What is the step-by-step approach to managing acute respiratory failure?

Step-by-Step Approach to Managing Acute Respiratory Failure

The management of acute respiratory failure requires immediate identification of the underlying cause, followed by a systematic approach to restore adequate gas exchange through oxygen therapy, non-invasive or invasive ventilation, and treatment of the precipitating condition. 1

Initial Assessment

• Perform clinical evaluation and arterial blood gas (ABG) analysis to determine the type and severity of respiratory failure 1
• Type I (hypoxemic): PaO2 < 60 mmHg with normal or low PaCO2 2
• Type II (hypercapnic): PaCO2 > 50 mmHg (often with hypoxemia) 2
• Obtain chest radiography to identify potential causes or complications 1
• Document an individualized treatment plan, including measures to be taken if initial therapy fails 1
• Place patient in semi-recumbent position (head of bed raised to 30–45°) unless hemodynamically unstable 3
• Place unconscious patients in lateral position to maintain airway patency 3

Oxygen Therapy

• Administer controlled oxygen therapy targeting saturation of 88-92% in all causes of acute hypercapnic respiratory failure 3, 1
• Entrain oxygen as close to the patient as possible 3
• Continuously monitor oxygen saturation for at least 24 hours after commencing treatment 3, 1
• Check arterial blood gases after starting oxygen therapy to ensure adequate oxygenation without worsening hypercapnia 1

Pharmacological Management

• For COPD exacerbations:
  • Administer nebulized bronchodilators (β-agonists and/or anticholinergics) 3, 1
  • Consider systemic corticosteroids (prednisolone 30 mg/day or 100 mg hydrocortisone if oral route not possible) for 7-14 days 3, 1
  • Consider intravenous methylxanthines (aminophylline 0.5 mg/kg per hour) if not responding to initial therapy 3
• Prescribe antibiotics for patients with increased sputum purulence or requiring mechanical ventilation 1
• Consider diuretics if peripheral edema and raised jugular venous pressure are present 3
• Consider prophylactic subcutaneous heparin for patients with acute-on-chronic respiratory failure 3

Non-Invasive Ventilation (NIV)

• Initiate NIV when pH < 7.35, PaCO2 > 6.5 kPa, and respiratory rate > 23 breaths/min persist or develop after one hour of optimal medical therapy 3, 1
• For patients with PaCO2 between 6.0 and 6.5 kPa, consider NIV based on clinical assessment 3
• Use only ventilators specifically designed to deliver NIV 3
• Both pressure support and pressure control modes are effective 3
• Ensure adequate mask fit and circuit setup to minimize leaks 3
• Measure arterial blood gases after 1-2 hours of NIV and again after 4-6 hours if the earlier sample showed little improvement 3
• During the first 24 hours, ventilate the patient for as many hours as possible as clinically indicated and can be tolerated 3
• Consider heated humidification if the patient reports mucosal dryness or if respiratory secretions are thick 3

Invasive Mechanical Ventilation

• Consider invasive mechanical ventilation when:
  • NIV fails (no improvement in PaCO2 and pH after 4-6 hours) 3
  • Patient has contraindications to NIV 1
  • Patient develops complications such as pneumothorax, sputum retention, or deteriorating consciousness 3
• Factors favoring use of invasive ventilation include:
  • Demonstrable remedial reason for current decline (e.g., pneumonia)
  • First episode of respiratory failure
  • Acceptable quality of life or habitual level of activity 3, 1
• When using invasive ventilation, set adequate positive end-expiratory pressure with tidal volumes of 6 mL/kg ideal body weight 3
• Limit peak or plateau pressures to not exceed 30 cmH2O 3
• Prefer spontaneous breathing modes in intubated patients when possible 3

Management of Treatment Failure

If NIV is failing, check for:

• Optimal treatment of underlying condition 3
• Development of complications (pneumothorax, aspiration pneumonia) 3
• Excessive oxygen (adjust FiO2 to maintain SpO2 between 85-90%) 3
• Mask fit and circuit leaks 3
• Patient-ventilator synchrony 3
• Inadequate ventilation (consider increasing pressure, volume, or respiratory rate) 3

Sedation Considerations

• Use sedation only with close monitoring 3
• Infused sedative/anxiolytic drugs should only be used in an HDU or ICU setting 3
• For the agitated/distressed patient on NIV, consider intravenous morphine 2.5-5 mg (± benzodiazepine) to improve tolerance 3
• If intubation is not intended should NIV fail, use sedation/anxiolysis for symptom control 3

Monitoring and Follow-up

• Regularly monitor arterial blood gases, vital signs, and clinical status 1
• All patients treated with NIV for acute respiratory failure should undergo spirometric testing and arterial blood gas analysis while breathing air before discharge 3, 1
• Plan early follow-up (<30 days) after discharge to review therapy and assess for complications 1
• If NIV is still needed more than one week after the acute episode, consider referral to a center providing home NIV 3

Special Considerations

• Patients with adverse features should be considered for placement in HDU/ICU 3
• Patients with spinal cord lesions, neuromuscular disease, chest wall deformity, or morbid obesity who develop acute respiratory failure should be referred for assessment to a center providing long-term ventilation at home 3
• High-flow nasal oxygen (HFNO) may be considered as an alternative to NIV in certain patient groups with acute respiratory failure 4