NEET-PG 2013 Practice Questions

Q: Which of the following statements about Nitrous Oxide (N2O) is true?

Least potent inhalational anesthetic. **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.

Q: Inhalational agent of choice for neurosurgery?

Isoflurane. ***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.

Q: Which of the following anesthetic agents causes the LEAST severe complications when accidentally injected intra-arterially?

Propofol. **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.

Q: Which anaesthetic drug contributes to green house effect?

Desflurane. **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.

Q: Regarding propofol, which one of the following statements is false?

It causes severe vomiting. ***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.

Q: Dissociative anaesthesia is produced by?

Ketamine. ***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.

Q: Intrauterine adhesions best seen by?

Hysteroscopy. ***Hysteroscopy*** - **Hysteroscopy** provides direct visualization of the uterine cavity, allowing for precise identification and characterization of **intrauterine adhesions (IUA)** or **Asherman's syndrome**. - It not only diagnoses IUAs but also allows for simultaneous treatment through **adhesiolysis**, making it the gold standard for both diagnosis and management. *Ultrasound* - While ultrasound can sometimes suggest the presence of adhesions through abnormal endometrial appearances or fluid collections, it is generally **not definitive** for diagnosing IUAs. - Its sensitivity is limited, especially for subtle or fine adhesions, and it often requires confirmation by other methods. *Computed Tomography* - **Computed Tomography (CT)** scans are generally **not used** for the diagnosis of intrauterine adhesions. - CT provides limited soft tissue contrast in the endometrial cavity and exposes the patient to **ionizing radiation**, without offering a clear advantage over other imaging modalities. *Magnetic Resonance Imaging* - **Magnetic Resonance Imaging (MRI)** can provide good soft tissue detail and may visualize severe adhesions, but it is **not as sensitive or specific** as hysteroscopy for detecting all types of IUAs. - MRI is more expensive and less accessible than hysteroscopy, and it does not allow for immediate therapeutic intervention.

Q: Which hormone is primarily responsible for insulin resistance during pregnancy?

HPL. ***HPL*** - **Human placental lactogen (HPL)**, also known as **chorionic somatomammotropin**, directly induces maternal insulin resistance to ensure a continuous supply of glucose to the fetus. - HPL levels rise throughout pregnancy, peaking in the third trimester, correlating with increasing insulin resistance. *Estrogen* - While **estrogen** levels are high in pregnancy, its primary role is in supporting uterine growth and maintaining the pregnancy, not directly causing significant insulin resistance. - High estrogen levels can enhance insulin sensitivity in some contexts, contrasting with the overall insulin resistance of pregnancy. *Progesterone* - **Progesterone** is crucial for maintaining pregnancy and relaxing smooth muscle but does not directly cause the marked insulin resistance seen in gestation. - It works synergistically with other hormones but is not the primary driver of glucose intolerance in pregnancy. *GH* - **Growth hormone (GH)** does contribute to insulin resistance in non-pregnant individuals and at high levels can cause insulin resistance, but it is not the primary hormone responsible for the unique physiological insulin resistance of pregnancy. - While GH is present, **HPL** is the dominant somatotropic hormone of pregnancy directly impacting glucose metabolism.

Question 1

Which of the following statements about Nitrous Oxide (N2O) is true?

Accepted Answer

Least potent inhalational anesthetic

Answer

Lighter than air

Answer

Effective muscle relaxant

Answer

Does not cause diffusion hypoxia

Question 2

Inhalational agent of choice for neurosurgery?

Accepted Answer

Isoflurane

Answer

Halothane

Answer

Enflurane

Answer

N2O

Question 3

Which of the following anesthetic agents causes the LEAST severe complications when accidentally injected intra-arterially?

Accepted Answer

Propofol

Answer

Thiopentone

Answer

Methohexitone

Answer

Midazolam

Question 4

Which anaesthetic drug contributes to green house effect?

Accepted Answer

Desflurane

Answer

Enflurane

Answer

Sevoflurane

Answer

Halothane

Question 5

Regarding propofol, which one of the following statements is false?

Accepted Answer

It causes severe vomiting

Answer

It is painful on injecting intravenously

Answer

It has no muscle relaxant property

Answer

It is used as an intravenous induction agent

Question 6

Dissociative anaesthesia is produced by?

Accepted Answer

Ketamine

Answer

Etomidate

Answer

Propofol

Answer

Thiopentone

Question 7

Intrauterine adhesions best seen by?

Accepted Answer

Hysteroscopy

Answer

Ultrasound

Answer

Computed Tomography

Answer

Magnetic Resonance Imaging

Question 8

Which hormone is primarily responsible for insulin resistance during pregnancy?

Accepted Answer

HPL

Answer

Estrogen

Answer

Progesterone

Answer

GH

Question 9

Which of the following statements about gestational diabetes mellitus (GDM) is true?

Accepted Answer

Gestational diabetes mellitus is first recognized during pregnancy.

Answer

It is always associated with a previous history of IUGR.

Answer

There is no recurrence of GDM in future pregnancies.

Answer

There is no risk of developing overt diabetes in the future.

Question 10

What is the most common fetal complication associated with gestational diabetes?

Accepted Answer

There is a risk of macrosomia in babies born to mothers with gestational diabetes.

Answer

Only a small percentage of women with gestational diabetes develop overt diabetes.

Answer

Gestational diabetes is usually diagnosed in the second or third trimester.

Answer

Gestational diabetes can increase the risk of congenital malformations.

NEET-PG 2013

Anesthesiology

Obstetrics and Gynecology