DNB Anaesthesiology — Theory Mock Examination: Comprehensive Model Answers

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QUESTION 1 (10 Marks) — Obstetric Anesthesia: Mitral Stenosis in Pregnancy

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Part (a): Pathophysiology of Mitral Stenosis in Pregnancy (5 Marks)

Key Points

• Mitral stenosis (MS) is the most common rheumatic valvular lesion encountered in pregnancy
• Normal mitral valve area (MVA): 4–6 cm²; symptoms appear when MVA < 2 cm²; severe MS = MVA < 1 cm²
• Stenotic lesions are significantly worse tolerated than regurgitant lesions during pregnancy (Miller's Anesthesia, 10e)
• Moderate-to-severe MS carries significant risk of maternal morbidity and mortality (modified WHO Class III/IV)

Pathophysiology — the Pressure Gradient Cascade

↑ Blood Volume (40–50%) + ↑ Heart Rate in Pregnancy
              ↓
Reduced diastolic filling time across stenotic mitral valve
              ↓
↑ Left atrial (LA) pressure → LA dilatation → AF
              ↓
↑ Pulmonary venous pressure → Pulmonary congestion / Oedema
              ↓
↑ Pulmonary arterial pressure → RV pressure overload
              ↓
Right Heart Failure + Fixed Low Cardiac Output State

Changes in Pregnancy that Worsen MS

Key Haemodynamic Goals in MS

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Part (b): Anaesthetic Plan + Postoperative Pain Management (5 Marks)

Preoperative Assessment & Optimization

• Multidisciplinary team (MDT): Obstetrician + Cardiologist + Anaesthesiologist (shared decision-making 20–30 weeks per ACOG)
• Echocardiography: MVA, pulmonary artery pressure, LV function, LA size, presence of thrombus
• Modified WHO Risk Classification — best predictor of maternal morbidity/mortality
• Optimize medical therapy: rate control with β-blocker (metoprolol preferred), anticoagulation if AF/LA thrombus
• Consider elective PTMC (Percutaneous Transvenous Mitral Commissurotomy) if MVA < 1.5 cm² and symptomatic
• Avoid: NSAIDs, ACE inhibitors in pregnancy

Intraoperative Monitoring (Enhanced)

• Standard ASA monitors + invasive arterial blood pressure (continuous beat-to-beat)
• Large-bore IV access × 2
• Urinary catheter
• Consider central venous pressure (CVP) if pulmonary hypertension
• 5-lead ECG (detect AF, ischaemia)
• Temperature monitoring

Choice of Anaesthesia for LSCS

Option 1: Slow Titrated Epidural (PREFERRED)

FLOWCHART — Regional Technique for MS in Pregnancy:

Establish epidural (L2-L3 or L3-L4)
         ↓
Slow incremental dosing (3 mL aliquots of 0.5% Bupivacaine + Fentanyl)
         ↓
Avoid sudden sympathectomy → gradual onset
         ↓
Vasopressors: Phenylephrine (preferred over ephedrine — no tachycardia)
         ↓
Target T4 level for surgical anaesthesia
         ↓
Left lateral uterine displacement at all times

• Gradual sympathetic block → avoids sudden afterload drop
• Titrateable
• Can be used postoperatively for analgesia

Option 2: Combined Spinal-Epidural (CSE)

• Low-dose spinal (hyperbaric bupivacaine 5–7.5 mg + fentanyl 15 mcg) + epidural top-up
• Reduces haemodynamic instability vs. full spinal dose

Option 3: General Anaesthesia (if regional contraindicated — e.g., coagulopathy)

• Avoid: Thiopentone (bradycardia), Atropine (tachycardia), Ketamine (↑ HR, ↑ SVR)
• Prefer: Modified RSI with cricoid pressure; Etomidate (haemodynamically stable induction)
• Maintain with isoflurane/sevoflurane (avoid tachycardia); opioid blunting of intubation response (Fentanyl 2 mcg/kg)
• Vasopressors ready for post-delivery: Oxytocin as slow infusion (bolus → vasodilation + tachycardia)

