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NEET SS Anaesthesia - Complete Preparation Guide

Exam at a Glance

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Super-Specialty Courses You Are Competing For

1. Cardiac Anaesthesia
2. Neuro Anaesthesia
3. Organ Transplant Anaesthesia & Critical Care
4. Paediatric & Neonatal Anaesthesia

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Topic Weightage Distribution (Based on Past 5 Years)

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High-Yield Topic List (Category-Wise)

1. Airway Management (10-12%)

• ASA and DAS difficult airway algorithms
• Video laryngoscopy, fibreoptic bronchoscopy
• Rapid Sequence Induction (RSI) - agents, timing, cricoid pressure controversy
• Supraglottic airway devices (LMA types, insertion, limitations)
• Paediatric difficult airway
• Extubation criteria and awake extubation strategies
• Can't intubate, can't oxygenate (CICO) drill

2. General Anaesthesia & Pharmacology (20-25%)

• IV induction agents: propofol, thiopentone, ketamine, etomidate - mechanisms, contexts
• Volatile agents: MAC values, blood-gas partition coefficients, special properties of desflurane/sevoflurane/isoflurane
• Opioids: fentanyl, morphine, remifentanil, context-sensitive half-time
• Neuromuscular blocking drugs: depolarizing vs non-depolarizing, sugammadex reversal
• Total Intravenous Anaesthesia (TIVA) and target-controlled infusion (TCI)
• Malignant hyperthermia - triggers, management
• Awareness under anaesthesia

3. Regional Anaesthesia (15-20%)

• Spinal anaesthesia: level, dosing, baricity, complications (PDPH, TNS, cauda equina)
• Epidural: anatomy, test dose, top-up, high block management
• Combined spinal-epidural (CSE)
• Brachial plexus blocks (interscalene, supraclavicular, infraclavicular, axillary)
• Femoral nerve, adductor canal, popliteal, sciatic blocks
• Ultrasound-guided regional anaesthesia (USG-based blocks)
• Local anaesthetic systemic toxicity (LAST) - prevention and Intralipid treatment

4. Critical Care (20-22%) - Highest Priority

• Mechanical ventilation: modes (CMV, SIMV, PS, PRVC), lung-protective strategy
• ARDS: Berlin definition, prone ventilation, PEEP optimization
• Hemodynamic monitoring: arterial lines, CVP, PA catheter, cardiac output methods
• Shock: types, management, vasopressors (norepinephrine, vasopressin, dopamine)
• Sepsis & septic shock: Surviving Sepsis Campaign 2021 guidelines
• ABG interpretation: metabolic/respiratory acidosis/alkalosis, compensation
• Weaning from ventilator: SBT, RSBI
• Sedation and analgesia in ICU: sedation scales (RASS), SAT/SBT protocol
• Renal replacement therapy (CRRT vs IHD)
• Nutrition in ICU - enteral vs parenteral

5. System-Specific Anaesthesia

• Anaesthesia for CABG, valve surgery - goals per lesion (stenosis vs regurgitation)
• TEE interpretation basics
• Cardiopulmonary bypass management
• Off-pump CABG

• ICP physiology, Monro-Kellie doctrine
• Anaesthesia for craniotomy, sitting position
• Cerebral protection strategies
• Anaesthesia for carotid endarterectomy

• Physiological changes in pregnancy
• Spinal for LSCS, epidural for labour
• Pre-eclampsia/eclampsia management
• Difficult airway in obstetrics, Mendelson's syndrome
• Neonatal resuscitation

• Differences from adult airway and physiology
• Paediatric drug dosing, fluid management
• Anaesthesia for congenital heart disease

• Drug modifications in liver failure, renal failure
• Anaesthesia for liver transplant, renal transplant

