral vasodilation**, leading to a substantial drop in blood pressure. * Its use in shock would further compromise cardiovascular stability and is generally contraindicated due to its potent hemodynamic depressant effects.

Q: The fluoride level that can cause renal toxicity is

Above 50 micromol/litre. ***Above 50 micromol/litre*** - Clinically significant renal toxicity from fluoride is generally observed at plasma fluoride concentrations exceeding **50 micromol/L**, which is the established threshold in medical literature. - This level is particularly associated with **methoxyflurane anesthesia**, where fluoride metabolism leads to nephrotoxicity manifesting as **polyuria, polydipsia, and nephrogenic diabetes insipidus**. - At these concentrations, fluoride interferes with renal tubular function, causing **high-output renal failure** and electrolyte disturbances. *Above 20 micromol/litre* - While some subclinical renal effects may begin around 20 micromol/L, this is **below the threshold** for clinically significant renal toxicity. - This level may cause mild tubular dysfunction but does not typically result in the **overt nephrotoxicity** that characterizes fluoride-induced renal damage. - The consensus threshold for **clinical renal toxicity is 50 micromol/L**, not 20 micromol/L. *Above 5 micromol/litre* - A plasma fluoride level of 5 micromol/L is well within the **safe range** and is commonly seen with therapeutic fluoride exposure. - This level is associated with **dental prophylaxis** and normal environmental exposure without any renal toxicity. *Above 80 micromol/litre* - This represents a **severely toxic** fluoride level causing profound renal damage, but the threshold for **initial renal toxicity** is much lower at 50 micromol/L. - At 80 micromol/L, patients would experience severe systemic toxicity including **cardiac arrhythmias, CNS effects**, and potentially fatal complications.

Q: Which of the following inducing agent has analgesic property?

Nitrous oxide. ***Nitrous oxide*** - **Nitrous oxide** has significant **analgesic properties** due to its action on opioid receptors and NMDA receptor antagonism. - It is frequently used as an adjuvant to other inhalational anesthetics to reduce their required dose and provide pain relief. *Enflurane* - While an inhalational anesthetic, **enflurane** primarily provides **anesthesia** and **muscle relaxation** with minimal analgesic properties at clinically relevant concentrations. - It was associated with central nervous system stimulation (seizures) and is rarely used today. *Halothane* - **Halothane** is a potent volatile anesthetic that provides **muscle relaxation** and **anesthesia** but has very poor analgesic properties. - Its use has largely been replaced due to concerns about **hepatotoxicity**. *Sevoflurane* - **Sevoflurane** is a commonly used volatile anesthetic known for its rapid onset and offset, making it suitable for induction and maintenance of anesthesia. - However, its primary effect is **anesthesia** and it has very **limited analgesic properties** on its own.

Q: Which of the following muscle relaxants causes pain on injection?

Rocuronium. ***Rocuronium*** - **Rocuronium** is known to cause pain on injection, especially when administered in **small veins**, due to its **low pH** and high osmolarity. - This discomfort can be mitigated by injecting into a **larger vein** or by pre-treating with a small dose of **lidocaine**. *Succinylcholine* - **Succinylcholine** typically does not cause pain on injection, but it can lead to **muscle fasciculations** and subsequent **post-operative myalgia**. - Its mechanism of action involves initial depolarization of the neuromuscular junction, which can transiently increase **intracranial pressure** and **intraocular pressure**. *Vecuronium* - **Vecuronium** is a nondepolarizing neuromuscular blocker that is generally well-tolerated and **does not frequently cause pain on injection**. - It is known for its relatively **short duration of action** and minimal cardiovascular effects. *Pancuronium* - **Pancuronium** is a long-acting, nondepolarizing neuromuscular blocker that does **not typically cause pain on injection**. - It can, however, cause **tachycardia** due to its vagolytic effects, which is a significant differentiating characteristic.

