Anesthesiology
8 questionsWhich of the following statements about Nitrous Oxide (N2O) is true?
Inhalational agent of choice for neurosurgery?
Which of the following anesthetic agents causes the LEAST severe complications when accidentally injected intra-arterially?
Which anaesthetic drug contributes to green house effect?
Regarding propofol, which one of the following statements is false?
Dissociative anaesthesia is produced by?
Which of the following anesthetic agents is most notable for its analgesic properties?
Intraocular pressure is increased by which anaesthetic?
NEET-PG 2013 - Anesthesiology NEET-PG Practice Questions and MCQs
Question 1181: Which of the following statements about Nitrous Oxide (N2O) is true?
- A. Least potent inhalational anesthetic (Correct Answer)
- B. Lighter than air
- C. Effective muscle relaxant
- D. Does not cause diffusion hypoxia
Explanation: **Least potent inhalational anesthetic** - Nitrous oxide has a **high Minimum Alveolar Concentration (MAC)** of approximately 104%, making it the least potent of the commonly used inhalational anesthetics. - Its high MAC means a very high concentration is required to achieve surgical anesthesia, which is why it is typically used as an adjunct to more potent agents. *Lighter than air* - The molecular weight of nitrous oxide (N2O) is 44, which is **heavier than air** (average molecular weight approximately 29 g/mol). - Its density is greater than air, meaning it would tend to sink rather than rise. *Effective muscle relaxant* - Nitrous oxide provides **minimal to no skeletal muscle relaxation** benefits. - If muscle relaxation is required, a neuromuscular blocking agent must be administered separately. *Does not cause diffusion hypoxia* - Nitrous oxide rapidly diffuses out of the blood into the alveoli during emergence, diluting the oxygen and carbon dioxide there. - This rapid diffusion can lead to **diffusion hypoxia** (also known as the "second gas effect"), necessitating the administration of 100% oxygen during recovery to prevent this complication.
Question 1182: Inhalational agent of choice for neurosurgery?
- A. Halothane
- B. Enflurane
- C. Isoflurane (Correct Answer)
- D. N2O
Explanation: ***Isoflurane*** - **Isoflurane** is preferred in neurosurgery due to its minimal impact on **cerebral blood flow** and **intracranial pressure (ICP)**, allowing cerebral autoregulation to be largely preserved. - It maintains **cerebral perfusion pressure** well and has a relatively fast onset and offset, facilitating neurological assessment post-operatively. *Halothane* - **Halothane** significantly increases **cerebral blood flow** and **intracranial pressure (ICP)**, which is undesirable in neurosurgical patients. - Its slow elimination can prolong recovery and neurological assessment, making it unsuitable for neurosurgery. *Enflurane* - **Enflurane** can cause central nervous system excitation and has been associated with **seizure activity** at higher concentrations, making it contraindicated in neurosurgical procedures. - Like halothane, it can also increase **cerebral blood flow** and **intracranial pressure**. *N2O* - **Nitrous oxide (N2O)** should be avoided in neurosurgery, especially if there's a risk of **intracranial air** or **pneumocephalus**, as it can expand air-filled spaces and increase ICP. - It also has a weak anesthetic effect and is often combined with other agents, but its cerebral vasodilatory properties can still be problematic.
Question 1183: Which of the following anesthetic agents causes the LEAST severe complications when accidentally injected intra-arterially?
