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Bronchial Asthma in a Patient Posted for Laparoscopic Cholecystectomy

Pre-operative and Post-operative Anesthetic Management

(MD Anesthesia Exam-Ready Answer)

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PATHOPHYSIOLOGIC CONTEXT

• Bronchospasm develops in approximately 9% of asthmatics in the perioperative period
• 25% of asthmatics may present with wheezing after induction of anesthesia
• The most critical time is during instrumentation of the airway
• Even 50% of patients with non-allergic bronchospasm have no prior history of asthma (ASA Closed Claims Project)

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PRE-OPERATIVE MANAGEMENT

1. History and Severity Assessment

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2. Physical Examination

• Auscultate chest for wheeze, rhonchi, prolonged expiration
• Assess for features of severe disease: pulsus paradoxus, accessory muscle use, central cyanosis
• Document baseline SpO2 on room air

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3. Investigations

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4. Pre-operative Optimization

• Smoking cessation (minimum 8 weeks for pulmonary benefit; even 12-24 hours reduces CO, improves oxygenation)
• Chest physiotherapy if secretions are significant
• Patient education and anxiety reduction (emotional stress triggers bronchospasm)

• Anxiolytic: benzodiazepine (midazolam 1-2 mg IV) - reduces sympathetic stress without respiratory depression at usual doses
• Anti-sialagogue: glycopyrrolate preferred over atropine (less tachycardia); use if ketamine is induction agent
• Avoid morphine/meperidine for premedication (histamine releasers)
• Aspiration prophylaxis: pantoprazole 40 mg oral the night before + morning of surgery (note: avoid H2 blockers)

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INTRA-OPERATIVE MANAGEMENT

5. Anesthetic Technique

• Laparoscopic cholecystectomy requires general anesthesia with endotracheal intubation (pneumoperitoneum, Trendelenburg, muscle relaxation required)
• Spinal/epidural not suitable for laparoscopic surgery; also, high thoracic epidural (T1-T4 block) could block sympathetic bronchodilator tone and worsen bronchoconstriction

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6. Induction

• LMA (supraglottic airway) is preferred IF adequate muscle relaxation and low risk of aspiration are ensured - avoids tracheal stimulation
• If ETT required: use smaller size (7.0 in women, 7.5 in men), use armored tube for long laparoscopy
• Pretreat before intubation: IV/intratracheal lidocaine 1-2 mg/kg or additional induction agent bolus or volatile agent at 2-3 MAC for 5 min to blunt reflex bronchospasm
• Ensure deep anesthesia before intubating - light anesthesia is the most dangerous trigger

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7. Maintenance

• Use warmed, humidified gases
• Tidal volume: 6 mL/kg (low tidal volume)
• Prolonged expiratory time (I:E ratio 1:3 or 1:4) to prevent air trapping and auto-PEEP
• Moderate PEEP (3-5 cmH2O) to maintain FRC, counter pneumoperitoneum-induced atelectasis
• Monitor capnography - upward sloping (shark fin) end-tidal CO2 trace = expiratory obstruction
• Keep insufflation pressure <12-15 mmHg - higher pressures worsen airway pressures and AKI risk
• Accept permissive hypercapnia if no cardiovascular or neurologic contraindication
• Adjust ventilator rate to maintain ETCO2 35-45 mmHg (CO2 absorption from pneumoperitoneum will increase ETCO2; increase minute ventilation by ~15-25%)

• Standard ASA + invasive arterial line if severe disease
• SpO2, ETCO2, airway pressure (peak and plateau), tidal volume
• Neuromuscular blockade monitor (TOF)
• Temperature (use warm humidified gases)

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8. Intraoperative Bronchospasm - Recognition and Treatment

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9. Reversal and Extubation

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POST-OPERATIVE MANAGEMENT

10. Immediate Post-operative (PACU)

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11. Post-operative Analgesia (Critical Consideration)

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12. Post-operative Respiratory Physiotherapy

