Anesthesiology
7 questionsWhich anaesthetic is contraindicated in renal failure?
What is a significant disadvantage of ketamine?
Intraocular pressure is increased by which anaesthetic?
Which of the following anesthetic agents is most notable for its analgesic properties?
Dissociative anaesthesia is produced by?
Regarding propofol, which one of the following statements is false?
Which anaesthetic drug contributes to green house effect?
NEET-PG 2013 - Anesthesiology NEET-PG Practice Questions and MCQs
Question 1371: Which anaesthetic is contraindicated in renal failure?
- A. Isoflurane
- B. Desflurane
- C. Halothane
- D. Methoxyflurane (Correct Answer)
Explanation: ***Methoxyflurane*** - Methoxyflurane undergoes significant **metabolism** to produce inorganic **fluoride ions**, which are directly **nephrotoxic**. - This nephrotoxicity can cause **high-output renal failure** with reduced concentrating ability, making it contraindicated in patients with pre-existing renal impairment. *Isoflurane* - Isoflurane is minimally metabolized and produces very low levels of **fluoride ions**, making it generally **safe** for use in patients with renal failure. - Its elimination is primarily via the **lungs**, with very little hepatic metabolism or renal excretion of active compounds. *Desflurane* - Desflurane is also minimally metabolized, similar to isoflurane, and therefore produces negligible amounts of **fluoride ions**. - It is considered a **safe option** for patients with renal impairment due to its predominantly pulmonary elimination and lack of nephrotoxic metabolites. *Halothane* - While halothane can cause **hepatotoxicity**, it is generally **not directly nephrotoxic** in the way methoxyflurane is. - Its metabolism, though more extensive than isoflurane or desflurane, does not produce clinically significant levels of nephrotoxic fluoride ions to contraindicate its use in renal failure.
Question 1372: What is a significant disadvantage of ketamine?
- A. Increased heart rate
- B. Increased ICT
- C. Delirium (Correct Answer)
- D. All of the options
Explanation: ***Delirium*** - Ketamine is known to cause **emergence phenomena**, which include **vivid dreams, hallucinations**, and **delirium**, particularly during recovery from anesthesia. - This psychotomimetic effect can be distressing for patients and may necessitate the co-administration of a **benzodiazepine** to mitigate these symptoms. *Increased heart rate* - While ketamine does cause an **increase in heart rate** and **blood pressure** due to sympathetic stimulation, this is often considered a disadvantage but not the *most significant* when compared to the unique cognitive side effects. - This effect can be beneficial in patients with **hemodynamic instability**, but can be problematic in those with **cardiovascular disease**. *Increased ICT* - It is often considered a contraindication in patients with **elevated intracranial pressure (ICP)** as it can potentially increase **cerebral blood flow** and thus ICP. - However, recent studies suggest that in adequately ventilated patients, the effect on ICP may be less pronounced than previously thought, making delirium a more consistent and prominent disadvantage for many patients. *All of the options* - While ketamine can cause an **increased heart rate** and potentially affect **intracranial pressure**, **delirium** and other emergence phenomena are often highlighted as a unique and significant disadvantage because they are highly distressing and difficult to manage. - The psychotomimetic effects are a hallmark side effect that often governs its cautious use without concurrent medication.
Question 1373: Intraocular pressure is increased by which anaesthetic?
- A. Ketamine (Correct Answer)
- B. Nitrous Oxide
- C. Isoflurane
- D. Propofol
Explanation: ***Ketamine*** - **Ketamine** is known to increase **intraocular pressure (IOP)**, making it generally avoided in patients with glaucoma or penetrating eye injuries. - This effect is thought to be due to its dissociative properties, causing **nystagmus**, and stimulating extraocular muscles. *Nitrous Oxide* - **Nitrous oxide** by itself has minimal or no direct effect on **intraocular pressure (IOP)**. - However, in cases of an air-filled globe (e.g., after retinal detachment surgery), it can increase IOP by expanding the gas bubble. *Isoflurane* - **Isoflurane**, like most volatile anesthetics, typically **decreases intraocular pressure (IOP)**. - This reduction is generally due to its effects on reducing aqueous humor production and increasing uveoscleral outflow. *Propofol* - **Propofol** is known for its ability to **decrease intraocular pressure (IOP)**. - This effect is mediated by a reduction in aqueous humor production and an increase in uveoscleral outflow, making it a favorable choice in ophthalmic surgery.