6. Equipment & Monitoring (8-10%)

• Anaesthetic machine components, vaporizers, breathing circuits
• Capnography waveform interpretation
• Pulse oximetry physics, limitations
• BIS monitoring, depth of anaesthesia
• Nerve stimulators, train-of-four (TOF) interpretation
• Temperature monitoring and hypothermia prevention

7. Pain Management (8-10%)

• WHO analgesic ladder
• Multimodal analgesia - NSAIDs, paracetamol, gabapentinoids
• Chronic pain syndromes: CRPS, phantom limb
• Epidural analgesia for postoperative pain
• Interventional pain procedures

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Recommended Study Plan

3-Month Structured Plan

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Recommended Resources

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Exam Day Strategy

• Aim to attempt all 150 questions - do not leave unknowns unmarked if you can eliminate 1-2 options
• Negative marking is -1 (not -1/4), so avoid random guessing
• Clinical scenario questions: look for the single best answer, not technically perfect answers
• Time management: 1 minute per question strictly; flag and return to doubtful ones

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Quick Priority Ranking (What to Study First if Time is Short)

1. Critical care (ventilation + shock + sepsis) - highest question density
2. Airway algorithms (ASA/DAS) - frequently tested, finite number of facts
3. Pharmacology of common anaesthetic agents - very high yield
4. Regional anaesthesia complications and management
5. Obstetric anaesthesia emergencies
6. System-specific anaesthesia (cardiac > neuro > paediatric)

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50 High-Yield NEET SS Anaesthesia MCQs

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SECTION A: INHALATIONAL AGENTS & MAC (Q1-8)

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• A) 95% of patients
• B) 50% of patients
• C) 70% of patients
• D) 99% of patients

Answer: B MAC = ED50 - prevents movement in 50% of subjects. MAC-awake (~0.3 MAC) prevents response to verbal commands in 50%. MAC-BAR (~1.7 MAC) blocks adrenergic response in 50%. Miller's Anesthesia, 10e

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• A) Desflurane (0.45)
• B) Sevoflurane (0.65)
• C) Isoflurane (1.4)
• D) Halothane (2.4)

Answer: D Higher blood-gas partition coefficient = more soluble = slower induction and emergence. Halothane (2.4) > Isoflurane (1.4) > Sevoflurane (0.65) > Desflurane (0.45) > N2O (0.47). Desflurane and N2O are closest, allowing fastest wash-in/wash-out. Morgan & Mikhail's, 7e

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• A) Increasing age
• B) Hypothermia
• C) Chronic alcohol use
• D) Acute alcohol intoxication

Answer: C Chronic alcohol use INCREASES MAC (tolerance/cross-tolerance). Acute alcohol intoxication, increasing age, hypothermia, pregnancy, opioids, alpha-2 agonists, and hypoxia all DECREASE MAC. Morgan & Mikhail's, 7e

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• A) High MAC (6-7%)
• B) Pungency causing airway irritation and laryngospasm
• C) Requires heated vaporizer
• D) All of the above

Answer: D Desflurane (MAC 6-7%) is pungent and causes coughing, laryngospasm, and bronchospasm on inhalational induction. It also boils at room temperature requiring a special heated, pressurized vaporizer (Tec6). Sevoflurane is preferred for inhalational induction. Miller's Anesthesia, 10e

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• A) Desflurane - direct tubular toxicity
• B) Sevoflurane - Compound A formation
• C) Isoflurane - inorganic fluoride
• D) Halothane - hepatotoxicity

Answer: B Sevoflurane reacts with soda lime to produce Compound A (fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether), which is nephrotoxic in rats. Clinically significant nephrotoxicity in humans is controversial, but fresh gas flows >2 L/min are recommended. Inorganic fluoride from metabolism was the older concern with methoxyflurane. Barash's Clinical Anesthesia, 9e

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• A) Boiling point
• B) Oil-gas partition coefficient (lipid solubility)
• C) Molecular weight
• D) Blood-gas partition coefficient