Postoperative Pain Management

• Epidural infusion: 0.125% Bupivacaine + 2 mcg/mL Fentanyl — excellent analgesia, avoids systemic opioids, no tachycardia
• Intrathecal morphine (if spinal used): 100–200 mcg for prolonged analgesia
• Multimodal analgesia: Paracetamol 1g IV 6-hourly (safe, opioid-sparing)
• Avoid NSAIDs in cardiac patients and breastfeeding mothers
• Avoid PCA with opioids as primary modality (risk of hypoventilation, respiratory depression)
• Continued cardiac monitoring in HDU/ICU for minimum 24–48 hours postpartum
• Continue anticoagulation vigilance — highest risk of decompensation is 24–72 hours postpartum due to auto-transfusion

Potential Exam Questions — Q1

1. What are the haemodynamic goals in managing mitral stenosis for caesarean section?
2. Why are stenotic lesions more dangerous than regurgitant lesions in pregnancy?
3. What is the modified WHO classification for cardiac disease in pregnancy?
4. Why is phenylephrine preferred over ephedrine as a vasopressor in a patient with MS?
5. When would you consider general anaesthesia over regional anaesthesia in a cardiac parturient?
6. What are the haemodynamic dangers of oxytocin bolus in MS?
7. When is PTMC indicated during pregnancy?

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QUESTION 2 (10 Marks) — Airway & Equipment

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Part (a): Anatomy of the Larynx + Nerve Blocks for Awake Fibreoptic Intubation (5 Marks)

Anatomy of the Larynx

Structural Anatomy (Labelled)

LARYNX — ANTERIOR VIEW (Diagram):

    ┌──────────────────────────────────┐
    │         EPIGLOTTIS               │
    │      (Elastic cartilage)         │
    └────────────┬─────────────────────┘
                 │
    ┌────────────▼─────────────────────┐
    │       HYOID BONE                 │
    │   Thyrohyoid membrane            │
    ├──────────────────────────────────┤
    │     THYROID CARTILAGE            │
    │   (Largest cartilage)            │
    │   ← THYROID NOTCH (superior)     │
    │   Laryngeal prominence           │
    ├──────────────────────────────────┤
    │ Cricothyroid membrane ← (KEY)    │
    │   Emergency surgical airway      │
    ├──────────────────────────────────┤
    │     CRICOID CARTILAGE            │
    │ (Only complete ring in airway)   │
    └──────────────────────────────────┘

• Supraglottis: Epiglottis, aryepiglottic folds, false vocal cords (vestibular folds), laryngeal ventricles
• Glottis: True vocal cords (TA muscle + vocal ligament), anterior commissure, posterior commissure, rima glottidis
• Subglottis: Below vocal cords to inferior cricoid ring

Nerve Supply of the Larynx

Nerve Blocks for Awake Fibreoptic Intubation (AFOI)

FLOWCHART — Nerve Blocks for AFOI:

  1. SUPERIOR LARYNGEAL NERVE (SLN) BLOCK
     ├── Inject 2 mL 2% Lignocaine
     ├── Just below the greater cornu of the hyoid
     └── Piercing the thyrohyoid membrane
     Blocks: Sensation above cords (epiglottis, piriform fossa)

  2. RECURRENT LARYNGEAL NERVE — TRANSTRACHEAL BLOCK
     ├── Identify cricothyroid membrane
     ├── Insert 22G needle in midline
     ├── Aspirate air to confirm tracheal placement
     ├── Inject 4 mL of 4% Lignocaine rapidly at END EXPIRATION
     └── Cough reflex spreads local anaesthetic
     Blocks: Subglottis, vocal cords (from below), trachea

  3. TOPICAL ANAESTHESIA — Spray-as-you-go (SAYGO)
     ├── Via working channel of fibreoptic scope
     ├── Lignocaine 4% or 10% spray
     └── Applied to tongue, oropharynx, epiglottis, cords

• Dexmedetomidine infusion (0.3–1 mcg/kg/hr) — provides sedation without apnoea
• Midazolam 1–2 mg IV
• Remifentanil TCI (0.5–2 ng/mL)

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Part (b): Types of Laryngoscope Blades + McCoy Laryngoscope (5 Marks)

Types of Laryngoscope Blades

The McCoy Laryngoscope — Special Features

• Modified curved Macintosh blade
• Hinged, articulating tip — controlled by a lever mechanism at the handle
• Lever elevates the distal 1/3 of the blade (the tip) upward by up to 70°

DIAGRAM — McCoy Mechanism:

Standard Macintosh:
   Handle → Fixed blade → [TIP fixed]
   
McCoy:
   Handle → Blade → [Articulating TIP ↑]
              ↑
         LEVER on handle
         (Thumb-operated)

