How to manage type 2 respiratory failure?

Management of Type 2 Respiratory Failure

Initial Assessment and Blood Gas Analysis

Immediately obtain arterial blood gas (ABG) analysis to confirm type 2 respiratory failure, defined by PaO2 <8 kPa (60 mmHg) with PaCO2 >6 kPa (45 mmHg), and measure pH to determine severity of respiratory acidosis. 1, 2

• Position the patient semi-recumbent (30-45° head elevation) if hemodynamically stable 2
• Obtain chest radiography to identify underlying causes (COPD exacerbation, pneumonia, pulmonary edema) but do not delay treatment in severe acidosis 2
• Document a clear management plan upfront, including what will be done if initial therapy fails, after discussion with senior medical staff 1, 2
• Repeat ABG after 1 hour of maximal medical treatment and controlled oxygen to determine if NIV is indicated 1, 2

Controlled Oxygen Therapy

Administer controlled oxygen targeting SpO2 88-92% using Venturi masks or nasal cannulae to prevent worsening hypercapnia. 2

• Avoid excessive oxygen administration, which can worsen hypercapnia in susceptible patients 2
• Continuously monitor oxygen saturation for at least 24 hours after commencing treatment 2
• Recheck ABG 1-2 hours after starting oxygen therapy to ensure adequate oxygenation without worsening respiratory acidosis 2

Non-Invasive Ventilation (NIV) - The Cornerstone of Management

Initiate NIV when pH <7.35 and PaCO2 >6.5 kPa persist despite one hour of optimal medical therapy including controlled oxygen and bronchodilators. 1, 2

NIV Indications and Patient Selection

• Primary indications: COPD exacerbation, chest wall deformity, neuromuscular disorders, decompensated obstructive sleep apnea, and cardiogenic pulmonary edema unresponsive to CPAP 1
• For PaCO2 between 6.0-6.5 kPa, consider NIV on a case-by-case basis 2
• Patients with pH <7.25 (H+ >56 nmol/l) respond less well but severe acidosis alone does not preclude NIV trial in HDU/ICU with immediate intubation capability 1, 2

NIV Contraindications

• Impaired consciousness 1
• Severe life-threatening hypoxemia (high A-a gradient) - these patients require tracheal intubation 1
• Copious respiratory secretions 1

NIV Setup Protocol

Follow this systematic approach when initiating NIV: 1

1. Decide management plan if NIV fails and document in notes 1
2. Determine location (ICU, HDU, or respiratory ward) - patients with pH <7.30 should be in HDU/ICU 1, 2
3. Inform ICU of the patient 1
4. Explain NIV to the patient 1
5. Select appropriate mask and familiarize patient by holding it in place 1
6. Use bi-level pressure support ventilators (simpler, cheaper, more flexible than other types) 1
7. Start with low pressures: IPAP 10-12 cmH2O, EPAP 4-5 cmH2O 2
8. Attach pulse oximeter 1
9. Commence NIV, holding mask in place initially 1
10. Secure mask with straps/headgear 1
11. Add oxygen if SpO2 <85% 1, 2
12. Gradually increase pressures as tolerated 2

NIV Monitoring and Adjustment

Check ABG at 1-2 hours after starting NIV to assess response. 1, 2

• Monitor for improvement in pH and respiratory rate within 1-2 hours 2
• If little improvement at 1-2 hours, recheck ABG at 4-6 hours 2
• Maximize time on NIV in first 24 hours depending on patient tolerance 2
• Adjust ventilator settings if needed based on patient comfort and gas exchange 1
• If sleep-disordered breathing complicates the episode, use controlled mode overnight 2

NIV Failure Criteria

Institute alternative management (intubation) if pH and PaCO2 worsen after 1-2 hours on optimal NIV settings, or show no improvement by 4-6 hours. 1, 2

• Worsening physiological parameters (particularly pH and respiratory rate) indicate need to change strategy 2
• Do not delay escalation to invasive mechanical ventilation when more appropriate 2

Pharmacological Management

Administer nebulized bronchodilators during breaks from NIV. 2, 3, 4

• Use β-agonists (salbutamol) and/or anticholinergics (ipratropium) 2, 3, 4
• These can be mixed together in the nebulizer if used within one hour 4
• Administer systemic corticosteroids for COPD exacerbation 2
• Prescribe antibiotics for patients with increased sputum purulence or requiring mechanical ventilation 2
• Treat reversible underlying causes appropriately 2

Important Drug Precautions

• Avoid beta-blockers as they block pulmonary effects of beta-agonists and may cause severe bronchospasm 3
• Use caution with beta-agonists in patients with cardiovascular disorders, arrhythmias, or diabetes 3
• Monitor for hypokalemia with beta-agonist use, especially when combined with non-potassium-sparing diuretics 3

Invasive Mechanical Ventilation

Consider intubation when NIV fails (no improvement in pH and PaCO2 after 4-6 hours) or when risk/benefit analysis favors invasive ventilation. 2

• Set tidal volumes at 6 mL/kg ideal body weight 2
• Use adequate positive end-expiratory pressure 2
• Limit peak/plateau pressures below 30 cmH2O to prevent barotrauma 2
• Recognize that clinicians often underestimate survival in COPD exacerbations treated with invasive ventilation 2

NIV Weaning and Discontinuation

Discontinue NIV when pH and PaCO2 normalize and general condition improves. 2

• Taper NIV use during the day over 2-3 days, depending on PaCO2 while self-ventilating 2
• Discontinue overnight NIV last 2

Pre-Discharge and Long-Term Planning

All patients treated with NIV must undergo spirometry and ABG on room air before discharge. 2

• Discuss management of future episodes with patients, as recurrence risk is high 2
• Consider referral for long-term home NIV in appropriate patients 2

Staffing and Service Organization

Trained nurses, physiotherapists, or ICU staff can successfully set up and maintain NIV. 1

• Establish clear protocols for on-call medical staff regarding NIV indications, initiation, and supervision 1
• Transfer all patients started on NIV to respiratory physician care as soon as possible 1
• Ensure nursing numbers reflect the number of patients on ventilators, especially at night 1
• NIV facilities should be available 24 hours per day in all hospitals admitting such patients 1