LARYNGOSPASM Definition • Laryngospasm is an exaggerated protective glottic closure reflex causing forceful closure of the vocal cords that persists even after the stimulus is removed, leading to partial or complete upper airway obstruction. ⸻ Etiology 1. Patient Factors • Pediatric age group (most common) • Upper respiratory tract infection (URTI) • Chronic smokers • Reactive airway disease 2. Surgery-related Factors • ENT surgeries (tonsillectomy, adenoidectomy) • Airway procedures • Endoscopy • Esophagoscopy • Upper abdominal surgery • Pelvic, thoracic and abdominal visceral stimulation 3. Anesthetic Factors Light plane of anesthesia • Most common intraoperative cause Drugs • Morphine • Barbiturates (increase parasympathetic activity) Volatile anesthetics • Ether > Isoflurane > Halothane > Enflurane • Sevoflurane is least irritant Airway irritation • Secretions • Blood • Vomitus • Suctioning • Nasogastric tube • Oropharyngeal/nasopharyngeal airway • Nasal irritation ⸻ Postoperative Causes Immediate • Extubation during light anesthesia • Especially after halothane anesthesia Delayed • Secretions around vocal cords • Regurgitated gastric contents • Silent aspiration beside NG tube • Oropharyngeal airway irritation • Hypoxia causing vomiting • Epiglottitis ⸻ Pathophysiology Stimulus → Superior laryngeal nerve → Vagus nerve → Reflex contraction of laryngeal adductor muscles → Complete or partial glottic closure → Airway obstruction ↓ Hypoxia + Hypercarbia ↓ Negative intrathoracic pressure ↓ Pulmonary edema (Negative Pressure Pulmonary Edema) ⸻ Clinical Features Early Signs • Inspiratory stridor • Dyspnea • Tachypnea • Anxiety • Use of accessory muscles Progressive Obstruction • Intercostal retractions • Suprasternal indrawing • Tracheal tug • Paradoxical chest and abdominal movements • Chest sinks while abdomen rises during inspiration Complete Laryngospasm • Silent chest • No air entry • Rapid desaturation • Cyanosis • Bradycardia (especially children) • Cardiac arrest if untreated ⸻ Diagnosis Clinical diagnosis based on: • Sudden airway obstruction • No effective ventilation • Stridor or silent chest • Falling SpO₂ • Increased inspiratory effort ⸻ Management Step 1: Call for Help • Stop surgery • Inform surgeon • 100% oxygen ⸻ Step 2: Remove Stimulus • Stop surgical stimulation • Suction blood/secretions • Remove airway irritants • Remove nasogastric tube if indicated ⸻ Step 3: Deepen Anesthesia Propofol • 1–2 mg/kg IV • Drug of choice Volatile anesthetic • Sevoflurane preferred • Avoid irritant agents ⸻ Step 4: Open Airway • Head extension • Jaw thrust • Chin lift Larson’s Maneuver • Bilateral pressure behind angle of mandible just anterior to mastoid process • Stimulates painful point and breaks spasm ⸻ Step 5: Positive Pressure Ventilation • Tight face mask • 100% oxygen • CPAP 20–40 cm H₂O Avoid excessive pressure in complete obstruction because: • Gastric insufflation • Risk of aspiration ⸻ Step 6: Drugs Succinylcholine (Drug of Choice) IV • 0.1–0.5 mg/kg (break spasm while maintaining spontaneous breathing) • 1–2 mg/kg if rapid paralysis/intubation required IM • 4–5 mg/kg Alternative routes • Intralingual • Intraosseous Always ventilate with 100% oxygen. ⸻ Step 7: Secure Airway If obstruction persists: • Endotracheal intubation • Surgical airway if unable to ventilate/intubate • Cricothyrotomy or tracheostomy ⸻ Adjunctive Therapy Heliox • 70% Helium + 30% Oxygen • Reduces turbulent airflow • Decreases airway resistance • Improves tidal volume ⸻ Racemic Epinephrine • 1 mg of 1:1000 solution • Diluted in 5 mL normal saline • Nebulized every 30 minutes Action • Vasoconstriction • Reduces airway edema ⸻ Steroids Dexamethasone • 0.1 mg/kg IV every 6 hours • Onset: 4–6 hours • Prevents airway edema ⸻ Management of Negative Pressure Pulmonary Edema Occurs due to forceful inspiratory efforts against closed glottis. Management: • 100% oxygen • CPAP/PEEP • Mechanical ventilation if required • Head-end elevation • Diuretics (e.g., furosemide) ⸻ Postoperative Management Remove Irritants • Oropharyngeal suction • Nasopharyngeal suction • Empty NG tube • Remove airway devices Improve Ventilation • Oxygen therapy • CPAP • Larson’s maneuver Drugs • Racemic epinephrine • Heliox • Dexamethasone • Succinylcholine if severe Airway • Reintubation if persistent hypoxia • Do not force ET tube against closed cords • Consider emergency surgical airway ⸻ Prevention of Post-Extubation Laryngospasm • Adequate suctioning before extubation • Extubate in deep anesthesia or fully awake • Lateral recovery position • IV Lidocaine 1–1.5 mg/kg 2–3 minutes before extubation • Topical lidocaine to larynx • IV Magnesium sulphate • Gentle airway manipulation • Avoid extubation during light anesthesia ⸻ Complications • Severe hypoxemia • Hypercarbia • Bradycardia • Cardiac arrest • Aspiration • Negative pressure pulmonary edema • Pulmonary hemorrhage (rare) • Cerebral hypoxia ⸻ Differential Diagnosis of Post-Extubation Stridor • Laryngomalacia • Tracheomalacia • Vocal cord palsy • Laryngeal edema • Airway hematoma • Soft tissue obstruction • Retained throat pack/foreign body • Bronchospasm • Tracheal obstruction ⸻ Important Viva Points • Most common cause: Light plane of anesthesia with airway stimulation. • Most common surgeries: ENT surgeries, especially in children. • Drug of choice: Succinylcholine. • IV dose: 0.1–0.5 mg/kg (up to 1–2 mg/kg if intubation required). • IM dose: 4–5 mg/kg. • Propofol dose: 1–2 mg/kg IV. • Larson’s maneuver: Pressure behind the angle of the mandible anterior to the mastoid process. • CPAP: 20–40 cm H₂O with 100% oxygen. • Major complication: Negative pressure pulmonary edema. • Prevention: Adequate suctioning, awake/deep extubation, IV lidocaine, topical lidocaine, magnesium sulphate, gentle airway manipulation. INTRAOPERATIVE BRONCHOSPASM Definition • Bronchospasm is the sudden contraction of bronchial smooth muscle causing narrowing of the lower airways, increased airway resistance, and airflow obstruction during anesthesia. ⸻ Etiology A. Respiratory Causes Upper Airway • Laryngeal edema • Laryngeal/pharyngeal tumors • Tracheomalacia • Foreign body Lower Airway • Bronchial asthma • COPD • Acute bronchitis • Bronchiectasis • Cystic fibrosis Pulmonary Causes • Pneumonia • Pulmonary edema • Respiratory infection ⸻ B. Mechanical Causes • Airway manipulation • Endotracheal intubation • Endobronchial intubation • Secretions • Mucus plug • Aspiration of gastric contents ⸻ C. Drug-induced Causes Anesthetic agents • Desflurane (especially smokers) • Isoflurane during inhalational induction Other drugs • Morphine • Atracurium • Mivacurium • Rapacuronium • Doxacurium • β-blockers • Aspirin • NSAIDs • Neostigmine • Atropine (>1 mg) • Glycopyrrolate (>0.5 mg) ⸻ D. Allergy/Anaphylaxis • Latex allergy • Antibiotics • IV contrast • Blood transfusion • Muscle relaxants ⸻ E. Other Causes • Light plane of anesthesia • Distended urinary bladder • Peritoneal traction • Smoke inhalation • Carcinoid syndrome ⸻ Causes According to Stage of Anesthesia During Induction • Airway irritation • Intubation • Aspiration • Anaphylaxis • Pulmonary edema • Displaced ETT ⸻ During Maintenance (Most Common) • Anaphylaxis • Aspiration • Airway irritation • Endobronchial intubation • Pneumothorax • Pulmonary edema • Vancomycin • Protamine ⸻ During Emergence • Airway irritation • Extubation • Aspiration • Pulmonary edema • Anaphylaxis • Accidental extubation ⸻ Pathophysiology Trigger ↓ Bronchial smooth muscle contraction ↓ Bronchoconstriction ↓ Increased airway resistance ↓ Air trapping and hyperinflation ↓ V/Q mismatch ↓ Hypoxemia + Hypercapnia ↓ Increased work of breathing ⸻ Clinical Features Clinical Signs • Wheeze (expiratory) • Rhonchi • Prolonged expiration • Cough • Reduced chest expansion • Reduced breath sounds • Silent chest (severe obstruction) ⸻ Ventilator Findings • Increased peak airway pressure • Decreased tidal volume • Difficult manual ventilation • Poor reservoir bag compliance ⸻ Monitoring • Falling SpO₂ • Rising ETCO₂ initially • Severe obstruction → falling ETCO₂ • Hypercarbia • Tachycardia ⸻ Diagnosis Clinical diagnosis based on: • Expiratory wheeze • Increased airway pressure • Difficult ventilation • Decreased tidal volume • Hypoxemia ⸻ Differential Diagnosis Unilateral Wheeze • Endobronchial intubation • Foreign body • Tension pneumothorax • Kinked ETT • Obstructed ETT • Localized pulmonary edema ⸻ Raised Peak Airway Pressure • Bronchospasm • Kinked tube • Secretions • Excessive tidal volume • High inspiratory flow • Pneumothorax • Pleural effusion • Trendelenburg position • Ascites • Pneumoperitoneum • Abdominal packing ⸻ Prevention • Optimize asthma/COPD before surgery • Continue bronchodilators • Steroids in high-risk patients • Prefer LMA over ETT when appropriate • Adequate depth of anesthesia • Gentle airway manipulation • Careful suctioning • Adequate analgesia • Deep extubation in selected patients • Incentive spirometry and early mobilization postoperatively ⸻ Management 1. Call for Help • Inform surgical team • Stop surgery if possible ⸻ 2. Deliver 100% Oxygen • Switch to 100% FiO₂ • Manual ventilation ⸻ 3. Check Mechanical Causes (DOPE) • D – Displacement of ETT • O – Obstruction (secretions, kink, mucus plug) • P – Pneumothorax • E – Equipment failure Suction ETT if required. ⸻ 4. Deepen Anesthesia Preferred agents • Sevoflurane • Isoflurane • Propofol • Ketamine (drug of choice in asthmatics) ⸻ 5. β₂-Agonists (First-line Therapy) Salbutamol • 2.5 mg nebulization • Repeat every 20 minutes × 3 • Then every 2–4 hours Alternative: • MDI through ETT adapter (4–8 puffs) ⸻ Terbutaline • 0.25 mg SC • Every 20 minutes (maximum 3 doses) Others: • Albuterol • Levalbuterol • Pirbuterol ⸻ 6. Anticholinergic Ipratropium bromide • 0.5 mg nebulization • Every 30 minutes × 3 • Then every 2–4 hours ⸻ 7. Corticosteroids Methylprednisolone • 125 mg IV bolus • Then 40–60 mg IV every 6 hours Hydrocortisone • 200 mg IV every 4–6 hours Dexamethasone • IV as adjunct Steroids have delayed onset (4–6 hours). ⸻ 8. Epinephrine Indications: • Severe bronchospasm • Anaphylaxis Dose: • 0.3 mL of 1:1000 IM • IV infusion: 0.5–2 μg/min, titrated as required ⸻ 9. Magnesium Sulphate • 1–2 g IV over 20 minutes • Useful in refractory bronchospasm ⸻ 10. Aminophylline • Loading: 5 mg/kg IV slowly • Infusion: 0.5–0.9 mg/kg/hr (adjust to serum levels) ⸻ 11. Heliox • Helium 70–79% • Oxygen 21–30% Benefits: • Low density gas • Reduces turbulent airflow • Decreases airway resistance • Improves ventilation ⸻ 12. Racemic Epinephrine • Nebulized • Useful when upper airway edema coexists ⸻ If Ventilation Fails • Deepen anesthesia further • Administer muscle relaxant if needed • Exclude pneumothorax • ABG analysis • Mechanical ventilation with prolonged expiratory time • ICU admission if severe ⸻ Ventilator Strategy • Low respiratory rate • Low tidal volume (6–8 mL/kg) • High inspiratory flow • Prolonged expiratory time (I:E 1:3–1:5) • Avoid auto-PEEP • Accept permissive hypercapnia if necessary ⸻ Complications • Hypoxemia • Hypercapnia • Dynamic hyperinflation • Auto-PEEP • Barotrauma • Pneumothorax • Hypotension • Cardiac arrest • Respiratory failure ⸻ Viva Pearls • Most common cause intraoperatively: Airway irritation in a light plane of anesthesia. • Most common cause during maintenance: Anaphylaxis. • Drug of choice in asthmatics: Ketamine. • First-line bronchodilator: Salbutamol. • Steroids do not provide immediate relief (onset 4–6 hours). • Magnesium sulphate: 1–2 g IV in refractory bronchospasm. • Always rule out mechanical causes (DOPE) before diagnosing bronchospasm. • Silent chest indicates severe, life-threatening bronchospasm requiring immediate intervention.