Answer: B The Meyer-Overton hypothesis (lipid theory): anaesthetic potency correlates with lipid solubility (oil-gas partition coefficient). Agents that dissolve more readily in lipid membranes are more potent - hence MAC and oil-gas coefficient are inversely related. Morgan & Mikhail's, 7e

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• A) Sevoflurane
• B) Isoflurane
• C) Desflurane
• D) Halothane

Answer: C Desflurane > Enflurane > Isoflurane produce CO with dry soda lime (baralyme > soda lime). Halothane and sevoflurane produce negligible CO. This is a concern when the circuit has been left dry (e.g., weekend/Monday morning cases). Miller's Anesthesia, 10e

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• A) Same
• B) 10% lower
• C) 20-30% lower
• D) 50% lower

Answer: C MAC decreases ~6% per decade after age 40. A 70-year-old has roughly 20-30% lower MAC than a 40-year-old. Neonates have the lowest MAC for sevoflurane (~3.3%) which rises to peak in infants (~3.2%) then declines with age. Barash's Clinical Anesthesia, 9e

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SECTION B: IV INDUCTION AGENTS & PHARMACOLOGY (Q9-16)

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• A) Propofol
• B) Thiopentone
• C) Ketamine
• D) Etomidate

Answer: D Etomidate causes minimal cardiovascular depression (most haemodynamically stable induction agent). However, it causes adrenal suppression (inhibits 11-beta-hydroxylase) so a single induction dose is preferred over infusion. Ketamine is also acceptable in trauma but increases HR and BP via sympathomimetic effects - may be detrimental in catecholamine-depleted patients. Barash's Clinical Anesthesia, 9e

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• A) Metabolic acidosis
• B) Rhabdomyolysis
• C) Hepatomegaly
• D) Hyperglycaemia

Answer: D PRIS features: metabolic acidosis (lactic), cardiac failure (new LBBB or ST changes), rhabdomyolysis, hyperkalemia, hypertriglyceridemia, hepatomegaly/hepatic steatosis, and renal failure. Hyperglycaemia is NOT a feature. Risk factors: high doses (>4 mg/kg/hr), prolonged infusion (>48h), carbohydrate depletion, high fat intake. Miller's Anesthesia, 10e

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• A) GABA-A receptor agonism
• B) NMDA receptor antagonism
• C) Opioid receptor agonism
• D) Alpha-2 adrenoceptor agonism

Answer: B Ketamine is a non-competitive NMDA (N-methyl-D-aspartate) receptor antagonist. It dissociates the thalamo-neocortical system. It also has weak opioid, muscarinic, monoaminergic, and local anaesthetic actions. Benzodiazepines and propofol work at GABA-A; dexmedetomidine at alpha-2.

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• A) Remifentanil is much longer
• B) Both are similar
• C) Remifentanil is much shorter
• D) Remifentanil is slightly longer

Answer: C Remifentanil is metabolised by non-specific plasma and tissue esterases - context-sensitive half-time remains ~3-5 minutes regardless of infusion duration. Fentanyl's context-sensitive half-time increases dramatically with infusion duration (>200 min after 4 hours). This makes remifentanil ideal for TIVA and short procedures. Morgan & Mikhail's, 7e

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• A) Inhibiting acetylcholinesterase
• B) Encapsulating aminosteroid NMBDs in a modified gamma-cyclodextrin ring
• C) Competing at nicotinic receptors
• D) Activating muscarinic receptors

Answer: B Sugammadex is a modified gamma-cyclodextrin that forms a tight 1:1 inclusion complex with rocuronium (and vecuronium to a lesser extent). It does NOT work on succinylcholine or benzylisoquinolines (atracurium, cisatracurium, mivacurium). No need for anticholinergics (atropine/glycopyrrolate) as there is no cholinergic effect. Miller's Anesthesia, 10e

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• A) Rocuronium
• B) Atracurium
• C) Succinylcholine
• D) Mivacurium

Answer: C Succinylcholine is the only depolarizing NMBD. It causes phase I (depolarizing, fasciculations, no TOF fade) then phase II block (resembles non-depolarizing) with large/repeated doses. Onset: 60 seconds; duration: 10-15 min. Absolute contraindication: burns, denervation, prolonged immobility (risk of hyperkalemia).