Q: An anaesthetic agent with boiling temperature more than 75°C

Methoxyflurane. ***Methoxyflurane*** - Methoxyflurane has a **boiling point of 104.7 °C**, making it the only agent listed with a boiling temperature above 75°C. - Its high boiling point and low vapor pressure necessitate the use of specialized **calibrated vaporizers** for safe administration [1]. *Halothane* - Halothane has a **boiling point of 50.2 °C**, which is significantly lower than 75°C [1]. - It was a commonly used inhalational anesthetic but has largely been replaced due to concerns about **hepatotoxicity**. *Cyclopropane* - Cyclopropane is a gas at room temperature and has a very low boiling point of **-32.9 °C**. - It is highly **flammable and explosive**, limiting its modern use in anesthesia. *Ether* - Diethyl ether (commonly known as simply "ether") has a boiling point of **34.6 °C**. - It was one of the earliest general anesthetics but is no longer used due to its **flammability** and slow induction/recovery.

Q: Which of the following anesthetic agent can cause adrenocortical suppression?

Etomidate. ***Etomidate*** - Etomidate is a common **IV anesthetic** that causes dose-dependent, reversible **adrenocortical suppression** by inhibiting the enzyme **11β-hydroxylase**. - This enzyme is crucial for the synthesis of **cortisol** and other adrenal steroids, leading to a temporary decrease in their production, which can be clinically relevant in critically ill patients. *Halothane* - Halothane is an **inhaled anesthetic** known for its potential to cause **hepatotoxicity** (halothane hepatitis) but is not directly associated with adrenocortical suppression. - Its primary cardiovascular effect is **myocardial depression**, leading to reduced cardiac output and hypotension. *Ketamine* - Ketamine is a **dissociative anesthetic** that generally has minimal effects on the adrenal cortex and can even cause a **sympathomimetic effect**, leading to increased heart rate and blood pressure. - It is known for its **bronchodilatory** properties and is often used in patients with asthma or in situations where hemodynamic stability is crucial. *Propofol* - Propofol is a widely used **IV anesthetic** that often causes **hemodynamic depression** (hypotension) and respiratory depression but does not directly induce adrenocortical suppression. - It is rapidly metabolized and is associated with a clear-headed recovery, making it suitable for outpatient procedures.

Q: Which of the following inhalational agent is contraindicated in a patient with history of epilepsy -

Enflurane. ***Enflurane*** - **Enflurane** is known to cause **epileptiform EEG changes** and seizures, especially at high concentrations or in the presence of hypocarbia. - This proconvulsant effect makes it contraindicated in patients with a history of **epilepsy** due to the risk of inducing or exacerbating seizure activity. *Isoflurane* - **Isoflurane** is generally considered safe in patients with epilepsy as it has **minimal proconvulsant activity** and can even have anticonvulsant properties. - It does not typically produce epileptiform EEG patterns or clinical seizures. *Sevoflurane* - **Sevoflurane** is also considered safe in epileptic patients and is widely used for induction and maintenance of anesthesia. - While there have been reports of seizure-like activity during **Sevoflurane** induction, these are rare and usually resolve quickly without long-term complications. *Halothane* - **Halothane** is largely historical and not commonly used today due to its association with **hepatotoxicity** and cardiac dysrhythmias. - It does not typically induce seizures and historically was not contraindicated in patients with epilepsy based on seizure risk.

Q: "Active core rewarming" refers to

Heated crystalloids. ***Heated crystalloids*** - **Heated crystalloids** administered intravenously contribute to active core rewarming by directly introducing warm fluids into the circulatory system, raising the internal body temperature. - This method is particularly effective for **moderate to severe hypothermia** as it rapidly delivers heat to the body's core. *Heated humidified O2* - Administering **heated and humidified oxygen** helps prevent further heat loss from the respiratory tract and contributes to rewarming. - While beneficial, it is generally considered a less aggressive or primary method of **active core rewarming** compared to direct intravenous fluid administration because it does not directly warm the bloodstream. *Peritoneal dialysis* - **Peritoneal dialysis** involves introducing warm dialysate into the peritoneal cavity, allowing for heat exchange. - This is an invasive procedure primarily used when other rewarming methods are insufficient, and it is a specific type of active core rewarming, but not the only one or most common representation of the term itself. *All of the options* - While **heated humidified O2** and **peritoneal dialysis** are methods of active rewarming, the question asks for what "active core rewarming" refers to. - Each of these options represents a specific technique, and while all contribute to rewarming the core, **heated crystalloids** are a more general and common representation encompassed by the term "active core rewarming."

