What are the indications to start BiPAP (Bilevel Positive Airway Pressure) therapy?

Indications to Start BiPAP

BiPAP should be considered as first-line therapy in patients with acute respiratory acidosis (pH <7.35) due to COPD exacerbation who remain hypercapnic despite maximum medical treatment on controlled oxygen therapy. 1

Primary Indications for BiPAP Therapy

BiPAP (Bilevel Positive Airway Pressure) is indicated in several clinical scenarios where non-invasive ventilatory support can improve outcomes and potentially avoid endotracheal intubation:

Acute Respiratory Failure

• COPD Exacerbation: Strong evidence supports BiPAP use in patients with COPD exacerbation with respiratory acidosis (pH <7.35, H+ >45 nmol/l) despite maximal medical therapy 1
• Cardiogenic Pulmonary Edema: BiPAP should be used when CPAP is unsuccessful in patients with cardiogenic pulmonary edema who remain hypoxic despite maximal medical treatment 1
• Neuromuscular Disease: Indicated in acute or acute-on-chronic hypercapnic respiratory failure due to neuromuscular disease 1
• Chest Wall Deformity: Indicated for acute or acute-on-chronic hypercapnic respiratory failure 1

Sleep-Related Breathing Disorders

• Decompensated Obstructive Sleep Apnea: BiPAP should be used if respiratory acidosis is present 1
• Central Hypoventilation: A backup rate (ST mode) should be used in all patients with central hypoventilation 1

Other Indications

• Weaning from Invasive Ventilation: BiPAP has been successfully used to wean patients from invasive ventilation when conventional weaning strategies fail 1
• Pneumonia: Can be used as an alternative to tracheal intubation if the patient becomes hypercapnic, but only in an ICU setting for patients who would be candidates for intubation if BiPAP fails 1

Contraindications and Cautions

BiPAP should NOT be routinely used in:

• Acute asthma 1
• Routine treatment of bronchiectasis (excessive secretions limit effectiveness) 1
• Patients with respiratory arrest or severe hemodynamic instability
• Patients unable to protect their airway
• Patients with facial trauma or recent facial surgery

Initial Settings and Titration Protocol

Initial Settings

• Minimum starting IPAP: 8 cm H₂O 1
• Minimum starting EPAP: 4 cm H₂O 1
• Minimum IPAP-EPAP differential: 4 cm H₂O 1
• Maximum IPAP-EPAP differential: 10 cm H₂O 1
• Maximum IPAP: 30 cm H₂O for patients ≥12 years; 20 cm H₂O for patients <12 years 1

Titration Process

1. Increase IPAP and/or EPAP by at least 1 cm H₂O with intervals no shorter than 5 minutes 1
2. Increase IPAP and EPAP for obstructive apneas 1
3. Increase IPAP for hypopneas, RERAs, and snoring 1
4. Increase pressure support (PS) if tidal volume is low (<6-8 mL/kg) 1
5. Increase PS if PCO₂ remains 10 mm Hg or more above goal for 10+ minutes 1
6. Consider adding a backup rate (ST mode) for central hypoventilation, significant central apneas, or inappropriately low respiratory rate 1

Monitoring and Assessment

During BiPAP therapy, monitor:

• Arterial blood gases or transcutaneous/end-tidal CO₂
• Oxygen saturation
• Respiratory rate and pattern
• Patient comfort and synchrony with the device
• Mask fit and air leaks
• Hemodynamic stability

Clinical Response Evaluation

BiPAP therapy is considered successful when:

• Respiratory acidosis improves (pH normalizes)
• Work of breathing decreases
• Respiratory rate normalizes
• Oxygen saturation improves
• Patient comfort improves
• Avoidance of endotracheal intubation

Common Pitfalls and How to Avoid Them

1. Poor mask fit: Ensure proper mask fitting before starting therapy to minimize air leaks
2. Patient intolerance: Start with lower pressures and gradually increase; consider sedation cautiously if needed
3. Inadequate pressure settings: Titrate pressures based on clinical response and blood gas measurements
4. Delayed escalation of care: Have a clear plan for when to proceed to intubation if BiPAP fails
5. Inappropriate patient selection: Carefully assess patients for contraindications before initiating BiPAP

BiPAP therapy has been shown to reduce intubation rates, ICU stays, and mortality when used appropriately in selected patients 2. However, it should be initiated with careful consideration of the patient's underlying condition and monitored closely for response.