• Deep breathing exercises
• Incentive spirometry (target >70% of predicted)
• Early ambulation (within 4-6 hours for laparoscopic cholecystectomy - day surgery)
• Positioning: semi-recumbent (30-45°) to maximize FRC and diaphragmatic excursion
• Humidification
• Continue nebulized salbutamol q4-6h for 24 hours in moderate-severe asthmatic

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13. Steroid Management Post-operative

• If stress doses given intra-op: taper hydrocortisone to baseline regimen within 24-48 hours
• Monitor blood glucose (steroids cause hyperglycemia)
• Do not abruptly stop long-term oral steroids

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14. Discharge Criteria (Day Surgery)

• No wheeze on auscultation
• SpO2 ≥95% on room air
• Pain controlled on oral analgesics
• Tolerating oral fluids
• Passed urine
• Stable vital signs
• Written asthma action plan if exacerbation occurs at home
• Early follow-up (24-48 hours post-discharge)

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EXAM-READY TABLES

Table 1: Drugs to Avoid vs. Prefer in Asthmatic Patients

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Table 2: Severity-Based Pre-op Management Strategy

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Table 3: Physiological Effects of CO2 Pneumoperitoneum Relevant to Asthma

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Table 4: Ventilation Strategy Comparison (Normal vs. Asthmatic with Pneumoperitoneum)

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Table 5: Intraoperative Bronchospasm - Step-wise Treatment

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Table 6: Extubation Strategy in Asthmatic

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Table 7: Post-operative Complications to Watch for

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SPECIAL EXAM POINTS

1. H2 blockers are CONTRAINDICATED as premedication in asthmatics - they leave H1 stimulation unopposed when histamine is released, worsening bronchoconstriction. Use PPIs instead.
2. Aspirin-sensitive asthma (Samter's Triad) = asthma + nasal polyps + NSAID intolerance. These patients must receive paracetamol and COX-2 inhibitors only for post-op analgesia.
3. Desflurane must be avoided in all asthmatics - it is a potent airway irritant and increases airway resistance.
4. Sevoflurane is the volatile of choice - most potent bronchodilator, least pungent, smooth inhalation.
5. Deep extubation vs. awake extubation - always justify your choice based on airway difficulty and aspiration risk.
6. Permissive hypercapnia is acceptable in asthmatics under laparoscopy - do not aggressively hyperventilate (worsens auto-PEEP, air trapping, barotrauma).
7. Sugammadex is preferred over neostigmine for reversal - avoids the cholinergic surge and its bronchospastic potential.
8. CO2 pneumoperitoneum will increase ETCO2 by ~15-25%; increase minute ventilation pre-emptively before insufflation.
9. The capnograph "shark fin" or sawtooth pattern (slow upslope on expiration) is the earliest sensitive sign of airway obstruction intraoperatively.
10. Dexamethasone (given for PONV prophylaxis in laparoscopy) has the added benefit of reducing airway inflammation - use 8 mg IV at induction.

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Bronchial Asthma in a Patient Posted for Laparoscopic Cholecystectomy

Perioperative Anesthetic Management - MD Anesthesia Exam

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INTRODUCTION / CLINICAL SIGNIFICANCE

• Bronchospasm occurs in ~9% of asthmatics in the perioperative period
• 25% of asthmatics may wheeze after induction of anesthesia
• 1.7% sustain a poor respiratory outcome
• ASA Closed Claims Project: 40 bronchospasm-related claims - 88% resulted in brain damage or death; only half had pre-existing asthma/COPD
• Key principle: Well-controlled asthma is NOT a risk factor for perioperative complications. Poorly controlled asthma is. (Morgan & Mikhail, 7e)

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PART I: PRE-OPERATIVE MANAGEMENT