• Provides indirect upward displacement of the epiglottis without increasing force on the upper teeth
• Improves Cormack-Lehane grade from Grade 3 to Grade 2 or better in ~80% of cases
• Reduces the need for external laryngeal manipulation (BURP/OELM)
• Reduced cervical spine movement — preferred in patients with restricted neck mobility, cervical spondylosis, cervical collar fixation
• Less hemodynamic response than increased force intubation
• Lower force of laryngoscopy → less dental trauma, mucosal injury

• Predicted or encountered difficult laryngoscopy
• Cervical spine injury/limitation
• Obese patients (reducing need for extra blade length)
• Grade 3 laryngoscopic view on standard laryngoscopy

• Tip articulation may push epiglottis down (if too far anterior or in patients with large floppy epiglottis)
• Not a substitute for video laryngoscopy in truly failed airway

Potential Exam Questions — Q2

1. Draw and label the nerve supply of the larynx.
2. Describe the technique of transtracheal block for AFOI.
3. What is the Cormack-Lehane grading of laryngoscopic view?
4. How does the McCoy differ from a standard Macintosh blade mechanically?
5. Name the only abductor of the vocal cords.
6. What are the differences between Miller and Macintosh blades?
7. What is the maximum safe dose of lignocaine for airway topicalisation?

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QUESTION 3 (10 Marks) — Clinical Physiology & Monitoring

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Part (a): Capnography — Principle + Labelled Time Capnogram (6 Marks)

Principle of Capnography

• Capnography: continuous, real-time measurement and graphical display of CO₂ concentration in expired gases
• Principle: Infrared Absorption Spectrophotometry — CO₂ absorbs infrared radiation at wavelength 4.26 µm
• Beer-Lambert Law: Absorbance proportional to CO₂ concentration
• Two types:
  • Mainstream: sensor placed directly in breathing circuit (fast response, no water trap needed)
  • Sidestream: gas aspirated via side port to remote analyser (small lumen, can clog with secretions, slight delay)

Normal ETCO₂ Values

• Normal ETCO₂ = 35–45 mmHg
• Arterial–ETCO₂ gradient (PaCO₂ − PETCO₂) = 2–5 mmHg (ETCO₂ slightly lower due to dead space)

The Time Capnogram — Phases (LABELLED)

LABELLED TIME CAPNOGRAM:

CO₂ (mmHg)
   │
45 │         ___C_____D
   │        /         \
   │       /           \
   │      /B            \E
   │_____/               \________
   │  A                   A'
   └──────────────────────────────▶ Time

PHASES:
  A  → Baseline (0 mmHg): Inspiratory phase — CO₂-free gas enters
  A→B → Phase I: Expiration begins — anatomical dead space gas (no CO₂)
  B→C → Phase II (α angle): Rising slope — mixing of dead space + alveolar gas; exhalation of early alveolar air
  C→D → Phase III (Alveolar Plateau): Flat plateau — pure alveolar gas; ETCO₂ measured at point D
  D   → Point D = Peak ETCO₂ (End-Tidal CO₂ = ETCO₂) — best approximation of alveolar PCO₂
  D→E → Phase IV (Descending slope): Rapid fall — inspiration begins, CO₂-free gas dilutes alveolar gas

KEY ANGLES:
  α (alpha angle): between Phase II and Plateau — steep in obstructive disease
  β (beta angle): between plateau and downstroke (inspiration) — normally ~90°
  Normally: rectangular waveform

Abnormal Capnograms and Clinical Significance

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Part (b): The Oxygen Cascade + Clinical Significance of P(A-a)O₂ (4 Marks)

The Oxygen Cascade

OXYGEN CASCADE — Step-by-step descent from atmosphere to mitochondria:

  ATMOSPHERIC AIR
  PO₂ = 160 mmHg (FiO₂ 0.21 × 760 mmHg)
         ↓ (humidification — water vapour 47 mmHg at 37°C)

  TRACHEA/CONDUCTING AIRWAYS
  PO₂ = 150 mmHg [PiO₂ = FiO₂ × (Patm − 47)]
         ↓ (dilution with alveolar CO₂ + gas mixing)

  ALVEOLAR GAS
  PAO₂ = 100–105 mmHg
  [Alveolar Gas Equation: PAO₂ = PiO₂ − (PaCO₂/RQ)]
  [= 150 − (40/0.8) = 150 − 50 = 100 mmHg]
         ↓ (V/Q mismatch + diffusion + shunt)

