Anesthesiology
2 questionsWhat is the definition of conscious sedation?
Drug of choice for Bier's block ?
NEET-PG 2013 - Anesthesiology NEET-PG Practice Questions and MCQs
Question 1241: What is the definition of conscious sedation?
- A. CNS depression with unconsciousness
- B. Sedation with inability to respond to verbal commands
- C. Sedation with ability to respond to verbal commands (Correct Answer)
- D. None of the options
Explanation: ***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**.
Question 1242: Drug of choice for Bier's block ?
- A. Bupivacaine
- B. Etidocaine
- C. Ropivacaine
- D. Lidocaine (Correct Answer)
Explanation: ***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.
Dental
1 questionsPercentage of adrenaline with lignocaine for local infiltration is?
NEET-PG 2013 - Dental NEET-PG Practice Questions and MCQs
Question 1241: Percentage of adrenaline with lignocaine for local infiltration is?
- A. 1:1000
- B. 1:10000
- C. 1:50000 (Correct Answer)
- D. 1:200000
Explanation: ***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.
Internal Medicine
1 questionsIn a patient with heart disease, which condition is most commonly associated with left atrial enlargement?
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 1241: In a patient with heart disease, which condition is most commonly associated with left atrial enlargement?
- A. Mitral stenosis (Correct Answer)
- B. Tricuspid regurgitation
- C. AR
- D. None of the options
Explanation: ***Mitral stenosis*** - **Mitral stenosis** leads to an obstruction of blood flow from the **left atrium to the left ventricle**, causing pressure buildup in the left atrium [1]. - This increased pressure over time results in **left atrial enlargement** as the chamber struggles to push blood through the narrowed valve [1]. *Tricuspid regurgitation* - **Tricuspid regurgitation** involves the backflow of blood from the **right ventricle to the right atrium**. - This condition primarily affects the **right side of the heart**, leading to **right atrial enlargement**, not left. *AR* - **Aortic regurgitation (AR)** is the backflow of blood from the **aorta into the left ventricle**. - While AR can cause **left ventricular enlargement** and eventually lead to left atrial dilation, it is not the most common direct cause of *primary* left atrial enlargement compared to mitral stenosis [2]. *None of the options* - **Mitral stenosis** is a well-established cause of significant left atrial enlargement due to the direct pressure overload it imposes on the left atrium [1].
Physiology
1 questionsThe Doppler effect in medical ultrasound is caused by:
NEET-PG 2013 - Physiology NEET-PG Practice Questions and MCQs
Question 1241: The Doppler effect in medical ultrasound is caused by:
- A. Change in direction of sound
- B. Change in amplitude of sound
- C. None of the options
- D. Change in frequency of sound (Correct Answer)
Explanation: ***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.
Radiology
5 questionsWhich view is best for visualizing the collapse of the middle lobe of the lung?
Which imaging modality delivers the highest dose of radiation?
Gyromagnetic property of proton is seen in -
Frequency of ultrasound waves in USG -
What is an X-ray artifact?
NEET-PG 2013 - Radiology NEET-PG Practice Questions and MCQs
Question 1241: Which view is best for visualizing the collapse of the middle lobe of the lung?
- A. Anteroposterior (AP)
- B. Oblique
- C. Lateral (Correct Answer)
- D. Lordotic
Explanation: ***Lateral*** - A **lateral chest X-ray** is crucial for localizing abnormalities to specific lung lobes because it allows for a clear visualization of the **fissures** which define the lung lobes. - Collapse of the right middle lobe is particularly well-visualized on a lateral view as a **triangular opacity** that points towards the hilum, often obliterating the right heart border. *Anteroposterior (AP)* - While an AP or PA view can show collapse, it often appears as a **non-specific wedge or triangular opacity** and struggles with precise lobar localization due to superimposed structures. - The **heart shadow and mediastinum** can obscure parts of the middle lobe, making definitive diagnosis challenging from this view alone. *Oblique* - Oblique views are typically used for specific purposes, such as evaluating the **pleura** or **ribs**, and are not a standard view for initial assessment of lobar collapse. - They introduce **distortion and superimposition** that can make the identification and characterization of lobar collapse more difficult than a standard lateral projection. *Lordotic* - A lordotic view is primarily used to visualize the **lung apices** and to differentiate apical lesions from superimposed clavicular shadows. - It is not effective for visualizing the middle lobe, which is located more inferiorly, and would introduce significant distortion, making assessment of its collapse unreliable.