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• A) Blocking the acetylcholine receptor
• B) Blocking ryanodine receptor (RYR1) - preventing Ca²⁺ release from SR
• C) Blocking voltage-gated Ca²⁺ channels on sarcolemma
• D) Increasing hepatic Ca²⁺ uptake

Answer: B Malignant hyperthermia is a pharmacogenetic disorder of skeletal muscle Ca²⁺ regulation (RYR1 mutation). Triggering agents (succinylcholine, volatile agents except N2O/xenon) cause uncontrolled Ca²⁺ release from SR. Dantrolene blocks RYR1, reducing Ca²⁺ release. Dose: 2.5 mg/kg IV, repeat every 5-10 min up to 10 mg/kg. Katzung Pharmacology, 16e

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• A) Morphine
• B) Pethidine (meperidine)
• C) Fentanyl
• D) Codeine

Answer: C Fentanyl is primarily hepatically metabolised to inactive metabolites - safe in renal failure. Morphine accumulates active metabolite M6G (morphine-6-glucuronide) causing prolonged respiratory depression. Pethidine accumulates norpethidine (normeperidine) causing seizures. Codeine's active metabolite also accumulates.

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SECTION C: AIRWAY MANAGEMENT (Q17-22)

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• A) Mallampati class III/IV
• B) Reduced thyromental distance
• C) Presence of a beard
• D) BMI >35

Answer: C The MOANS mnemonic for difficult mask ventilation: Mask seal (beard, facial trauma), Obesity/Obstruction, Age >55, No teeth, Stiffness (COPD, asthma). A beard is the single most reliable predictor because it prevents an airtight mask seal. This is testable because it's counterintuitive given the focus on Mallampati.

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• A) LMA insertion
• B) Retrograde intubation
• C) Emergency front-of-neck access (surgical cricothyrotomy)
• D) Awake fibreoptic intubation

Answer: C In a CICO scenario (failed intubation + failed oxygenation), emergency front-of-neck access (FONA) - surgical cricothyrotomy - is the definitive airway. Needle cricothyrotomy can provide temporary oxygenation but is a bridge only. The DAS (Difficult Airway Society) 2015 guidelines and ASA algorithm both mandate this sequence. Barash's Clinical Anesthesia, 9e

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• A) 0.5 mg/kg
• B) 1.0-1.5 mg/kg
• C) 2.0 mg/kg
• D) 0.3 mg/kg

Answer: B Succinylcholine 1.0-1.5 mg/kg IV provides intubating conditions in ~60 seconds. In obese patients, dosing is by total body weight. For RSI in children: 2 mg/kg (infants/children require higher doses due to larger volume of distribution). Rocuronium 1.2 mg/kg is the alternative for RSI when succinylcholine is contraindicated. Miller's Anesthesia, 10e

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• A) RSI with succinylcholine and direct laryngoscopy
• B) Awake fibreoptic intubation
• C) Video laryngoscopy under general anaesthesia
• D) Blind nasal intubation

Answer: B Awake fibreoptic intubation (AFOI) is the gold standard for anticipated difficult airway with cervical spine instability because: (1) the patient maintains their own airway, (2) neurological status can be monitored, (3) minimal neck movement required, (4) allows post-intubation neurological assessment.

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• A) Larynx at the level of the epiglottis
• B) Oesophagus by compression between cricoid cartilage and C6 vertebra
• C) Trachea at the subglottic level
• D) Pharynx

Answer: B Cricoid pressure compresses the cervical oesophagus between the cricoid cartilage (the only complete cartilaginous ring) and the C6 vertebral body, preventing regurgitation and aspiration. Force: 30-44 N in awake patients. Controversy exists about efficacy - BURP (Backwards, Upwards, Rightwards Pressure) is for improving laryngoscopic view, not aspiration prevention.

