NEET-PG 2013 Practice Questions

Q: Which of the following is not a sign of stellate ganglion block?

Exophthalmos. ***Exophthalmos*** - A stellate ganglion block paralyses the **sympathetic nervous system** to the head and neck. - **Exophthalmos** (bulging of the eye) is a sign of sympathetic **hyperactivity**, not blockade. *Miosis* - **Miosis** (pupil constriction) is a classic sign of sympathetic blockade. - The **dilator pupillae muscle** is paralyzed, leading to unopposed parasympathetic action. *Nasal congestion* - **Nasal congestion** is a common sign due to the **vasodilation** of nasal blood vessels from sympathetic blockade. - Sympathetic nerves normally cause **vasoconstriction** in the nasal mucosa. *Conjunctival redness* - **Conjunctival redness** occurs due to **vasodilation** of conjunctival blood vessels, a direct effect of sympathetic blockade. - This is part of the **Horner's syndrome** presentation.

Q: Which anesthetic agent is known for providing smooth induction?

Isoflurane. ***Isoflurane*** - **Isoflurane** is frequently chosen for its capacity to induce a **smooth and rapid loss of consciousness**, primarily due to its low blood solubility which facilitates quick changes in anesthetic depth. - Its **minimal irritation** to the respiratory tract and **stable cardiovascular profile** during induction contribute to a smoother process for the patient. *Sevoflurane* - While sevoflurane also offers a **smooth and rapid induction** due to its low solubility, it is sometimes associated with a higher incidence of **airway irritation** (e.g., coughing) compared to isoflurane, especially in children. - It is known for its **pleasant odor**, making it a good choice for mask induction in pediatric patients. *Halothane* - **Halothane** provides a relatively smooth induction but has a higher risk of **hepatotoxicity** and cardiac arrhythmias, which have led to its decreased use. - Its higher blood solubility means a **slower onset and offset** compared to modern volatile agents like isoflurane. *Enflurane* - **Enflurane** can cause **CNS excitation** at deeper levels of anesthesia, potentially leading to seizures, making its induction less smooth and predictable. - It also has a greater potential to cause **myocardial depression** and arrhythmias than isoflurane.

Q: Drug of choice for Bier's block ?

Lidocaine. ***Lidocaine*** - **Lidocaine** is the preferred local anesthetic for **Bier's block** (intravenous regional anesthesia) due to its rapid onset and good safety profile. - Its relatively short duration of action and **minimal cardiotoxicity** upon systemic release are favorable for this technique. *Bupivacaine* - **Bupivacaine** has a **longer duration of action** and is associated with a higher risk of **cardiotoxicity** when inadvertently delivered systemically, making it less suitable for Bier's block. - Its use in Bier's block is generally avoided due to the potential for significant adverse events if the tourniquet malfunctions or is released prematurely. *Etidocaine* - **Etidocaine** is a potent, **long-acting local anesthetic** with a similar toxicity profile to bupivacaine, making it less ideal for Bier's block. - Its prolonged action and higher potential for systemic toxicity make it less favorable for a procedure where rapid washout and lower systemic risk are desired. *Ropivacaine* - **Ropivacaine** is an amide-type local anesthetic with a similar efficacy to bupivacaine but with a **lower potential for cardiotoxicity**. - While safer than bupivacaine, **lidocaine** is still generally preferred for Bier's block due to its established safety record, faster onset, and lower cost.

Q: What is the definition of conscious sedation?

Sedation with ability to respond to verbal commands. ***Sedation with ability to respond to verbal commands*** - Conscious sedation involves a drug-induced depression of consciousness during which the patient **retains the ability to respond purposefully to verbal commands**. - This level of sedation ensures that the patient's **airway reflexes** and **ventilatory function** remain intact. *CNS depression with unconsciousness* - This describes **general anesthesia** or **deep sedation**, where the patient is unable to respond purposefully to verbal commands. - In such states, spontaneous ventilation may be **inadequate**, and **airway support** is often required. *Sedation with inability to respond to verbal commands* - This definition aligns with **deep sedation** or **general anesthesia**, where the patient's consciousness is significantly depressed. - At this level, patients may require assistance in maintaining a **patent airway** and adequate ventilation. *None of the options* - This option is incorrect because one of the provided definitions accurately describes conscious sedation. - The definition of conscious sedation is well-established in clinical practice, emphasizing the **preservation of responsiveness**.

