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20 DNB Anaesthesiology Final Exam Questions (5 Marks Each)

Recent Updates, New Topics & Techniques - NBEMS Pattern

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Q1. Write a note on Remimazolam. (5 marks)

• An ester-based benzodiazepine that acts as a positive allosteric modulator at GABA-A receptors
• Rapidly hydrolysed by tissue carboxylesterase-1 (CES-1) to the inactive metabolite CNS7054
• Minimal accumulation due to organ-independent metabolism

• Onset: 1-3 minutes; Duration: 5-10 minutes per dose
• Metabolism: Plasma esterases (independent of hepatic/renal function)
• No dose adjustment required in hepatic or renal impairment (though effects may be prolonged in severe hepatic impairment)
• Low oral bioavailability; intranasal use under investigation

• Initial bolus: 2.5-5 mg IV
• Supplemental doses: 1.25-2.5 mg as needed
• EU: Initial dose up to 7 mg if no opioid supplementation used

• Less hypotension and vasopressor requirement vs. propofol
• Comparable hemodynamics to midazolam
• Lower respiratory depression vs. midazolam
• Reversible with flumazenil (rarely needed)
• Safe in ASA III/IV patients, elderly, hemodynamically unstable patients

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Q2. Describe Target-Controlled Infusion (TCI). Discuss its pharmacokinetic models and clinical advantages over manual infusion. (5 marks)

• Plasma (Cp): Targets plasma drug concentration
• Effect-site (Ce): Targets the biophase/effect compartment - clinically preferred as it corresponds to drug effect

1. Rapidly achieves and maintains steady-state drug concentration
2. Reduces variability of drug-response relationships
3. Fewer episodes of hypotension, bradycardia, and rigidity on induction
4. Better hemodynamic control (especially in cardiac surgery)
5. Reduced naloxone use for post-operative ventilation
6. Improved awakening times in awake-asleep epilepsy surgery
7. Better respiratory stability in endoscopic procedures
8. Facilitates awake fibreoptic intubation (remifentanil TCI)

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Q3. Discuss Enhanced Recovery After Surgery (ERAS) - principles, components, and anaesthetic implications. (5 marks)

• Patient education and counselling
• Carbohydrate loading up to 2 hours before surgery (clear fluids) - replaces prolonged fasting
• Optimisation of comorbidities
• Prehabilitation (exercise, nutritional support)
• Avoidance of bowel preparation (most surgeries)
• Multimodal analgesia premedication (paracetamol, NSAIDs, gabapentinoids)

• Short-acting anaesthetic agents; TIVA preferred (less PONV)
• Goal-directed fluid therapy (avoid over- and under-hydration)
• Avoidance of nasogastric tubes and routine drains
• Normothermia maintenance (forced air warming)
• Regional/neuraxial analgesia (epidural, TAP, ESP blocks)
• Opioid-minimising multimodal analgesia
• Minimally invasive surgical techniques

• Early oral feeding (within hours of surgery)
• Early mobilisation (day of or next day)
• PONV prophylaxis (multimodal)
• Opioid-sparing analgesia
• Avoidance of routine urinary catheters
• Thromboprophylaxis

• Decreased length of stay (appendectomy: 9.7 h vs. 23.2 h in conventional care)
• Reduced opioid consumption
• Same-day discharge rates improved (e.g., breast surgery: 7.2% to 58.6%)
• Reduced readmissions

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Q4. Describe Point-of-Care Ultrasound (POCUS) in anaesthesia - applications, technique, and limitations. (5 marks)

• POCUS (FoCUS - Focused Cardiac Ultrasound): Goal-directed, yes/no format, qualitative assessment, answers specific clinical questions
• Limited TTE: Broader scope, quantitative techniques, requires advanced training
• Comprehensive Echo: Full diagnostic study by cardiologist