- A. Thiopentone
- B. Propofol (Correct Answer)
- C. Methohexitone
- D. Midazolam
Explanation: **Propofol** * **Propofol** has a relatively low incidence and severity of complications if accidentally injected intra-arterially because of its **lipid emulsion formulation** and mild irritant properties compared to other agents. * While any intra-arterial injection can cause problems, the milder venoconstriction and less direct tissue damage make its intra-arterial complication profile less severe than alternative agents. *Thiopentone* * **Thiopentone** (Thiopental) is highly alkaline, and accidental intra-arterial injection can cause **intense pain**, **vasospasm**, and **gangrene** due to precipitation in the arterioles and widespread endothelial damage. * This severe complication arises from its extreme pH and crystal formation, leading to profound ischemia. *Midazolam* * Accidental intra-arterial injection of **Midazolam** can cause **pain**, **spasm**, and **local tissue damage** due to its relatively acidic pH and solvent properties, though generally less severe than thiopentone. * While not as catastrophic as thiopentone, it can still lead to significant discomfort and localized vascular issues. *Methohexitone* * **Methohexitone** is also an alkaline barbiturate derivative, similar in nature to thiopentone, and its intra-arterial injection carries a significant risk of **vasospasm**, **pain**, and potentially **tissue necrosis**. * Its strong irritant properties and ability to precipitate within the vasculature make it a dangerous agent for inadvertent intra-arterial administration.
Question 1184: 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.
Question 1185: 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 1186: 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 1187: 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 1188: 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.
Pharmacology
1 questionsWhich of the following medications is not typically used for the treatment of erectile dysfunction?
NEET-PG 2013 - Pharmacology NEET-PG Practice Questions and MCQs
Question 1181: Which of the following medications is not typically used for the treatment of erectile dysfunction?
- A. Beta blockers (Correct Answer)
- B. Papaverine
- C. Sildenafil
- D. PG-E
Explanation: ***Beta blockers*** - **Beta blockers** are primarily used to treat conditions like **hypertension** and **heart disease**. - While they can cause ED as a side effect, they are **not used for its treatment**. *Sildenafil* - **Sildenafil** is a **PDE5 inhibitor** that works by increasing **blood flow to the penis**, facilitating an erection. - It is a **first-line oral medication** widely prescribed for erectile dysfunction. *PG-E* - **PG-E** refers to **Prostaglandin E1** (alprostadil), which can be administered via **intracavernosal injection** or **urethral suppository**. - It directly causes **vasodilation** in the penis, leading to an erection, and is used when oral medications are ineffective or contraindicated. *Papaverine* - **Papaverine** is a **non-specific vasodilator** that can be used as an **intracavernosal injection** for ED. - It works by relaxing **smooth muscle** in the penile arteries, increasing blood flow and inducing an erection, often used in combination with phentolamine.
Psychiatry
1 questionsAccording to DSM-5 criteria, symptoms of brief psychotic disorder must resolve within what time period to differentiate it from longer-term psychotic conditions like schizophreniform disorder?
NEET-PG 2013 - Psychiatry NEET-PG Practice Questions and MCQs
Question 1181: According to DSM-5 criteria, symptoms of brief psychotic disorder must resolve within what time period to differentiate it from longer-term psychotic conditions like schizophreniform disorder?
- A. 1 week
- B. 3 weeks
- C. 2 weeks
- D. 1 month (Correct Answer)
Explanation: ***1 month*** - According to **DSM-5 criteria**, brief psychotic disorder is characterized by symptoms lasting more than **1 day** but less than **1 month**. - If psychotic symptoms persist for **1 month or longer**, it indicates a different diagnosis, such as schizophreniform disorder or schizophrenia, requiring further evaluation. *1 week* - While psychotic symptoms may be present for 1 week in brief psychotic disorder, this duration is within the disorder's diagnostic window but not its defining upper limit. - The key differentiator for brief psychotic disorder is that symptoms resolve within **1 month**. *2 weeks* - Similar to 1 week, 2 weeks is a duration that can occur within brief psychotic disorder, but it does not represent the minimum duration that distinguishes it from longer-term conditions. - The crucial threshold for duration in brief psychotic disorder is **less than 1 month**. *3 weeks* - Three weeks also falls within the diagnostic duration for brief psychotic disorder. - The essential criteria specify that psychotic symptoms must last **less than 1 month** to be classified as brief psychotic disorder.