Q: Percentage of adrenaline with lignocaine for local infiltration is?

1:50000. ***1:50000*** - This concentration of **adrenaline (epinephrine)** is commonly used with **lignocaine (lidocaine)** for local infiltration to prolong the anesthetic effect and reduce bleeding. - At this concentration, adrenaline acts as a **vasoconstrictor**, decreasing systemic absorption of lignocaine and allowing a higher dose locally. *1:1000* - This concentration of adrenaline is typically used for the treatment of **anaphylaxis** and is considered too high for local infiltration with lignocaine. - Using such a high concentration locally can lead to severe **vasoconstriction**, tissue ischemia, and systemic side effects like **tachycardia** and **hypertension**. *1:10000* - This concentration is too strong for routine local infiltration and is usually reserved for **cardiac arrest** protocols or severe anaphylaxis when administered intravenously. - It would carry a significant risk of **tissue damage** and systemic effects if used for local infiltration. *1:200000* - While sometimes used, **1:50000** is generally the more common and effective concentration for achieving **hemostasis** and prolonging anesthesia during local infiltration. - A 1:200000 concentration provides a lesser degree of **vasoconstriction**, potentially leading to less prolonged local anesthetic effect and reduced bleeding control compared to 1:50000.

Q: The best local anesthetic for prolonged ophthalmic surgery requiring extended post-operative analgesia is:

Bupivacaine. ***Bupivacaine*** - **Bupivacaine** is an amide-type local anesthetic known for its **long duration of action** due to its high protein binding and lipid solubility. - This property makes it ideal for procedures requiring **prolonged analgesia**, such as extended ophthalmic surgery and post-operative pain control. *Tetracaine* - **Tetracaine** is an ester-type local anesthetic primarily used for **topical anesthesia**, especially in ophthalmology. - While effective for surface anesthesia, its duration of action is relatively short, making it unsuitable for prolonged surgical procedures requiring sustained nerve block. *Procaine* - **Procaine** is an ester-type local anesthetic with a **short duration of action** and is generally associated with a higher incidence of allergic reactions. - It is rarely used today for major regional blocks due to its limited potency and short effect, unlike the requirement for prolonged ophthalmic surgery. *Prilocaine* - **Prilocaine** is an amide-type local anesthetic with an **intermediate duration of action**. - Its use is limited in some cases due to its potential to cause **methemoglobinemia** at higher doses, making it less suitable for applications requiring extensive or prolonged regional anesthesia compared to bupivacaine.

Q: Which local anaesthetic is known to cause methemoglobinemia?

Prilocaine. ***Prilocaine*** - **Prilocaine** is metabolized into **ortho-toluidine**, which can oxidize hemoglobin to **methemoglobin**, especially at higher doses or in susceptible individuals. - **Methemoglobinemia** symptoms include **cyanosis**, **dyspnea**, and in severe cases, central nervous system depression, due to reduced oxygen-carrying capacity of blood. *Procaine* - **Procaine** is an ester-type local anesthetic. It is metabolized to **para-aminobenzoic acid (PABA)**, which can cause allergic reactions, but it is not associated with methemoglobinemia. - It has a relatively **short duration of action** and is less commonly used now compared to amide-type local anesthetics. *Etidocaine* - **Etidocaine** is an amide-type local anesthetic that is known for its **long duration of action** and high potency. - While it can cause systemic toxicity with high doses due to its cardiac and neurological effects, **methemoglobinemia** is not a characteristic side effect. *Ropivacaine* - **Ropivacaine** is an amide-type local anesthetic similar to bupivacaine, known for its **motor-sparing effect** and use in regional anesthesia. - It is associated with a lower risk of **cardiotoxicity** compared to bupivacaine but does not cause methemoglobinemia.