  ARTERIAL BLOOD
  PaO₂ = 90–95 mmHg (P(A-a)O₂ gradient here)
         ↓ (capillary shunting, Hb-O₂ binding)

  CAPILLARY/VENOUS BLOOD
  PvO₂ = 40 mmHg (mixed venous)
         ↓

  INTRACELLULAR / MITOCHONDRIA
  PO₂ = 2–20 mmHg (varies by metabolic rate)
         ↓
  Cytochrome oxidase PO₂ threshold = ~0.1 mmHg

The Alveolar Gas Equation

PAO₂ = FiO₂ × (Patm − PH₂O) − (PaCO₂ / RQ) PAO₂ = FiO₂ × (760 − 47) − (PaCO₂ / 0.8)

P(A-a)O₂ Gradient — Clinical Significance

• Young adults (room air): 5–15 mmHg
• Approximate normal = Age/4 + 4 (on room air, upright)
• On 100% O₂: up to 100 mmHg (acceptable)

• Hypoventilation: PaCO₂ ↑, PAO₂ ↓, but P(A-a) normal — distinguishes pure hypoventilation from V/Q mismatch
• High altitude: Low PiO₂, low PAO₂, but P(A-a) normal

Potential Exam Questions — Q3

1. What is the alveolar gas equation and what does each term represent?
2. Label all phases of a normal capnogram and describe what occurs physiologically in each.
3. What does a "shark-fin" capnogram indicate?
4. Distinguish between mainstream and sidestream capnography.
5. What is the clinical significance of a widening A-a gradient?
6. What is the normal P(A-a)O₂ on room air in a 40-year-old?
7. How does ETCO₂ change during pulmonary embolism and why?

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QUESTION 4 (10 Marks) — Pediatric & Geriatric Anesthesia

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Part (a): Pediatric vs. Adult Airway — Anatomical Differences & Anaesthetic Implications (5 Marks)

Comparative Anatomy Table

ETT Size Formulas (Paediatric)

• Uncuffed: (Age/4) + 4 mm
• Cuffed: (Age/4) + 3.5 mm
• Oral length: (Age/2) + 12 cm
• Nasal length: (Age/2) + 15 cm

Flowchart: Anaesthetic Implications

LARGE OCCIPUT
      → Pad under shoulders → sniffing position for intubation

LARGE TONGUE + HIGH ANTERIOR LARYNX
      → Use Miller blade (size 0 neonate, size 1 infant)
      → Straight blade lifts floppy epiglottis directly

SUBGLOTTIC NARROWEST POINT
      → Air leak at 20–25 cmH₂O with ETT (uncuffed)
      → ETT 0.5 mm smaller if resistance
      → Laryngeal subglottic oedema → critical obstruction

SHORT TRACHEA
      → Fix ETT securely
      → Check bilateral air entry after any position change
      → Bilateral auscultation mandatory post-intubation

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Part (b): Physiological Changes in Geriatric Patients — Impact on Regional Anaesthesia (5 Marks)

System-wise Physiological Changes

Practical Implications for Regional Technique

• Reduce dose by 20–30% (e.g., heavy bupivacaine 7.5–10 mg instead of 12.5 mg for spinal in elderly)
• Anticipate higher block level — position carefully
• Block onset faster, duration longer
• Pre-hydration cautiously (cardiac reserve ↓)
• Have vasopressors ready (ephedrine or phenylephrine)

• Reduce volume — fibrous epidural space restricts spread predictably in some but unpredictably in others
• Reduce concentration to avoid dense motor block (↑ fall risk)
• Slow, titrated dosing

• Bupivacaine: ↑ cardiac toxicity in elderly (↓ threshold) → use levobupivacaine or ropivacaine
• Adjuvants: Low-dose fentanyl (0.5–1 mcg/mL) opioid-sparing
• Avoid hyperbaric bupivacaine large doses (fixed spread unpredictable)

Potential Exam Questions — Q4

1. What is the narrowest part of the paediatric airway and why is it clinically significant?
2. Why is a straight laryngoscope blade preferred in neonates?
3. Calculate the ETT size and oral fixation length for a 4-year-old child.
4. Why does spinal anaesthesia spread more in elderly patients?
5. What anatomical changes in the spine of the elderly make epidural placement technically challenging?
6. How does ageing affect the pharmacokinetics of local anaesthetics?
7. What formula approximates normal P(A-a) gradient with age?