1. Cardiac (FoCUS):
   • LV/RV function (qualitative)
   • Pericardial effusion/tamponade
   • Volume status (IVC collapsibility index)
   • Valvular pathology screening
2. Pulmonary:
   • Pneumothorax (absence of lung sliding, B-lines)
   • Pleural effusion
   • Lung consolidation/atelectasis
   • Pulmonary oedema (B-lines/comet-tail artefacts)
3. Airway:
   • Tracheal intubation confirmation
   • Cricothyroid membrane identification
   • Gastric content assessment (fasting status, aspiration risk)
4. Vascular Access:
   • Central venous cannulation (real-time guidance - reduces failure and complications)
   • Arterial line placement
5. Regional Anaesthesia Guidance:
   • All peripheral nerve blocks
   • Neuraxial identification
6. Abdominal:
   • FAST exam (trauma)
   • Bladder volume

• Phased array (cardiac): 1-5 MHz
• Linear (vascular, superficial structures): 5-15 MHz
• Curvilinear (abdominal, deep structures): 2-5 MHz

• Operator-dependent
• Obesity, subcutaneous emphysema limit views
• Cannot replace formal echocardiography for complex diagnoses
• Requires structured training and competency assessment

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Q5. Describe the Erector Spinae Plane (ESP) Block - anatomy, technique, indications, and advantages. (5 marks)

• The erector spinae muscle group (iliocostalis, longissimus, spinalis) extends bilaterally along the spine
• They lie superficial to the transverse processes
• Local anaesthetic is deposited deep to the erector spinae, over the periosteum of the transverse process
• Spread occurs both cephalad and caudad within the fascial plane

• Exact mechanism not fully established
• Postulated spread to the dorsal rami and ventral rami via the costotransverse foramen
• May also block sympathetic fibres

1. Patient position: Seated or lateral decubitus
2. Parasagittal approach, probe placed 2-3 cm lateral to midline
3. Identify transverse process (hyperechoic with acoustic shadow)
4. Three layers visible: trapezius, rhomboid major, erector spinae (at thoracic level)
5. In-plane needle insertion (craniocaudal or caudocranial)
6. Deposit local anaesthetic deep to erector spinae, over transverse process periosteum
7. Volume: 15-30 mL per side (reduce for bilateral blocks)

• Thoracic surgery (VATS, thoracotomy)
• Breast surgery
• Rib fractures/chest trauma
• Cardiac surgery (sternotomy analgesia)
• Abdominal surgery (when performed at lower thoracic/lumbar levels)
• Spine surgery

• More superficial - remote from lung (less pneumothorax risk)
• Easily visualised under ultrasound
• No risk of epidural/intrathecal spread
• Simpler technique with less steep learning curve
• Suitable for anticoagulated patients

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Q6. Describe the Quadratus Lumborum (QL) Block - variants, technique, and clinical applications. (5 marks)

• QL lies between the transverse processes, iliac crest, and lower ribs
• Surrounded by thoracolumbar fascia (TLF) - contains mechanoreceptors, nociceptors, and sympathetic fibres
• LA spread from TLF to paravertebral space produces visceral analgesia
• Dermatomal spread: T8 to L1, including iliohypogastric and ilioinguinal nerves

• Transverse probe placed on midaxillary line between costal margin and iliac crest
• Identify three abdominal wall muscles (TAP block view), slide posteriorly
• "Shamrock sign": QL and psoas = leaves; transverse process = stem
• Curved probe (C5-1 MHz) for adults; high-frequency linear for children
• Needle in-plane to avoid ipsilateral kidney injury
• Dose: 0.5 mL/kg of 0.2% ropivacaine per side (max 3 mg/kg, max 20 mL)

• Caesarean section (QL3)
• Total hip replacement
• Colonic surgery
• Nephrectomy/renal procedures
• Appendicectomy
• Hernia repair

• Provides both somatic and visceral analgesia (unlike TAP block)
• No risk of neuraxial spread
• Ultrasound-only technique (no nerve stimulation needed)

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Q7. Discuss Sugammadex - mechanism, pharmacokinetics, dosing, and clinical applications. (5 marks)