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• A) Chest rise bilaterally
• B) Condensation in tube
• C) End-tidal CO2 waveform (capnography)
• D) Auscultation of breath sounds

Answer: C Continuous waveform capnography is the gold standard for confirming endotracheal intubation. A persistent CO2 waveform over multiple breaths confirms tracheal placement. Colorimetric CO2 detectors can give false positives (gastric CO2) or false negatives (cardiac arrest/low output). All other signs are unreliable.

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SECTION D: REGIONAL ANAESTHESIA (Q23-29)

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• A) IV morphine
• B) Bed rest and oral hydration only
• C) Caffeine, NSAIDs, paracetamol, and adequate hydration
• D) Epidural blood patch

Answer: C Conservative management for PDPH: caffeine (300-500 mg), simple analgesics (NSAIDs, paracetamol), adequate hydration, and bed rest. Epidural blood patch (15-20 mL autologous blood at the same level) has ~85-90% success and is used when conservative measures fail after 24-48 hours or for severe/disabling PDPH.

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• A) Cardiovascular collapse
• B) Seizures
• C) Circumoral numbness, metallic taste, tinnitus (prodromal CNS signs)
• D) Ventricular fibrillation

Answer: C LAST progression: CNS excitation (circumoral numbness, tinnitus, metallic taste, visual disturbance) → CNS depression (LOC) → cardiovascular (conduction block, arrhythmias, VF). Bupivacaine is most cardiotoxic (due to slow dissociation from Na+ channels - "fast in, slow out"). Treatment: stop injection, 20% Intralipid 1.5 mL/kg bolus + infusion, avoid vasopressin. Barash's Clinical Anesthesia, 9e

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• A) Lignocaine (lidocaine)
• B) Bupivacaine
• C) Mepivacaine
• D) Prilocaine

Answer: B Duration of action: Bupivacaine (~4-12 hours for nerve block) > Ropivacaine > Mepivacaine > Lignocaine (1-2 hours). Bupivacaine pKa = 8.1, protein binding = 95%, lipid soluble. Ropivacaine has similar duration but is less cardiotoxic (S-enantiomer only) and less motor blockade.

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• A) T6
• B) T4
• C) T10
• D) T8

Answer: B For LSCS, spinal block must reach T4 (nipple line) to prevent peritoneal pain and visceral traction discomfort. T10 is sufficient for labour pain. T6 is for upper abdominal surgery. The key concept: peritoneum is innervated by T4-T6, so LSCS requires T4 level.

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• A) Loss of resistance to saline or air
• B) Paraesthesia on needle advancement
• C) Blood in the syringe
• D) Hanging drop sign

Answer: A Loss of resistance (LOR) - to either saline or air - is the standard method to identify the epidural space as the needle passes through the ligamentum flavum. Hanging drop sign (epidural negative pressure) is unreliable. Paraesthesia indicates dural puncture risk. Both LOR to saline and air are used; LOR to saline is preferred (air can cause patchy block or pneumocephalus).

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• A) Bupivacaine
• B) Hyperbaric lignocaine (lidocaine)
• C) Ropivacaine
• D) Levobupivacaine

Answer: B TNS (transient neurological symptoms) - buttock/leg pain resolving within 72 hours - is most associated with hyperbaric lignocaine 5%, especially in the lithotomy position. Incidence: up to 30% with lignocaine vs <1% with bupivacaine. Mechanism unclear - possibly direct neurotoxicity from pooling of hyperbaric solution.