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QUESTION 5 (10 Marks) — Critical Care & Pain

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Part (a): ARDS — Pathophysiology + Lung-Protective Ventilation (6 Marks)

Berlin Definition (2012) of ARDS

Pathophysiology of ARDS

PATHOPHYSIOLOGY FLOWCHART:

DIRECT INJURY (Pneumonia, aspiration, inhalation)
INDIRECT INJURY (Sepsis, pancreatitis, transfusion – TRALI)
              ↓
Activation of macrophages, neutrophils, release of IL-1β, IL-8, TNF-α
              ↓
Endothelial and Epithelial (Type I pneumocyte) INJURY
              ↓
↑ Alveolar-capillary permeability
              ↓
EXUDATIVE PHASE (0–7 days):
• Protein-rich oedema floods alveoli
• Hyaline membrane formation
• Type II pneumocyte hyperplasia (attempts repair)
• Surfactant loss → ↑ surface tension → alveolar collapse
• Intrapulmonary shunt ↑ → Refractory hypoxaemia
              ↓
PROLIFERATIVE PHASE (7–21 days):
• Fibroblast proliferation
• Resolution of oedema (partial)
• Some patients improve, others progress
              ↓
FIBROTIC PHASE (>21 days):
• Dense fibrosis
• Stiff, non-compliant lung
• Chronic hypoxia, pulmonary hypertension

Lung-Protective Ventilation Strategy (ARDS Network / ARDSNet Protocol)

Additional Strategies

• Prone Positioning: Recommended for severe ARDS (PF ratio <150) — mortality reduction in PROSEVA trial; improves V/Q matching, recruits dorsal alveoli
• High PEEP strategy: PEEP titration based on best compliance or FiO₂-PEEP tables
• Recruitment manoeuvres: Sustained inflations to 35–40 cmH₂O for 40 sec; controversial — risk of haemodynamic instability
• Neuromuscular blockade: Cisatracurium infusion (ACURASYS trial: suggested 48-hr NMB benefit for PF<150; ROSE trial questioned this — current evidence mixed)
• Fluid management: Conservative after resuscitation (FACTT trial: conservative = more ventilator-free days)
• Corticosteroids: Methylprednisolone in early/moderate-severe ARDS (COVIDSteroid-2 / Meduri regimen)
• NO inhaled / Almitrine: Selective pulmonary vasodilator for refractory hypoxaemia (bridge to ECMO)
• ECMO: Veno-venous ECMO for refractory ARDS (PF < 80, pH < 7.25 despite optimal ventilation) — EOLIA trial

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Part (b): Brain Death — Definition, Diagnosis & Certification (4 Marks)

Definition

• Death by Neurological Criteria (DNC) / Brain Death = irreversible cessation of all functions of the entire brain, including the brainstem (Adams and Victor's Neurology, 12e; Miller's Anesthesia, 10e)
• Legally, ethically, and morally equivalent to biological death
• Harvard Committee Criteria (1968) → AAN Guidelines (2010, updated 2023)

Prerequisites (Must ALL be met before formal testing)

• Irreversible and proximate cause of coma established (neuroimaging, clinical history)
• Exclude confounders:
  • Drug/metabolic: No sedatives, opioids, neuromuscular blocking agents (confirmed by train-of-four × 4); screen for drug levels
  • Temperature: Core temperature >36°C (normothermia)
  • Haemodynamics: Systolic BP ≥100 mmHg
  • Metabolic: Correct severe acidosis, electrolyte, endocrine disturbance
  • Hypothermia (<36°C must be corrected before testing)

Clinical Examination (3 Cardinal Components)

BRAIN DEATH CLINICAL CRITERIA — FLOWCHART:

PREREQUISITE MET?
       ↓ YES
1. ABSENCE OF ALL CEREBRAL FUNCTIONS
   • No purposeful response to noxious stimuli
   • No response to verbal commands
   • Only spinal reflexes may remain (acceptable — they are not brain-mediated)

       ↓
2. ABSENCE OF ALL BRAINSTEM REFLEXES
   • Pupillary reflex: Fixed, unreactive to light (mydriasis; >4 mm bilateral)
   • Corneal reflex: No blink to cotton wool
   • Oculocephalic (Doll's eyes): No conjugate eye movement with head rotation
   • Oculovestibular: No nystagmus after 50 mL ice water injection into each ear (30 min apart)
   • Gag reflex: No gag to pharyngeal stimulation
   • Cough reflex: No cough to deep tracheal suctioning
   • Facial pain: No grimace to supraorbital pressure

