What is the appropriate management for a patient with respiratory failure?

Management of Respiratory Failure

The appropriate management of respiratory failure requires immediate controlled oxygen therapy targeting 88-92% saturation in patients at risk of hypercapnia (or 94-98% in others), followed by non-invasive ventilation (NIV) when pH <7.35 and PaCO2 >6.5 kPa persist despite optimal medical therapy, with early consideration of invasive ventilation if NIV fails after 4-6 hours. 1, 2

Initial Assessment and Stabilization

Rapidly assess three critical parameters to guide management:

• Oxygenation status - Measure oxygen saturation via pulse oximetry immediately in all patients 1, 2
• Acid-base status - Obtain arterial blood gas (ABG) analysis for patients with risk factors for hypercapnic respiratory failure (COPD, neuromuscular disease, chest wall deformities, morbid obesity) 1, 2
• Evidence of organ dysfunction - Check vital signs including respiratory rate, heart rate, and blood pressure to assess severity 2

Oxygen Therapy

Administer controlled oxygen based on hypercapnia risk:

• For patients WITHOUT hypercapnia risk: Target oxygen saturation of 94-98% 2
• For patients WITH hypercapnia risk (COPD, neuromuscular disease, chest wall deformity, obesity): Target 88-92% saturation using Venturi mask at 24-28% 1, 2
• Recheck blood gases after 30-60 minutes in at-risk patients, even if initial PaCO2 was normal, or sooner if clinical deterioration occurs 2

Critical pitfall: High inspired oxygen concentrations can cause severe acidosis by worsening ventilation/perfusion mismatching and inducing hypoventilation in hypercapnic patients 3

Non-Invasive Ventilation (NIV)

Initiate NIV when respiratory acidosis persists despite optimal medical therapy:

Indications for NIV 4, 1

• PaCO2 >45 mmol/L (>6.5 kPa) with pH <7.35 despite maximal medical treatment and controlled oxygen
• Appropriate patient populations: COPD, chest wall deformity, neuromuscular disorders, decompensated obstructive sleep apnea, cardiogenic pulmonary edema unresponsive to CPAP
• Premorbid state: Potential for recovery to acceptable quality of life

NIV Setup Protocol 4

1. Decide management plan if NIV fails - Document in notes after discussion with senior staff
2. Determine location - HDU/ICU for pH <7.30 (H+ >50 nmol/L); respiratory ward acceptable for less severe acidosis with close monitoring
3. Inform ICU - Early consultation for patients at risk of requiring intubation
4. Initial ventilator settings: Start with IPAP 10-12 cmH2O, EPAP 4-5 cmH2O, gradually increase as tolerated 1
5. Select appropriate mask interface based on patient comfort and facial anatomy 1
6. Add supplemental oxygen if SpO2 <85% to maintain saturations 85-90% 4

Monitoring NIV Response 4, 1

• Check ABG at 1-2 hours after initiating NIV
• If no improvement in PaCO2 and pH after 1-2 hours: Continue NIV and recheck ABG at 4-6 hours
• If no improvement by 4-6 hours: Discontinue NIV and proceed to invasive ventilation 4
• Monitor continuously: Oxygen saturation for at least 24 hours 4
• Ventilate as much as possible during first 24 hours if patient shows benefit, with breaks only for medications, physiotherapy, and meals 4

Contraindications to NIV 4

• Severe life-threatening hypoxemia (low A-a gradient patients are more appropriate for tracheal intubation)
• Patients with pH <7.25 (H+ >56 nmol/L) respond less well and should be managed in HDU/ICU with immediate intubation capability
• Pneumonia, ARDS, asthma - NIV role not clearly established; only use in HDU/ICU with immediate intubation capability
• Confused patients or large volume secretions - Less likely to respond well 4

High-Flow Nasal Oxygen (HFNO)

Consider HFNO as an alternative to NIV for acute hypoxemic respiratory failure:

• May be better tolerated than NIV and results in modest reduction in hospital-acquired pneumonia 1
• Appropriate for patients with acute hypoxic respiratory failure who cannot tolerate NIV 2

Pharmacological Management

Administer during initial assessment phase: 1, 3, 5

• Bronchodilators - Nebulized beta-agonists and anticholinergics improve spirometric results in exacerbations
• Corticosteroids - Prednisolone 30 mg/day orally (or 100 mg hydrocortisone IV if oral route not possible) for 7-14 days 4
• Antibiotics - When bacterial infection is suspected as precipitating factor 5
• Diuretics - If peripheral edema and raised jugular venous pressure present 4

Invasive Mechanical Ventilation

Consider invasive ventilation when: 4, 1

• NIV fails after 4-6 hours with no improvement in PaCO2 and pH
• pH <7.26 with rising PaCO2 despite supportive treatment
• Patient has contraindications to NIV
• Severe life-threatening hypoxemia requiring immediate airway control

Factors Favoring Invasive Ventilation 4

• Demonstrable remedial cause (pneumonia, drug overdose)
• First episode of respiratory failure
• Acceptable baseline quality of life

Factors Against Invasive Ventilation 4

• Previously documented severe COPD unresponsive to maximal therapy
• Poor baseline quality of life (housebound despite maximal therapy)
• Severe comorbidities (pulmonary edema, malignancy)

Note: Age alone should not determine ventilation decisions 4

Location of Care

Appropriate setting depends on severity: 4

• ICU/HDU: pH <7.30 (H+ >50 nmol/L), no improvement after 1-2 hours on ward, pneumonia/ARDS/asthma requiring NIV, immediate intubation capability needed
• Respiratory ward: Less severe acidosis (pH 7.30-7.35) with experienced staff, clear protocols, and ability to transfer rapidly to higher level care
• Designated area with trained staff cohort should be available in each hospital 4

Monitoring for Treatment Failure

Assess for deterioration indicators: 1

• Worsening blood gases despite therapy
• Deteriorating mental status or increased work of breathing
• Development of complications (pneumothorax, aspiration)
• Intolerance of ventilatory support

Discharge Planning

Before discharge, all patients treated with NIV must have: 4, 1

• Spirometric testing while breathing room air
• Arterial blood gas analysis while breathing room air
• Referral to specialist center for patients with spinal cord lesions, neuromuscular disease, chest wall deformity, or morbid obesity who developed acute hypercapnic respiratory failure 4
• Arrangements for pulmonary rehabilitation and smoking cessation as indicated 1