'New BPD' is characterized by alveolar simplification, dysmorphic pulmonary microvasculature, non-homogeneous airway resistance, and chronic oxygen dependency in ELBW infants.
Key Physiological Equations & Formulas
- BPD Mechanics Shift: $$\tau_{BPD} \text{ is markedly prolonged and heterogeneous}$$ Evolving BPD lungs behave like chronic obstructive airways, requiring longer expiratory times and larger tidal volumes.
Practical Clinical Pearls & Bedside Rules
- Ventilator Strategy in Established BPD: Transition from rapid shallow ventilation to larger tidal volumes (6.0-8.5 mL/kg), slower respiratory rates (15-25 bpm), and higher PEEP (7-10 cmH2O) to overcome malacia and airway collapse.
- Diuretics and Systemic Steroids: Targeted low-dose dexamethasone (DART protocol) facilitates extubation in ventilator-dependent infants after 2-4 weeks of age.
Initial Settings & Clinical Titration Protocol
| Parameter | Recommended Initial Setting | Titration Goal / Safety Threshold |
|---|---|---|
| Target Tidal Volume | 6.0 - 8.0 mL/kg (in Volume Guarantee) | Overcomes high dead-space fraction. |
| Target PaCO2 | 45 - 65 mmHg (with normal arterial pH >= 7.25-7.30) | Avoid aggressive hyperventilation. |
Bedside Troubleshooting & Red Flags
Warning
Tracheobronchomalacia Collapse: Sudden cyanotic spells during agitation in BPD are often dynamic airway collapse. Increase PEEP to stent central airways.
Key Takeaways & Summary
- Always evaluate patient synchrony and physiological response before changing ventilator parameters.
- Maintain lung-protective strategies to minimize driving pressure ($\Delta P$) and mechanical power.
- Continuously reassess liberation and extubation readiness on daily morning rounds.