• Forms a water-soluble 1:1 guest-host complex with rocuronium/vecuronium
• The hydrophobic cavity of cyclodextrin encapsulates the steroidal NMBD
• Stability: rocuronium-sugammadex association rate 25,000,000:1 (extremely tight complex)
• Creates a concentration gradient drawing rocuronium away from the NMJ back into plasma
• Does NOT act on cholinergic transmission - no need for anticholinergics (glycopyrrolate/atropine)
• Affinity: Rocuronium > Vecuronium; Pancuronium binding too low for clinical effect

• Volume of distribution: 18 L
• Elimination half-life: ~100 minutes
• Plasma clearance: 120 mL/min
• Excreted: 80% unchanged in urine (24 hours)
• Note: Renal failure causes accumulation - but the complex remains intact and inactive

• Complete reversal at all depths of block
• Faster reversal vs. neostigmine+anticholinergic
• Eliminates residual neuromuscular block (RNMB) in PACU
• Enables "rocuronium RSI" as an alternative to succinylcholine
• Can be used in myasthenia gravis, pseudocholinesterase deficiency, malignant hyperthermia-susceptible patients

• May reduce contraceptive efficacy (additional contraception needed for 7 days)
• Not effective for benzylisoquinolinium NMBDs (atracurium, cisatracurium, mivacurium)
• Renal failure: use with caution; haemodialysis may be required to clear complex

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Q8. Describe Perioperative Neurocognitive Disorders (PNDs) - classification, risk factors, pathophysiology, and prevention. (5 marks)

• Age >65 years (most significant)
• Pre-existing cognitive impairment/dementia
• Low educational level
• Prolonged surgery duration
• Major cardiovascular/orthopaedic procedures
• Perioperative hypoxia, hypotension, hypoglycaemia
• Sleep disturbance
• Polypharmacy

• Neuroinflammation (surgical stress-induced cytokine release)
• Neurotransmitter imbalance (cholinergic deficit)
• Decreased brain-derived neurotrophic factor (BDNF)
• Volatile anaesthetic-induced neuroapoptosis (animal models)
• Cerebral microemboli
• Blood-brain barrier disruption

• Animal studies: causal link via neuroinflammation and BDNF reduction
• Human studies: results are conflicting
• Processed EEG monitoring to reduce volatile anaesthetic depth can reduce but not eliminate post-op delirium
• No definitive difference between GA and regional anaesthesia in RCTs on long-term cognitive outcomes

1. Processed EEG monitoring (avoid burst suppression, keep BIS 40-60)
2. Regional anaesthesia where feasible
3. Multimodal analgesia with opioid minimisation
4. Dexmedetomidine (reduces delirium incidence in ICU)
5. Early mobilisation and non-pharmacological sleep promotion
6. Avoid anticholinergic drugs
7. ERAS protocol implementation
8. Pre-operative cognitive screening and optimisation

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Q9. Discuss Local Anaesthetic Systemic Toxicity (LAST) - mechanism, clinical features, and management including lipid emulsion rescue. (5 marks)

• LA crosses the blood-brain barrier rapidly after intravascular injection
• CNS toxicity: Blockade of inhibitory neurons causes excitation, then generalised CNS depression
• CVS toxicity: Blockade of Na+ channels in myocardium - PR prolongation, QRS widening, ventricular arrhythmias, cardiac arrest
• Bupivacaine: Highest CVS toxicity - dissociates slowly from Na+ channels ("fast in, slow out")

• Highly vascular injection sites (intercostal > caudal > epidural > brachial plexus)
• High total dose, high concentration
• Extremes of age, hepatic impairment, cardiac disease
• Hyponatraemia, acidosis, hyperkalaemia

• Incremental injection with aspiration
• Epinephrine test dose (3 mcg/kg)
• Fractionated dosing
• Use lowest effective concentration and dose
• Ultrasound guidance

1. Stop injection immediately
2. Call for help; Get lipid emulsion rescue kit
3. Airway: 100% O₂, intubate if needed
4. Seizures: Benzodiazepines (first-line); avoid propofol in haemodynamic compromise
5. Cardiac Arrest: CPR; avoid vasopressin, calcium channel blockers, beta-blockers, lidocaine
6. Lipid Emulsion Therapy (20% Intralipid):
   • Bolus: 1.5 mL/kg IV over 2-3 minutes
   • Infusion: 0.25 mL/kg/min
   • Can repeat bolus x2 if no response (5 min intervals)
   • Maximum dose: 12 mL/kg
7. Consider ECMO for refractory cardiac arrest
8. Avoid epinephrine in high doses (small doses <1 mcg/kg preferred)