Q: All are features of emergence delirium with ketamine anesthesia except:-

Cortical blindness. **Cortical blindness** - **Cortical blindness** is a rare neurological condition resulting from damage to the **visual cortex** in the brain, leading to an inability to process visual information. It is not typically associated with ketamine emergence delirium. - While ketamine can cause visual disturbances, true cortical blindness is not a characteristic feature of **emergence delirium**. *Auditory, proprioceptive and confusional illusions* - Ketamine emergence delirium is well-known for causing various **illusions**, including auditory, proprioceptive, and confusional experiences, due to its dissociative effects on the central nervous system. - Patients may experience distorted perceptions of sound, body position, and their surroundings during recovery from anesthesia. *No hallucination* - This statement is incorrect because **hallucinations** are a common feature of ketamine emergence delirium, particularly vivid and sometimes disturbing visual or auditory hallucinations. - Ketamine's mechanism, involving NMDA receptor antagonism, can lead to these profound perceptual alterations. *Visual illusions* - **Visual illusions** are a very common symptom of ketamine emergence delirium, where patients may perceive objects or their environment in a distorted or unreal way. - These illusions contribute to the disorientation and agitation experienced during recovery from ketamine anesthesia.

Q: A patient with mitral stenosis is having surgery tomorrow. There is some liver compromise. Which of the following inhalational agents is preferred?

Sevoflurane. ***Sevoflurane*** - **Sevoflurane** is preferred due to its **minimal hepatic metabolism** and rapid elimination, making it a safer option in patients with **liver compromise**. - It maintains **cardiovascular stability**, which is beneficial in mitral stenosis and avoids the arrhythmogenic potential seen with other agents. *Enflurane* - **Enflurane** is extensively metabolized in the liver, leading to the production of inorganic fluoride ions, which can cause **renal toxicity**. - It can also induce a decrease in **hepatic blood flow**, exacerbating existing liver compromise. *Xenon* - While **Xenon** has excellent cardiovascular stability and minimal metabolism, its **high cost** and **limited availability** make it an impractical choice for routine use. - Its anesthetic potency is relatively low, requiring **higher concentrations** for surgical anesthesia. *Halothane* - **Halothane** is associated with a significant risk of **halothane-induced hepatitis** due to its extensive hepatic metabolism and the production of toxic metabolites. - It can also cause **cardiac depression** and **arrhythmias**, which are undesirable in patients with mitral stenosis.

Question 1

The inducing agent of choice in shock -

Accepted Answer

Ketamine

Answer

Isoflurane

Answer

Desflurane

Answer

Thiopentone

Question 2

The fluoride level that can cause renal toxicity is

Accepted Answer

Above 50 micromol/litre

Answer

Above 5 micromol/litre

Answer

Above 20 micromol/litre

Answer

Above 80 micromol/litre

Question 3

Which of the following inducing agent has analgesic property?

Accepted Answer

Nitrous oxide

Answer

Enflurane

Answer

Halothane

Answer

Sevoflurane

Question 4

Which of the following muscle relaxants causes pain on injection?

Accepted Answer

Rocuronium

Answer

Succinylcholine

Answer

Vecuronium

Answer

Pancuronium

Question 5

An anaesthetic agent with boiling temperature more than 75°C

Accepted Answer

Methoxyflurane

Answer

Halothane

Answer

Cyclopropane

Answer

Ether

Question 6

Which of the following anesthetic agent can cause adrenocortical suppression?

Accepted Answer

Etomidate

Answer

Halothane

Answer

Ketamine

Answer

Propofol

Question 7

Which of the following inhalational agent is contraindicated in a patient with history of epilepsy -

Accepted Answer

Enflurane

Answer

Isoflurane

Answer

Sevoflurane

Answer

Halothane

Question 8

"Active core rewarming" refers to

Accepted Answer

Heated crystalloids

Answer

Heated humidified O2

Answer

Peritoneal dialysis

Answer

All of the options

Question 9

All are features of emergence delirium with ketamine anesthesia except:-

Accepted Answer

Cortical blindness

Answer

No hallucination

Answer

Auditory, proprioceptive and confusional illusions

Answer

Visual illusions

Question 10

A patient with mitral stenosis is having surgery tomorrow. There is some liver compromise. Which of the following inhalational agents is preferred?

Accepted Answer

Sevoflurane

Answer

Enflurane

Answer

Xenon

Answer

Halothane

General Anesthesia — MCQs

General Anesthesia — MCQs

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