AIIMS PG (DM/MCh) Entrance Radiology, Anesthesiology and Critical Care Flashcards

24 sample cards from the Radiology, Anesthesiology and Critical Care deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. What are standard ASA preoperative fasting guidelines for clear fluids, breast milk, and solid food/full meal?

   Clear fluids: 2 hours. Breast milk: 4 hours. Light meal/non-human milk/formula: 6 hours. Fatty/full meal: 8 hours.

2. What is the mechanism of action of most inhalational (volatile) anesthetic agents?

   Primarily potentiation of inhibitory GABA-A receptors (and effects on glycine and NMDA receptors), producing dose-dependent CNS depression.

3. Define MAC (Minimum Alveolar Concentration).

   The alveolar concentration of an inhaled anesthetic at 1 atm that prevents movement in 50% of patients in response to a surgical (skin) incision; a measure of anesthetic potency.

4. What is the mechanism and key advantage of propofol as an IV induction agent?

   GABA-A receptor agonist; advantages: rapid onset, rapid smooth recovery, antiemetic properties. Drawbacks: hypotension, pain on injection, no analgesia.

5. Which IV induction agent is most cardiostable and what is its main adverse effect?

   Etomidate - maintains hemodynamic stability (good in shock/cardiac patients); main adverse effect is adrenocortical suppression (inhibits 11-beta-hydroxylase).

6. What is unique about ketamine's anesthetic action and hemodynamics?

   NMDA receptor antagonist producing 'dissociative anesthesia' with analgesia and bronchodilation; it increases BP, HR, and cardiac output (sympathomimetic), useful in shock/asthma. Side effect: emergence delirium/hallucinations.

7. What is the mechanism of action of local anesthetics?

   Reversible blockade of voltage-gated sodium channels on the inner axonal membrane, preventing depolarization and nerve impulse conduction.

8. What is the difference between depolarizing and non-depolarizing neuromuscular blockers? Give an example of each.

   Depolarizing (succinylcholine): agonist causing persistent depolarization, rapid onset/short duration, fasciculations. Non-depolarizing (rocuronium, vecuronium): competitive ACh-receptor antagonists, reversible by neostigmine/sugammadex.

9. What are the classic signs/triggers of malignant hyperthermia and its specific treatment?

   Triggered by volatile anesthetics and succinylcholine; signs: rising end-tidal CO2, masseter spasm, tachycardia, hyperthermia, rigidity, acidosis. Treatment: dantrolene plus supportive cooling.

10. What are the standard ASA basic intraoperative monitoring requirements?

    Continuous evaluation of oxygenation (pulse oximetry, FiO2), ventilation (capnography/end-tidal CO2), circulation (ECG, blood pressure at least every 5 min), and temperature.

11. What does capnography (end-tidal CO2) confirm and what is a normal EtCO2 value?

    Confirms correct endotracheal tube placement, ventilation adequacy, and circulation/cardiac output. Normal EtCO2 = 35-45 mmHg.

12. What is a sudden drop in EtCO2 to near zero most concerning for intraoperatively?

    Esophageal intubation, circuit disconnection/obstruction, or cardiac arrest (loss of pulmonary blood flow).

13. What does the pulse oximeter measure, and what is its key limitation?

    Measures peripheral oxygen saturation (SpO2) by differential absorption of red/infrared light by oxy- vs deoxyhemoglobin. Limitation: unreliable in carbon monoxide poisoning, methemoglobinemia, poor perfusion, and motion.

14. Describe the WHO analgesic ladder for pain management.

    Step 1: non-opioids (NSAIDs/paracetamol) +/- adjuvant. Step 2: weak opioids (codeine/tramadol) +/- non-opioid/adjuvant. Step 3: strong opioids (morphine) +/- non-opioid/adjuvant for moderate-to-severe pain.

15. What is the mechanism of action of opioids in pain control?

    Agonism at mu (and kappa/delta) opioid receptors in CNS, inhibiting ascending pain transmission and altering pain perception; mu effects include analgesia, respiratory depression, and miosis.

16. What is the antidote for opioid overdose and a key caution with its use?

    Naloxone (mu-receptor antagonist). Caution: short half-life may require repeat dosing, and it can precipitate acute withdrawal in dependent patients.

17. What class of drugs is first-line for neuropathic pain and give examples?

    Anticonvulsants (gabapentin, pregabalin) and tricyclic antidepressants (amitriptyline) or SNRIs (duloxetine); standard NSAIDs/opioids are less effective for neuropathic pain.

18. Classify the four main types of shock by mechanism.

    Hypovolemic (volume loss), Cardiogenic (pump failure), Obstructive (mechanical obstruction - PE, tamponade, tension pneumothorax), and Distributive (vasodilation - septic, anaphylactic, neurogenic).

19. Compare hemodynamic profiles (CO, SVR, preload) of hypovolemic vs septic (distributive) vs cardiogenic shock.

    Hypovolemic: low CO, high SVR, low preload (cold). Cardiogenic: low CO, high SVR, high preload (cold). Septic/distributive: high CO, low SVR, low/normal preload (warm).

20. What is the qSOFA score and its criteria?

    A bedside screen for sepsis-related mortality risk: RR >=22/min, altered mentation (GCS <15), systolic BP <=100 mmHg. Score >=2 suggests higher risk.

21. State the formula for Mean Arterial Pressure (MAP) and the typical resuscitation target in shock/sepsis.

    MAP = DBP + 1/3(SBP - DBP), or (CO x SVR). Target MAP in sepsis resuscitation is >= 65 mmHg.

22. In acute respiratory failure, distinguish Type I from Type II by blood gases.

    Type I (hypoxemic): low PaO2 with normal/low PaCO2 (e.g., pneumonia, ARDS, PE). Type II (hypercapnic): low PaO2 with high PaCO2 (ventilatory failure - COPD, drug overdose, neuromuscular).

23. What are the Berlin criteria diagnostic features of ARDS?

    Acute onset within 1 week, bilateral pulmonary infiltrates not fully explained by cardiac failure/overload, and impaired oxygenation graded by PaO2/FiO2 ratio (mild <=300, moderate <=200, severe <=100, on PEEP >=5).

24. What is the lung-protective ventilation strategy for ARDS?

    Low tidal volume (~6 mL/kg predicted body weight), plateau pressure <30 cmH2O, adequate PEEP, and permissive hypercapnia; prone positioning for severe ARDS.

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Radiology, Anesthesiology and Critical Care flashcards FAQ