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• A) Axillary
• B) Infraclavicular
• C) Supraclavicular
• D) Interscalene

Answer: C Supraclavicular block has the highest risk of pneumothorax (~0.5-6% without ultrasound guidance) because the apex of the lung is in close proximity to the block site. Interscalene blocks the musculocutaneous nerve but misses ulnar nerve (C8-T1); causes ipsilateral hemidiaphragm paralysis (phrenic nerve) in 100% of cases.

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SECTION E: CRITICAL CARE & MECHANICAL VENTILATION (Q30-38)

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• A) >300
• B) 200-300 (mild)
• C) 100-200
• D) <100

Answer: C Berlin 2012 ARDS definition:

• Mild: PaO2/FiO2 200-300 with PEEP ≥5 cmH2O
• Moderate: PaO2/FiO2 100-200 with PEEP ≥5 cmH2O
• Severe: PaO2/FiO2 <100 with PEEP ≥5 cmH2O Additional criteria: bilateral infiltrates, non-cardiac origin, onset within 7 days of known insult. Miller's Anesthesia, 10e

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• A) 10-12 mL/kg ideal body weight
• B) 8 mL/kg ideal body weight
• C) 6 mL/kg ideal body weight
• D) 4 mL/kg ideal body weight

Answer: C ARDSNet (ARMA) trial: 6 mL/kg predicted (ideal) body weight with plateau pressure ≤30 cmH2O reduced mortality from 40% to 31% vs 12 mL/kg. Driving pressure (Plateau - PEEP) should be <15 cmH2O. This is the most-tested critical care fact in NEET SS Anaesthesia. Miller's Anesthesia, 10e

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• A) Dopamine
• B) Adrenaline (epinephrine)
• C) Norepinephrine (noradrenaline)
• D) Vasopressin

Answer: C Norepinephrine is the first-line vasopressor in septic shock (Surviving Sepsis Campaign 2021 guidelines). Target MAP ≥65 mmHg. Vasopressin (0.03-0.04 units/min) is added as a second agent to reduce norepinephrine dose. Adrenaline is third-line or used in anaphylaxis. Dopamine is associated with higher arrhythmia rates and is NOT preferred.

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• A) RSBI <80
• B) RSBI <100
• C) RSBI <105
• D) RSBI >105

Answer: C RSBI = Respiratory rate / Tidal volume (L). RSBI <105 breaths/min/L predicts successful extubation. Values <80 are very predictive of success; >105 predicts failure. Used during spontaneous breathing trial (SBT) of 30-120 minutes to assess readiness for extubation.

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• A) Reduced lung compliance (ARDS)
• B) Increased airway resistance (bronchospasm, kinked ETT, secretions)
• C) Auto-PEEP
• D) Pneumothorax

Answer: B Peak pressure reflects both resistance and compliance; plateau pressure (measured at zero flow) reflects only lung/chest wall compliance. High peak with normal plateau = increased airway resistance (bronchospasm, secretions, kinked tube, biting ETT). High peak AND high plateau = reduced compliance (ARDS, pneumothorax, pulmonary oedema, abdominal compartment syndrome).

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• A) pH 7.25, pCO2 55, HCO3 24
• B) pH 7.52, pCO2 28, HCO3 22
• C) pH 7.30, pCO2 40, HCO3 15
• D) pH 7.45, pCO2 40, HCO3 28

Answer: B Hyperventilation causes respiratory alkalosis: high pH, low pCO2, normal-to-slightly-low HCO3 (acute - minimal renal compensation). Option A = respiratory acidosis; Option C = metabolic acidosis (normal anion gap or high); Option D = compensated metabolic alkalosis.

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• A) Cardiac dysfunction (left ventricular failure)
• B) Respiratory muscle weakness
• C) Excessive secretions
• D) Anxiety and agitation

Answer: A Weaning failure is most commonly due to cardiac dysfunction - weaning increases cardiac workload (spontaneous breathing increases venous return and afterload). Patients with underlying LV dysfunction may develop flash pulmonary oedema on spontaneous breathing trial. B-type natriuretic peptide (BNP) can help diagnose cardiac causes of weaning failure.