Q: The Doppler effect in medical ultrasound is caused by:

Change in frequency of sound. ***Change in frequency of sound*** - The **Doppler effect** in medical ultrasound is fundamentally based on **frequency changes** that occur when sound waves reflect off moving structures like blood cells or tissues. - When ultrasound waves encounter moving objects, the frequency of reflected waves **shifts upward** (if moving toward transducer) or **shifts downward** (if moving away), enabling detection and measurement of blood flow and tissue movement. *Change in direction of sound* - While sound waves do change direction through **reflection** at tissue interfaces, this directional change doesn't explain the **frequency shift** characteristic of the Doppler effect. - Direction changes are related to **acoustic impedance** differences between tissues, not the motion-dependent frequency variations used in Doppler imaging. *Change in amplitude of sound* - Changes in **amplitude** relate to the **intensity** or strength of the sound waves, affected by factors like **attenuation** and **scattering**. - Amplitude variations don't create the **frequency shift** that allows Doppler ultrasound to detect moving structures and measure velocities. *None of the options* - This is incorrect because **frequency change** is indeed the correct mechanism underlying the Doppler effect in medical ultrasound. - The frequency shift phenomenon is what enables **color Doppler**, **pulsed-wave Doppler**, and **continuous-wave Doppler** imaging techniques to function.

Q: Frequency of ultrasound waves in USG -

>2 MHz. ***>2 MHz*** - Medical diagnostic ultrasound typically uses frequencies in the **range of 2-15 MHz**, with some applications extending from 1-20 MHz. - Frequencies **above 2 MHz** are considered the standard for diagnostic ultrasonography, providing adequate **spatial resolution** and tissue penetration for imaging internal structures. - **Frequency selection** depends on the application: - **2-5 MHz**: Deep structures (abdominal, obstetric imaging) - better penetration - **5-10 MHz**: Vascular studies, cardiac imaging - **7-15 MHz**: Superficial structures (thyroid, breast, musculoskeletal) - better resolution - Higher frequencies provide better resolution but less penetration; the choice represents a trade-off based on clinical needs. *2000 Hz* - This frequency (2 kHz) falls within the **audible range** for humans (20 Hz to 20 kHz). - Such low frequencies would not provide the necessary **spatial resolution** for diagnostic imaging and lack the characteristics needed for medical ultrasound. *5000 Hz* - At 5 kHz, this is still within the **audible frequency range**. - These frequencies are far too low for medical ultrasound imaging, which requires **megahertz frequencies** to generate diagnostically useful images with adequate detail. * 20 kHz), are generally **below the diagnostic range** for most clinical applications. - Although lower frequencies offer better tissue penetration, frequencies below 2 MHz provide **insufficient spatial resolution** for standard diagnostic medical imaging.

Question 1

Which of the following is not a sign of stellate ganglion block?

Accepted Answer

Exophthalmos

Answer

Miosis

Answer

Conjunctival redness

Answer

Nasal congestion

Question 2

Which anesthetic agent is known for providing smooth induction?

Accepted Answer

Isoflurane

Answer

Halothane

Answer

Enflurane

Answer

Sevoflurane

Question 3

Drug of choice for Bier's block ?

Accepted Answer

Lidocaine

Answer

Bupivacaine

Answer

Etidocaine

Answer

Ropivacaine

Question 4

What is the definition of conscious sedation?

Accepted Answer

Sedation with ability to respond to verbal commands

Answer

CNS depression with unconsciousness

Answer

Sedation with inability to respond to verbal commands

Answer

None of the options

Question 5

Percentage of adrenaline with lignocaine for local infiltration is?

Accepted Answer

1:50000

Answer

1:1000

Answer

1:10000

Answer

1:200000

Question 6

The best local anesthetic for prolonged ophthalmic surgery requiring extended post-operative analgesia is:

Accepted Answer

Bupivacaine

Answer

Tetracaine

Answer

Procaine

Answer

Prilocaine

Question 7

Which local anaesthetic is known to cause methemoglobinemia?

Accepted Answer

Prilocaine

Answer

Procaine

Answer

Ropivacaine

Answer

Etidocaine

Question 8

The Doppler effect in medical ultrasound is caused by:

Accepted Answer

Change in frequency of sound

Answer

Change in direction of sound

Answer

Change in amplitude of sound

Answer

None of the options

Question 9

What is an X-ray artifact?

Accepted Answer

An unwanted image distortion that doesn't represent actual anatomy

Answer

A radiographic finding that indicates disease pathology

Answer

A normal anatomical structure visible on X-ray

Answer

An image distortion produced when the patient moves during the X-ray procedure

Question 10

Frequency of ultrasound waves in USG -

Accepted Answer

>2 MHz

Answer

2000 Hz

Answer

5000 Hz

Answer

< 2 MHz

NEET-PG 2013

Anesthesiology

Dental

Ophthalmology

Pharmacology

Physiology

Radiology