Question 1374: Which of the following anesthetic agents is most notable for its analgesic properties?
- A. Ketamine (Correct Answer)
- B. Thiopentone
- C. Propofol
- D. None of the options
Explanation: ***Ketamine*** - **Ketamine** is unique among general anesthetics for its significant **analgesic properties**, which stem from its action as an **NMDA receptor antagonist**. - Its ability to provide pain relief makes it useful in scenarios where both **anesthesia** and **analgesia** are desired, such as for painful procedures or in trauma settings. *Propofol* - While **propofol** is a widely used intravenous anesthetic, it lacks intrinsic **analgesic properties**. Its primary effects are **sedation** and **hypnosis**. - Pain during propofol injection is common, and other analgesics are usually co-administered for painful procedures. *Thiopentone* - **Thiopentone** is an ultrashort-acting barbiturate primarily used for **induction of anesthesia** due to its rapid onset and profound hypnotic effects. - It has **no analgesic properties** and can even lower the pain threshold, requiring concurrent administration of analgesics.
Question 1375: Dissociative anaesthesia is produced by?
- A. Ketamine (Correct Answer)
- B. Etomidate
- C. Propofol
- D. Thiopentone
Explanation: ***Ketamine*** - **Ketamine** is a unique anesthetic that produces a state of **dissociative anesthesia**, characterized by a trance-like state, analgesia, amnesia, and catalepsy. - This effect is primarily due to its antagonism of the **N-methyl-D-aspartate (NMDA) receptor**. *Etomidate* - **Etomidate** is an intravenous anesthetic characterized by its **cardiovascular stability**, making it suitable for patients with heart conditions. - It works primarily by modulating **GABA-A receptors** but does not produce dissociative anesthesia. *Propofol* - **Propofol** is a widely used intravenous anesthetic known for its **rapid onset and recovery**, and it is often used for induction and maintenance of general anesthesia. - Its primary mechanism of action involves enhancing the effects of **GABA-A receptors**, leading to central nervous system depression, but not dissociative anesthesia. *Thiopentone* - **Thiopentone** (Thiopental) is a barbiturate anesthetic that causes rapid loss of consciousness and has been historically used for inducing general anesthesia. - It acts as a **GABA-A receptor agonist**, depressing the central nervous system, but it does not produce the distinct dissociative state seen with ketamine.
Question 1376: Regarding propofol, which one of the following statements is false?
- A. It is painful on injecting intravenously
- B. It has no muscle relaxant property
- C. It is used as an intravenous induction agent
- D. It causes severe vomiting (Correct Answer)
Explanation: ***It causes severe vomiting*** - Propofol is actually known for its **antiemetic properties**, meaning it helps *prevent* rather than cause nausea and vomiting. - This makes it a preferred anesthetic for procedures where **postoperative nausea and vomiting (PONV)** are a concern. *It is used as an intravenous induction agent* - **Propofol** is a widely used **intravenous anesthetic** for the **induction and maintenance of general anesthesia**. - It provides a rapid onset of unconsciousness due to its high lipid solubility. *It is painful on injecting intravenously* - Injection of propofol can often cause **pain at the injection site**, particularly when administered into smaller veins. - This pain can be mitigated by co-administering **lidocaine** or using larger veins. *It has no muscle relaxant property* - Propofol does **not possess intrinsic muscle relaxant properties**; patients require additional neuromuscular blocking agents for surgical relaxation. - It facilitates intubation by causing **loss of consciousness** and **reducing airway reflexes**, but does not directly relax skeletal muscles.
Question 1377: Which anaesthetic drug contributes to green house effect?
- A. Enflurane
- B. Sevoflurane
- C. Halothane
- D. Desflurane (Correct Answer)
Explanation: **Desflurane** - **Desflurane** has the highest **global warming potential (GWP)** among commonly used volatile anesthetics, primarily due to its long atmospheric half-life and potent infrared absorption. - Its environmental impact is also amplified by its high **minimum alveolar concentration (MAC)** and low blood solubility, requiring higher delivered concentrations for anesthesia. *Enflurane* - **Enflurane** has a lower GWP compared to desflurane and is less commonly used in modern practice. - While it contributes to the greenhouse effect, its impact is significantly less than that of desflurane due to differences in chemical structure and atmospheric persistence. *Sevoflurane* - **Sevoflurane** has a relatively low GWP and a short atmospheric half-life compared to desflurane, making it a more environmentally friendly option among volatile anesthetics. - Although it still contributes to atmospheric warming, its overall environmental impact is considerably less than desflurane's. *Halothane* - **Halothane** is a potent greenhouse gas but is no longer used in many parts of the world due to concerns about hepatotoxicity and its significant ozone-depleting potential. - While it contributes to atmospheric warming, its current lack of clinical use limits its ongoing contribution to the greenhouse effect compared to currently utilized agents.