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• A) Glasgow Coma Scale (GCS)
• B) Richmond Agitation-Sedation Scale (RASS)
• C) Ramsay Sedation Scale
• D) Modified Observer's Assessment of Alertness/Sedation (MOAAS)

Answer: B RASS (Richmond Agitation-Sedation Scale) is the most validated and widely used. Score range: -5 (unarousable) to +4 (combative). Target for most ICU patients: RASS -2 to 0 (light sedation). The ABCDE bundle (SAT/SBT - spontaneous awakening + breathing trials) uses RASS-guided daily sedation interruption to improve outcomes.

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• A) Reducing anatomical dead space
• B) Redistributing ventilation to previously dependent (dorsal) lung regions
• C) Increasing FRC
• D) Reducing hypoxic pulmonary vasoconstriction

Answer: B In supine ARDS, dorsal (dependent) lung regions are atelectatic and perfused (shunt). Prone positioning redistributes ventilation to these well-perfused dorsal regions, improving V/Q matching. PROSEVA trial (2013) showed 28-day mortality benefit with prone positioning ≥16 hours/day in severe ARDS (PaO2/FiO2 <150).

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SECTION F: OBSTETRIC ANAESTHESIA (Q39-43)

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• A) Post-dural puncture headache
• B) Bronchospasm
• C) Pulmonary aspiration of gastric contents (Mendelson's syndrome)
• D) Endobronchial intubation

Answer: C Mendelson's syndrome (acid aspiration) is the most feared complication. Pregnancy causes: decreased lower oesophageal sphincter tone (progesterone), increased intra-abdominal pressure, delayed gastric emptying. Prevention: antacids (sodium citrate 30 mL), H2 blockers (ranitidine), metoclopramide, and RSI with cricoid pressure.

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• A) Head-down tilt (Trendelenburg)
• B) Left lateral tilt of 15° (left uterine displacement)
• C) Sitting position
• D) Right lateral tilt

Answer: B After 20 weeks gestation, the gravid uterus compresses the inferior vena cava (aortocaval compression / supine hypotension syndrome) causing hypotension, fetal hypoxia. Prevention: left lateral tilt of 15-20° (wedge under right hip) to displace uterus off IVC. This is standard position for LSCS under spinal.

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• A) IV ephedrine infusion pre-spinal
• B) IV phenylephrine infusion (prophylactic)
• C) IV fluid preloading with 1L crystalloid
• D) Head-down tilt

Answer: B Prophylactic phenylephrine infusion (100 mcg/min) is now the standard of care for preventing spinal hypotension in LSCS (compared to ephedrine). Phenylephrine causes less fetal acidosis than ephedrine and is more effective. Coloading (simultaneous IV fluid during spinal, not preloading) is also recommended. Ephedrine causes fetal tachycardia and acidosis.

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• A) Diazepam
• B) Phenytoin
• C) Magnesium sulphate
• D) Levetiracetam

Answer: C Magnesium sulphate is the drug of choice for eclampsia treatment and severe pre-eclampsia seizure prophylaxis (Collaborative Eclampsia Trial, 1995). Loading dose: 4g IV over 20 min, maintenance 1-2g/hour. Signs of toxicity: loss of patellar reflexes (first sign, Mg ~7-10 mEq/L) → respiratory depression → cardiac arrest. Antidote: calcium gluconate 10 mL of 10%.

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• A) Headache
• B) Hypotension and bradycardia
• C) Respiratory failure (phrenic nerve paralysis at C3-C5)
• D) Nausea/vomiting

Answer: C Total spinal / high spinal block can cause phrenic nerve paralysis (C3-C5) causing respiratory failure requiring immediate airway management (RSI, intubation). Cardiovascular collapse with bradycardia and hypotension also occurs due to high sympathetic block. Management: immediate airway control, vasopressors (ephedrine/epinephrine), atropine for bradycardia.