Question 1242: Which imaging modality delivers the highest dose of radiation?
- A. Cardiac perfusion scan (Correct Answer)
- B. CT scan of the chest
- C. Mammogram
- D. CT scan of the brain
Explanation: ***Cardiac perfusion scan*** - A **cardiac perfusion scan (nuclear cardiology)** involves the administration of a radioactive tracer, and the radiation dose can be significant due to the nature and energy of the isotopes used. - While varying, the effective dose for these scans can range from **10 to 30 mSv**, placing it among some of the highest radiation exposures from medical imaging. *CT scan of the chest* - A **CT scan of the chest** provides a relatively high radiation dose compared to plain X-rays, typically ranging from **5 to 7 mSv**. - This is generally lower than some nuclear medicine studies, particularly complex or prolonged cardiac perfusion scans. *Mammogram* - A **mammogram** involves a relatively low dose of radiation, typically in the range of **0.2 to 0.7 mSv**. - Its objective is to image the breast tissue with minimal exposure, making it one of the lower-dose imaging modalities available. *CT scan of the brain* - A **CT scan of the brain** usually delivers a moderate radiation dose, estimated to be around **1 to 2 mSv**. - This is often less than a chest CT due to the smaller volume and different shielding considerations, and significantly less than a cardiac perfusion scan.
Question 1243: Gyromagnetic property of proton is seen in -
- A. MRI (Correct Answer)
- B. CT
- C. PET scan
- D. USG
Explanation: ***MRI*** - Magnetic Resonance Imaging (MRI) relies on the **gyromagnetic properties of protons**, primarily hydrogen nuclei in water and fat. - These protons align with a strong magnetic field and, when pulsed with radiofrequency waves, emit detectable signals that form the image. *CT* - Computed Tomography (CT) utilizes **X-rays** and their differential absorption by various tissues to create cross-sectional images. - It does not involve the gyromagnetic properties of protons. *PET scan* - Positron Emission Tomography (PET) scans detect **gamma rays** emitted from radiotracers, typically radionuclides like Fluorine-18, that accumulate in metabolically active tissues. - This imaging modality is based on radioactive decay, not proton spin. *USG* - Ultrasonography (USG) generates images by sending **high-frequency sound waves** into the body and detecting the echoes that bounce back from various tissues. - It relies on acoustic properties and tissue interfaces, not magnetic properties of protons.
Question 1244: Frequency of ultrasound waves in USG -
- A. 2000 Hz
- B. 5000 Hz
- C. < 2 MHz
- D. >2 MHz (Correct Answer)
Explanation: ***>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. *< 2 MHz* - Frequencies below 2 MHz, while technically ultrasound (>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 1245: What is an X-ray artifact?
- A. A radiographic finding that indicates disease pathology
- B. A normal anatomical structure visible on X-ray
- C. An image distortion produced when the patient moves during the X-ray procedure
- D. An unwanted image distortion that doesn't represent actual anatomy (Correct Answer)
Explanation: ***An unwanted image distortion that doesn't represent actual anatomy*** - An **X-ray artifact** is any feature or distortion on a radiographic image that is not present in the actual object being imaged. - These can arise from various sources such as patient movement, equipment malfunction, or improper technique, leading to **misinterpretation** of the image. - Artifacts are unwanted findings that can obscure true pathology or mimic disease. *A normal anatomical structure visible on X-ray* - This describes a **true anatomical finding**, which is the intended purpose of an X-ray. - Normal anatomical structures are expected and assist in diagnosis, unlike artifacts which obscure or mimic pathology. *An image distortion produced when the patient moves during the X-ray procedure* - While **patient motion** is a common cause of X-ray artifacts, this describes just one specific type (motion artifact), not a comprehensive definition of what an artifact is. - Other sources like metallic objects, scatter radiation, or detector issues can also cause artifacts. *A radiographic finding that indicates disease pathology* - This describes **true pathology** or disease findings, which is what radiologists aim to identify. - Artifacts are the opposite - they are false findings that do not represent actual anatomy or pathology.