Asthma 

 

 

Considerations

 

  • Risk of perioperative respiratory complications:

    • Bronchospasm, mucous plugging, pneumothorax, atelectasis, pneumonia

  • Possible pulmonary hypertension & RV failure 

  • Need for preoperative optimization:

    • Treatment of bronchospasm, infection, atelectasis

  • Avoidance of triggers & exacerbating factors:

    • Avoid general anesthesia, endotracheal intubation, histamine releasing medications, light anesthesia

  • Medication management:

    • Continue usual inhalers pre-operatively

    • Stress dose steroids if recent high dose steroid use 

 

 

Goals & Conflicts

 

  • Assess preoperative respiratory function for stability:

    • Stable symptoms (sputum, bronchospasm), PFTs, imaging, ABG

    • Assess for pulmonary hypertension, cor pulmonale

  • Medical optimization: bronchodilators, glucocorticoids, antibiotics, BiPAP

  • Anesthetic management principles:

    • Avoid airway instrumentation

    • Blunt airway reflexes: deep anesthesia, topical local anesthetics, opioids

    • Bronchodilation: avoid histamine releasing medications (e.g., morphine), use ketamine, volatiles, MgSO4, salbutamol, ipratropium, epinephrine

    • Permissive hypercapnia: ↓ respiratory rate, ↑ expiratory time, adequate tidal volumes

    • Monitor intrinsic PEEP, presence of dynamic hyperinflation & pulmonary tamponade

    • Postoperative monitoring for bronchospasm, respiratory failure

 

 

Severe Asthma Exacerbation Treatment Options 

 

  • Salbutamol 2.5-5mg via nebulizer q20 minutes 

  • Ipratropium 500mcg via nebulizer q20 minutes

  • Corticosteroids:

    • Prednisone PO 40-60mg single dose 

    • Methylprednisolone 60-80mg IV q6-12h 

  • Epinephrine if anaphylaxis suspected or severe asthma refractory to standard therapy:

    • Dose is 0.3-0.5mg IM/SC or 10-50 mcg IV bolus, followed by infusion @ 2-10 mcg/min 

  • Magnesium for life-threatening exacerbation: 2g IV over 20 min

  • Heliox & humidified O2 (conflicting studies) 

  • Anesthetics:

    • Ketamine

    • Propofol

    • Volatiles all are bronchodilators but sevoflurane is likely best choice 

  • Leukotriene receptor antagonists (only PO available in Canada) 

  • Always consider noninvasive PPV as rescue before intubation 

  • If intubation & ventilation:

    • Use permissive hypercapnia

    • Use low respiratory rates: start at 10-12 breaths/minute but may need lower rates 

    • Use prolonged expiratory time (e.g. I:E ratios 1:3, 1:4, or even 1:5) 

    • Tidal volume 6-8cc/kg 

    • FiO2 to achieve PaO2 >60mm Hg

  • ECMO as last resort 

 

 

Asthma Severity Based on Airflow Obstruction 

 

 

 

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