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SECTION G: CARDIAC & NEURO ANAESTHESIA (Q44-47)

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• A) Maintain sinus rhythm, avoid tachycardia, maintain SVR
• B) Reduce SVR, allow tachycardia
• C) Reduce preload aggressively
• D) Induce hypotension to reduce afterload

Answer: A Severe AS anaesthetic goals: SLOW, FULL, TIGHT - Sinus rhythm (avoid AF, arrhythmias), adequate heart rate (50-70 bpm, avoid tachycardia = reduces filling time), avoid bradycardia, maintain preload (full ventricle), maintain/increase SVR (tight - hypotension is poorly tolerated). Spinal anaesthesia is relatively contraindicated due to sudden SVR drop.

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• A) MAP - CVP
• B) MAP - ICP
• C) SAP - ICP
• D) MAP - PCWP

Answer: B CPP = MAP - ICP (or CVP, whichever is higher). Normal CPP: 60-70 mmHg. Below 50 mmHg: ischaemia. Target in head injury: CPP 60-70 mmHg (BTF guidelines). This requires ICP monitoring for accurate calculation.

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• A) Sevoflurane
• B) Isoflurane
• C) Desflurane
• D) Halothane

Answer: D Halothane causes the greatest increase in CBF (cerebral vasodilation) among inhalational agents - hence most problematic in raised ICP. Order of cerebral vasodilation: Halothane > Enflurane > Isoflurane > Desflurane > Sevoflurane. Sevoflurane has the least effect on CBF and is preferred for neuroanaesthesia. N2O also increases CBF.

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• A) Compression of brain parenchyma
• B) Displacement of CSF to the spinal subarachnoid space
• C) Reduction in cerebral blood volume
• D) Herniation through tentorium

Answer: B Monro-Kellie doctrine: skull is a rigid box; contents (brain ~80%, blood ~10%, CSF ~10%) are incompressible. Initial compensation: CSF displaced to spinal subarachnoid space + some venous blood displacement. Once compliance is exhausted, small volume increases cause rapid ICP rise (decompensation on the ICP-volume curve).

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SECTION H: PAEDIATRIC ANAESTHESIA & EQUIPMENT (Q48-50)

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• A) 4.0 mm
• B) 4.5 mm
• C) 5.0 mm
• D) 5.5 mm

Answer: C Uncuffed ETT size (ID) = (Age/4) + 4. For a 4-year-old: (4/4) + 4 = 5.0 mm. Cuffed ETT = (Age/4) + 3.5, so 4.5 mm for a 4-year-old. Insertion depth (oral) = Age/2 + 12 cm. Cuffed tubes are now recommended even for infants (Microcuff).

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• A) Oesophageal intubation
• B) Obstructive airways disease (bronchospasm/COPD)
• C) Cardiac arrest
• D) Rebreathing of CO2

Answer: B Normal capnography: Phase I (dead space, no CO2) → Phase II (sharp upslope, mixing) → Phase III (alveolar plateau) → Phase 0 (inspiration, drops to zero). In obstructive disease (bronchospasm, COPD, kinked ETT), uneven emptying causes a sloping Phase III ("shark fin" / "upward sloping plateau"), no clear alveolar plateau. Rebreathing: elevated baseline.

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• A) Adequate reversal - safe to extubate
• B) Deep neuromuscular block
• C) Moderate neuromuscular block
• D) 75% of receptors still blocked

Answer: A TOF ratio (T4/T1) of >0.9 is required to ensure adequate neuromuscular recovery for safe extubation (reduced risk of residual paralysis and pulmonary aspiration). A TOF count of 4 without fade can occur with up to 75% receptor occupancy - fade disappears at 70-75%, not full recovery. Quantitative (acceleromyographic) monitoring is mandatory before extubation. Miller's Anesthesia, 10e

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