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Q10. Discuss the Processed EEG (pEEG) monitoring in anaesthesia - indices, clinical utility, and limitations. (5 marks)

• Delta (δ): 0-3 Hz - deep sleep/anaesthesia
• Theta (θ): 4-7 Hz
• Alpha (α): 8-13 Hz
• Beta (β): >13 Hz - awake state

• Awake: 97-100
• Light sedation: 70-90
• General anaesthesia: 40-60
• Deep anaesthesia/burst suppression: <40

• <1 MAC: Increases frequency and amplitude
• 1-2 MAC: Decreasing frequency, increasing amplitude

• 2 MAC: Burst suppression or isoelectric silence

• Also affected by: hypoxia, hypercarbia, hypothermia

1. Reduction of Awareness Under Anaesthesia (AUA) - especially high-risk patients
2. Titration of anaesthetic agents (reduces drug use by ~25-38%)
3. Reduction of PONV and faster recovery when BIS-guided
4. Guidance in TIVA (no end-tidal agent monitoring available)
5. Reduction of post-operative delirium (reducing burst suppression)
6. ICU sedation monitoring

• B-Aware Trial: BIS monitoring reduces awareness from 0.91% to 0.17%
• BAG-RECALL Trial: No significant difference vs. end-tidal agent monitoring in low-risk patients
• Reducing burst suppression (BIS <40) associated with reduced POCD at 1 year

• Cannot reliably predict awareness in all patients
• Affected by EMG interference (muscle activity)
• Ketamine, nitrous oxide, and dexmedetomidine cause paradoxical high BIS values
• Epileptiform activity, hypothermia, cardiac bypass may confound readings
• Electrode placement critical

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Q11. Discuss the role of Artificial Intelligence (AI) and Machine Learning in Anaesthesia practice. (5 marks)

• Closed-loop anaesthesia delivery: AI adjusts drug infusion rates in real-time based on BIS/entropy feedback
• Bayesian AI pharmacokinetic models for personalised TCI (incorporating patient phenotypes)
• Automated propofol delivery systems (McGill system, CLADS)

• AI-powered video laryngoscopy image analysis predicting Cormack-Lehane grade
• Deep learning models predicting difficult airway from facial photographs
• Computer vision for intubation confirmation

• AI-based hypotension prediction index (HPI) - predicts hypotension 15 minutes before occurrence using arterial waveform analysis
• Automated fluid responsiveness prediction
• Goal-directed therapy algorithms

• Risk stratification AI tools for procedural sedation outside OR
• Automated screening for fasting status, drug allergies, comorbidities

• Preoperative risk stratification (ML models outperform ASA-PS in predicting mortality)
• Prediction of PONV, difficult intubation, post-op complications

• pEEG algorithm refinement using deep learning
• Automated artefact detection in monitoring waveforms

• NLP for automated documentation
• Predictive analytics for resource planning (OR scheduling)

• Simulation training personalised to trainee performance using AI feedback loops

• "Black box" nature - interpretability concerns
• Bias in training datasets
• Regulatory approval hurdles
• Liability in case of AI-guided adverse outcomes
• Data privacy and security (HIPAA/GDPR compliance)
• Integration with existing hospital information systems

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Q12. Describe Hypotension Prediction Index (HPI) and goal-directed haemodynamic management using arterial waveform analysis. (5 marks)

• Intraoperative hypotension (IOH) - MAP <65 mmHg - is associated with myocardial injury, AKI, stroke, and increased 30-day mortality
• Even brief episodes (1-5 minutes) cause significant organ damage
• Traditional monitoring is reactive; HPI enables proactive management

