How to manage a patient with refractory bronchospasm on High Flow Nasal Cannula (HFNC) Non-Invasive Ventilation (NIV)?

Management of Refractory Bronchospasm in Patients on HFNC/NIV

If a patient with refractory bronchospasm shows no improvement after 1-2 hours of optimized HFNC/NIV therapy, you must discontinue non-invasive support and proceed to invasive mechanical ventilation. 1

Immediate Assessment and Optimization

Before declaring NIV failure, systematically optimize the current therapy:

Verify Optimal Medical Management

• Ensure maximal bronchodilator therapy is administered: continuous nebulized albuterol (10-20 mg/hr), intravenous corticosteroids, and intravenous magnesium sulfate 2, 3
• Consider ipratropium bromide: If refractory to β2-agonists, continuous high-dose ipratropium (1000 mcg/hr) may provide rapid improvement within 1-4 hours 3
• Address secretion clearance: Physiotherapy and suctioning are critical, as inability to clear secretions is a common cause of NIV failure 1

Optimize NIV/HFNC Settings 1, 4

• Check for excessive oxygen: Adjust FiO2 to maintain SpO2 85-90% (not higher, as this may worsen hypercapnia) 1
• Assess mask fit and leaks: Excessive leakage reduces effectiveness; consider switching from nasal to full-face mask 1
• Verify circuit integrity: Check all connections and expiratory valve patency 1
• Optimize ventilator synchrony: Adjust inspiratory/expiratory triggers and consider increasing EPAP if patient is fighting the ventilator 1
• Increase ventilatory support: If PaCO2 remains elevated, increase IPAP/target pressure, consider increasing inspiratory time, or increase respiratory rate 1
• For HFNC: Ensure flow rates are 50-60 L/min for maximal PEEP effect and dead space washout 1, 4

Monitoring for Treatment Failure

Obtain arterial blood gases after 1-2 hours of NIV, and again at 4-6 hours if initial improvement is minimal. 1

Criteria Indicating NIV Failure 1

• No improvement or worsening in PaCO2 and pH after 4-6 hours
• Deteriorating conscious level or mental status
• Worsening respiratory distress: increasing respiratory rate, accessory muscle use, or inability to speak
• Development of complications: pneumothorax, aspiration, severe mask intolerance
• Inability to maintain SpO2 ≥85% despite optimized settings
• Patient exhaustion or inability to coordinate with ventilator

Escalation to Invasive Mechanical Ventilation

Do not delay intubation once NIV failure is evident—delayed intubation increases risk of deterioration and cardiac arrest. 1, 5

Pre-Intubation Considerations

• Use NIV for pre-oxygenation before intubation to improve safety 6
• Prepare for difficult airway management in the setting of severe bronchospasm and potential hypotension
• Have vasoactive medications immediately available as hypotension is common post-intubation in this population

Intubation and Initial Ventilator Management

• Use ketamine for induction: Ketamine has bronchodilatory properties and is the preferred induction agent for severe bronchospasm 7
• Apply lung-protective ventilation: Tidal volumes 6 mL/kg ideal body weight, plateau pressure <30 cmH2O 5
• Target permissive hypercapnia initially to avoid excessive airway pressures and barotrauma
• Verify endotracheal tube position immediately with clinical assessment and capnography 5

Advanced Therapies for Refractory Bronchospasm Post-Intubation

If bronchospasm remains refractory despite mechanical ventilation and maximal medical therapy:

Ketamine Infusion 7, 8

• Administer IV bolus of 2 mg/kg followed by continuous infusion at 20-60 mcg/kg/min
• Expect significant improvement in PaO2/FiO2 ratio and dynamic compliance within 1-8 hours
• Co-administer benzodiazepines to prevent emergence reactions and hallucinations
• Monitor for excessive secretions (may require glycopyrrolate) and hypotension

Inhaled Anesthetic Agents 9

• Isoflurane (0.3-2.5%) may be considered in specialized centers for life-threatening bronchospasm unresponsive to all other therapies
• Expect improvement in pH and PaCO2 within 4 hours of initiation
• Anticipate hypotension requiring vasopressors in 77% of patients
• This requires ICU with anesthetic delivery capability and experienced personnel

Location of Care

Patients with refractory bronchospasm on NIV should be managed in HDU/ICU where immediate intubation capability exists. 1

• Patients with pH <7.30 require higher dependency area (HDU or ICU) from the outset 1
• Asthma patients on NIV should only receive this therapy in HDU/ICU as the role of NIV in asthma is not clearly established and failure rates are high 1

Common Pitfalls to Avoid

• Do not simply increase FiO2 in response to worsening blood gases—this requires clinical re-evaluation and may worsen hypercapnia 1
• Do not persist with NIV hoping for gradual improvement when severe hypoxemia (SpO2 <85%) persists—this represents treatment failure requiring immediate intubation 1, 5
• Do not delay intubation in patients with deteriorating mental status—this is an absolute indication for invasive ventilation 1
• Do not underestimate the importance of secretion management—inability to clear secretions is a primary cause of NIV failure in bronchospasm 1