Orthopaedics
3 questionsWhat is the purpose of the Insall-Salvati index?
Which condition can lead to the formation of loose bodies in the joint?
Most common site of osteochondritis dissecans?
NEET-PG 2013 - Orthopaedics NEET-PG Practice Questions and MCQs
Question 1371: What is the purpose of the Insall-Salvati index?
- A. To measure ankle dorsiflexion range
- B. To assess patellar height and tendon length ratio (Correct Answer)
- C. To evaluate elbow joint stability
- D. To assess wrist bone alignment
Explanation: ***To assess patellar height and tendon length ratio*** - The **Insall-Salvati index** is a radiographic measurement used to determine **patellar height** by comparing the length of the patellar tendon to the greatest diagonal length of the patella. - It helps in diagnosing conditions like **patella alta** (high-riding patella) or **patella baja** (low-riding patella), which can contribute to knee pain and instability. *To evaluate elbow joint stability* - **Elbow joint stability** is typically assessed through clinical examination for ligamentous integrity (e.g., UCL, RCL) and sometimes dynamic imaging, not by the Insall-Salvati index. - The Insall-Salvati index is specific to the **knee joint** and **patellar position**. *To measure ankle dorsiflexion range* - **Ankle dorsiflexion range** is measured clinically using a goniometer or in 3D motion analysis, not with the Insall-Salvati index. - This index is a specialized measurement for the **patellofemoral joint**. *To assess wrist bone alignment* - **Wrist bone alignment** is evaluated using various radiographic measurements such as the scaphoid-lunate angle or carpal height ratio. - The Insall-Salvati index has no application in the assessment of the **wrist**.
Question 1372: Which condition can lead to the formation of loose bodies in the joint?
- A. Rheumatoid arthritis
- B. Ankylosing spondylitis
- C. Osteoarthritis (Correct Answer)
- D. Systemic lupus erythematosus
Explanation: ***Osteoarthritis*** - In **osteoarthritis**, the **degenerative process** of cartilage can lead to fragments breaking off and floating within the joint space, forming **loose bodies**. - These loose bodies, also known as **joint mice**, can cause mechanical symptoms like locking, clicking, or catching in the joint. *Rheumatoid arthritis* - **Rheumatoid arthritis** is an **inflammatory autoimmune disease** primarily affecting the synovium. - While it can cause joint damage, it typically does not lead to the formation of cartilaginous or bony loose bodies. *Ankylosing spondylitis* - **Ankylosing spondylitis** is a **chronic inflammatory disease** primarily affecting the spine and sacroiliac joints. - Its hallmark is new bone formation and fusion of vertebrae, not the formation of loose bodies within the joint. *Systemic lupus erythematosus* - **Systemic lupus erythematosus (SLE)** is a systemic autoimmune disease that can affect multiple organs, including joints. - While it can cause **non-erosive arthritis**, it does not typically result in the formation of loose bodies.
Question 1373: Most common site of osteochondritis dissecans?
- A. Lateral part of the medial femoral condyle (Correct Answer)
- B. Medial part of the medial femoral condyle
- C. Lateral part of the lateral femoral condyle
- D. Medial part of the lateral femoral condyle
Explanation: ***Lateral part of the medial femoral condyle*** - This is the **most common site** for osteochondritis dissecans in the knee, accounting for about 85% of cases. - The condition involves a localized area of **osteonecrosis and subchondral bone separation** from the epiphysis, typically afflicting this specific load-bearing region. *Medial part of the medial femoral condyle* - This location is **less common** for osteochondritis dissecans compared to the lateral aspect of the medial femoral condyle. - While osteochondral lesions can occur on any part of the condyle, the specific biomechanical stresses make the lateral part more susceptible. *Lateral part of the lateral femoral condyle* - Osteochondritis dissecans is **rarely found** in this location. - The lateral femoral condyle is generally less involved in osteochondritis dissecans of the knee. *Medial part of the lateral femoral condyle* - This site is also an **uncommon location** for osteochondritis dissecans. - The disease has a strong predilection for the medial femoral condyle, particularly its lateral aspect.