Intubate and Transition to Invasive Mechanical Ventilation with Lung-Protective Settings
When a patient on BiPAP with high FiO2 fails to improve, you should proceed to endotracheal intubation and invasive mechanical ventilation to prevent complications and mortality associated with delayed intubation. 1, 2
Immediate Action: Prepare for Intubation
The WHO recommends that patients receiving BiPAP should be supervised by experienced clinicians capable of performing endotracheal intubation if the patient fails to improve or rapidly deteriorates 1. Delayed intubation in patients failing noninvasive ventilation is associated with increased mortality 2, so recognizing failure early is critical.
Preoxygenation Protocol
- Preoxygenate with 100% FiO2 for 5 minutes using face mask, bag-valve mask, high-flow nasal oxygen, or NIV prior to intubation 1
- Have an experienced clinician perform the intubation using appropriate protective equipment 1
Lung-Protective Ventilation Strategy
Once intubated, immediately implement lung-protective ventilation to minimize ventilator-induced lung injury and reduce mortality 2:
Initial Ventilator Settings
- Tidal volume: 6 mL/kg predicted body weight (may increase to 8 mL/kg if not tolerated) 1, 2
- Target plateau pressure: <30 cmH2O (ideally <28 cmH2O) 1, 2
- PEEP titration: Guided by FiO2 requirements to achieve SpO2 >90% using ARDSnet protocol 1
- Permissive hypercapnia: Allow PaCO2 to rise while maintaining arterial pH >7.20 1, 2
Advanced Interventions if No Improvement After 12 Hours
- Consider early prone ventilation if PaO2/FiO2 <150 despite ventilator optimization 1
- Prone positioning should last 12-16 hours daily and improves oxygenation in approximately 65% of ARDS patients 2
- Consider ECMO for refractory hypoxemia despite lung-protective ventilation if extracorporeal life support is available 1
Critical Pitfalls to Avoid
Do Not Delay Intubation
The European Society of Intensive Care Medicine advises against delaying intubation in patients failing noninvasive ventilation, as this increases mortality risk 2. Monitor closely for BiPAP failure, as delayed intubation is associated with increased mortality 2.
Do Not Use High Tidal Volumes
Never use tidal volumes >8 mL/kg predicted body weight, even if hypercapnia develops, as this increases mortality 2. Do not attempt to normalize blood gases at the expense of lung-protective ventilation parameters 2.
Ensure Adequate pH Management
When permitting hypercapnia, ensure arterial pH remains >7.20 2. If pH falls below this threshold despite optimal ventilation, consider adjusting ventilator settings or treating the underlying metabolic component.
Monitoring for BiPAP Failure
Before reaching the point of intubation, recognize BiPAP failure by assessing 1:
- Deterioration in arterial blood gases after 1-2 hours of optimal BiPAP settings
- Deteriorating conscious level
- Development of complications (pneumothorax, sputum retention)
- Persistent or worsening hypoxemia despite high FiO2
- Patient intolerance or failure to synchronize with ventilator
The expected improvement with NIV varies by underlying pathology, but if there is no improvement in PaCO2 and pH after 1-2 hours on optimal settings, NIV should be discontinued and invasive ventilation considered 1.