A. Pre-anaesthetic Assessment

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• Auscultate chest: wheeze, prolonged expiration, reduced air entry
• Signs of severe disease: accessory muscle use, pulsus paradoxus >10 mmHg, central cyanosis, inability to speak full sentences
• Baseline SpO2 on room air
• Signs of steroid side effects (moon face, central obesity, proximal myopathy, skin fragility - alert to adrenal suppression)

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Exam point: Spirometry has limited value in predicting postoperative pulmonary complications outside cardiothoracic surgery. Its perioperative role is to confirm and quantify obstruction and measure reversibility. (Berek & Novak / Morgan & Mikhail)

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B. Pre-operative Optimization

1. Review asthmatic control, including need for oral steroids
2. Optimize symptomatic control with long-acting pharmacotherapy, including oral steroids if needed
3. For patients on oral steroids within 6 months, or large-dose ICS users - consider perioperative stress-dose steroids

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Critical Exam Point - H2 Blockers: Ranitidine, famotidine, and cimetidine are contraindicated as premedication in asthmatics. H2 receptor activation normally produces bronchodilation. Blocking H2 while leaving H1 unopposed means any histamine release will cause unmitigated bronchoconstriction via H1. Use PPI instead. (Morgan & Mikhail, 7e)

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• Smoking cessation: minimum 12-24 hours improves CO levels and oxygenation; 8 weeks for significant pulmonary benefit; 2 months reduces post-op pulmonary complication risk
• Chest physiotherapy and breathing exercises if secretions present
• Treat active respiratory infection before surgery
• Patient counselling and anxiety reduction (emotional stress triggers bronchospasm)

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PART II: INTRA-OPERATIVE MANAGEMENT

Understanding the Added Challenge: CO2 Pneumoperitoneum

• Peak airway pressure increases by 50%, plateau pressure by 81% during CO2 pneumoperitoneum
• Bronchopulmonary compliance decreases by 47% (Maingot's Abdominal Operations)
• CO2 absorbed across peritoneum → hypercapnia/respiratory acidosis
• Trendelenburg position further reduces FRC, worsens atelectasis and V/Q mismatch
• These effects are compounded on top of pre-existing airway obstruction in an asthmatic

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A. Choice of Anaesthetic Technique

Note: High spinal/epidural (T1-T4) can block sympathetic bronchodilator tone, allowing unopposed parasympathetic bronchoconstriction. Therefore, regional anaesthesia is not a preferred approach for this case. (Morgan & Mikhail, 7e)

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B. Induction

• Additional bolus of induction agent before laryngoscopy
• OR ventilate with 2-3 MAC sevoflurane for 5 min before intubation
• IV or intratracheal lidocaine 1-2 mg/kg to blunt laryngeal reflexes
  • Caution: Intratracheal lidocaine itself can trigger bronchospasm if anaesthesia is too light
• Ensure adequate depth of anaesthesia before any airway instrumentation - this is the single most important preventive measure

• LMA (Proseal/Supreme) can be considered if airway is easy and aspiration risk is low - avoids tracheal stimulation entirely
• Endotracheal tube if RSI required (full stomach), obese, or surgical factors demand full relaxation and airway control
• If ETT: use appropriate size; confirm bilateral equal air entry immediately after intubation and after each position change (risk of tube migration in Trendelenburg)

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C. Muscle Relaxants

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D. Maintenance

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E. Ventilation Strategy

• Pre-emptively increase minute ventilation by ~15-25% before insufflation to compensate for CO2 absorption
• Use alveolar recruitment maneuvers at safe intervals to counter atelectasis
• Monitor for auto-PEEP (incomplete expiration): increase expiratory time, reduce RR, reduce tidal volume

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F. Monitoring

• Standard ASA monitors (SpO2, ETCO2, ECG, NIBP, temperature)
• Capnography waveform - earliest indicator of expiratory obstruction
• Airway pressures: peak AND plateau pressure (plateau unchanged in bronchospasm = pure resistance problem)
• Neuromuscular blockade monitoring (TOF) - essential; adequate relaxation reduces insufflation pressure needed
• Arterial line if severe asthma, significant co-morbidities, or arterial blood gas monitoring required