• Analyses the arterial pressure waveform morphology in real-time
• Machine learning algorithm trained on >35,000 intraoperative arterial waveforms
• Outputs a score from 0-100
• Score >85 predicts hypotension (MAP <65 for ≥1 min) within the next 15 minutes with ~88% sensitivity and ~87% specificity

• eGDT (estimated GDT): Stroke volume, cardiac output, SVR
• dP/dt: Rate of arterial pressure change
• PPV (Pulse Pressure Variation): Dynamic fluid responsiveness index
• SVV (Stroke Volume Variation): Preload dependence

• Haemodynamic targets: Cardiac Output, SV, SVV <13%
• Stepwise algorithm: Fluid challenge → vasopressors → inotropes
• Reduces rate of IOH vs. standard of care in multiple RCTs

1. Radial/femoral arterial line connected to compatible transducer
2. HPI displayed continuously on monitor
3. Alert system warns provider when score rises above threshold
4. Provider implements targeted intervention (fluid, vasopressor, anaesthetic adjustment)

• HYPE trial: HPI guidance reduced time-weighted average hypotension significantly
• Applicable in cardiac surgery, major abdominal, high-risk non-cardiac surgery

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Q13. Discuss perioperative analgesia in thoracic surgery with special reference to new regional techniques. (5 marks)

• Paracetamol (regular dosing, opioid-sparing)
• NSAIDs/COX-2 inhibitors (reduce opioid requirement by 30-40%)
• IV lidocaine infusion (1-1.5 mg/kg/h) - reduces pain scores and opioid use
• Ketamine infusion (sub-anaesthetic: 0.1-0.5 mg/kg/h) - opioid-sparing, prevents central sensitisation
• Dexamethasone (anti-inflammatory, analgesic, anti-emetic)
• Gabapentinoids (acute use debated due to sedation in elderly)

• LA deposited between serratus anterior and intercostal muscles
• Blocks long thoracic nerve + intercostal nerves (T2-T9)
• Ideal for VATS, anterior chest wall, mastectomy, and rib fractures
• Does not provide posterior coverage

• Pain persisting >3 months after surgery
• Incidence: 30-80% after open thoracotomy; lower with VATS
• Prevention: Pre-emptive regional analgesia, minimising intercostal nerve trauma, NMDA antagonists

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Q14. Discuss anaesthetic management for Non-Operating Room Anaesthesia (NORA) - unique challenges and safety considerations. (5 marks)

• Endoscopy suites (GI, bronchoscopy)
• Radiology (MRI, CT, interventional radiology)
• Cardiac catheterisation labs (EP studies, TAVI, structural heart)
• Radiation oncology (radiotherapy in children)
• ECT suites
• Dental chairs
• Ophthalmology

1. Remote Location:
   • Distance from main OT (anaesthetic support, equipment, blood bank)
   • Limited help in emergencies
   • Communication barriers
2. Patient Population:
   • Higher ASA class (procedures performed because patient too sick for GA)
   • Extremes of age
   • Comorbidities: COPD, cardiac failure, morbid obesity
3. Environment:
   • Darkness (radiology, endoscopy)
   • Narrow access to patient (MRI bore, radiology table)
   • MRI: Ferromagnetic equipment contraindicated - need MRI-conditional equipment
   • Ionising radiation - need lead shielding, distance from source
4. Equipment Limitations:
   • May not have full anaesthetic machine (use TIVA instead)
   • Older facilities may lack piped gases
   • Limited suction, monitoring, or reversal agents
5. Procedural Hazards:
   • Shared airway (bronchoscopy, oesophagoscopy)
   • Patient in prone or unusual positions
   • Contrast dye reactions (anaphylaxis preparedness)

• Oxygen supply and suction available
• Full monitoring: SpO₂, NIBP, ECG, ETCO₂ (capnography mandatory even during sedation)
• Resuscitation drugs and defibrillator
• Trained assistant
• Post-procedure recovery area with qualified personnel

• Natural airway with supplemental O₂: Minimal procedures, low-risk patients
• LMA/SAD: Intermediate risk
• ETT/RIMA: Airway-sharing procedures, aspiration risk, prolonged cases