       ↓
3. APNOEA TEST (KEY)
   • Pre-oxygenate: 100% O₂ for 10 min → PaO₂ >200 mmHg
   • Baseline ABG: PaCO₂ 35–45 mmHg; pH, SpO₂
   • Disconnect ventilator; deliver passive O₂ via catheter at 6 L/min
   • Observe chest wall for 8–10 minutes
   • Repeat ABG: PaCO₂ must rise to ≥60 mmHg (or ≥20 mmHg above baseline)
   • NO respiratory effort = POSITIVE apnoea test (supports brain death)
   • Abort if: SpO₂ <85%, arrhythmia, haemodynamic instability
   
       ↓
   TWO EXAMINATIONS by two independent senior physicians
   (At least one should be a Neurologist or Neurosurgeon in India)
   Time interval between examinations: 6 hours (adults); 24 hours (neonates)

Ancillary / Confirmatory Tests (if clinical exam inconclusive)

Indian Regulations (Transplantation of Human Organs Act, THOA 1994, amended 2011)

• Brain Stem Death (not whole brain death) is the accepted legal criterion in India
• Certification requires a panel of 4 doctors:
  1. Medical Officer In-Charge of the Hospital
  2. An authorized Medical Officer (appointed by appropriate authority)
  3. A Neurologist / Neurosurgeon
  4. The treating physician / surgeon
• All 4 must sign Form 10 (certification of brain stem death)
• Two sets of tests: 6 hours apart
• Organ donation can proceed only after legal certification

Spinal Reflexes Compatible with Brain Death (DO NOT invalidate diagnosis)

• Limb withdrawal to stimulation
• Babinski sign
• Deep tendon reflexes
• Lazarus sign (complex limb movements due to spinal cord activity)

Potential Exam Questions — Q5

1. What are the Berlin criteria for ARDS classification?
2. Why is tidal volume limited to 4–6 mL/kg IBW in ARDS?
3. What is driving pressure and why is it considered the best ventilatory predictor of mortality in ARDS?
4. What is the PROSEVA trial and what did it demonstrate?
5. Define brain death. How does it differ from persistent vegetative state (PVS)?
6. Describe the apnoea test — procedure, criteria for positive result, and when to abort.
7. What are the legal requirements for brain death certification in India (THOA)?
8. Name four ancillary tests for brain death and their findings.
9. Can spinal reflexes (Lazarus sign) invalidate a brain death diagnosis? Explain.
10. What temperature, blood pressure, and drug-clearance criteria must be met before brain death testing?

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Supplementary: Cross-Cutting High-Yield Summary

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Summary of What's Included

Q1 — Mitral Stenosis in Pregnancy (10 marks)

• Complete pathophysiology cascade (preload/HR/CO interactions), haemodynamic goals table, MDT planning, preferred anaesthetic technique (slow epidural > CSE > GA with rationale), vasopressor choice (phenylephrine), oxytocin dangers, postoperative HDU care

Q2 — Airway Anatomy & Equipment (10 marks)

• Labelled larynx diagrams (cross-section image + ASCII anterior view), full nerve supply table, step-by-step nerve block flowchart for AFOI (SLN block + transtracheal + SAYGO topicalisation), all laryngoscope blade types in a comparison table, McCoy mechanism diagram with advantages/indications

Q3 — Capnography & Oxygen Cascade (10 marks)

• Infrared absorption principle, fully labelled time capnogram with all phases (A–E) and angles (α, β), abnormal waveform interpretation table, complete Oxygen Cascade step-diagram, Alveolar Gas Equation derivation, P(A-a)O₂ clinical significance with causes

Q4 — Paediatric vs. Geriatric (10 marks)

• Full anatomical comparison table (8 features, implications for each), ETT size formulas, anaesthetic implication flowchart; geriatric changes by system with specific dose reductions and regional technique modifications

Q5 — ARDS & Brain Death (10 marks)

• Berlin criteria table, pathophysiology flowchart (exudative → proliferative → fibrotic phases), ARDS CT + histology image, ARDSNet ventilation parameter table, prone positioning/ECMO/NMB evidence; brain death clinical flowchart (3 cardinal criteria), apnoea test procedure, ancillary tests, India-specific THOA legal requirements (Form 10, 4-doctor panel)