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G. Intraoperative Bronchospasm - Recognition and Management

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H. Reversal and Extubation

• Ensure patient is wheeze-free before extubation
• Ensure complete neuromuscular reversal (TOF ratio ≥ 0.9)
• IV Lidocaine 1.5-2 mg/kg 90 seconds before extubation blunts airway reflexes on emergence (Morgan & Mikhail, 7e)
• Avoid deep suctioning at light planes - potent bronchospasm trigger

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PART III: POST-OPERATIVE MANAGEMENT

A. Immediate Post-Operative (Recovery Room / PACU)

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B. Post-operative Analgesia - Critical Consideration

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C. Post-operative Respiratory Care

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D. Shoulder Tip Pain (Unique to Laparoscopy)

• Caused by residual CO2 accumulating under the diaphragm, irritating the phrenic nerve (referred to C3-C5 dermatome = shoulder)
• Ensure adequate CO2 desufflation at end of surgery
• Treatment: Semi-recumbent positioning, paracetamol, COX-2 inhibitors (if not NSAID-sensitive), warm packs

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E. Steroid Management Post-operative

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F. Discharge Criteria (Day Surgery - Laparoscopic Cholecystectomy)

• No wheeze on auscultation
• SpO2 ≥ 95% on room air for ≥30 min
• Pain controlled on oral analgesics
• Tolerating oral fluids; passed urine
• Vital signs stable
• Written discharge instructions including asthma action plan if worsening wheeze/dyspnoea at home
• Review appointment within 24-48 hours

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EXAM-CRITICAL TABLES (HIGH-YIELD)

Table 1: Drugs to PREFER vs. AVOID in Asthma - Comprehensive

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Table 2: Severity-Based Pre-operative Strategy

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Table 3: Physiological Effects of CO2 Pneumoperitoneum in the Asthmatic

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Table 4: Intraoperative Bronchospasm - Stepwise Drug Treatment

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Table 5: Extubation Decision in the Asthmatic

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Table 6: Post-operative Pulmonary Complications and Management

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KEY EXAM POINTS TO REMEMBER

1. The single most important preventive measure for perioperative bronchospasm is ensuring adequate depth of anaesthesia before airway instrumentation.
2. H2 blockers are contraindicated as premedication - they leave H1 unopposed and worsen histamine-triggered bronchoconstriction.
3. Desflurane is absolutely avoided in asthmatics - it is the most pungent volatile agent and increases airway resistance.
4. Sevoflurane is the volatile agent of choice - most potent bronchodilator, smooth, non-irritant.
5. Deep extubation is preferred over awake extubation in asthmatics with an easy airway and no aspiration risk.
6. Sugammadex is preferred over neostigmine for NMB reversal - avoids cholinergic surge and its bronchospastic potential.
7. The "shark fin" capnograph (slowly rising ETCO2 on expiration) is the earliest and most sensitive indicator of expiratory obstruction intraoperatively.
8. Permissive hypercapnia is acceptable during laparoscopy in asthmatics - aggressive hyperventilation worsens auto-PEEP and barotrauma.
9. Always ask about NSAID/aspirin tolerance before prescribing any post-operative analgesia - Samter's triad (asthma + nasal polyps + NSAID sensitivity) affects ~5-10% of asthmatics.
10. CO2 pneumoperitoneum increases ETCO2 by 15-25% above baseline - pre-emptively increase minute ventilation before insufflation.
11. ETCO2 and peak airway pressure both rise during pneumoperitoneum - do not confuse this physiologic increase with bronchospasm. The key differentiator: bronchospasm shows rising PEAK with UNCHANGED PLATEAU; pneumoperitoneum raises both.
12. Dexamethasone 8 mg at induction serves double duty in laparoscopy - PONV prophylaxis AND airway anti-inflammatory effect.

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