• Propofol (workhorse) or Remimazolam (new alternative)
• Dexmedetomidine (sedation without respiratory depression - MRI, endoscopy)
• Remifentanil TCI (short procedures with pain)
• Ketamine (paediatric procedures, ECT adjunct)

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Q15. Discuss the role of Dexmedetomidine in modern anaesthetic practice. (5 marks)

• Sedation/Hypnosis: Alpha-2 agonism at locus coeruleus (brain's main noradrenergic nucleus) - produces "cooperative sedation" mimicking natural NREM sleep
• Analgesia: Spinal cord (dorsal horn) and supraspinal alpha-2 receptors
• Sympatholysis: Reduces norepinephrine release - decreases HR, BP, and sympathetic stress response

• Loading dose: 0.5-1 mcg/kg IV over 10 minutes
• Infusion: 0.2-0.7 mcg/kg/h
• Context-sensitive half-time: ~4 hours
• Hepatic metabolism (CYP2A6)

• Minimal respiratory depression (UNIQUE)
• Arousable, cooperative sedation
• No GABA-ergic mechanism
• Analgesic-sparing (reduces opioid requirement by 30-50%)
• Anti-shivering effect

1. ICU Sedation:
   • Superior to benzodiazepines in reducing delirium (MIDEX/PRODEX trials)
   • Allows daily awakening with maintained cooperation
   • Reduces duration of mechanical ventilation
2. Procedural Sedation:
   • MRI in uncooperative patients (especially children)
   • Awake fibreoptic intubation (attenuates sympathetic response)
   • Awake craniotomy (cooperative sedation)
   • Regional anaesthesia with MAC
3. Awake Intubation Adjunct:
   • Attenuates hypertensive response to laryngoscopy
   • Reduces secretions (drying effect)
4. Perioperative Analgesia:
   • Reduces intraoperative opioid use
   • Reduces postoperative shivering
   • Adjunct in regional anaesthesia (prolongs block duration when used as additive)
5. Cardiac Surgery:
   • Reduces tachyarrhythmias
   • Organ protective (preconditioning) effects on heart and kidney
6. Paediatric Anaesthesia:
   • Emergence agitation prevention (intranasal dexmedetomidine - 1-2 mcg/kg)
   • Premedication alternative to midazolam

• Bradycardia and hypotension (most significant)
• Initial transient hypertension with rapid bolus (peripheral alpha-2b activation)
• Dry mouth
• Avoid in heart block

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Q16. Discuss anaesthetic considerations for patients undergoing TAVI (Transcatheter Aortic Valve Implantation). (5 marks)

• Severe aortic stenosis (AVA <1 cm², mean gradient >40 mmHg)
• High/intermediate surgical risk (STS score >4-8%)
• Frail elderly patients, multiple comorbidities
• Prior mediastinal radiation or pericarditis

• Transfemoral (most common, 95%): Percutaneous
• Transapical: Surgical incision, requires OLV
• Transaortic, transsubclavian, transcaval (alternatives)

1. Maintain sinus rhythm (AF can cause haemodynamic collapse)
2. Maintain preload (AS patients are preload-dependent)
3. Maintain SVR (avoid vasodilation)
4. Avoid tachycardia (reduces diastolic filling time)
5. Maintain contractility

• Rapid ventricular pacing (RVP): Required during valve deployment to reduce cardiac output temporarily (180-220 bpm) - causes profound hypotension
• Complete heart block: Post-deployment (especially LBBB patients) - temporary pacemaker on standby
• Coronary obstruction: Valve leaflet occlusion - emergency PCI preparedness
• Aortic regurgitation: Paravalvular leak post-deployment
• Stroke: Embolic events - 2-3%

• Arterial line (mandatory - continuous BP during RVP)
• Central venous access
• TOE (TEE) if GA (assesses valve positioning, complications)
• External defibrillator pads
• Pacing capability

• ICU/CCU monitoring for 24-48 hours
• Watch for: new heart block, access site haematoma, acute kidney injury (contrast)
• Dual antiplatelet therapy initiated

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Q17. Discuss Opioid-Free Anaesthesia (OFA) - rationale, techniques, and limitations. (5 marks)

1. Opioid-Induced Hyperalgesia (OIH): Paradoxical increased pain sensitivity with opioid use - particularly with remifentanil
2. Opioid-Induced Respiratory Depression (OIRD): Leading cause of post-anaesthetic mortality
3. Postoperative Nausea and Vomiting (PONV): Opioids are the strongest trigger
4. Ileus: Mu-receptor activation in gut delays GI recovery (ERAS incompatibility)
5. Opioid Epidemic Context: Reducing perioperative opioid exposure to prevent dependency
6. Immunosuppression: Opioids suppress NK cell function
7. Tolerance: Opioid-tolerant patients require escalating doses

• Pre-op: Pregabalin 150 mg + Paracetamol 1g + Celecoxib 400 mg
• Induction: Propofol + Ketamine (0.5 mg/kg) + Dexmedetomidine bolus
• Maintenance: TIVA propofol + Dexmedetomidine infusion + Ketamine infusion + IV Lidocaine infusion
• Regional technique: ESP catheter or epidural
• Post-op: Regular paracetamol/NSAIDs ± PCA (non-opioid rescue)

• Morbidly obese (OSA) patients
• Opioid-tolerant/dependent patients
• Bariatric surgery
• ERAS programmes
• Chronic pain patients

• Not universally applicable (severe pain procedures may still need opioids as rescue)
• Ketamine: psychomimetic effects, increased secretions
• Dexmedetomidine: bradycardia, hypotension, cost
• IV lidocaine: LAST risk
• NSAIDs: renal, GI, platelet effects
• Evidence base still evolving (heterogeneous protocols)

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Q18. Discuss awake craniotomy - anaesthetic technique, indications, and challenges. (5 marks)

• Tumour resection in eloquent cortex (motor, speech, language areas)
• Epilepsy surgery (cortical mapping before resection)
• Deep brain stimulation (DBS) electrode placement
• Stereotactic biopsies (less common)

• Phase 1 (Asleep): Induction, airway secured (LMA preferred), pin placement, craniotomy
• Phase 2 (Awake): Reversal/lightening, patient cooperative for mapping
• Phase 3 (Asleep): Resection/wound closure under GA
• Airway: Flexible LMA (FLMA) or ETT - removed during awake phase
• Drugs: Propofol TIVA + Remifentanil TCI; Dexmedetomidine as adjunct

• Conscious sedation throughout
• Drugs: Propofol/dexmedetomidine infusion + remifentanil
• No formal airway device (natural airway maintained)
• Requires highly cooperative patient

• Scalp nerve block: Supraorbital, supratrochlear, auriculotemporal, lesser/greater occipital, zygomaticotemporal nerves
• Reduces pain during pin placement and scalp incision

• Remifentanil TCI (target 1-3 ng/mL Ce) provides excellent titrateable sedation and analgesia during awake phase
• Dexmedetomidine: Co-sedation without respiratory depression
• Patient positioning: Semi-sitting/lateral - allows access to face for neurological testing
• Communication: Continuous reassurance; task-based testing (counting, moving limb, speech tasks)

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Q19. Discuss Fascial Plane Blocks for abdominal surgery - TAP, QL, and ESP blocks with comparative merits. (5 marks)

• Target: Between internal oblique and transversus abdominis muscles
• Nerves blocked: T10-L1 (anterior rami)
• Coverage: Anterior abdominal wall, parietal peritoneum
• Variants: Subcostal TAP (T6-T9), lateral TAP (T10-L1), posterior TAP (T10-L1 + some visceral)
• Volume: 15-20 mL 0.25% bupivacaine per side
• Limitation: No visceral analgesia with anterior approach; does not cover upper abdomen well

• Target: Thoracolumbar fascia (anterior, lateral, or posterior to QL muscle)
• Nerves blocked: T6-L1 + ilioinguinal/iliohypogastric (visceral component via sympathetics)
• Advantage over TAP: Provides both somatic AND visceral analgesia
• Best for: Caesarean section, hip surgery, colorectal procedures, nephrectomy
• Volume: 0.5 mL/kg per side

• Target: Deep to erector spinae, over transverse process
• Coverage: Bilateral: thoracic and abdominal dermatomal coverage (T4-L2 depending on level)
• Best for: Thoracic procedures, breast surgery, upper abdominal surgery, spine surgery
• Unique advantage: Covers both anterior and posterior chest/abdomen

• All blocks are easier and safer under ultrasound guidance
• Combination approaches (e.g., bilateral QL + TAP for colorectal surgery) improve coverage
• Catheter-based continuous infusions extend duration for postoperative pain management
• Part of ERAS protocols for opioid-sparing analgesia

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Q20. Discuss anaesthetic management of a patient with suspected Malignant Hyperthermia (MH) - pathophysiology, diagnosis, and treatment including new developments. (5 marks)

• Genetic mutations (predominantly RYR1 gene - ryanodine receptor type 1; also CACNA1S gene)
• Abnormal release of Ca²⁺ from sarcoplasmic reticulum triggered by volatile halogenated anaesthetics (halothane, isoflurane, sevoflurane, desflurane) and succinylcholine
• Sustained skeletal muscle contraction → massive ATP consumption → heat generation, acidosis, rigidity
• Rhabdomyolysis → hyperkalemia, acute kidney injury

• All volatile halogenated agents (including desflurane - recently withdrawn in many countries partly due to environmental concerns AND MH risk)
• Succinylcholine

• Propofol, ketamine, etomidate (IV induction agents - all safe)
• All non-depolarising NMBDs
• Benzodiazepines, opioids, local anaesthetics, nitrous oxide
• Dexmedetomidine, neostigmine, sugammadex

• Early: Masseter muscle spasm after succinylcholine, unexplained tachycardia, rising ETCO₂ (earliest sign)
• Late: Hyperthermia (>1°C per 5 minutes), generalised rigidity, metabolic acidosis, hyperkalemia, cyanosis, arrhythmias
• Mottled skin, cola-coloured urine (myoglobinuria)

• Clinical (rising ETCO₂ + fever + rigidity after trigger)
• Caffeine-Halothane Contracture Test (CHCT) - gold standard confirmatory test on muscle biopsy
• Genetic testing: RYR1/CACNA1S mutations (detects ~70% of susceptible patients)

1. Call for help; activate MH protocol
2. Discontinue triggering agent - switch to TIVA immediately
3. Hyperventilate with 100% O₂ at 2-3x minute ventilation (flush volatile from circuit)
4. Dantrolene (CORNERSTONE TREATMENT):
   • Initial: 2.5 mg/kg IV bolus (rapid)
   • Repeat 2.5 mg/kg every 5 minutes until symptoms resolve
   • Maximum: 10 mg/kg (rarely need >10 mg/kg)
   • Mechanism: Inhibits RyR1, reducing Ca²⁺ release from SR
   • Maintenance: 1 mg/kg IV 6-hourly for 24-48 hours (prevent recurrence)
5. Cool patient actively: Ice packs, cold IV fluids, cold gastric/bladder irrigation
6. Treat hyperkalemia: Calcium chloride, bicarbonate, insulin-dextrose
7. Treat acidosis: Sodium bicarbonate
8. Treat arrhythmias: Avoid calcium channel blockers (can worsen with dantrolene)
9. Maintain urine output >1 mL/kg/h (prevent myoglobin-induced AKI) with IV fluids ± furosemide

• Desflurane phase-out: Many countries (EU, India) are withdrawing desflurane due to high global warming potential (GWP2500) AND MH risk
• Remimazolam as safe alternative sedative in MH-susceptible patients
• Point-of-care Ca²⁺ testing for rapid MH confirmation in research settings
• Gene therapy targeting RYR1 (experimental)
• Digital MH registries improving epidemiological understanding

• ICU monitoring for 24-48 hours (recurrence in ~25%)
• Genetic counselling for patient and family
• Alert bracelet/MedicAlert identification
• Test first-degree relatives (CHCT or genetic testing)

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Summary Index of Topics Covered

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